backend/main.py

@@ -18,7 +18,7 @@ Base.metadata.create_all(bind=engine)
 ENVIRONMENT = os.getenv("ENVIRONMENT", "production")
 
 # Initialize FastAPI app
-VERSION = "0.2.2"
+VERSION = "0.2.3"
 app = FastAPI(
     title="Seismo Fleet Manager",
     description="Backend API for managing seismograph fleet status",

backend/migrate_add_user_preferences.py

@@ -0,0 +1,80 @@
+"""
+Migration script to add user_preferences table.
+
+This creates a new table for storing persistent user preferences:
+- Display settings (timezone, theme, date format)
+- Auto-refresh configuration
+- Calibration defaults
+- Status threshold customization
+
+Run this script once to migrate an existing database.
+"""
+
+import sqlite3
+import os
+
+# Database path
+DB_PATH = "./data/seismo_fleet.db"
+
+def migrate_database():
+    """Create user_preferences table"""
+
+    if not os.path.exists(DB_PATH):
+        print(f"Database not found at {DB_PATH}")
+        print("The database will be created automatically when you run the application.")
+        return
+
+    print(f"Migrating database: {DB_PATH}")
+
+    conn = sqlite3.connect(DB_PATH)
+    cursor = conn.cursor()
+
+    # Check if user_preferences table already exists
+    cursor.execute("SELECT name FROM sqlite_master WHERE type='table' AND name='user_preferences'")
+    table_exists = cursor.fetchone()
+
+    if table_exists:
+        print("Migration already applied - user_preferences table exists")
+        conn.close()
+        return
+
+    print("Creating user_preferences table...")
+
+    try:
+        cursor.execute("""
+            CREATE TABLE user_preferences (
+                id INTEGER PRIMARY KEY DEFAULT 1,
+                timezone TEXT DEFAULT 'America/New_York',
+                theme TEXT DEFAULT 'auto',
+                auto_refresh_interval INTEGER DEFAULT 10,
+                date_format TEXT DEFAULT 'MM/DD/YYYY',
+                table_rows_per_page INTEGER DEFAULT 25,
+                calibration_interval_days INTEGER DEFAULT 365,
+                calibration_warning_days INTEGER DEFAULT 30,
+                status_ok_threshold_hours INTEGER DEFAULT 12,
+                status_pending_threshold_hours INTEGER DEFAULT 24,
+                updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+            )
+        """)
+        print("  ✓ Created user_preferences table")
+
+        # Insert default preferences
+        cursor.execute("""
+            INSERT INTO user_preferences (id) VALUES (1)
+        """)
+        print("  ✓ Inserted default preferences")
+
+        conn.commit()
+        print("\nMigration completed successfully!")
+
+    except sqlite3.Error as e:
+        print(f"\nError during migration: {e}")
+        conn.rollback()
+        raise
+
+    finally:
+        conn.close()
+
+
+if __name__ == "__main__":
+    migrate_database()

backend/models.py

@@ -1,4 +1,4 @@
-from sqlalchemy import Column, String, DateTime, Boolean, Text, Date
+from sqlalchemy import Column, String, DateTime, Boolean, Text, Date, Integer
 from datetime import datetime
 from backend.database import Base
 
@@ -57,3 +57,23 @@ class IgnoredUnit(Base):
     id = Column(String, primary_key=True, index=True)
     reason = Column(String, nullable=True)
     ignored_at = Column(DateTime, default=datetime.utcnow)
+
+
+class UserPreferences(Base):
+    """
+    User preferences: persistent storage for application settings.
+    Single-row table (id=1) to store global user preferences.
+    """
+    __tablename__ = "user_preferences"
+
+    id = Column(Integer, primary_key=True, default=1)
+    timezone = Column(String, default="America/New_York")
+    theme = Column(String, default="auto")  # auto, light, dark
+    auto_refresh_interval = Column(Integer, default=10)  # seconds
+    date_format = Column(String, default="MM/DD/YYYY")
+    table_rows_per_page = Column(Integer, default=25)
+    calibration_interval_days = Column(Integer, default=365)
+    calibration_warning_days = Column(Integer, default=30)
+    status_ok_threshold_hours = Column(Integer, default=12)
+    status_pending_threshold_hours = Column(Integer, default=24)
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

backend/routers/settings.py

@@ -2,11 +2,13 @@ from fastapi import APIRouter, Depends, HTTPException, UploadFile, File
 from fastapi.responses import StreamingResponse
 from sqlalchemy.orm import Session
 from datetime import datetime, date
+from pydantic import BaseModel
+from typing import Optional
 import csv
 import io
 
 from backend.database import get_db
-from backend.models import RosterUnit, Emitter, IgnoredUnit
+from backend.models import RosterUnit, Emitter, IgnoredUnit, UserPreferences
 
 router = APIRouter(prefix="/api/settings", tags=["settings"])
 
@@ -239,3 +241,87 @@ def clear_ignored(db: Session = Depends(get_db)):
     except Exception as e:
         db.rollback()
         raise HTTPException(status_code=500, detail=f"Clear failed: {str(e)}")
+
+
+# User Preferences Endpoints
+
+class PreferencesUpdate(BaseModel):
+    """Schema for updating user preferences (all fields optional)"""
+    timezone: Optional[str] = None
+    theme: Optional[str] = None
+    auto_refresh_interval: Optional[int] = None
+    date_format: Optional[str] = None
+    table_rows_per_page: Optional[int] = None
+    calibration_interval_days: Optional[int] = None
+    calibration_warning_days: Optional[int] = None
+    status_ok_threshold_hours: Optional[int] = None
+    status_pending_threshold_hours: Optional[int] = None
+
+
+@router.get("/preferences")
+def get_preferences(db: Session = Depends(get_db)):
+    """
+    Get user preferences. Creates default preferences if none exist.
+    """
+    prefs = db.query(UserPreferences).filter(UserPreferences.id == 1).first()
+
+    if not prefs:
+        # Create default preferences
+        prefs = UserPreferences(id=1)
+        db.add(prefs)
+        db.commit()
+        db.refresh(prefs)
+
+    return {
+        "timezone": prefs.timezone,
+        "theme": prefs.theme,
+        "auto_refresh_interval": prefs.auto_refresh_interval,
+        "date_format": prefs.date_format,
+        "table_rows_per_page": prefs.table_rows_per_page,
+        "calibration_interval_days": prefs.calibration_interval_days,
+        "calibration_warning_days": prefs.calibration_warning_days,
+        "status_ok_threshold_hours": prefs.status_ok_threshold_hours,
+        "status_pending_threshold_hours": prefs.status_pending_threshold_hours,
+        "updated_at": prefs.updated_at.isoformat() if prefs.updated_at else None
+    }
+
+
+@router.put("/preferences")
+def update_preferences(
+    updates: PreferencesUpdate,
+    db: Session = Depends(get_db)
+):
+    """
+    Update user preferences. Accepts partial updates.
+    Creates default preferences if none exist.
+    """
+    prefs = db.query(UserPreferences).filter(UserPreferences.id == 1).first()
+
+    if not prefs:
+        # Create default preferences
+        prefs = UserPreferences(id=1)
+        db.add(prefs)
+
+    # Update only provided fields
+    update_data = updates.dict(exclude_unset=True)
+    for field, value in update_data.items():
+        setattr(prefs, field, value)
+
+    prefs.updated_at = datetime.utcnow()
+
+    db.commit()
+    db.refresh(prefs)
+
+    return {
+        "message": "Preferences updated successfully",
+        "timezone": prefs.timezone,
+        "theme": prefs.theme,
+        "auto_refresh_interval": prefs.auto_refresh_interval,
+        "date_format": prefs.date_format,
+        "table_rows_per_page": prefs.table_rows_per_page,
+        "calibration_interval_days": prefs.calibration_interval_days,
+        "calibration_warning_days": prefs.calibration_warning_days,
+        "status_ok_threshold_hours": prefs.status_ok_threshold_hours,
+        "status_pending_threshold_hours": prefs.status_pending_threshold_hours,
+        "updated_at": prefs.updated_at.isoformat() if prefs.updated_at else None
+    }

