:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --bg-panel: #ffffff;
    --bg-app: #f8fafc;
    --border-color: #e2e8f0;
    --text-main: #0f172a;
    --text-muted: #475569;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

body, html {
    width: 100vw;
    height: 100vh;
    overflow: hidden;
    background: var(--bg-app);
}

/* Flex Container Split Layout Architecture */
.app-container {
    display: flex;
    width: 100%;
    height: 100%;
    position: relative;
    overflow: hidden;
}

/* Sidebar Container Asset Block with Height Safeguards */
.sidebar-panel {
    width: 380px;
    height: 100%;
    min-height: 450px; /* Prevent vertical collapse on ultra-short screens */
    background: var(--bg-panel);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    position: relative;
    flex-shrink: 0;
    z-index: 1000;
    transition: margin-left 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: var(--shadow);
}

.sidebar-panel.collapsed {
    margin-left: -380px;
}

/* Map Canvas Interface Section */
#map {
    flex-grow: 1;
    height: 100%;
    z-index: 1;
    background: #cbd5e1;
}

/* Tabs Ribbon Interface Header */
.tabs-header {
    display: flex;
    background: #f1f5f9;
    border-bottom: 1px solid var(--border-color);
    padding: 6px 8px 0 8px;
    gap: 4px;
}

.tab-link {
    padding: 8px 16px;
    border: 1px solid var(--border-color);
    border-bottom: none;
    background: #e2e2e2;
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--text-muted);
    cursor: pointer;
    border-radius: 6px 6px 0 0;
    transition: all 0.15s ease;
    display: flex;
    align-items: center;
    gap: 6px;
}

.tab-link:hover {
    background: #f8fafc;
    color: var(--text-main);
}

.tab-link.active {
    background: var(--bg-panel);
    color: var(--primary-color);
    border-color: var(--border-color);
    padding-bottom: 9px;
    margin-bottom: -1px;
    z-index: 2;
}

.tab-badge {
    background: var(--primary-color);
    color: white;
    font-size: 0.65rem;
    font-weight: 700;
    padding: 1px 5px;
    border-radius: 8px;
    line-height: 1.2;
}
.tab-link.active .tab-badge {
    background: #dbeafe;
    color: var(--primary-color);
}

/* Body Wrapper Element Layout Frame */
.panel-body-container {
    display: flex;
    flex-direction: column;
    flex-grow: 1;
    overflow: hidden;
    background: var(--bg-panel);
}

.tab-content {
    display: none;
    flex-direction: column;
    flex-grow: 1;
    overflow: hidden;
}

.tab-content.active {
    display: flex;
}

/* HIGH VISIBILITY MECH PANEL TOGGLE HANDLE */
.panel-toggle-handle {
    position: absolute;
    right: -32px;
    top: 20px;
    width: 32px;
    height: 76px;
    background: var(--bg-panel);
    border: 1px solid var(--border-color);
    border-left: none;
    border-radius: 0 10px 10px 0;
    cursor: pointer;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    box-shadow: 4px 0 8px rgba(0,0,0,0.08);
    z-index: 1001;
    transition: background 0.1s ease;
}

.panel-toggle-handle:hover {
    background: #f8fafc;
}

.panel-toggle-handle span#toggle-arrow {
    font-size: 0.85rem;
    font-weight: 900;
    color: var(--primary-color);
    line-height: 1;
    margin-bottom: 3px;
}

.panel-toggle-handle .toggle-label {
    writing-mode: vertical-rl;
    text-orientation: mixed;
    font-size: 0.62rem;
    font-weight: 700;
    letter-spacing: 0.8px;
    text-transform: uppercase;
    color: var(--text-main);
}

/* COMPACT / COLLAPSIBLE FILTER AND SORT DOCK */
.filter-container {
    padding: 0;
    background: #f8fafc;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
}

.filter-summary-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px 14px;
    background: #f1f5f9;
    cursor: pointer;
    user-select: none;
}
.filter-summary-bar:hover {
    background: #e2e8f0;
}

.filter-toggle-title {
    font-size: 0.78rem;
    font-weight: 700;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    gap: 4px;
}

/* Space-Optimized Sorting Module Controls */
.sort-inline-group {
    display: flex;
    align-items: center;
    gap: 2px;
    position: relative;
    z-index: 5;
}
.sort-inline-label {
    font-size: 0.72rem;
    font-weight: 600;
    color: var(--text-muted);
    margin-right: 4px;
}
.sort-mini-btn {
    background: transparent;
    border: 1px solid transparent;
    border-radius: 4px;
    padding: 2px 5px;
    font-size: 0.75rem;
    cursor: pointer;
    transition: all 0.1s ease;
}
.sort-mini-btn:hover {
    background: #cbd5e1;
}
.sort-mini-btn.active {
    background: var(--bg-panel);
    border-color: var(--border-color);
    box-shadow: 0 1px 2px rgba(0,0,0,0.05);
}

/* Collapsible Filtering Core Tray */
.filter-collapsible-drawer {
    display: none;
    padding: 10px 14px;
    flex-direction: column;
    gap: 6px;
    border-top: 1px solid var(--border-color);
    background: #f8fafc;
}
.filter-collapsible-drawer.expanded {
    display: flex;
}

.search-row input {
    width: 100%;
    padding: 6px 10px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 0.85rem;
    outline: none;
}

.dropdown-row {
    display: flex;
    gap: 6px;
}

.dropdown-row select {
    flex: 1;
    padding: 5px 8px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background: white;
    font-size: 0.8rem;
    cursor: pointer;
}

