/* CSS Variables */
:root {
    --bg-primary: #0a0a0f;
    --bg-secondary: #12121a;
    --bg-tertiary: #1a1a25;
    --bg-hover: #22222f;
    --text-primary: #f0f0f5;
    --text-secondary: #a0a0b0;
    --text-muted: #606070;
    --accent-primary: #6366f1;
    --accent-secondary: #8b5cf6;
    --accent-tertiary: #a855f7;
    --border-color: #2a2a3a;
    --border-light: #3a3a4a;
    --success: #22c55e;
    --warning: #f59e0b;
    --error: #ef4444;
    --gradient-1: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #a855f7 100%);
    --gradient-2: linear-gradient(135deg, #3b82f6 0%, #6366f1 100%);
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.3);
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 400ms ease;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

    /* Component colors for architecture */
    --comp-embedding: #3b82f6;
    --comp-attention: #8b5cf6;
    --comp-ffn: #22c55e;
    --comp-norm: #f59e0b;
    --comp-output: #ef4444;
    --comp-positional: #06b6d4;
    --comp-residual: #ec4899;
    --comp-softmax: #f97316;
}

[data-theme="light"] {
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-tertiary: #f0f1f3;
    --bg-hover: #e8e9eb;
    --text-primary: #1a1a2e;
    --text-secondary: #4a4a5a;
    --text-muted: #8a8a9a;
    --border-color: #e0e0e8;
    --border-light: #d0d0d8;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
    --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.15);
}

/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

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

body {
    font-family: var(--font-sans);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
}

/* Navbar */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 120px;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    padding: 0 24px;
    gap: 32px;
    z-index: 100;
    backdrop-filter: blur(10px);
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 600;
    font-size: 1.1rem;
    color: var(--text-primary);
    flex-shrink: 0;
}

.logo {
    width: 28px;
    height: 28px;
    color: var(--accent-primary);
}

.nav-timeline {
    flex: 1;
    position: relative;
    padding: 0 20px;
    height: 110px;
}

.timeline-track {
    position: absolute;
    top: 50%;
    left: 20px;
    right: 20px;
    height: 3px;
    background: transparent;
    transform: translateY(-50%);
}

/* SVG-based curved timeline */
.timeline-svg {
    position: absolute;
    top: 0;
    left: 20px;
    right: 20px;
    height: 100%;
    overflow: visible;
}

.timeline-path {
    fill: none;
    stroke: var(--border-color);
    stroke-width: 3;
    stroke-linecap: round;
}

.timeline-progress-path {
    fill: none;
    stroke: url(#timeline-gradient);
    stroke-width: 3;
    stroke-linecap: round;
    stroke-dasharray: 2000;
    stroke-dashoffset: 2000;
    transition: stroke-dashoffset 0.6s ease-out;
}

.timeline-progress-path.training-progress-path {
    stroke: url(#training-gradient);
    stroke-width: 2;
}

.timeline-path.training-path {
    stroke: rgba(245, 158, 11, 0.2);
    stroke-width: 2;
}

.branch-connector {
    opacity: 0.6;
    transition: opacity 0.3s ease;
}

.timeline-progress {
    position: absolute;
    top: 0;
    left: 0;
    height: 100%;
    background: var(--gradient-1);
    border-radius: 2px;
    transition: width var(--transition-slow);
    width: 0%;
    display: none; /* Hidden, replaced by SVG */
}

.timeline-items {
    display: flex;
    justify-content: space-between;
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 100%;
    z-index: 1;
    padding: 0 0;
}

.timeline-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    cursor: pointer;
    transition: transform var(--transition-fast);
    position: relative;
}

/* Architecture items on main track */
.timeline-item[data-category="architecture"] {
    padding-top: 10px;
}

/* Training items on secondary track (below) */
.timeline-item[data-category="training"] {
    padding-top: 60px;
}

/* Era groupings with subtle backgrounds */
.timeline-item[data-era="foundation"] {
    --era-color: rgba(99, 102, 241, 0.1);
}

.timeline-item[data-era="scaling"] {
    --era-color: rgba(34, 197, 94, 0.1);
}

.timeline-item[data-era="alignment"] {
    --era-color: rgba(245, 158, 11, 0.1);
}

.timeline-item[data-era="frontier"] {
    --era-color: rgba(236, 72, 153, 0.1);
}