templates/base.html

@@ -149,6 +149,116 @@
         } else if (localStorage.getItem('theme') === 'dark') {
             document.documentElement.classList.add('dark');
         }
+
+        // Helper function: Convert timestamp to relative time
+        function timeAgo(dateString) {
+            if (!dateString) return 'Never';
+
+            const date = new Date(dateString);
+            const now = new Date();
+            const seconds = Math.floor((now - date) / 1000);
+
+            if (seconds < 60) return `${seconds}s ago`;
+
+            const minutes = Math.floor(seconds / 60);
+            if (minutes < 60) return `${minutes}m ago`;
+
+            const hours = Math.floor(minutes / 60);
+            if (hours < 24) {
+                const remainingMins = minutes % 60;
+                return remainingMins > 0 ? `${hours}h ${remainingMins}m ago` : `${hours}h ago`;
+            }
+
+            const days = Math.floor(hours / 24);
+            if (days < 7) {
+                const remainingHours = hours % 24;
+                return remainingHours > 0 ? `${days}d ${remainingHours}h ago` : `${days}d ago`;
+            }
+
+            const weeks = Math.floor(days / 7);
+            if (weeks < 4) {
+                const remainingDays = days % 7;
+                return remainingDays > 0 ? `${weeks}w ${remainingDays}d ago` : `${weeks}w ago`;
+            }
+
+            const months = Math.floor(days / 30);
+            return `${months}mo ago`;
+        }
+
+        // Helper function: Get user's selected timezone
+        function getTimezone() {
+            return localStorage.getItem('timezone') || 'America/New_York';
+        }
+
+        // Helper function: Format timestamp with tooltip (timezone-aware)
+        function formatTimestamp(dateString) {
+            if (!dateString) return '<span class="text-gray-400">Never</span>';
+
+            const date = new Date(dateString);
+            const timezone = getTimezone();
+
+            const fullDate = date.toLocaleString('en-US', {
+                weekday: 'short',
+                year: 'numeric',
+                month: 'short',
+                day: 'numeric',
+                hour: '2-digit',
+                minute: '2-digit',
+                second: '2-digit',
+                timeZone: timezone,
+                timeZoneName: 'short'
+            });
+
+            return `<span title="${fullDate}" class="cursor-help">${timeAgo(dateString)}</span>`;
+        }
+
+        // Helper function: Format timestamp as full date/time (no relative time)
+        // Format: "9/10/2020 8:00 AM EST"
+        function formatFullTimestamp(dateString) {
+            if (!dateString) return 'Never';
+
+            const date = new Date(dateString);
+            const timezone = getTimezone();
+
+            return date.toLocaleString('en-US', {
+                month: 'numeric',
+                day: 'numeric',
+                year: 'numeric',
+                hour: 'numeric',
+                minute: '2-digit',
+                timeZone: timezone,
+                timeZoneName: 'short'
+            });
+        }
+
+        // Update all timestamps on page load and periodically
+        function updateAllTimestamps() {
+            document.querySelectorAll('[data-timestamp]').forEach(el => {
+                const timestamp = el.getAttribute('data-timestamp');
+                el.innerHTML = formatTimestamp(timestamp);
+            });
+        }
+
+        // Run on load and every minute
+        updateAllTimestamps();
+        setInterval(updateAllTimestamps, 60000);
+
+        // Copy to clipboard helper
+        function copyToClipboard(text, button) {
+            navigator.clipboard.writeText(text).then(() => {
+                // Visual feedback
+                const originalHTML = button.innerHTML;
+                button.innerHTML = '<svg class="w-3 h-3" fill="currentColor" viewBox="0 0 20 20"><path fill-rule="evenodd" d="M16.707 5.293a1 1 0 010 1.414l-8 8a1 1 0 01-1.414 0l-4-4a1 1 0 011.414-1.414L8 12.586l7.293-7.293a1 1 0 011.414 0z" clip-rule="evenodd"/></svg>';
+                button.classList.add('text-green-500');
+
+                setTimeout(() => {
+                    button.innerHTML = originalHTML;
+                    button.classList.remove('text-green-500');
+                }, 1500);
+            }).catch(err => {
+                console.error('Failed to copy:', err);
+            });
+        }
     </script>
 
     {% block extra_scripts %}{% endblock %}

templates/dashboard.html

@@ -10,10 +10,16 @@
 </div>
 {% endif %}
 
-<div class="mb-8">
+<div class="mb-8 flex justify-between items-center">
+    <div>
         <h1 class="text-3xl font-bold text-gray-900 dark:text-white">Dashboard</h1>
         <p class="text-gray-600 dark:text-gray-400 mt-1">Fleet overview and recent activity</p>
     </div>
+    <div class="text-right">
+        <p class="text-xs text-gray-500 dark:text-gray-400">Last updated</p>
+        <p id="last-refresh" class="text-sm text-gray-700 dark:text-gray-300 font-mono">--</p>
+    </div>
+</div>
 
 <!-- Dashboard cards with auto-refresh -->
 <div hx-get="/api/status-snapshot"
@@ -48,23 +54,35 @@
                 </div>
                 <div class="border-t border-gray-200 dark:border-gray-700 pt-3 mt-3">
                     <p class="text-xs text-gray-500 dark:text-gray-500 mb-2 italic">Deployed Status:</p>
-                    <div class="flex justify-between items-center mb-2">
+                    <div class="flex justify-between items-center mb-2" title="Units reporting normally (last seen < 12 hours)">
                         <div class="flex items-center">
-                            <span class="w-3 h-3 rounded-full bg-green-500 mr-2"></span>
+                            <span class="w-3 h-3 rounded-full bg-green-500 mr-2 flex items-center justify-center">
+                                <svg class="w-2 h-2 text-white" fill="currentColor" viewBox="0 0 20 20">
+                                    <path fill-rule="evenodd" d="M16.707 5.293a1 1 0 010 1.414l-8 8a1 1 0 01-1.414 0l-4-4a1 1 0 011.414-1.414L8 12.586l7.293-7.293a1 1 0 011.414 0z" clip-rule="evenodd"/>
+                                </svg>
+                            </span>
                             <span class="text-sm text-gray-600 dark:text-gray-400">OK</span>
                         </div>
                         <span id="status-ok" class="font-semibold text-green-600 dark:text-green-400">--</span>
                     </div>
-                    <div class="flex justify-between items-center mb-2">
+                    <div class="flex justify-between items-center mb-2" title="Units with delayed reports (12-24 hours)">
                         <div class="flex items-center">
-                            <span class="w-3 h-3 rounded-full bg-yellow-500 mr-2"></span>
+                            <span class="w-3 h-3 rounded-full bg-yellow-500 mr-2 flex items-center justify-center">
+                                <svg class="w-2 h-2 text-white" fill="currentColor" viewBox="0 0 20 20">
+                                    <path fill-rule="evenodd" d="M10 18a8 8 0 100-16 8 8 0 000 16zm1-12a1 1 0 10-2 0v4a1 1 0 00.293.707l2.828 2.829a1 1 0 101.415-1.415L11 9.586V6z" clip-rule="evenodd"/>
+                                </svg>
+                            </span>
                             <span class="text-sm text-gray-600 dark:text-gray-400">Pending</span>
                         </div>
                         <span id="status-pending" class="font-semibold text-yellow-600 dark:text-yellow-400">--</span>
                     </div>
-                    <div class="flex justify-between items-center">
+                    <div class="flex justify-between items-center" title="Units not reporting (> 24 hours)">
                         <div class="flex items-center">
-                            <span class="w-3 h-3 rounded-full bg-red-500 mr-2"></span>
+                            <span class="w-3 h-3 rounded-full bg-red-500 mr-2 flex items-center justify-center">
+                                <svg class="w-2 h-2 text-white" fill="currentColor" viewBox="0 0 20 20">
+                                    <path fill-rule="evenodd" d="M4.293 4.293a1 1 0 011.414 0L10 8.586l4.293-4.293a1 1 0 111.414 1.414L11.414 10l4.293 4.293a1 1 0 01-1.414 1.414L10 11.414l-4.293 4.293a1 1 0 01-1.414-1.414L8.586 10 4.293 5.707a1 1 0 010-1.414z" clip-rule="evenodd"/>
+                                </svg>
+                            </span>
                             <span class="text-sm text-gray-600 dark:text-gray-400">Missing</span>
                         </div>
                         <span id="status-missing" class="font-semibold text-red-600 dark:text-red-400">--</span>
@@ -185,6 +203,17 @@ function updateDashboard(event) {
     try {
         const data = JSON.parse(event.detail.xhr.response);
 
