/* ==========================================================================
   DESIGN SYSTEM & VARIABLES (Siemens Mobility Inspired)
   ========================================================================== */
:root {
    /* Color Palette */
    --color-dark-bg: #000f14;       /* Deepest Teal-Black */
    --color-dark-surface: #0a1c24;  /* Dark Slate */
    --color-dark-surface-2: #102a35;/* Medium Slate */
    --color-light-bg: #f5f7f8;      /* Stone/Light Gray */
    --color-white: #ffffff;
    --color-petrol: #009999;        /* Siemens Petrol */
    --color-petrol-hover: #00b2b2;  /* Bright Petrol */
    --color-petrol-dark: #005f60;   /* Deep Petrol */
    --color-text-light: #ffffff;
    --color-text-dark: #0f1e24;
    --color-text-muted: #8fa0a6;
    --color-border-dark: #1b3846;
    --color-border-light: #e1e7eb;

    /* Theme Accents (Taipei MRT Lines) */
    --val256-accent: #e87722;       /* Wenhu Line Brown */
    --c301-accent: #d02c2c;         /* Tamsui Line Red */
    --c321-accent: #0070bc;         /* Bannan Line Blue */
    --c371-accent: #008559;         /* Songshan-Xindian Line Green */
    --c381-accent: #e3001b;         /* Tamsui-Xinyi Red / Songshan-Xindian Green */

    /* Typography */
    --font-heading: 'Outfit', sans-serif;
    --font-body: 'Inter', sans-serif;

    /* Transitions & Borders */
    --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --border-radius-sm: 4px;
    --border-radius-md: 8px;
    --border-radius-lg: 16px;
    --glass-blur: blur(12px);
    --glass-background: rgba(10, 28, 36, 0.75);
    --glass-border: rgba(27, 56, 70, 0.5);
}

/* ==========================================================================
   BASE STYLES
   ========================================================================== */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-body);
    background-color: var(--color-dark-bg);
    color: var(--color-text-light);
    line-height: 1.6;
    overflow-x: hidden;
}

a {
    color: inherit;
    text-decoration: none;
    transition: var(--transition-smooth);
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    line-height: 1.2;
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ==========================================================================
   HEADER NAVIGATION (Frosted Glass)
   ========================================================================== */
.main-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background-color: var(--glass-background);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border-bottom: 1px solid var(--glass-border);
    transition: var(--transition-smooth);
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 72px;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

.logo {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 800;
    letter-spacing: 1px;
    color: var(--color-white);
}

.logo-accent {
    color: var(--color-petrol);
}

.mode-toggle-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background-color: var(--color-dark-surface-2);
    border: 1px solid var(--color-petrol);
    color: var(--color-white);
    padding: 6px 14px;
    font-size: 0.85rem;
    font-family: var(--font-heading);
    font-weight: 600;
    border-radius: 20px;
    cursor: pointer;
    transition: var(--transition-smooth);
    margin-left: auto;
    margin-right: 24px;
    z-index: 10;
}

.mode-toggle-btn:hover {
    background-color: var(--color-petrol);
    box-shadow: 0 0 12px rgba(0, 153, 153, 0.5);
}

.mode-toggle-btn .mode-icon {
    font-size: 1.1rem;
}

/* ==========================================================================
   DUAL MODE (ADULT / KIDS EXPLORER) VISIBILITY CONTROLS
   ========================================================================== */
body.kids-mode .text-adult {
    display: none !important;
}

body.kids-mode .text-kids {
    display: block !important;
}

body:not(.kids-mode) .text-kids {
    display: none !important;
}

body:not(.kids-mode) .text-adult {
    display: block !important;
}

/* Inline tag display overrides */
span.text-kids {
    display: none;
}

body.kids-mode span.text-kids {
    display: inline !important;
}

body.kids-mode span.text-adult {
    display: none !important;
}

li.text-kids {
    display: none;
}

body.kids-mode li.text-kids {
    display: list-item !important;
}

body.kids-mode li.text-adult {
    display: none !important;
}

.tech-pill.text-kids {
    display: none;
}

body.kids-mode .tech-pill.text-kids {
    display: inline-block !important;
}

body.kids-mode .tech-pill.text-adult {
    display: none !important;
}

@media (max-width: 768px) {
    .mode-toggle-btn {
        margin-right: 12px;
        padding: 4px 10px;
    }
    .mode-toggle-btn .mode-text {
        display: none; /* Hide text on small screens, show icon only */
    }
}