.timeline-item:hover {
    transform: translateY(-3px);
}

/* Track labels */
.track-label {
    position: absolute;
    left: 0;
    font-size: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    font-weight: 600;
    writing-mode: vertical-rl;
    text-orientation: mixed;
    transform: rotate(180deg);
    opacity: 0.5;
}

.arch-track-label {
    top: 8px;
    color: var(--accent-primary);
}

.training-track-label {
    top: 60px;
    color: #f59e0b;
}

.timeline-dot {
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--bg-tertiary);
    border: 2px solid var(--border-color);
    transition: all var(--transition-normal);
    position: relative;
    z-index: 2;
}

/* Different dot shapes for categories */
.timeline-dot.arch {
    border-radius: 50%;
}

.timeline-dot.training {
    border-radius: 3px;
    transform: rotate(45deg);
}

.timeline-item.active .timeline-dot,
.timeline-item.passed .timeline-dot {
    background: var(--accent-primary);
    border-color: var(--accent-primary);
    box-shadow: var(--shadow-glow);
}

.timeline-item.active .timeline-dot {
    width: 18px;
    height: 18px;
}

.timeline-item.active .timeline-dot::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 28px;
    height: 28px;
    border-radius: 50%;
    border: 2px solid var(--accent-primary);
    transform: translate(-50%, -50%);
    animation: pulse 2s infinite;
}

/* Training category dots have different color */
.timeline-dot.training {
    background: var(--bg-tertiary);
    border-color: #f59e0b;
}

.timeline-item.active .timeline-dot.training,
.timeline-item.passed .timeline-dot.training {
    background: #f59e0b;
    border-color: #f59e0b;
    box-shadow: 0 0 15px rgba(245, 158, 11, 0.4);
}

.timeline-item.active .timeline-dot.training::after {
    border-color: #f59e0b;
    border-radius: 3px;
}

@keyframes pulse {
    0%, 100% { opacity: 1; transform: translate(-50%, -50%) scale(1); }
    50% { opacity: 0; transform: translate(-50%, -50%) scale(1.5); }
}

.timeline-label {
    font-size: 0.65rem;
    font-weight: 500;
    color: var(--text-muted);
    margin-top: 6px;
    white-space: nowrap;
    transition: all var(--transition-fast);
    text-align: center;
    line-height: 1.2;
}

.timeline-label small {
    font-size: 0.55rem;
    opacity: 0.7;
}

.timeline-item.active .timeline-label {
    color: var(--accent-primary);
    font-weight: 600;
    transform: scale(1.05);
}

.timeline-item:hover .timeline-label {
    color: var(--text-primary);
}

/* Year markers at bottom */
.timeline-year-marker {
    position: absolute;
    bottom: -5px;
    font-size: 0.6rem;
    color: var(--text-muted);
    opacity: 0.6;
}

/* Era labels */
.timeline-era {
    position: absolute;
    top: -18px;
    font-size: 0.55rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--text-muted);
    opacity: 0.5;
    white-space: nowrap;
}

.theme-toggle {
    width: 40px;
    height: 40px;
    border-radius: 10px;
    border: 1px solid var(--border-color);
    background: var(--bg-tertiary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
    flex-shrink: 0;
}

.theme-toggle:hover {
    background: var(--bg-hover);
    border-color: var(--accent-primary);
}

.theme-toggle svg {
    width: 20px;
    height: 20px;
    color: var(--text-secondary);
}

.sun-icon { display: none; }
.moon-icon { display: block; }

[data-theme="light"] .sun-icon { display: block; }
[data-theme="light"] .moon-icon { display: none; }

/* Main Content */
.main-content {
    display: grid;
    grid-template-columns: 300px 1fr 380px;
    min-height: 100vh;
    padding-top: 120px;
}

/* Sidebar */
.sidebar {
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    padding: 24px;
    overflow-y: auto;
    height: calc(100vh - 64px);
    position: sticky;
    top: 64px;
}

.sidebar-header {
    display: flex;
    align-items: baseline;
    gap: 12px;
    margin-bottom: 16px;
}

.sidebar-header h2 {
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient-1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.arch-year {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--accent-primary);
    background: rgba(99, 102, 241, 0.15);
    padding: 2px 10px;
    border-radius: 20px;
}