+        // Update "Last updated" timestamp with timezone
+        const now = new Date();
+        const timezone = localStorage.getItem('timezone') || 'America/New_York';
+        document.getElementById('last-refresh').textContent = now.toLocaleTimeString('en-US', {
+            hour: '2-digit',
+            minute: '2-digit',
+            second: '2-digit',
+            timeZone: timezone,
+            timeZoneName: 'short'
+        });
+
         // ===== Fleet summary numbers =====
         document.getElementById('total-units').textContent = data.summary?.total ?? 0;
         document.getElementById('deployed-units').textContent = data.summary?.active ?? 0;

templates/partials/active_table.html

@@ -46,5 +46,11 @@
     {% endfor %}
 </div>
 {% else %}
-<p class="text-sm text-gray-500 dark:text-gray-400 text-center py-8">No active units</p>
+<div class="text-center py-12">
+    <svg class="mx-auto h-12 w-12 text-gray-400" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M20 13V6a2 2 0 00-2-2H6a2 2 0 00-2 2v7m16 0v5a2 2 0 01-2 2H6a2 2 0 01-2-2v-5m16 0h-2.586a1 1 0 00-.707.293l-2.414 2.414a1 1 0 01-.707.293h-3.172a1 1 0 01-.707-.293l-2.414-2.414A1 1 0 006.586 13H4"></path>
+    </svg>
+    <h3 class="mt-2 text-sm font-medium text-gray-900 dark:text-gray-100">No active units</h3>
+    <p class="mt-1 text-sm text-gray-500 dark:text-gray-400">Get started by adding a new unit to the fleet.</p>
+</div>
 {% endif %}

templates/partials/benched_table.html

@@ -46,5 +46,11 @@
     {% endfor %}
 </div>
 {% else %}
-<p class="text-sm text-gray-500 dark:text-gray-400 text-center py-8">No benched units</p>
+<div class="text-center py-12">
+    <svg class="mx-auto h-12 w-12 text-gray-400" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 5H7a2 2 0 00-2 2v12a2 2 0 002 2h10a2 2 0 002-2V7a2 2 0 00-2-2h-2M9 5a2 2 0 002 2h2a2 2 0 002-2M9 5a2 2 0 012-2h2a2 2 0 012 2"></path>
+    </svg>
+    <h3 class="mt-2 text-sm font-medium text-gray-900 dark:text-gray-100">No benched units</h3>
+    <p class="mt-1 text-sm text-gray-500 dark:text-gray-400">Units awaiting deployment will appear here.</p>
+</div>
 {% endif %}

templates/roster.html

@@ -34,6 +34,21 @@
 <!-- Fleet Roster with Tabs -->
 <div class="rounded-xl shadow-lg bg-white dark:bg-slate-800 p-6">
 
+    <!-- Search Bar -->
+    <div class="mb-4">
+        <div class="relative">
+            <input
+                type="text"
+                id="roster-search"
+                placeholder="Search by Unit ID, Type, or Note..."
+                class="w-full px-4 py-2 pl-10 pr-4 text-gray-900 dark:text-gray-100 bg-gray-100 dark:bg-gray-700 border border-gray-300 dark:border-gray-600 rounded-lg focus:outline-none focus:ring-2 focus:ring-seismo-orange"
+                onkeyup="filterRosterTable()">
+            <svg class="absolute left-3 top-3 w-5 h-5 text-gray-400" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M21 21l-6-6m2-5a7 7 0 11-14 0 7 7 0 0114 0z"></path>
+            </svg>
+        </div>
+    </div>
+
     <!-- Tab Bar -->
     <div class="flex border-b border-gray-200 dark:border-gray-700 mb-4">
         <button
@@ -805,6 +820,31 @@
             alert(`Error: ${error.message}`);
         }
     }
+
+    // Filter roster table based on search input
+    function filterRosterTable() {
+        const searchInput = document.getElementById('roster-search').value.toLowerCase();
+        const table = document.querySelector('#roster-content table tbody');
+
+        if (!table) return;
+
+        const rows = table.getElementsByTagName('tr');
+
+        for (let row of rows) {
+            const cells = row.getElementsByTagName('td');
+            if (cells.length === 0) continue; // Skip header or empty rows
+
+            const unitId = cells[1]?.textContent?.toLowerCase() || '';
+            const unitType = cells[2]?.textContent?.toLowerCase() || '';
+            const note = cells[6]?.textContent?.toLowerCase() || '';
+
+            const matches = unitId.includes(searchInput) ||
+                          unitType.includes(searchInput) ||
+                          note.includes(searchInput);
+
+            row.style.display = matches ? '' : 'none';
+        }
+    }
 </script>
 
 <style>

templates/settings.html

@@ -4,16 +4,130 @@
 
 {% block content %}
 <div class="mb-8">
-    <h1 class="text-3xl font-bold text-gray-900 dark:text-white">Roster Manager</h1>
-    <p class="text-gray-600 dark:text-gray-400 mt-1">Manage your fleet roster data - import, export, and reset</p>
+    <h1 class="text-3xl font-bold text-gray-900 dark:text-white">Settings</h1>
+    <p class="text-gray-600 dark:text-gray-400 mt-1">Configure application preferences and manage fleet data</p>
 </div>
 