.nav-menu ul {
    display: flex;
    gap: 32px;
}

.nav-link {
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--color-text-muted);
    padding: 8px 0;
    position: relative;
}

.nav-link:hover, .nav-link.active {
    color: var(--color-white);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--color-petrol);
    transition: var(--transition-smooth);
}

.nav-link:hover::after, .nav-link.active::after {
    width: 100%;
}

/* Nav Mobile Toggle */
.nav-toggle {
    display: none;
    flex-direction: column;
    justify-content: space-between;
    width: 24px;
    height: 18px;
    background: transparent;
    border: none;
    cursor: pointer;
    z-index: 1001;
}

.nav-toggle span {
    width: 100%;
    height: 2px;
    background-color: var(--color-white);
    transition: var(--transition-smooth);
}

/* ==========================================================================
   HERO SECTION
   ========================================================================== */
.hero-section {
    position: relative;
    height: 100vh;
    min-height: 600px;
    display: flex;
    align-items: center;
    overflow: hidden;
    padding-top: 72px;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;
    z-index: 1;
    transform: scale(1.05);
    animation: zoomOutBg 12s forwards;
}

@keyframes zoomOutBg {
    to { transform: scale(1); }
}

.hero-container {
    position: relative;
    z-index: 2;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    width: 100%;
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 48px;
    align-items: center;
}

.hero-content {
    animation: slideUpFade 1s 0.2s both;
}

.hero-tag {
    display: inline-block;
    font-family: var(--font-heading);
    font-size: 0.8rem;
    font-weight: 700;
    letter-spacing: 2px;
    color: var(--color-petrol);
    margin-bottom: 16px;
    text-transform: uppercase;
}

.hero-section h1 {
    font-size: 3.5rem;
    margin-bottom: 24px;
    letter-spacing: -0.5px;
    color: var(--color-white);
}

.hero-section p {
    font-size: 1.1rem;
    color: var(--color-text-muted);
    margin-bottom: 40px;
    max-width: 600px;
}

.hero-actions {
    display: flex;
    gap: 16px;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 28px;
    font-family: var(--font-heading);
    font-weight: 600;
    font-size: 1rem;
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    transition: var(--transition-smooth);
}

.btn-primary {
    background-color: var(--color-petrol);
    color: var(--color-white);
    border: 1px solid var(--color-petrol);
}

.btn-primary:hover {
    background-color: var(--color-petrol-hover);
    border-color: var(--color-petrol-hover);
    box-shadow: 0 0 20px rgba(0, 178, 178, 0.4);
}

.btn-secondary {
    background-color: transparent;
    color: var(--color-white);
    border: 1px solid var(--color-border-dark);
}

.btn-secondary:hover {
    background-color: rgba(255, 255, 255, 0.05);
    border-color: var(--color-text-muted);
}

/* Hero Stats */
.hero-stats {
    display: flex;
    flex-direction: column;
    gap: 20px;
    animation: slideUpFade 1s 0.5s both;
}

.stat-card {
    background-color: var(--glass-background);
    border: 1px solid var(--glass-border);
    backdrop-filter: var(--glass-blur);
    padding: 20px;
    border-radius: var(--border-radius-md);
    display: flex;
    flex-direction: column;
    border-left: 4px solid var(--color-petrol);
}

.stat-number {
    font-family: var(--font-heading);
    font-size: 2.2rem;
    font-weight: 800;
    color: var(--color-white);
}

.stat-number small {
    font-size: 1rem;
    font-weight: 500;
    color: var(--color-text-muted);
}