.arch-description {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.7;
    margin-bottom: 24px;
}

.arch-meta {
    display: flex;
    flex-direction: column;
    gap: 12px;
    padding: 16px;
    background: var(--bg-tertiary);
    border-radius: 12px;
    margin-bottom: 24px;
}

.meta-item {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.meta-label {
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.meta-value {
    font-size: 0.9rem;
    color: var(--text-primary);
}

.meta-value.link {
    color: var(--accent-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.meta-value.link:hover {
    color: var(--accent-secondary);
    text-decoration: underline;
}

.changes-section h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.changes-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.change-item {
    display: flex;
    gap: 12px;
    padding: 12px;
    background: var(--bg-tertiary);
    border-radius: 10px;
    border-left: 3px solid var(--accent-primary);
}

.change-icon {
    width: 24px;
    height: 24px;
    border-radius: 6px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.change-icon.added {
    background: rgba(34, 197, 94, 0.2);
    color: var(--success);
}

.change-icon.removed {
    background: rgba(239, 68, 68, 0.2);
    color: var(--error);
}

.change-icon.modified {
    background: rgba(245, 158, 11, 0.2);
    color: var(--warning);
}

.change-icon svg {
    width: 14px;
    height: 14px;
}

.change-content h4 {
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 4px;
}

.change-content p {
    font-size: 0.8rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

/* Architecture View */
.architecture-view {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 40px;
    overflow: hidden;
    background:
        radial-gradient(circle at 20% 20%, rgba(99, 102, 241, 0.05) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(139, 92, 246, 0.05) 0%, transparent 50%),
        var(--bg-primary);
}

.architecture-container {
    position: relative;
    transform-origin: center;
    transition: transform var(--transition-normal);
}

.architecture-container svg {
    max-width: 100%;
    height: auto;
}

/* Architecture Components */
.arch-component {
    cursor: pointer;
    transition: all var(--transition-fast);
}

.arch-component:hover {
    filter: brightness(1.1);
}

.arch-component:hover .component-bg {
    stroke-width: 3;
}

.arch-component.selected .component-bg {
    stroke: var(--accent-primary);
    stroke-width: 3;
    filter: drop-shadow(0 0 10px rgba(99, 102, 241, 0.5));
}

.arch-component.highlighted {
    animation: highlightPulse 1s ease-in-out infinite;
}

@keyframes highlightPulse {
    0%, 100% { filter: brightness(1); }
    50% { filter: brightness(1.3); }
}

.arch-component.faded {
    opacity: 0.3;
}

.component-bg {
    transition: all var(--transition-fast);
}

.component-label {
    font-family: var(--font-sans);
    font-size: 11px;
    font-weight: 500;
    fill: white;
    pointer-events: none;
}

.component-sublabel {
    font-family: var(--font-sans);
    font-size: 9px;
    fill: rgba(255, 255, 255, 0.7);
    pointer-events: none;
}

/* Zoom Controls */
.zoom-controls {
    position: absolute;
    bottom: 24px;
    right: 24px;
    display: flex;
    flex-direction: column;
    gap: 8px;
    background: var(--bg-secondary);
    padding: 8px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-md);
}

.zoom-btn {
    width: 36px;
    height: 36px;
    border: none;
    border-radius: 8px;
    background: var(--bg-tertiary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.zoom-btn:hover {
    background: var(--bg-hover);
}

.zoom-btn svg {
    width: 18px;
    height: 18px;
    color: var(--text-secondary);
}

/* Detail Panel */
.detail-panel {
    background: var(--bg-secondary);
    border-left: 1px solid var(--border-color);
    height: calc(100vh - 64px);
    position: sticky;
    top: 64px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
}

.panel-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 20px 24px;
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    background: var(--bg-secondary);
    z-index: 10;
}

.panel-header h3 {
    font-size: 1.1rem;
    font-weight: 600;
}

.close-panel {
    width: 32px;
    height: 32px;
    border: none;
    border-radius: 8px;
    background: var(--bg-tertiary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.close-panel:hover {
    background: var(--bg-hover);
}

.close-panel svg {
    width: 16px;
    height: 16px;
    color: var(--text-secondary);
}

.panel-content {
    flex: 1;
    padding: 24px;
}

.placeholder-message {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 60px 20px;
    color: var(--text-muted);
}