-<!-- CSV Export Section -->
-<div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-6 mb-6">
+<!-- Tab Navigation -->
+<div class="flex border-b border-gray-200 dark:border-gray-700 mb-6">
+    <button class="settings-tab active-settings-tab" data-tab="general" onclick="showTab('general')">
+        <svg class="w-4 h-4 inline-block mr-1" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M12 6V4m0 2a2 2 0 100 4m0-4a2 2 0 110 4m-6 8a2 2 0 100-4m0 4a2 2 0 110-4m0 4v2m0-6V4m6 6v10m6-2a2 2 0 100-4m0 4a2 2 0 110-4m0 4v2m0-6V4"></path>
+        </svg>
+        General
+    </button>
+    <button class="settings-tab" data-tab="data" onclick="showTab('data')">
+        <svg class="w-4 h-4 inline-block mr-1" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M7 16a4 4 0 01-.88-7.903A5 5 0 1115.9 6L16 6a5 5 0 011 9.9M15 13l-3-3m0 0l-3 3m3-3v12"></path>
+        </svg>
+        Data Management
+    </button>
+    <button class="settings-tab" data-tab="advanced" onclick="showTab('advanced')">
+        <svg class="w-4 h-4 inline-block mr-1" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M10.325 4.317c.426-1.756 2.924-1.756 3.35 0a1.724 1.724 0 002.573 1.066c1.543-.94 3.31.826 2.37 2.37a1.724 1.724 0 001.065 2.572c1.756.426 1.756 2.924 0 3.35a1.724 1.724 0 00-1.066 2.573c.94 1.543-.826 3.31-2.37 2.37a1.724 1.724 0 00-2.572 1.065c-.426 1.756-2.924 1.756-3.35 0a1.724 1.724 0 00-2.573-1.066c-1.543.94-3.31-.826-2.37-2.37a1.724 1.724 0 00-1.065-2.572c-1.756-.426-1.756-2.924 0-3.35a1.724 1.724 0 001.066-2.573c-.94-1.543.826-3.31 2.37-2.37.996.608 2.296.07 2.572-1.065z"></path>
+            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M15 12a3 3 0 11-6 0 3 3 0 016 0z"></path>
+        </svg>
+        Advanced
+    </button>
+    <button class="settings-tab text-red-600 dark:text-red-400" data-tab="danger" onclick="showTab('danger')">
+        <svg class="w-4 h-4 inline-block mr-1" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M12 9v2m0 4h.01m-6.938 4h13.856c1.54 0 2.502-1.667 1.732-3L13.732 4c-.77-1.333-2.694-1.333-3.464 0L3.34 16c-.77 1.333.192 3 1.732 3z"></path>
+        </svg>
+        Danger Zone
+    </button>
+</div>
+
+<!-- General Tab -->
+<div id="general-tab" class="tab-content">
+    <div class="space-y-6">
+        <!-- Display Preferences Card -->
+        <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-6">
+            <h2 class="text-xl font-semibold text-gray-900 dark:text-white mb-4">Display Preferences</h2>
+
+            <div class="space-y-4">
+                <!-- Timezone -->
+                <div>
+                    <label for="timezone-select" class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">
+                        Timezone
+                    </label>
+                    <select id="timezone-select"
+                            class="w-full max-w-md px-4 py-2 text-gray-900 dark:text-gray-100 bg-gray-50 dark:bg-gray-700 border border-gray-300 dark:border-gray-600 rounded-lg focus:outline-none focus:ring-2 focus:ring-seismo-orange">
+                        <option value="America/New_York">Eastern Time (ET)</option>
+                        <option value="America/Chicago">Central Time (CT)</option>
+                        <option value="America/Denver">Mountain Time (MT)</option>
+                        <option value="America/Los_Angeles">Pacific Time (PT)</option>
+                        <option value="America/Anchorage">Alaska Time (AKT)</option>
+                        <option value="Pacific/Honolulu">Hawaii Time (HT)</option>
+                        <option value="UTC">UTC</option>
+                        <option value="Europe/London">London (GMT/BST)</option>
+                        <option value="Europe/Paris">Paris (CET/CEST)</option>
+                        <option value="Asia/Tokyo">Tokyo (JST)</option>
+                        <option value="Australia/Sydney">Sydney (AEST/AEDT)</option>
+                    </select>
+                    <p class="text-xs text-gray-500 dark:text-gray-400 mt-1">
+                        All timestamps will be displayed in this timezone
+                    </p>
+                </div>
+
+                <!-- Theme -->
+                <div>
+                    <label class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">
+                        Theme
+                    </label>
+                    <div class="flex gap-4">
+                        <label class="flex items-center gap-2 cursor-pointer">
+                            <input type="radio" name="theme" value="auto" class="w-4 h-4 text-seismo-orange focus:ring-seismo-orange">
+                            <span class="text-sm text-gray-700 dark:text-gray-300">Auto (System)</span>
+                        </label>
+                        <label class="flex items-center gap-2 cursor-pointer">
+                            <input type="radio" name="theme" value="light" class="w-4 h-4 text-seismo-orange focus:ring-seismo-orange">
+                            <span class="text-sm text-gray-700 dark:text-gray-300">Light</span>
+                        </label>
+                        <label class="flex items-center gap-2 cursor-pointer">
+                            <input type="radio" name="theme" value="dark" class="w-4 h-4 text-seismo-orange focus:ring-seismo-orange">
+                            <span class="text-sm text-gray-700 dark:text-gray-300">Dark</span>
+                        </label>
+                    </div>
+                    <p class="text-xs text-gray-500 dark:text-gray-400 mt-1">
+                        Choose your preferred color scheme
+                    </p>
+                </div>
+
+                <!-- Auto-refresh Interval -->
+                <div>
+                    <label for="refresh-interval" class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">
+                        Auto-Refresh Interval
+                    </label>
+                    <select id="refresh-interval"
+                            class="w-full max-w-md px-4 py-2 text-gray-900 dark:text-gray-100 bg-gray-50 dark:bg-gray-700 border border-gray-300 dark:border-gray-600 rounded-lg focus:outline-none focus:ring-2 focus:ring-seismo-orange">
+                        <option value="5">5 seconds</option>
+                        <option value="10" selected>10 seconds</option>
+                        <option value="30">30 seconds</option>
+                        <option value="60">1 minute</option>
+                        <option value="0">Disabled</option>
+                    </select>
+                    <p class="text-xs text-gray-500 dark:text-gray-400 mt-1">
+                        How often the dashboard should refresh automatically
+                    </p>
+                </div>
+            </div>
+
+            <button onclick="saveGeneralSettings()" class="mt-6 px-6 py-3 bg-seismo-orange hover:bg-orange-600 text-white rounded-lg transition-colors">
+                Save Changes
+            </button>
+        </div>
+    </div>
+</div>
+
+<!-- Data Management Tab -->
+<div id="data-tab" class="tab-content hidden">
+    <div class="space-y-6">
+        <!-- Export Section -->
+        <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-6">
             <div class="flex items-start justify-between">
                 <div class="flex-1">
-            <h2 class="text-xl font-semibold text-gray-900 dark:text-white mb-2">Export Roster</h2>
-            <p class="text-gray-600 dark:text-gray-400 mb-4">
+                    <h2 class="text-xl font-semibold text-gray-900 dark:text-white mb-2">Export Data</h2>
+                    <p class="text-gray-600 dark:text-gray-400">
                         Download all roster data as CSV for backup or editing externally
                     </p>
                 </div>
@@ -29,43 +143,21 @@
             </div>
         </div>
 
-<!-- CSV Import Section -->
-<div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-6 mb-6">
-    <h2 class="text-xl font-semibold text-gray-900 dark:text-white mb-4">Import Roster</h2>
+        <!-- Import Section (Merge Mode Only) -->
+        <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-6">
+            <h2 class="text-xl font-semibold text-gray-900 dark:text-white mb-4">Import Data (Merge Mode)</h2>
 
-    <form id="importSettingsForm" class="space-y-4">
+            <form id="importMergeForm" class="space-y-4">
                 <div>
-            <label class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">CSV File *</label>
+                    <label class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">CSV File</label>
                     <input type="file" name="file" accept=".csv" required
                            class="block w-full text-sm text-gray-900 dark:text-white border border-gray-300 dark:border-gray-600 rounded-lg cursor-pointer bg-gray-50 dark:bg-slate-700 focus:outline-none">
                     <p class="text-xs text-gray-500 dark:text-gray-400 mt-1">
-                CSV must include column: unit_id (required)
+                        CSV must include column: unit_id (required). Existing units will be updated, new units will be added.
                     </p>
                 </div>
 
-        <div>
-            <label class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-3">Import Mode *</label>
-            <div class="space-y-3">
-                <label class="flex items-start gap-3 p-3 rounded-lg border border-gray-200 dark:border-gray-700 hover:bg-gray-50 dark:hover:bg-slate-700 cursor-pointer">
-                    <input type="radio" name="mode" value="merge" checked
-                           class="mt-1 w-4 h-4 text-seismo-orange focus:ring-seismo-orange">
-                    <div>
-                        <div class="font-medium text-gray-900 dark:text-white">Merge/Overwrite</div>
-                        <div class="text-sm text-gray-600 dark:text-gray-400">Update existing units, add new units (safe)</div>
-                    </div>
-                </label>
-                <label class="flex items-start gap-3 p-3 rounded-lg border border-red-300 dark:border-red-800 hover:bg-red-50 dark:hover:bg-red-900/20 cursor-pointer">
-                    <input type="radio" name="mode" value="replace"
-                           class="mt-1 w-4 h-4 text-red-600 focus:ring-red-600">
-                    <div>
-                        <div class="font-medium text-red-600 dark:text-red-400">Replace All</div>
-                        <div class="text-sm text-red-600 dark:text-red-400">⚠️ Delete ALL roster units first, then import (DANGEROUS)</div>
-                    </div>
-                </label>
-            </div>
-        </div>
-
-        <div id="importResult" class="hidden"></div>
+                <div id="importMergeResult" class="hidden"></div>
 
                 <button type="submit" class="px-6 py-3 bg-seismo-orange hover:bg-orange-600 text-white rounded-lg transition-colors">
                     Import CSV
@@ -74,7 +166,7 @@
         </div>
 
         <!-- Roster Management Table -->
-<div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-6 mb-6">
+        <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-6">
             <div class="flex items-center justify-between mb-4">
                 <div>
                     <h2 class="text-xl font-semibold text-gray-900 dark:text-white">Roster Units</h2>
@@ -122,91 +214,449 @@
                 <p class="text-gray-600 dark:text-gray-400 mt-2">No roster units found</p>
             </div>
         </div>
+    </div>
+</div>
 