.comparison-card {
    gap: 16px !important;
}

.comp-box {
    background-color: var(--glass-background);
    border: 1px solid var(--glass-border);
    backdrop-filter: var(--glass-blur);
    padding: 24px;
    border-radius: var(--border-radius-md);
    flex: 1;
}

.comp-box h3 {
    font-size: 1.25rem;
    color: var(--color-petrol);
    margin-bottom: 16px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    padding-bottom: 12px;
}

.comp-box ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.comp-box li {
    font-size: 0.95rem;
    color: var(--color-text-muted);
    line-height: 1.6;
    margin-bottom: 12px;
}

.comp-box li:last-child {
    margin-bottom: 0;
}

.comp-box strong {
    color: var(--color-white);
    font-weight: 600;
}

.stat-label {
    font-size: 0.85rem;
    color: var(--color-text-muted);
    margin-top: 4px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* Scroll Indicator */
.scroll-indicator {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    font-size: 0.8rem;
    color: var(--color-text-muted);
    letter-spacing: 1px;
    z-index: 2;
}

.mouse-icon {
    width: 24px;
    height: 38px;
    border: 2px solid var(--color-text-muted);
    border-radius: 12px;
    position: relative;
}

.mouse-icon .wheel {
    width: 4px;
    height: 8px;
    background-color: var(--color-petrol);
    border-radius: 2px;
    position: absolute;
    top: 6px;
    left: 50%;
    transform: translateX(-50%);
    animation: mouseScroll 1.5s infinite;
}

@keyframes mouseScroll {
    0% { top: 6px; opacity: 1; }
    100% { top: 18px; opacity: 0; }
}

@keyframes slideUpFade {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ==========================================================================
   TRAIN SHOWCASE SECTIONS
   ========================================================================== */
.train-section {
    padding: 100px 0;
    position: relative;
    border-bottom: 1px solid var(--color-border-dark);
}

/* Theme Accents for Sections */
.val256-theme {
    background: linear-gradient(135deg, #000f14 0%, #0c1815 100%);
    --accent: var(--val256-accent);
}
.val256-theme .tab-btn.active,
.val256-theme .tab-link:hover {
    border-bottom-color: var(--val256-accent);
    color: var(--val256-accent);
}
.val256-theme .model-badge { background-color: var(--val256-accent); }
.val256-theme .timeline-bullets li::before { background-color: var(--val256-accent); }

.c301-theme {
    background: linear-gradient(135deg, #000f14 0%, #1c0808 100%);
    --accent: var(--c301-accent);
}
.c301-theme .tab-btn.active,
.c301-theme .tab-link:hover {
    border-bottom-color: var(--c301-accent);
    color: var(--c301-accent);
}
.c301-theme .model-badge { background-color: var(--c301-accent); }
.c301-theme .timeline-bullets li::before { background-color: var(--c301-accent); }

.c321-theme {
    background: linear-gradient(135deg, #000f14 0%, #051421 100%);
    --accent: var(--c321-accent);
}
.c321-theme .tab-btn.active,
.c321-theme .tab-link:hover {
    border-bottom-color: var(--c321-accent);
    color: var(--c321-accent);
}
.c321-theme .model-badge { background-color: var(--c321-accent); }
.c321-theme .timeline-bullets li::before { background-color: var(--c321-accent); }

.c371-theme {
    background: linear-gradient(135deg, #000f14 0%, #061912 100%);
    --accent: var(--c371-accent);
}
.c371-theme .tab-btn.active,
.c371-theme .tab-link:hover {
    border-bottom-color: var(--c371-accent);
    color: var(--c371-accent);
}
.c371-theme .model-badge { background-color: var(--c371-accent); }
.c371-theme .timeline-bullets li::before { background-color: var(--c371-accent); }

.c381-theme {
    background: linear-gradient(135deg, #000f14 0%, #170d10 100%);
    --accent: var(--c381-accent);
}
.c381-theme .tab-btn.active,
.c381-theme .tab-link:hover {
    border-bottom-color: var(--c381-accent);
    color: var(--c381-accent);
}
.c381-theme .model-badge { background-color: var(--c381-accent); }
.c381-theme .timeline-bullets li::before { background-color: var(--c381-accent); }

