:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary: #ec4899;
    --success: #10b981;
    --success-bg: #d1fae5;
    --warning: #f59e0b;
    --warning-bg: #fef3c7;
    --danger: #ef4444;
    --danger-bg: #fee2e2;
    --info: #3b82f6;
    --info-bg: #dbeafe;
    
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-tertiary: #f3f4f6;
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --text-tertiary: #9ca3af;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    
    --header-height: 56px;
    --bottom-nav-height: 64px;
    --transition-speed: 200ms;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg-primary: #1a1a2e;
        --bg-secondary: #16213e;
        --bg-tertiary: #0f3460;
        --text-primary: #f9fafb;
        --text-secondary: #d1d5db;
        --text-tertiary: #9ca3af;
        --border-color: #374151;
        --success-bg: rgba(16, 185, 129, 0.1);
        --warning-bg: rgba(245, 158, 11, 0.1);
        --danger-bg: rgba(239, 68, 68, 0.1);
        --info-bg: rgba(59, 130, 246, 0.1);
    }
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: var(--bg-secondary);
    color: var(--text-primary);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.app-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    z-index: 100;
    box-shadow: var(--shadow-sm);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
    padding: 0 var(--spacing-md);
}

.app-title {
    font-size: 1.25rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--primary);
}

.status-badge {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-sm);
    background: var(--success-bg);
    color: var(--success);
    border-radius: var(--radius-lg);
    font-size: 0.875rem;
    font-weight: 600;
}

.status-dot {
    width: 8px;
    height: 8px;
    background: currentColor;
    border-radius: 50%;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

.app-content {
    margin-top: var(--header-height);
    margin-bottom: 0; /* Remove bottom margin to prevent overlap */
    padding: var(--spacing-md);
    padding-bottom: calc(var(--bottom-nav-height) + 350px); /* Extra space for footer + nav */
    min-height: calc(100vh - var(--header-height) - var(--bottom-nav-height));
    overflow-y: auto;
}

.tab-content {
    display: none;
    animation: fadeIn 0.3s ease-in-out;
}

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

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
}

.stat-card {
    background: var(--bg-primary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    box-shadow: var(--shadow-sm);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.stat-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
}

.stat-info {
    flex: 1;
}

.stat-value {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text-primary);
}

.stat-label {
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-top: 2px;
}

.section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--spacing-md);
}

.section-header h2 {
    font-size: 1.25rem;
    font-weight: 700;
}

.filters {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.filter-select {
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 0.875rem;
    cursor: pointer;
    white-space: nowrap;
    outline: none;
    transition: all var(--transition-speed);
}

.filter-select:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.vehicle-list,
.threat-list,
.maintenance-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.vehicle-card,
.threat-card,
.maintenance-card {
    background: var(--bg-primary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    box-shadow: var(--shadow-sm);
    cursor: pointer;
    transition: all var(--transition-speed);
    border: 1px solid var(--border-color);
}

.vehicle-card:active,
.threat-card:active,
.maintenance-card:active {
    transform: scale(0.98);
    box-shadow: var(--shadow-md);
}

.vehicle-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--spacing-sm);
}

.vehicle-plate {
    font-size: 1.125rem;
    font-weight: 700;
    color: var(--text-primary);
}

.vehicle-model {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
}

.vehicle-stats {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
}

.vehicle-stat {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 0.875rem;
}

.vehicle-stat i {
    width: 16px;
    text-align: center;
    color: var(--text-tertiary);
}

.chip {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 4px var(--spacing-sm);
    border-radius: var(--radius-lg);
    font-size: 0.75rem;
    font-weight: 600;
}

.chip.success {
    background: var(--success-bg);
    color: var(--success);
}

.chip.warning {
    background: var(--warning-bg);
    color: var(--warning);
}

.chip.danger {
    background: var(--danger-bg);
    color: var(--danger);
}

.chip.info {
    background: var(--info-bg);
    color: var(--info);
}

.chip.low {
    background: var(--success-bg);
    color: var(--success);
}

.chip.medium {
    background: var(--warning-bg);
    color: var(--warning);
}

.chip.high, .chip.critical {
    background: var(--danger-bg);
    color: var(--danger);
}

.threat-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    margin-bottom: var(--spacing-sm);
}

.threat-type {
    font-weight: 700;
    font-size: 1rem;
    margin-bottom: 4px;
}

.threat-time {
    font-size: 0.75rem;
    color: var(--text-tertiary);
}

.threat-target {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-top: var(--spacing-xs);
}

.pipeline-container {
    background: var(--bg-primary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
    overflow-x: auto;
}

.pipeline-title {
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.pipeline {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    min-width: max-content;
}

.pipeline-step {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm);
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    font-size: 0.75rem;
    text-align: center;
    transition: all var(--transition-speed);
}