-<!-- Danger Zone -->
-<div class="bg-red-50 dark:bg-red-900/20 rounded-xl border-2 border-red-200 dark:border-red-800 p-6">
-    <div class="flex items-start gap-3 mb-6">
-        <svg class="w-6 h-6 text-red-600 dark:text-red-400 flex-shrink-0 mt-1" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+<!-- Advanced Tab -->
+<div id="advanced-tab" class="tab-content hidden">
+    <div class="space-y-6">
+        <!-- Warning Banner -->
+        <div class="bg-yellow-50 dark:bg-yellow-900/20 border-l-4 border-yellow-500 p-4">
+            <div class="flex">
+                <svg class="w-5 h-5 text-yellow-500 mr-2 flex-shrink-0" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                     <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M12 9v2m0 4h.01m-6.938 4h13.856c1.54 0 2.502-1.667 1.732-3L13.732 4c-.77-1.333-2.694-1.333-3.464 0L3.34 16c-.77 1.333.192 3 1.732 3z"></path>
                 </svg>
                 <div>
-            <h2 class="text-xl font-semibold text-red-600 dark:text-red-400 mb-1">Danger Zone</h2>
-            <p class="text-sm text-gray-700 dark:text-gray-300">
-                Irreversible operations - use with extreme caution
+                    <p class="font-semibold text-yellow-800 dark:text-yellow-300">Advanced Settings</p>
+                    <p class="text-sm text-yellow-700 dark:text-yellow-400 mt-1">These settings can affect system behavior. Change with caution.</p>
+                </div>
+            </div>
+        </div>
+
+        <!-- CSV Import - Replace Mode -->
+        <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-6 border-2 border-yellow-200 dark:border-yellow-800">
+            <h2 class="text-xl font-semibold text-yellow-800 dark:text-yellow-300 mb-2">CSV Import - Replace Mode</h2>
+            <p class="text-sm text-gray-600 dark:text-gray-400 mb-4">
+                This will DELETE all existing roster units before importing.
+            </p>
+
+            <form id="importReplaceForm" class="space-y-4">
+                <div>
+                    <label class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">CSV File</label>
+                    <input type="file" name="file" accept=".csv" required
+                           class="block w-full text-sm text-gray-900 dark:text-white border border-gray-300 dark:border-gray-600 rounded-lg cursor-pointer bg-gray-50 dark:bg-slate-700 focus:outline-none">
+                    <p class="text-xs text-gray-500 dark:text-gray-400 mt-1">
+                        All roster data will be replaced with this CSV file
+                    </p>
+                </div>
+
+                <div id="importReplaceResult" class="hidden"></div>
+
+                <button type="submit" class="px-6 py-3 bg-yellow-600 hover:bg-yellow-700 text-white rounded-lg transition-colors">
+                    Replace All Roster Data
+                </button>
+            </form>
+        </div>
+
+        <!-- Status Thresholds -->
+        <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-6">
+            <h2 class="text-xl font-semibold text-gray-900 dark:text-white mb-4">Status Thresholds</h2>
+
+            <div class="space-y-4">
+                <div>
+                    <label for="ok-threshold" class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">
+                        OK Threshold (hours)
+                    </label>
+                    <input type="number" id="ok-threshold" min="1" max="24"
+                           class="w-full max-w-md px-4 py-2 text-gray-900 dark:text-gray-100 bg-gray-50 dark:bg-gray-700 border border-gray-300 dark:border-gray-600 rounded-lg focus:outline-none focus:ring-2 focus:ring-seismo-orange">
+                    <p class="text-xs text-gray-500 dark:text-gray-400 mt-1">
+                        Units are OK if last seen within this many hours
+                    </p>
+                </div>
+
+                <div>
+                    <label for="pending-threshold" class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">
+                        Pending Threshold (hours)
+                    </label>
+                    <input type="number" id="pending-threshold" min="1" max="48"
+                           class="w-full max-w-md px-4 py-2 text-gray-900 dark:text-gray-100 bg-gray-50 dark:bg-gray-700 border border-gray-300 dark:border-gray-600 rounded-lg focus:outline-none focus:ring-2 focus:ring-seismo-orange">
+                    <p class="text-xs text-gray-500 dark:text-gray-400 mt-1">
+                        Units are Pending if last seen within this many hours (units exceeding this are Missing)
                     </p>
                 </div>
             </div>
 
+            <button onclick="saveStatusThresholds()" class="mt-6 px-6 py-3 bg-seismo-orange hover:bg-orange-600 text-white rounded-lg transition-colors">
+                Save Thresholds
+            </button>
+        </div>
+
+        <!-- Calibration Defaults -->
+        <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-6">
+            <h2 class="text-xl font-semibold text-gray-900 dark:text-white mb-4">Calibration Defaults</h2>
+
             <div class="space-y-4">
-        <!-- Clear All Data -->
-        <div class="flex flex-col sm:flex-row sm:items-center sm:justify-between gap-4 p-4 bg-white dark:bg-slate-800 rounded-lg border border-red-200 dark:border-red-800">
-            <div class="flex-1">
-                <h3 class="font-semibold text-gray-900 dark:text-white mb-1">Clear All Data</h3>
-                <p class="text-sm text-gray-600 dark:text-gray-400">
-                    Delete ALL roster units, emitters, and ignored units
+                <div>
+                    <label for="cal-interval" class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">
+                        Calibration Interval (days)
+                    </label>
+                    <input type="number" id="cal-interval" min="1"
+                           class="w-full max-w-md px-4 py-2 text-gray-900 dark:text-gray-100 bg-gray-50 dark:bg-gray-700 border border-gray-300 dark:border-gray-600 rounded-lg focus:outline-none focus:ring-2 focus:ring-seismo-orange">
+                    <p class="text-xs text-gray-500 dark:text-gray-400 mt-1">
+                        Default interval between calibrations
                     </p>
                 </div>
-            <button onclick="confirmClearAll()"
-                    class="px-4 py-2 bg-red-600 hover:bg-red-700 text-white rounded-lg transition-colors whitespace-nowrap">
+
+                <div>
+                    <label for="cal-warning" class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">
+                        Warning Threshold (days before due)
+                    </label>
+                    <input type="number" id="cal-warning" min="1"
+                           class="w-full max-w-md px-4 py-2 text-gray-900 dark:text-gray-100 bg-gray-50 dark:bg-gray-700 border border-gray-300 dark:border-gray-600 rounded-lg focus:outline-none focus:ring-2 focus:ring-seismo-orange">
+                    <p class="text-xs text-gray-500 dark:text-gray-400 mt-1">
+                        Show warnings when calibration is due within this many days
+                    </p>
+                </div>
+            </div>
+
+            <button onclick="saveCalibrationDefaults()" class="mt-6 px-6 py-3 bg-seismo-orange hover:bg-orange-600 text-white rounded-lg transition-colors">
+                Save Defaults
+            </button>
+        </div>
+    </div>
+</div>
+
+<!-- Danger Zone Tab -->
+<div id="danger-tab" class="tab-content hidden">
+    <div class="space-y-6">
+        <!-- Warning Banner -->
+        <div class="bg-red-50 dark:bg-red-900/20 border-l-4 border-red-500 p-4">
+            <div class="flex">
+                <svg class="w-5 h-5 text-red-500 mr-2 flex-shrink-0" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                    <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M12 9v2m0 4h.01m-6.938 4h13.856c1.54 0 2.502-1.667 1.732-3L13.732 4c-.77-1.333-2.694-1.333-3.464 0L3.34 16c-.77 1.333.192 3 1.732 3z"></path>
+                </svg>
+                <div>
+                    <p class="font-semibold text-red-800 dark:text-red-300">Danger Zone</p>
+                    <p class="text-sm text-red-700 dark:text-red-400 mt-1">These operations are PERMANENT and CANNOT be undone. Proceed with extreme caution.</p>
+                </div>
+            </div>
+        </div>
+
+        <!-- Clear All Data -->
+        <div class="border-2 border-red-300 dark:border-red-800 rounded-lg p-6 bg-white dark:bg-slate-800">
+            <div class="flex justify-between items-start">
+                <div>
+                    <h3 class="font-semibold text-red-600 dark:text-red-400 text-lg">Clear All Data</h3>
+                    <p class="text-sm text-gray-600 dark:text-gray-400 mt-1">
+                        Deletes roster units, emitters, and ignored units. Everything will be lost.
+                    </p>
+                </div>
+                <button onclick="confirmClearAll()" class="px-4 py-2 bg-red-600 hover:bg-red-700 text-white rounded-lg transition-colors whitespace-nowrap">
                     Clear All
                 </button>
             </div>
+        </div>
 
         <!-- Clear Roster Only -->
-        <div class="flex flex-col sm:flex-row sm:items-center sm:justify-between gap-4 p-4 bg-white dark:bg-slate-800 rounded-lg border border-red-200 dark:border-red-800">
-            <div class="flex-1">
-                <h3 class="font-semibold text-gray-900 dark:text-white mb-1">Clear Roster Table</h3>
-                <p class="text-sm text-gray-600 dark:text-gray-400">
+        <div class="border border-red-200 dark:border-red-800 rounded-lg p-6 bg-white dark:bg-slate-800">
+            <div class="flex justify-between items-start">
+                <div>
+                    <h3 class="font-semibold text-gray-900 dark:text-white">Clear Roster Table</h3>
+                    <p class="text-sm text-gray-600 dark:text-gray-400 mt-1">
                         Delete all roster units only (keeps emitters and ignored units)
                     </p>
                 </div>
-            <button onclick="confirmClearRoster()"
-                    class="px-4 py-2 bg-red-600 hover:bg-red-700 text-white rounded-lg transition-colors whitespace-nowrap">
+                <button onclick="confirmClearRoster()" class="px-4 py-2 bg-red-600 hover:bg-red-700 text-white rounded-lg transition-colors whitespace-nowrap">
                     Clear Roster
                 </button>
             </div>
+        </div>
 