.train-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 64px;
    align-items: flex-start;
}

.train-grid.reverse {
    direction: ltr;
}
.train-grid.reverse .train-visual {
    order: 2;
}

/* Visual Panel */
.train-visual {
    display: flex;
    flex-direction: column;
    gap: 32px;
}

.image-wrapper {
    position: relative;
    border-radius: var(--border-radius-lg);
    overflow: hidden;
    box-shadow: 0 20px 40px rgba(0,0,0,0.5);
    border: 1px solid var(--color-border-dark);
}

.train-img {
    width: 100%;
    height: 360px;
    object-fit: cover;
    transition: var(--transition-smooth);
}

.image-wrapper:hover .train-img {
    transform: scale(1.05);
}

.image-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(180deg, rgba(0,0,0,0) 60%, rgba(0,0,0,0.8) 100%);
}

.model-badge {
    position: absolute;
    top: 24px;
    left: 24px;
    padding: 8px 16px;
    border-radius: var(--border-radius-sm);
    font-family: var(--font-heading);
    font-weight: 700;
    font-size: 0.9rem;
    color: var(--color-white);
    letter-spacing: 1px;
}

.tech-spec-summary {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
}

.tech-pill {
    background-color: var(--color-dark-surface);
    border: 1px solid var(--color-border-dark);
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--color-text-muted);
}

/* Info Panel */
.section-tag {
    font-family: var(--font-heading);
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--color-petrol);
    letter-spacing: 2px;
    text-transform: uppercase;
    margin-bottom: 12px;
}

.train-info h2 {
    font-size: 2.2rem;
    color: var(--color-white);
    margin-bottom: 32px;
}

/* Tab Controls */
.tabs-container {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.tab-buttons {
    display: flex;
    border-bottom: 1px solid var(--color-border-dark);
    gap: 24px;
}

.tab-btn {
    background: transparent;
    border: none;
    padding: 12px 4px;
    font-family: var(--font-heading);
    font-size: 1rem;
    font-weight: 600;
    color: var(--color-text-muted);
    cursor: pointer;
    border-bottom: 2px solid transparent;
    transition: var(--transition-smooth);
}

.tab-btn:hover {
    color: var(--color-white);
}

.tab-btn.active {
    color: var(--color-white);
    border-bottom: 2px solid var(--color-petrol);
}

.tab-content {
    display: none;
    animation: fadeIn 0.4s ease;
}

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

/* Timeline Bullets style in tabs */
.timeline-bullets {
    display: flex;
    flex-direction: column;
    gap: 20px;
    max-height: 480px;
    overflow-y: auto;
    padding-right: 8px;
}

/* Custom Scrollbar */
.timeline-bullets::-webkit-scrollbar {
    width: 6px;
}
.timeline-bullets::-webkit-scrollbar-track {
    background: transparent;
}
.timeline-bullets::-webkit-scrollbar-thumb {
    background: var(--color-border-dark);
    border-radius: 3px;
}

.timeline-bullets li {
    position: relative;
    padding-left: 24px;
    font-size: 0.95rem;
    color: var(--color-text-muted);
    line-height: 1.7;
}

.timeline-bullets li strong {
    color: var(--color-white);
    display: inline;
}

.timeline-bullets li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 8px;
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background-color: var(--color-petrol);
}

/* Specs Details Grid */
.specs-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 16px;
}

.spec-item {
    background-color: rgba(10, 28, 36, 0.4);
    border: 1px solid var(--color-border-dark);
    padding: 16px 20px;
    border-radius: var(--border-radius-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 16px;
}

.spec-label {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--color-text-muted);
}

.spec-value {
    font-family: var(--font-heading);
    font-size: 1rem;
    font-weight: 600;
    color: var(--color-white);
    text-align: right;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* ==========================================================================
   AUDIO PLAYER COMPONENTS
   ========================================================================== */
.audio-container {
    background-color: var(--color-dark-surface);
    border: 1px solid var(--color-border-dark);
    border-radius: var(--border-radius-md);
    padding: 20px;
    margin-top: 16px;
}