.bulk-actions {
    display: flex;
    gap: 4px;
}

.bulk-actions button {
    flex: 1;
    padding: 5px;
    font-size: 0.72rem;
    font-weight: 600;
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    cursor: pointer;
}

.bulk-actions button:hover { background: #f1f5f9; }
.bulk-actions button.reset-btn { background: #fff1f2; color: #e11d48; border-color: #fecdd3; }
.bulk-actions button.reset-btn:hover { background: #ffe4e6; }

/* Scroll Feed Control Engines */
.scroll-content {
    flex-grow: 1;
    overflow-y: auto;
    list-style: none;
    background: white;
}

/* Checkbox Directory Rows Styles */
.person-item {
    display: flex;
    align-items: center;
    padding: 8px 14px;
    border-bottom: 1px solid var(--border-color);
    cursor: pointer;
}
.person-item:hover { background: #f1f5f9; }
.person-item input[type="checkbox"] { margin-right: 10px; width: 14px; height: 14px; }
.person-info { flex-grow: 1; }
.person-name { font-weight: 600; font-size: 0.85rem; display: flex; align-items: center; gap: 4px; }
.person-dates { font-size: 0.75rem; color: var(--text-muted); }
.tag { font-size: 0.6rem; background: #e2e8f0; padding: 1px 4px; border-radius: 3px; font-weight: 600; }
.color-dot { width: 8px; height: 8px; border-radius: 50%; opacity: 0; }
.person-item.selected .color-dot { opacity: 1; }

/* ULTRA-COMPACT MINIMALIST EVENT RENDERING ENGINE */
.event-card {
    padding: 5px 12px;
    border-bottom: 1px solid #f1f5f9;
    cursor: pointer;
    transition: background 0.1s ease;
    background: white;
    text-align: left;
}
.event-card:hover { background: #f0f7ff; }

.event-meta-line {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.78rem;
    flex-wrap: wrap;
    line-height: 1.2;
}
.event-figure { font-weight: 700; }
.event-years {
    font-size: 0.68rem;
    font-weight: 700;
    color: #64748b;
    background: #f1f5f9;
    padding: 0px 4px;
    border-radius: 3px;
    white-space: nowrap;
}
.event-age {
    font-size: 0.68rem;
    font-weight: 600;
    color: #64748b;
    background: #f1f5f9;
    padding: 0px 4px;
    border-radius: 3px;
    white-space: nowrap;
}
.event-loc-inline { color: var(--text-muted); font-weight: 500; font-size: 0.75rem; flex-basis: 100% }

.event-desc {
    font-size: 0.8rem;
    color: var(--text-main);
    line-height: 1.25;
    margin-top: 6px;
}

/* Hyper-dense Time-Gap Interceptions Layout */
.timeline-gap {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 12px 12px;
    position: relative;
    background: #f8fafc;
}
.timeline-gap::before {
    content: '';
    position: absolute;
    left: 12px;
    right: 12px;
    height: 1px;
    background: #e2e8f0;
    z-index: 1;
}
.timeline-gap span {
    background: #f8fafc;
    padding: 0 8px;
    font-size: 0.68rem;
    color: var(--text-muted);
    font-weight: 600;
    z-index: 2;
}

/* Map Popup Engine Shared Design Token Overrides */
.leaflet-popup-content-wrapper {
    background: var(--bg-panel);
    border-radius: 8px;
    padding: 0;
    box-shadow: 0 10px 15px -3px rgba(0,0,0,0.1);
    border: 1px solid var(--border-color);
    overflow: hidden;
}
.leaflet-popup-content {
    margin: 0 !important;
    width: 310px !important;
    max-height: 240px;
    overflow-y: auto !important;
}
.popup-timeline-header {
    padding: 6px 12px;
    background: #f1f5f9;
    border-bottom: 1px solid var(--border-color);
    font-size: 0.78rem;
    font-weight: 700;
    color: var(--text-main);
    position: sticky;
    top: 0;
    z-index: 10;
}

/* Responsive Layout Engine System updates */
@media (max-width: 768px) {
    .app-container { flex-direction: column; }
    .sidebar-panel {
        width: 100%;
        height: max(38vh, 280px);
        min-height: 0;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
        transition: margin-top 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        margin-left: 0;
    }
    .sidebar-panel.collapsed {
        margin-top: calc(-100% - 10px);
    }
    #map { width: 100%; height: 62vh; }

    .panel-toggle-handle {
        position: fixed;
        right: auto;
        left: 50%;
        bottom: auto;
        top: 0;
        width: 88px;
        height: 28px;
        transform: translateX(-50%);
        border-left: 1px solid var(--border-color);
        border-right: 1px solid var(--border-color);
        border-bottom: 1px solid var(--border-color);
        border-top: none;
        border-radius: 0 0 8px 8px;
        box-shadow: 0 4px 8px rgba(0,0,0,0.08);
    }
    .sidebar-panel:not(.collapsed) .panel-toggle-handle {
        position: absolute;
        top: auto;
        bottom: -28px;
    }
    /* FIXED: Removed transform: rotate(90deg) which was corrupting the JS character switch */
    .panel-toggle-handle span#toggle-arrow {
        display: inline-block;
        margin-bottom: 0;
        margin-right: 4px;
    }
    .panel-toggle-handle .toggle-label { writing-mode: horizontal-tb; margin-top: 0; }
}