:root {
    /* Palette - Indigo & Slate */
    --color-primary: #6366f1;
    --color-primary-hover: #4f46e5;
    --color-bg-app: #0f172a;
    /* Page background */
    --color-bg-surface: #1e293b;
    /* Cards, Sidebar */
    --color-border: #334155;

    --color-text-main: #f8fafc;
    --color-text-muted: #94a3b8;

    --color-accent-electric: #4ade80;
    /* Fresh Green */
    --color-accent-petrol: #fb7185;
    --color-accent-diesel: #fbbf24;
    --color-success: #34d399;
    --color-danger: #ef4444;

    /* Metrics */
    --header-height: 64px;
    --sidebar-width: 300px;
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;

    /* Transitions */
    --trans-speed: 0.3s;
    --trans-ease: cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: 'Outfit', sans-serif;
    background-color: var(--color-bg-app);
    color: var(--color-text-main);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

/* --- Sticky Header --- */
.app-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background-color: rgba(15, 23, 42, 0.8);
    /* Semi-transparent */
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border);
    z-index: 50;
    display: flex;
    align-items: center;
    padding: 0 1rem;
}

.header-content {
    display: flex;
    align-items: center;
    gap: 1rem;
    width: 100%;
}

.app-header h1 {
    font-size: 1.25rem;
    font-weight: 700;
    background: linear-gradient(135deg, #fff 0%, var(--color-primary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.menu-btn {
    background: none;
    border: none;
    color: var(--color-text-main);
    padding: 0;
    cursor: pointer;
    display: flex;
    /* Hidden on Desktop via Media Query */
}

/* --- Layout Grid --- */
.app-layout {
    display: flex;
    min-height: 100vh;
    padding-top: var(--header-height);
    /* Offset for sticky header */
}

/* --- Sidebar (Mobile: Off-canvas) --- */
.app-sidebar {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    width: var(--sidebar-width);
    background-color: var(--color-bg-surface);
    border-right: 1px solid var(--color-border);
    z-index: 100;
    transform: translateX(-100%);
    /* Hidden by default on mobile */
    transition: transform var(--trans-speed) var(--trans-ease);
    display: flex;
    flex-direction: column;
    padding: 1.5rem;
}

.app-sidebar.open {
    transform: translateX(0);
    box-shadow: 20px 0 50px rgba(0, 0, 0, 0.5);
}

.sidebar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.sidebar-header h2 {
    font-size: 1.25rem;
    font-weight: 600;
}

.close-btn {
    background: none;
    border: none;
    color: var(--color-text-muted);
    font-size: 2rem;
    line-height: 1;
    cursor: pointer;
}

.settings-group {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    flex-grow: 1;
}

.sidebar-footer {
    margin-top: auto;
    font-size: 0.8rem;
    color: var(--color-text-muted);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 1rem;
}

.sidebar-footer a {
    color: var(--color-text-muted);
}

/* Sidebar Overlay */
.sidebar-overlay {
    position: fixed;
    inset: 0;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 90;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--trans-speed) ease;
    backdrop-filter: blur(2px);
}

.sidebar-overlay.visible {
    opacity: 1;
    pointer-events: auto;
}

/* --- Main Content --- */
.app-content {
    flex-grow: 1;
    padding: 1.5rem;
    width: 100%;
    /* Ensure it takes full width initially */
}

/* --- Inputs --- */
.input-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.input-group label {
    font-size: 0.85rem;
    color: var(--color-text-muted);
    font-weight: 500;
}

.input-wrapper {
    position: relative;
}

.input-group input {
    width: 100%;
    background-color: rgba(0, 0, 0, 0.2);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    padding: 0.6rem 0.8rem;
    color: var(--color-text-main);
    font-family: inherit;
    font-size: 0.95rem;
    transition: border-color 0.2s;
}

.input-group input:focus {
    outline: none;
    border-color: var(--color-primary);
}

.api-status {
    position: absolute;
    right: 10px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 0.7rem;
    color: var(--color-text-muted);
}

.api-status.success {
    color: var(--color-success);
}

.api-status.error {
    color: var(--color-danger);
}

/* --- Comparison Table --- */
.comparison-section {
    background-color: var(--color-bg-surface);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    overflow: hidden;
    margin-bottom: 2rem;
}

.comparison-section.hidden {
    display: none;
}

.section-header {
    padding: 1.25rem;
    border-bottom: 1px solid var(--color-border);
    background-color: rgba(255, 255, 255, 0.02);
}

.section-header h2 {
    font-size: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-muted);
}