         <!-- Clear Emitters Only -->
-        <div class="flex flex-col sm:flex-row sm:items-center sm:justify-between gap-4 p-4 bg-white dark:bg-slate-800 rounded-lg border border-red-200 dark:border-red-800">
-            <div class="flex-1">
-                <h3 class="font-semibold text-gray-900 dark:text-white mb-1">Clear Emitters Table</h3>
-                <p class="text-sm text-gray-600 dark:text-gray-400">
+        <div class="border border-red-200 dark:border-red-800 rounded-lg p-6 bg-white dark:bg-slate-800">
+            <div class="flex justify-between items-start">
+                <div>
+                    <h3 class="font-semibold text-gray-900 dark:text-white">Clear Emitters Table</h3>
+                    <p class="text-sm text-gray-600 dark:text-gray-400 mt-1">
                         Delete all auto-discovered emitters (will repopulate automatically)
                     </p>
                 </div>
-            <button onclick="confirmClearEmitters()"
-                    class="px-4 py-2 bg-red-600 hover:bg-red-700 text-white rounded-lg transition-colors whitespace-nowrap">
+                <button onclick="confirmClearEmitters()" class="px-4 py-2 bg-red-600 hover:bg-red-700 text-white rounded-lg transition-colors whitespace-nowrap">
                     Clear Emitters
                 </button>
             </div>
+        </div>
 
-        <!-- Clear Ignored Only -->
-        <div class="flex flex-col sm:flex-row sm:items-center sm:justify-between gap-4 p-4 bg-white dark:bg-slate-800 rounded-lg border border-red-200 dark:border-red-800">
-            <div class="flex-1">
-                <h3 class="font-semibold text-gray-900 dark:text-white mb-1">Clear Ignored Units</h3>
-                <p class="text-sm text-gray-600 dark:text-gray-400">
+        <!-- Clear Ignored Units -->
+        <div class="border border-red-200 dark:border-red-800 rounded-lg p-6 bg-white dark:bg-slate-800">
+            <div class="flex justify-between items-start">
+                <div>
+                    <h3 class="font-semibold text-gray-900 dark:text-white">Clear Ignored Units</h3>
+                    <p class="text-sm text-gray-600 dark:text-gray-400 mt-1">
                         Remove all units from the ignore list
                     </p>
                 </div>
-            <button onclick="confirmClearIgnored()"
-                    class="px-4 py-2 bg-red-600 hover:bg-red-700 text-white rounded-lg transition-colors whitespace-nowrap">
+                <button onclick="confirmClearIgnored()" class="px-4 py-2 bg-red-600 hover:bg-red-700 text-white rounded-lg transition-colors whitespace-nowrap">
                     Clear Ignored
                 </button>
             </div>
         </div>
     </div>
+</div>
+
+<style>
+.settings-tab {
+    padding: 0.75rem 1.5rem;
+    font-size: 0.875rem;
+    font-weight: 500;
+    color: #6b7280;
+    border-bottom: 2px solid transparent;
+    transition: all 0.2s;
+    background: none;
+    cursor: pointer;
+}
+
+.settings-tab:hover {
+    color: #374151;
+    background-color: rgba(249, 250, 251, 0.5);
+}
+
+.dark .settings-tab:hover {
+    color: #d1d5db;
+    background-color: rgba(55, 65, 81, 0.3);
+}
+
+.active-settings-tab {
+    color: #f48b1c !important;
+    border-bottom-color: #f48b1c !important;
+}
+
+.tab-content {
+    animation: fadeIn 0.3s ease-in;
+}
+
+@keyframes fadeIn {
+    from { opacity: 0; transform: translateY(-10px); }
+    to { opacity: 1; transform: translateY(0); }
+}
+</style>
 
 <script>
-// CSV Import Handler
-document.getElementById('importSettingsForm').addEventListener('submit', async function(e) {
+// ========== TAB MANAGEMENT ==========
+
+function showTab(tabName) {
+    // Hide all tabs
+    document.querySelectorAll('.tab-content').forEach(tab => {
+        tab.classList.add('hidden');
+    });
+
+    // Remove active class from all buttons
+    document.querySelectorAll('.settings-tab').forEach(btn => {
+        btn.classList.remove('active-settings-tab');
+    });
+
+    // Show selected tab
+    document.getElementById(tabName + '-tab').classList.remove('hidden');
+
+    // Add active class to clicked button
+    const clickedButton = document.querySelector(`[data-tab="${tabName}"]`);
+    if (clickedButton) {
+        clickedButton.classList.add('active-settings-tab');
+    }
+
+    // Save last active tab to localStorage
+    localStorage.setItem('settings-last-tab', tabName);
+
+    // Load roster table when data tab is shown
+    if (tabName === 'data') {
+        loadRosterTable();
+    }
+}
+
+// Restore last active tab on page load
+window.addEventListener('DOMContentLoaded', () => {
+    const lastTab = localStorage.getItem('settings-last-tab') || 'general';
+    showTab(lastTab);
+    loadPreferences();
+});
+
+// ========== GENERAL TAB - PREFERENCES ==========
+
+let currentPreferences = {};
+
+async function loadPreferences() {
+    try {
+        const response = await fetch('/api/settings/preferences');
+        const prefs = await response.json();
+        currentPreferences = prefs;
+
+        // Load timezone
+        document.getElementById('timezone-select').value = prefs.timezone || 'America/New_York';
+
+        // Load theme
+        const themeRadios = document.querySelectorAll('input[name="theme"]');
+        themeRadios.forEach(radio => {
+            radio.checked = radio.value === (prefs.theme || 'auto');
+        });
+
+        // Load auto-refresh interval
+        document.getElementById('refresh-interval').value = prefs.auto_refresh_interval || 10;
+
+        // Load status thresholds
+        document.getElementById('ok-threshold').value = prefs.status_ok_threshold_hours || 12;
+        document.getElementById('pending-threshold').value = prefs.status_pending_threshold_hours || 24;
+
+        // Load calibration defaults
+        document.getElementById('cal-interval').value = prefs.calibration_interval_days || 365;
+        document.getElementById('cal-warning').value = prefs.calibration_warning_days || 30;
+
+    } catch (error) {
+        console.error('Error loading preferences:', error);
+    }
+}
+
+async function saveGeneralSettings() {
+    const timezone = document.getElementById('timezone-select').value;
+    const theme = document.querySelector('input[name="theme"]:checked').value;
+    const autoRefreshInterval = parseInt(document.getElementById('refresh-interval').value);
+
+    try {
+        const response = await fetch('/api/settings/preferences', {
+            method: 'PUT',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify({
+                timezone,
+                theme,
+                auto_refresh_interval: autoRefreshInterval
+            })
+        });
+
+        if (response.ok) {
+            // Also update localStorage for immediate effect
+            localStorage.setItem('timezone', timezone);
+
+            // Visual feedback
+            alert('Settings saved successfully!');
+
+            // Refresh timestamps on page
+            if (typeof updateAllTimestamps === 'function') {
+                updateAllTimestamps();
+            }
+        } else {
+            const result = await response.json();
+            alert('Error saving settings: ' + (result.detail || 'Unknown error'));
+        }
+    } catch (error) {
+        alert('Error saving settings: ' + error.message);
+    }
+}
+
+async function saveStatusThresholds() {
+    const okThreshold = parseInt(document.getElementById('ok-threshold').value);
+    const pendingThreshold = parseInt(document.getElementById('pending-threshold').value);
+
+    try {
+        const response = await fetch('/api/settings/preferences', {
+            method: 'PUT',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify({
+                status_ok_threshold_hours: okThreshold,
+                status_pending_threshold_hours: pendingThreshold
+            })
+        });
+
+        if (response.ok) {
+            alert('Status thresholds saved successfully!');
+        } else {
+            const result = await response.json();
+            alert('Error saving thresholds: ' + (result.detail || 'Unknown error'));
+        }
+    } catch (error) {
+        alert('Error saving thresholds: ' + error.message);
+    }
+}
+
+async function saveCalibrationDefaults() {
+    const calInterval = parseInt(document.getElementById('cal-interval').value);
+    const calWarning = parseInt(document.getElementById('cal-warning').value);
+
+    try {
+        const response = await fetch('/api/settings/preferences', {
+            method: 'PUT',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify({
+                calibration_interval_days: calInterval,
+                calibration_warning_days: calWarning
+            })
+        });
+
+        if (response.ok) {
+            alert('Calibration defaults saved successfully!');
+        } else {
+            const result = await response.json();
+            alert('Error saving defaults: ' + (result.detail || 'Unknown error'));
+        }
+    } catch (error) {
+        alert('Error saving defaults: ' + error.message);
+    }
+}
+
+// ========== DATA TAB - IMPORT/EXPORT ==========
+
+// Merge Mode Import
+document.getElementById('importMergeForm').addEventListener('submit', async function(e) {
     e.preventDefault();
 
     const formData = new FormData(this);
-    const mode = formData.get('mode');
-    const resultDiv = document.getElementById('importResult');
+    const resultDiv = document.getElementById('importMergeResult');
 