.pipeline-step i {
    font-size: 1.25rem;
    color: var(--text-secondary);
}

.pipeline-step.active {
    background: var(--primary);
    color: white;
    transform: scale(1.1);
}

.pipeline-step.active i {
    color: white;
}

.pipeline-arrow {
    color: var(--text-tertiary);
    font-weight: 700;
}

.maintenance-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    margin-bottom: var(--spacing-sm);
}

.maintenance-component {
    font-weight: 700;
    font-size: 1rem;
}

.maintenance-probability {
    font-size: 2rem;
    font-weight: 700;
    color: var(--danger);
    margin: var(--spacing-sm) 0;
}

.maintenance-action {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-top: var(--spacing-xs);
}

.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: var(--bottom-nav-height);
    background: var(--bg-primary);
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: space-around;
    align-items: center;
    z-index: 1000;
    box-shadow: 0 -1px 3px 0 rgba(0, 0, 0, 0.05);
}

.nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 4px;
    flex: 1;
    height: 100%;
    background: none;
    border: none;
    color: var(--text-tertiary);
    cursor: pointer;
    transition: all var(--transition-speed);
}

.nav-item i {
    font-size: 1.5rem;
}

.nav-item span {
    font-size: 0.75rem;
    font-weight: 500;
}

.nav-item.active {
    color: var(--primary);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    border: none;
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-speed);
    outline: none;
}

.btn-primary {
    background: var(--primary);
    color: white;
}

.btn-primary:active {
    background: var(--primary-dark);
    transform: scale(0.95);
}

.btn-small {
    padding: 6px var(--spacing-sm);
    font-size: 0.75rem;
}

.icon-btn {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-tertiary);
    border: none;
    border-radius: var(--radius-md);
    color: var(--text-primary);
    cursor: pointer;
    transition: all var(--transition-speed);
}

.icon-btn:active {
    transform: scale(0.9);
    background: var(--border-color);
}

.bottom-sheet {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--bg-primary);
    border-radius: var(--radius-xl) var(--radius-xl) 0 0;
    box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.1);
    transform: translateY(100%);
    transition: transform 0.3s ease-out;
    z-index: 200;
    max-height: 80vh;
    overflow-y: auto;
}

.bottom-sheet.open {
    transform: translateY(0);
}

.bottom-sheet-handle {
    width: 40px;
    height: 4px;
    background: var(--border-color);
    border-radius: 2px;
    margin: var(--spacing-sm) auto;
}

.bottom-sheet-content {
    padding: 0 var(--spacing-md) var(--spacing-lg);
}

.toast-container {
    position: fixed;
    bottom: calc(var(--bottom-nav-height) + var(--spacing-md));
    left: var(--spacing-md);
    right: var(--spacing-md);
    z-index: 300;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    pointer-events: none;
}

.toast {
    background: var(--bg-primary);
    color: var(--text-primary);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    animation: slideUp 0.3s ease-out;
    pointer-events: all;
    border-left: 4px solid var(--primary);
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.toast.success {
    border-left-color: var(--success);
}

.toast.warning {
    border-left-color: var(--warning);
}

.toast.danger {
    border-left-color: var(--danger);
}

.offline-banner {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--warning);
    color: white;
    padding: var(--spacing-sm) var(--spacing-md);
    text-align: center;
    z-index: 150;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    font-size: 0.875rem;
    font-weight: 600;
}

.offline-banner.hidden {
    display: none;
}

.app-footer {
    background: var(--bg-primary);
    border-top: 1px solid var(--border-color);
    padding: var(--spacing-lg) var(--spacing-md);
    margin-top: auto;
    margin-bottom: var(--bottom-nav-height);
    position: relative;
    z-index: 1;
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
    max-width: 1200px;
    margin: 0 auto;
}

.footer-section h3 {
    font-size: 1.125rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: var(--spacing-sm);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.footer-section h4 {
    font-size: 0.875rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.footer-section p {
    font-size: 0.875rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: var(--spacing-xs);
}

.footer-link {
    color: var(--text-secondary);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    transition: color var(--transition-speed);
    padding: var(--spacing-xs) 0;
}

.footer-link:hover {
    color: var(--primary);
}

.footer-link i {
    width: 16px;
    text-align: center;
}

.footer-bottom {
    margin-top: var(--spacing-lg);
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--border-color);
    text-align: center;
}

.footer-bottom p {
    font-size: 0.75rem;
    color: var(--text-tertiary);
    margin: var(--spacing-xs) 0;
}

.footer-notice {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    color: var(--info);
    background: var(--info-bg);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-md);
}

.hidden {
    display: none !important;
}

.skeleton {
    background: linear-gradient(90deg, var(--bg-tertiary) 25%, var(--border-color) 50%, var(--bg-tertiary) 75%);
    background-size: 200% 100%;
    animation: loading 1.5s ease-in-out infinite;
    border-radius: var(--radius-md);
}

@keyframes loading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}