.audio-title {
    font-family: var(--font-heading);
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--color-text-muted);
    letter-spacing: 1px;
    margin-bottom: 16px;
    text-transform: uppercase;
}

.custom-player {
    display: flex;
    align-items: center;
    gap: 20px;
}

.play-btn {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background-color: var(--color-petrol);
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    transition: var(--transition-smooth);
}

.play-btn:hover {
    background-color: var(--color-petrol-hover);
    transform: scale(1.05);
    box-shadow: 0 0 15px rgba(0, 178, 178, 0.4);
}

.play-btn svg {
    width: 24px;
    height: 24px;
    fill: var(--color-white);
}

.hidden {
    display: none !important;
}

.player-info {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.waveform-container {
    height: 40px;
    background-color: rgba(0,0,0,0.25);
    border-radius: var(--border-radius-sm);
    overflow: hidden;
    position: relative;
}

.waveform-canvas {
    width: 100%;
    height: 100%;
    display: block;
}

.player-status {
    font-size: 0.8rem;
    color: var(--color-text-muted);
}

/* Video Player Components */
.video-container {
    background-color: var(--color-dark-surface);
    border: 1px solid var(--color-border-dark);
    border-radius: var(--border-radius-md);
    padding: 20px;
    margin-top: 16px;
}

.video-title {
    font-family: var(--font-heading);
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--color-text-muted);
    letter-spacing: 1px;
    margin-bottom: 16px;
    text-transform: uppercase;
}

.video-wrapper {
    width: 100%;
    position: relative;
    border-radius: var(--border-radius-sm);
    overflow: hidden;
    background: #000;
    aspect-ratio: 16 / 9;
}

.train-video {
    width: 100%;
    height: 100%;
    object-fit: contain;
    display: block;
}

.video-caption {
    font-size: 0.75rem;
    color: var(--color-text-muted);
    text-align: right;
    margin-top: 8px;
}

/* ==========================================================================
   INTERACTIVE IDENTIFIER SECTION
   ========================================================================== */
.identifier-section {
    padding: 100px 0;
    background-color: #000c10;
}

.section-header {
    text-align: center;
    max-width: 800px;
    margin: 0 auto 64px auto;
}

.section-desc {
    color: var(--color-text-muted);
    font-size: 1.1rem;
    margin-top: 16px;
}

.identifier-layout {
    display: flex;
    flex-direction: column;
    gap: 48px;
}

/* Cards style */
.id-card {
    background-color: var(--color-dark-surface);
    border: 1px solid var(--color-border-dark);
    border-radius: var(--border-radius-lg);
    padding: 40px;
    position: relative;
    overflow: hidden;
}

.card-num {
    position: absolute;
    top: -15px;
    right: 20px;
    font-family: var(--font-heading);
    font-size: 8rem;
    font-weight: 800;
    color: rgba(27, 56, 70, 0.15);
    line-height: 1;
    pointer-events: none;
    user-select: none;
}

.id-card h3 {
    font-size: 1.5rem;
    margin-bottom: 16px;
    color: var(--color-white);
    position: relative;
    z-index: 2;
}

.id-card > p {
    color: var(--color-text-muted);
    font-size: 1rem;
    margin-bottom: 32px;
    max-width: 800px;
    position: relative;
    z-index: 2;
}

/* Step 1: Number Rule layout */
.number-rule-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.rule-badge {
    background-color: rgba(16, 42, 53, 0.5);
    border: 1px solid var(--color-border-dark);
    padding: 24px;
    border-radius: var(--border-radius-md);
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    transition: var(--transition-smooth);
}

.rule-badge:hover {
    border-color: var(--color-petrol);
    background-color: rgba(16, 42, 53, 0.8);
    transform: translateY(-4px);
}

.badge-num {
    font-family: var(--font-heading);
    font-size: 2rem;
    font-weight: 700;
    letter-spacing: 2px;
    text-transform: uppercase;
}