-    // For replace mode, get confirmation
-    if (mode === 'replace') {
+    try {
+        const response = await fetch('/api/roster/import-csv', {
+            method: 'POST',
+            body: formData
+        });
+
+        const result = await response.json();
+
+        if (response.ok) {
+            resultDiv.className = 'mt-4 p-4 rounded-lg bg-green-100 dark:bg-green-900 text-green-800 dark:text-green-200';
+            resultDiv.innerHTML = `
+                <p class="font-semibold mb-2">Import Successful!</p>
+                <ul class="text-sm space-y-1">
+                    <li>✅ Added: ${result.summary.added}</li>
+                    <li>🔄 Updated: ${result.summary.updated}</li>
+                    <li>⏭️ Skipped: ${result.summary.skipped}</li>
+                    <li>❌ Errors: ${result.summary.errors}</li>
+                </ul>
+            `;
+            resultDiv.classList.remove('hidden');
+
+            // Refresh roster table
+            setTimeout(() => {
+                this.reset();
+                resultDiv.classList.add('hidden');
+                loadRosterTable();
+            }, 3000);
+        } else {
+            resultDiv.className = 'mt-4 p-4 rounded-lg bg-red-100 dark:bg-red-900 text-red-800 dark:text-red-200';
+            resultDiv.innerHTML = `<p class="font-semibold">Import Failed</p><p class="text-sm">${result.detail || 'Unknown error'}</p>`;
+            resultDiv.classList.remove('hidden');
+        }
+    } catch (error) {
+        resultDiv.className = 'mt-4 p-4 rounded-lg bg-red-100 dark:bg-red-900 text-red-800 dark:text-red-200';
+        resultDiv.innerHTML = `<p class="font-semibold">Import Failed</p><p class="text-sm">${error.message}</p>`;
+        resultDiv.classList.remove('hidden');
+    }
+});
+
+// Replace Mode Import
+document.getElementById('importReplaceForm').addEventListener('submit', async function(e) {
+    e.preventDefault();
+
+    const formData = new FormData(this);
+    const resultDiv = document.getElementById('importReplaceResult');
+
+    // Get confirmation
     try {
         const stats = await fetch('/api/settings/stats').then(r => r.json());
 
@@ -227,15 +677,9 @@ Continue?`;
         alert('Error fetching statistics: ' + error.message);
         return;
     }
-    }
-
-    // Choose endpoint based on mode
-    const endpoint = mode === 'replace'
-        ? '/api/settings/import-csv-replace'
-        : '/api/roster/import-csv';
 
     try {
-        const response = await fetch(endpoint, {
+        const response = await fetch('/api/settings/import-csv-replace', {
             method: 'POST',
             body: formData
         });
@@ -244,32 +688,20 @@ Continue?`;
 
         if (response.ok) {
             resultDiv.className = 'mt-4 p-4 rounded-lg bg-green-100 dark:bg-green-900 text-green-800 dark:text-green-200';
-
-            if (mode === 'replace') {
             resultDiv.innerHTML = `
-                    <p class="font-semibold mb-2">Import Successful!</p>
+                <p class="font-semibold mb-2">Replace Import Successful!</p>
                 <ul class="text-sm space-y-1">
-                        <li>✅ Deleted: ${result.deleted}</li>
+                    <li>🗑️ Deleted: ${result.deleted}</li>
                     <li>✅ Added: ${result.added}</li>
                 </ul>
             `;
-            } else {
-                resultDiv.innerHTML = `
-                    <p class="font-semibold mb-2">Import Successful!</p>
-                    <ul class="text-sm space-y-1">
-                        <li>✅ Added: ${result.summary.added}</li>
-                        <li>🔄 Updated: ${result.summary.updated}</li>
-                        <li>⏭️ Skipped: ${result.summary.skipped}</li>
-                        <li>❌ Errors: ${result.summary.errors}</li>
-                    </ul>
-                `;
-            }
             resultDiv.classList.remove('hidden');
 
-            // Reset form after 3 seconds
+            // Refresh roster table
             setTimeout(() => {
                 this.reset();
                 resultDiv.classList.add('hidden');
+                loadRosterTable();
             }, 3000);
         } else {
             resultDiv.className = 'mt-4 p-4 rounded-lg bg-red-100 dark:bg-red-900 text-red-800 dark:text-red-200';
@@ -283,132 +715,8 @@ Continue?`;
     }
 });
 
-// Clear All Data
-async function confirmClearAll() {
-    try {
-        const stats = await fetch('/api/settings/stats').then(r => r.json());
-
-        const message = `⚠️ CLEAR ALL DATA WARNING ⚠️
-
-You are about to DELETE ALL data:
-
-• Roster units: ${stats.roster}
-• Emitters: ${stats.emitters}
-• Ignored units: ${stats.ignored}
-• TOTAL: ${stats.total} records
-
-THIS ACTION CANNOT BE UNDONE!
-
-Export a backup first if needed.
-
-Are you absolutely sure?`;
-
-        if (!confirm(message)) {
-            return;
-        }
-
-        const response = await fetch('/api/settings/clear-all', {
-            method: 'POST'
-        });
-
-        if (response.ok) {
-            const result = await response.json();
-            alert(`✅ Success! Deleted ${result.deleted.total} records\n\n• Roster: ${result.deleted.roster}\n• Emitters: ${result.deleted.emitters}\n• Ignored: ${result.deleted.ignored}`);
-            location.reload();
-        } else {
-            const result = await response.json();
-            alert('❌ Error: ' + (result.detail || 'Unknown error'));
-        }
-    } catch (error) {
-        alert('❌ Error: ' + error.message);
-    }
-}
-
-// Clear Roster Only
-async function confirmClearRoster() {
-    try {
-        const stats = await fetch('/api/settings/stats').then(r => r.json());
-
-        if (!confirm(`Delete all ${stats.roster} roster units?\n\nThis cannot be undone!`)) {
-            return;
-        }
-
-        const response = await fetch('/api/settings/clear-roster', {
-            method: 'POST'
-        });
-
-        if (response.ok) {
-            const result = await response.json();
-            alert(`✅ Success! Deleted ${result.deleted} roster units`);
-            location.reload();
-        } else {
-            const result = await response.json();
-            alert('❌ Error: ' + (result.detail || 'Unknown error'));
-        }
-    } catch (error) {
-        alert('❌ Error: ' + error.message);
-    }
-}
-
-// Clear Emitters Only
-async function confirmClearEmitters() {
-    try {
-        const stats = await fetch('/api/settings/stats').then(r => r.json());
-
-        if (!confirm(`Delete all ${stats.emitters} emitters?\n\nEmitters will repopulate automatically from ACH files.`)) {
-            return;
-        }
-
-        const response = await fetch('/api/settings/clear-emitters', {
-            method: 'POST'
-        });
-
-        if (response.ok) {
-            const result = await response.json();
-            alert(`✅ Success! Deleted ${result.deleted} emitters`);
-            location.reload();
-        } else {
-            const result = await response.json();
-            alert('❌ Error: ' + (result.detail || 'Unknown error'));
-        }
-    } catch (error) {
-        alert('❌ Error: ' + error.message);
-    }
-}
-
-// Clear Ignored Only
-async function confirmClearIgnored() {
-    try {
-        const stats = await fetch('/api/settings/stats').then(r => r.json());
-
-        if (!confirm(`Remove all ${stats.ignored} units from ignore list?\n\nThey will appear as unknown emitters again.`)) {
-            return;
-        }
-
-        const response = await fetch('/api/settings/clear-ignored', {
-            method: 'POST'
-        });
-
-        if (response.ok) {
-            const result = await response.json();
-            alert(`✅ Success! Removed ${result.deleted} units from ignore list`);
-            location.reload();
-        } else {
-            const result = await response.json();
-            alert('❌ Error: ' + (result.detail || 'Unknown error'));
-        }
-    } catch (error) {
-        alert('❌ Error: ' + error.message);
-    }
-}
-
 // ========== ROSTER MANAGEMENT TABLE ==========
 