.placeholder-message svg {
    width: 48px;
    height: 48px;
    margin-bottom: 16px;
    opacity: 0.5;
}

.placeholder-message p {
    font-size: 0.9rem;
    line-height: 1.6;
}

.component-details {
    animation: fadeIn 0.3s ease;
}

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

.detail-section {
    margin-bottom: 24px;
}

.detail-section h4 {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 12px;
}

.detail-section p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.7;
}

.math-block {
    background: var(--bg-tertiary);
    padding: 16px;
    border-radius: 10px;
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--text-primary);
    overflow-x: auto;
    line-height: 1.8;
}

.code-block {
    background: var(--bg-tertiary);
    border-radius: 12px;
    overflow: hidden;
}

.code-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 16px;
    background: var(--bg-hover);
    border-bottom: 1px solid var(--border-color);
}

.code-lang {
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--text-muted);
    text-transform: uppercase;
}

.copy-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 6px 12px;
    border: none;
    border-radius: 6px;
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    font-size: 0.75rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

.copy-btn svg {
    width: 14px;
    height: 14px;
}

.code-block pre {
    margin: 0;
    padding: 16px;
    overflow-x: auto;
}

.code-block code {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    line-height: 1.6;
}

#component-tips {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

#component-tips li {
    position: relative;
    padding-left: 20px;
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

#component-tips li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 8px;
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--accent-primary);
}

/* Transition Overlay */
.transition-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.9);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-slow);
}

.transition-overlay.active {
    opacity: 1;
    visibility: visible;
}

.transition-content {
    text-align: center;
    transform: scale(0.9);
    transition: transform var(--transition-slow);
}

.transition-overlay.active .transition-content {
    transform: scale(1);
}

.transition-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 24px;
    background: var(--gradient-1);
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    animation: iconPulse 2s ease-in-out infinite;
}

@keyframes iconPulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

.transition-icon svg {
    width: 40px;
    height: 40px;
    color: white;
}

.transition-content h2 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 12px;
    background: var(--gradient-1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.transition-content p {
    font-size: 1.1rem;
    color: var(--text-secondary);
    max-width: 400px;
}

/* Connection lines */
.connection-line {
    stroke: var(--border-light);
    stroke-width: 2;
    fill: none;
    marker-end: url(#arrowhead);
}

.connection-line.data-flow {
    stroke: var(--accent-primary);
    opacity: 0.6;
}

.connection-line.residual {
    stroke: var(--comp-residual);
    stroke-dasharray: 5, 5;
}

/* Responsive */
@media (max-width: 1200px) {
    .main-content {
        grid-template-columns: 260px 1fr 320px;
    }
}

@media (max-width: 992px) {
    .main-content {
        grid-template-columns: 1fr;
    }

    .sidebar {
        position: relative;
        height: auto;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
    }

    .detail-panel {
        position: fixed;
        right: 0;
        top: 64px;
        width: 380px;
        transform: translateX(100%);
        transition: transform var(--transition-normal);
        box-shadow: var(--shadow-lg);
    }

    .detail-panel.open {
        transform: translateX(0);
    }

    .architecture-view {
        min-height: 60vh;
    }
}

@media (max-width: 768px) {
    .navbar {
        padding: 0 16px;
    }

    .nav-brand span {
        display: none;
    }

    .timeline-label {
        font-size: 0.6rem;
    }

    .detail-panel {
        width: 100%;
    }

    .architecture-view {
        padding: 20px;
    }
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--border-light);
}

/* Animation classes for architecture transitions */
.component-enter {
    animation: componentEnter 0.5s ease forwards;
}

.component-exit {
    animation: componentExit 0.5s ease forwards;
}

.component-move {
    transition: transform 0.5s ease, opacity 0.5s ease;
}

.component-highlight-change {
    animation: highlightChange 1.5s ease;
}

@keyframes componentEnter {
    from {
        opacity: 0;
        transform: scale(0.8);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

@keyframes componentExit {
    from {
        opacity: 1;
        transform: scale(1);
    }
    to {
        opacity: 0;
        transform: scale(0.8);
    }
}

@keyframes highlightChange {
    0%, 100% {
        filter: brightness(1);
    }
    25%, 75% {
        filter: brightness(1.5) drop-shadow(0 0 15px currentColor);
    }
}