.badge-c301 .badge-num { color: #f2a900; }
.badge-c321 .badge-num { color: var(--c321-accent); }
.badge-c371 .badge-num { color: #008559; }

.badge-model {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--color-white);
    margin-top: 8px;
}

.badge-desc {
    font-size: 0.8rem;
    color: var(--color-text-muted);
    margin-top: 4px;
}

.rule-audio {
    width: 100%;
    max-width: 210px;
    height: 32px;
    margin-top: 16px;
    border-radius: 20px;
    outline: none;
}

/* Step 2: Schematic & Hotspots */
.hotspot-diagram-container {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 40px;
    align-items: stretch;
}

.diagram-wrapper {
    background-color: #040d12;
    border: 1px solid var(--color-border-dark);
    border-radius: var(--border-radius-md);
    padding: 60px 40px;
    display: flex;
    justify-content: center;
    align-items: center;
}

/* Train CSS Schematic Drawing */
.train-schematic {
    display: flex;
    gap: 20px;
    align-items: flex-end;
    width: 100%;
    max-width: 500px;
    height: 180px;
    position: relative;
}

.train-front-view {
    width: 120px;
    height: 140px;
    background: linear-gradient(180deg, #53646f 0%, #303b42 100%);
    border: 4px solid #23292e;
    border-top-left-radius: 20px;
    border-top-right-radius: 20px;
    position: relative;
    box-shadow: inset 0 2px 10px rgba(255,255,255,0.3);
}

.windshield-area {
    width: 104px;
    height: 50px;
    background-color: #12181b;
    border: 3px solid #23292e;
    margin: 8px auto;
    border-top-left-radius: 12px;
    border-top-right-radius: 12px;
    position: relative;
    overflow: hidden;
}

.destination-display {
    position: absolute;
    top: 4px;
    left: 50%;
    transform: translateX(-50%);
    background-color: #000;
    color: #ff9900;
    font-family: monospace;
    font-size: 7px;
    padding: 1px 4px;
    border: 1px solid #ff9900;
    border-radius: 2px;
    white-space: nowrap;
}

.headlight-area {
    position: absolute;
    bottom: 12px;
    left: 0;
    width: 100%;
    height: 14px;
    display: flex;
    justify-content: space-between;
    padding: 0 10px;
}

.headlight-area::before, .headlight-area::after {
    content: '';
    width: 18px;
    height: 10px;
    background-color: #e6e6e6;
    border: 2px solid #23292e;
    box-shadow: 0 0 10px rgba(255,255,255,0.8);
}

.train-side-view {
    flex-grow: 1;
    height: 120px;
    background: linear-gradient(180deg, #7b8e9b 0%, #4f5f69 100%);
    border: 4px solid #23292e;
    border-left: none;
    border-top-right-radius: 8px;
    position: relative;
    box-shadow: inset 0 2px 10px rgba(255,255,255,0.3);
}

.side-door {
    position: absolute;
    top: 15px;
    left: 20%;
    width: 44px;
    height: 97px;
    background-color: #2e373c;
    border: 2px solid #23292e;
}

.door-window {
    width: 32px;
    height: 44px;
    background-color: #12181b;
    border: 2px solid #23292e;
    margin: 6px auto;
}

.side-display-box {
    position: absolute;
    top: 15px;
    left: 60%;
    width: 30px;
    height: 12px;
    background-color: #12181b;
    border: 1.5px solid #23292e;
}

.gangway-bellows {
    position: absolute;
    top: 5px;
    right: -10px;
    width: 10px;
    height: 106px;
    background-color: #1a1a1a;
    border-top: 2px solid #000;
    border-bottom: 2px solid #000;
}

/* Hotspots core styling */
.hotspot {
    position: absolute;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background-color: rgba(0, 153, 153, 0.4);
    border: 2px solid var(--color-petrol);
    cursor: pointer;
    transform: translate(-50%, -50%);
    z-index: 10;
    transition: var(--transition-smooth);
}

.hotspot::after {
    content: '';
    position: absolute;
    top: -2px;
    left: -2px;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    border: 2px solid var(--color-petrol);
    animation: pulse 1.8s infinite;
}