-// Load roster table on page load
-document.addEventListener('DOMContentLoaded', function() {
-    loadRosterTable();
-});
-
 async function loadRosterTable() {
     const loading = document.getElementById('rosterTableLoading');
     const container = document.getElementById('rosterTableContainer');
@@ -551,7 +859,6 @@ async function toggleRetired(unitId, currentState) {
 }
 
 function editUnit(unitId) {
-    // Navigate to unit detail page for full editing
     window.location.href = `/unit/${unitId}`;
 }
 
@@ -580,5 +887,122 @@ async function confirmDeleteUnit(unitId) {
 function refreshRosterTable() {
     loadRosterTable();
 }
+
+// ========== DANGER ZONE ==========
+
+async function confirmClearAll() {
+    try {
+        const stats = await fetch('/api/settings/stats').then(r => r.json());
+
+        const message = `⚠️ CLEAR ALL DATA WARNING ⚠️
+
+You are about to DELETE ALL data:
+
+• Roster units: ${stats.roster}
+• Emitters: ${stats.emitters}
+• Ignored units: ${stats.ignored}
+• TOTAL: ${stats.total} records
+
+THIS ACTION CANNOT BE UNDONE!
+
+Export a backup first if needed.
+
+Are you absolutely sure?`;
+
+        if (!confirm(message)) {
+            return;
+        }
+
+        const response = await fetch('/api/settings/clear-all', {
+            method: 'POST'
+        });
+
+        if (response.ok) {
+            const result = await response.json();
+            alert(`✅ Success! Deleted ${result.deleted.total} records\n\n• Roster: ${result.deleted.roster}\n• Emitters: ${result.deleted.emitters}\n• Ignored: ${result.deleted.ignored}`);
+            location.reload();
+        } else {
+            const result = await response.json();
+            alert('❌ Error: ' + (result.detail || 'Unknown error'));
+        }
+    } catch (error) {
+        alert('❌ Error: ' + error.message);
+    }
+}
+
+async function confirmClearRoster() {
+    try {
+        const stats = await fetch('/api/settings/stats').then(r => r.json());
+
+        if (!confirm(`Delete all ${stats.roster} roster units?\n\nThis cannot be undone!`)) {
+            return;
+        }
+
+        const response = await fetch('/api/settings/clear-roster', {
+            method: 'POST'
+        });
+
+        if (response.ok) {
+            const result = await response.json();
+            alert(`✅ Success! Deleted ${result.deleted} roster units`);
+            location.reload();
+        } else {
+            const result = await response.json();
+            alert('❌ Error: ' + (result.detail || 'Unknown error'));
+        }
+    } catch (error) {
+        alert('❌ Error: ' + error.message);
+    }
+}
+
+async function confirmClearEmitters() {
+    try {
+        const stats = await fetch('/api/settings/stats').then(r => r.json());
+
+        if (!confirm(`Delete all ${stats.emitters} emitters?\n\nEmitters will repopulate automatically from heartbeats.`)) {
+            return;
+        }
+
+        const response = await fetch('/api/settings/clear-emitters', {
+            method: 'POST'
+        });
+
+        if (response.ok) {
+            const result = await response.json();
+            alert(`✅ Success! Deleted ${result.deleted} emitters`);
+            location.reload();
+        } else {
+            const result = await response.json();
+            alert('❌ Error: ' + (result.detail || 'Unknown error'));
+        }
+    } catch (error) {
+        alert('❌ Error: ' + error.message);
+    }
+}
+
+async function confirmClearIgnored() {
+    try {
+        const stats = await fetch('/api/settings/stats').then(r => r.json());
+
+        if (!confirm(`Remove all ${stats.ignored} units from ignore list?\n\nThey will appear as unknown emitters again.`)) {
+            return;
+        }
+
+        const response = await fetch('/api/settings/clear-ignored', {
+            method: 'POST'
+        });
+
+        if (response.ok) {
+            const result = await response.json();
+            alert(`✅ Success! Removed ${result.deleted} units from ignore list`);
+            location.reload();
+        } else {
+            const result = await response.json();
+            alert('❌ Error: ' + (result.detail || 'Unknown error'));
+        }
+    } catch (error) {
+        alert('❌ Error: ' + error.message);
+    }
+}
 </script>
 {% endblock %}

templates/unit_detail.html

@@ -4,14 +4,44 @@
 
 {% block content %}
 <div class="mb-6">
-    <a href="/roster" class="text-seismo-orange hover:text-seismo-burgundy inline-flex items-center mb-4">
-        <svg class="w-4 h-4 mr-1" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M15 19l-7-7 7-7"></path>
-        </svg>
-        Back to Fleet Roster
+    <!-- Breadcrumb Navigation -->
+    <nav class="flex mb-4 text-sm" aria-label="Breadcrumb">
+        <ol class="inline-flex items-center space-x-1 md:space-x-3">
+            <li class="inline-flex items-center">
+                <a href="/" class="text-gray-500 hover:text-seismo-orange dark:text-gray-400">
+                    Dashboard
                 </a>
+            </li>
+            <li>
+                <div class="flex items-center">
+                    <svg class="w-4 h-4 text-gray-400" fill="currentColor" viewBox="0 0 20 20">
+                        <path fill-rule="evenodd" d="M7.293 14.707a1 1 0 010-1.414L10.586 10 7.293 6.707a1 1 0 011.414-1.414l4 4a1 1 0 010 1.414l-4 4a1 1 0 01-1.414 0z" clip-rule="evenodd"></path>
+                    </svg>
+                    <a href="/roster" class="ml-1 text-gray-500 hover:text-seismo-orange dark:text-gray-400">
+                        Fleet Roster
+                    </a>
+                </div>
+            </li>
+            <li aria-current="page">
+                <div class="flex items-center">
+                    <svg class="w-4 h-4 text-gray-400" fill="currentColor" viewBox="0 0 20 20">
+                        <path fill-rule="evenodd" d="M7.293 14.707a1 1 0 010-1.414L10.586 10 7.293 6.707a1 1 0 011.414-1.414l4 4a1 1 0 010 1.414l-4 4a1 1 0 01-1.414 0z" clip-rule="evenodd"></path>
+                    </svg>
+                    <span class="ml-1 text-gray-700 dark:text-gray-300 font-medium" id="breadcrumb-unit">Unit</span>
+                </div>
+            </li>
+        </ol>
+    </nav>
+
     <div class="flex justify-between items-center">
+        <div class="flex items-center gap-2">
             <h1 class="text-3xl font-bold text-gray-900 dark:text-white" id="pageTitle">Loading...</h1>
+            <button onclick="copyToClipboard(window.currentUnitId, this)" class="text-gray-400 hover:text-gray-600 dark:hover:text-gray-300 transition-colors p-1" title="Copy Unit ID">
+                <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                    <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M8 16H6a2 2 0 01-2-2V6a2 2 0 012-2h8a2 2 0 012 2v2m-6 12h8a2 2 0 002-2v-8a2 2 0 00-2-2h-8a2 2 0 00-2 2v8a2 2 0 002 2z"></path>
+                </svg>
+            </button>
+        </div>
         <div class="flex gap-3">
             <button id="editButton" onclick="enterEditMode()" class="px-4 py-2 bg-seismo-orange hover:bg-orange-600 text-white rounded-lg transition-colors flex items-center gap-2">
                 <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
@@ -323,8 +353,10 @@ async function loadUnitData() {
 
 // Populate view mode (read-only display)
 function populateViewMode() {
-    // Update page title
+    // Update page title and store unit ID for copy function
+    window.currentUnitId = currentUnit.id;
     document.getElementById('pageTitle').textContent = `Unit ${currentUnit.id}`;
+    document.getElementById('breadcrumb-unit').textContent = currentUnit.id;
 
     // Get status info from snapshot
     let unitStatus = null;
@@ -348,7 +380,14 @@ function populateViewMode() {
         document.getElementById('statusIndicator').className = `w-3 h-3 rounded-full ${statusColors[unitStatus.status] || 'bg-gray-400'}`;
         document.getElementById('statusText').className = `font-semibold ${statusTextColors[unitStatus.status] || 'text-gray-600'}`;
         document.getElementById('statusText').textContent = unitStatus.status || 'Unknown';
+
+        // Format "Last Seen" with timezone-aware formatting
+        if (unitStatus.last && typeof formatFullTimestamp === 'function') {
+            document.getElementById('lastSeen').textContent = formatFullTimestamp(unitStatus.last);
+        } else {
             document.getElementById('lastSeen').textContent = unitStatus.last || '--';
+        }
+
         document.getElementById('age').textContent = unitStatus.age || '--';
     } else {
         document.getElementById('statusIndicator').className = 'w-3 h-3 rounded-full bg-gray-400';