.table-wrapper {
    overflow-x: auto;
    padding: 0;
}

#comparison-table {
    width: 100%;
    border-collapse: collapse;
    min-width: 600px;
}

#comparison-table th,
#comparison-table td {
    padding: 1rem;
    text-align: left;
    border-bottom: 1px solid var(--color-border);
    font-size: 0.9rem;
}

#comparison-table th {
    font-weight: 600;
    color: var(--color-text-muted);
}

#comparison-table tr:last-child td {
    border-bottom: none;
}

/* --- Vehicle Grid --- */
.results-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.results-header h2 {
    font-size: 1.5rem;
    font-weight: 700;
}

.sort-controls {
    display: flex;
    gap: 0.5rem;
    align-items: center;
}

.sort-controls button {
    background: transparent;
    border: 1px solid var(--color-border);
    color: var(--color-text-muted);
    padding: 0.4rem 0.8rem;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 0.85rem;
}

.sort-controls button.active {
    background-color: var(--color-primary);
    border-color: var(--color-primary);
    color: white;
}

.vehicle-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
}

.vehicle-card {
    background-color: var(--color-bg-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    position: relative;
    overflow: hidden;
    transition: transform 0.2s, border-color 0.2s;
    display: flex;
    flex-direction: column;
}

.vehicle-card:hover {
    transform: translateY(-2px);
    border-color: var(--color-primary);
}

.card-checkbox {
    position: absolute;
    top: 1rem;
    right: 1rem;
    width: 20px;
    height: 20px;
    z-index: 10;
    accent-color: var(--color-primary);
    cursor: pointer;
}

.vehicle-header {
    padding: 1.25rem;
    border-bottom: 1px solid var(--color-border);
    padding-right: 3rem;
    /* Space for checkbox */
}

.vehicle-info h3 {
    font-size: 1.1rem;
    font-weight: 600;
    line-height: 1.3;
}

.vehicle-brand {
    font-size: 0.75rem;
    text-transform: uppercase;
    color: var(--color-text-muted);
    letter-spacing: 0.05em;
}

.vehicle-badge {
    display: inline-block;
    margin-top: 0.5rem;
    font-size: 0.7rem;
    padding: 0.2rem 0.6rem;
    border-radius: 99px;
    font-weight: 600;
    text-transform: uppercase;
}

.vehicle-badge.electric {
    background: rgba(34, 211, 238, 0.15);
    color: var(--color-accent-electric);
}

.vehicle-badge.petrol {
    background: rgba(251, 113, 133, 0.15);
    color: var(--color-accent-petrol);
}

.vehicle-badge.diesel {
    background: rgba(251, 191, 36, 0.15);
    color: var(--color-accent-diesel);
}

.vehicle-body {
    padding: 1.25rem;
    flex-grow: 1;
}

.cost-display {
    text-align: center;
    margin-bottom: 1.5rem;
}

.cost-amount {
    font-size: 2rem;
    font-weight: 700;
    color: var(--color-text-main);
}

.cost-label {
    display: block;
    font-size: 0.8rem;
    color: var(--color-text-muted);
}

.stats-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.5rem;
    text-align: left;
}

.stat-item {
    background: rgba(0, 0, 0, 0.2);
    padding: 0.5rem;
    border-radius: var(--radius-sm);
}

.stat-label {
    font-size: 0.7rem;
    color: var(--color-text-muted);
    display: block;
}

.stat-value {
    font-size: 0.9rem;
    font-weight: 500;
}

.content-footer {
    text-align: center;
    padding: 3rem 0 1rem;
    color: var(--color-text-muted);
    font-size: 0.8rem;
}

/* --- Media Queries (Desktop) --- */
@media (min-width: 1024px) {
    .menu-btn {
        display: none;
    }

    /* Hide hamburger on desktop */
    .close-btn {
        display: none;
    }

    /* Hide close btn on desktop */
    .sidebar-overlay {
        display: none;
    }

    /* No overlay on desktop */

    .app-sidebar {
        position: fixed;
        /* Keep fixed to be sticky */
        transform: none;
        /* Always visible */
        border-right: 1px solid var(--color-border);
        padding-top: calc(var(--header-height) + 1.5rem);
        /* Add padding for header */
        top: 0;
        z-index: 40;
        /* Behind header if needed, or adjust z-index stack */
        height: 100vh;
    }

    .app-content {
        margin-left: var(--sidebar-width);
        /* Push content right */
        /* width is calculated automatically by flex/block layout respecting margin */
    }
}