.hotspot:hover, .hotspot.active {
    background-color: var(--color-petrol-hover);
    border-color: var(--color-white);
    transform: translate(-50%, -50%) scale(1.25);
    box-shadow: 0 0 15px var(--color-petrol-hover);
}

@keyframes pulse {
    0% { transform: scale(1); opacity: 1; }
    100% { transform: scale(2.2); opacity: 0; }
}

/* Info Panel style */
.hotspot-info-panel {
    background-color: rgba(16, 42, 53, 0.4);
    border: 1px solid var(--color-border-dark);
    border-radius: var(--border-radius-md);
    padding: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.hotspot-info-panel .empty-state {
    color: var(--color-text-muted);
    font-size: 0.95rem;
    text-align: center;
}

.info-content {
    width: 100%;
    animation: fadeIn 0.3s ease;
}

.info-content h4 {
    font-size: 1.25rem;
    color: var(--color-petrol-hover);
    margin-bottom: 20px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--color-border-dark);
}

.info-row {
    margin-bottom: 16px;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.info-row:last-child {
    margin-bottom: 0;
}

.info-model-name {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--color-white);
    background-color: var(--color-dark-surface-2);
    padding: 2px 8px;
    border-radius: 4px;
    align-self: flex-start;
}

.info-row p {
    font-size: 0.9rem;
    color: var(--color-text-muted);
    line-height: 1.5;
}

/* Step 3: Media Expansion Grid */
.playground-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
}

.upload-card {
    background-color: var(--color-dark-surface-2);
    border: 1px dashed var(--color-border-dark);
    padding: 24px;
    border-radius: var(--border-radius-md);
    display: flex;
    flex-direction: column;
    gap: 20px;
    transition: var(--transition-smooth);
}

.upload-card:hover {
    border-color: var(--color-petrol);
}

.upload-title {
    font-family: var(--font-heading);
    font-size: 1rem;
    font-weight: 600;
    color: var(--color-white);
    text-align: center;
}

.photo-placeholder {
    height: 160px;
    background-color: rgba(0,0,0,0.2);
    border-radius: var(--border-radius-sm);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 12px;
    color: var(--color-text-muted);
    font-size: 0.8rem;
    text-align: center;
    padding: 16px;
    transition: var(--transition-smooth);
    border: 1px solid transparent;
}

.photo-placeholder:hover {
    background-color: rgba(0, 153, 153, 0.05);
    border-color: rgba(0, 153, 153, 0.2);
}

.upload-icon {
    width: 36px;
    height: 36px;
    fill: var(--color-border-dark);
    transition: var(--transition-smooth);
}

.photo-placeholder:hover .upload-icon {
    fill: var(--color-petrol);
    transform: translateY(-2px);
}

.mini-player {
    padding: 12px;
    border-radius: var(--border-radius-sm);
    background-color: rgba(0,0,0,0.25);
    border: 1px solid var(--color-border-dark);
}

.mini-player .play-btn {
    width: 36px;
    height: 36px;
}

.mini-player .play-btn svg {
    width: 18px;
    height: 18px;
}

.mini-canvas {
    height: 30px;
}

.mini-text {
    font-size: 0.7rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

/* ==========================================================================
   FOOTER
   ========================================================================== */
.main-footer {
    background-color: var(--color-dark-bg);
    border-top: 1px solid var(--color-border-dark);
    padding: 80px 0 24px 0;
}

.footer-container {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr;
    gap: 64px;
    margin-bottom: 60px;
}

.footer-brand p {
    color: var(--color-text-muted);
    margin-top: 16px;
    max-width: 320px;
}

.footer-links h4, .footer-design h4 {
    font-size: 1.1rem;
    color: var(--color-white);
    margin-bottom: 24px;
}

.footer-links ul {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

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

.footer-links a:hover {
    color: var(--color-petrol);
}

.footer-design p {
    color: var(--color-text-muted);
    line-height: 1.7;
}

.footer-bottom {
    border-top: 1px solid var(--color-border-dark);
    padding-top: 24px;
    text-align: center;
    font-size: 0.85rem;
    color: var(--color-text-muted);
}

/* ==========================================================================
   RESPONSIVE DESIGN MEDIA QUERIES
   ========================================================================== */
@media (max-width: 1024px) {
    .hero-container {
        grid-template-columns: 1fr;
        gap: 32px;
    }
    .hero-stats {
        flex-direction: row;
        width: 100%;
    }
    .stat-card {
        flex: 1;
    }
    .train-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }
    .train-grid.reverse .train-visual {
        order: 0;
    }
    .hotspot-diagram-container {
        grid-template-columns: 1fr;
    }
    .playground-grid {
        grid-template-columns: 1fr;
        gap: 24px;
    }
}

@media (max-width: 768px) {
    html {
        font-size: 14px;
    }
    .nav-toggle {
        display: flex;
    }
    .nav-menu {
        position: fixed;
        top: 72px;
        left: 0;
        width: 100%;
        height: calc(100vh - 72px);
        background-color: var(--color-dark-bg);
        border-top: 1px solid var(--color-border-dark);
        padding: 40px 24px;
        transform: translateX(100%);
        transition: var(--transition-smooth);
    }
    .nav-menu.open {
        transform: translateX(0);
    }
    .nav-menu ul {
        flex-direction: column;
        gap: 24px;
        align-items: center;
    }
    .nav-link {
        font-size: 1.2rem;
    }
    .hero-section h1 {
        font-size: 2.8rem;
    }
    .hero-stats {
        flex-direction: column;
    }
    .number-rule-grid {
        grid-template-columns: 1fr;
    }
    .footer-container {
        grid-template-columns: 1fr;
        gap: 40px;
    }
}

/* ==========================================================================
   SCROLL REVEAL EFFECTS
   ========================================================================== */
.reveal-on-scroll {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s cubic-bezier(0.4, 0, 0.2, 1), transform 0.8s cubic-bezier(0.4, 0, 0.2, 1);
    will-change: opacity, transform;
}

.reveal-on-scroll.visible {
    opacity: 1;
    transform: translateY(0);
}


/* ==========================================================================
   CAPACITY & ROUTE MAP SECTION
   ========================================================================== */
.capacity-section {
    padding: 80px 0;
    background: linear-gradient(180deg, var(--color-bg) 0%, rgba(13, 27, 42, 0.8) 100%);
    position: relative;
}

.capacity-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    margin-bottom: 60px;
}

.capacity-card {
    background-color: var(--glass-background);
    border: 1px solid var(--glass-border);
    backdrop-filter: var(--glass-blur);
    padding: 30px;
    border-radius: var(--border-radius-md);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.capacity-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}

.capacity-title {
    font-size: 1.5rem;
    font-family: var(--font-heading);
    color: var(--color-petrol);
    margin-bottom: 10px;
    border-bottom: 2px solid var(--color-petrol);
    padding-bottom: 10px;
    display: inline-block;
}

.capacity-stats {
    margin: 20px 0;
}

.capacity-stats strong {
    color: var(--color-white);
    display: block;
    font-size: 1.1rem;
    margin-bottom: 5px;
}

.capacity-lines {
    background: rgba(0, 0, 0, 0.2);
    padding: 15px;
    border-radius: 8px;
    margin-top: 15px;
}

.capacity-lines p {
    color: var(--color-text-muted);
    font-size: 0.9rem;
    margin: 0;
}

.map-container {
    text-align: center;
    background-color: var(--glass-background);
    border: 1px solid var(--glass-border);
    backdrop-filter: var(--glass-blur);
    padding: 40px;
    border-radius: var(--border-radius-lg);
}

.map-container h3 {
    color: var(--color-white);
    font-size: 1.8rem;
    margin-bottom: 30px;
}

.map-image {
    max-width: 100%;
    border-radius: 8px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.5);
    border: 2px solid rgba(255, 255, 255, 0.1);
}

@media (max-width: 1024px) {
    .capacity-grid {
        grid-template-columns: 1fr;
    }
}