/* GPU Selector - GitHub Pages Theme */
:root {
    --bg-primary: #18181b;
    --bg-secondary: #27272a;
    --bg-card: #1f1f23;
    --text-primary: #e4e4e7;
    --text-secondary: #a1a1aa;
    --text-muted: #71717a;
    --accent: #ef4444;
    --accent-hover: #dc2626;
    --accent-rgb: 239, 68, 68;
    --accent-green: #10b981;
    --accent-blue: #3b82f6;
    --accent-amber: #f59e0b;
    --border: #3f3f46;
    --code-bg: #1a1a1e;
}

/* GPU vendor themes - detected via WebGL */
[data-gpu="nvidia"] {
    --accent: #22c55e;
    --accent-hover: #16a34a;
    --accent-rgb: 34, 197, 94;
}
[data-gpu="intel"] {
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --accent-rgb: 59, 130, 246;
}
[data-gpu="other"] {
    --accent: #a1a1aa;
    --accent-hover: #71717a;
    --accent-rgb: 161, 161, 170;
}

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

html { scroll-behavior: smooth; }

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
}

a { color: var(--accent); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--accent-hover); text-decoration: underline; }

/* ── Navigation ── */
.nav {
    background: rgba(39, 39, 42, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    padding: 0 2rem;
    position: sticky;
    top: 0;
    z-index: 100;
}
.nav-inner {
    max-width: 960px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    gap: 2rem;
    height: 56px;
}
.nav-brand {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 700;
    font-size: 1.1rem;
    color: var(--text-primary);
    text-decoration: none;
}
.nav-brand:hover { color: var(--text-primary); text-decoration: none; }
.nav-icon {
    width: 32px;
    height: 32px;
    background: linear-gradient(135deg, var(--accent), var(--accent-hover));
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: transform 0.3s, box-shadow 0.3s;
}
.nav-brand:hover .nav-icon {
    transform: scale(1.1) rotate(-3deg);
    box-shadow: 0 0 12px rgba(var(--accent-rgb), 0.4);
}
.nav-icon svg { width: 18px; height: 18px; color: white; }
.nav-links { display: flex; gap: 1.5rem; }
.nav-links a {
    color: var(--text-secondary);
    font-size: 0.9rem;
    padding: 0.25rem 0;
    border-bottom: 2px solid transparent;
    transition: color 0.2s, border-bottom-color 0.3s;
    position: relative;
}
.nav-links a:hover, .nav-links a.active {
    color: var(--text-primary);
    border-bottom-color: var(--accent);
    text-decoration: none;
}

/* ── Main content ── */
.container {
    max-width: 960px;
    margin: 0 auto;
    padding: 2rem;
}

/* ── Hero section ── */
.hero {
    text-align: center;
    padding: 4rem 2rem;
    animation: fadeInUp 0.6s ease-out;
}
.hero-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--accent), var(--accent-hover));
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
    box-shadow: 0 8px 32px rgba(var(--accent-rgb), 0.3);
    animation: heroGlow 3s ease-in-out infinite alternate;
    transition: transform 0.3s;
}
.hero-icon:hover { transform: scale(1.08) rotate(-5deg); }
.hero-icon svg { width: 44px; height: 44px; color: white; }
.hero h1 {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, #e4e4e7 0%, var(--accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.hero p {
    color: var(--text-secondary);
    font-size: 1.15rem;
    max-width: 600px;
    margin: 0 auto 2rem;
}
.hero-buttons { display: flex; gap: 1rem; justify-content: center; flex-wrap: wrap; }

/* ── Buttons ── */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    border-radius: 10px;
    font-weight: 600;
    font-size: 0.95rem;
    transition: all 0.25s ease;
    border: none;
    cursor: pointer;
    position: relative;
    overflow: hidden;
}
.btn::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(255,255,255,0.1) 0%, transparent 50%);
    opacity: 0;
    transition: opacity 0.25s;
}
.btn:hover::after { opacity: 1; }
.btn-primary {
    background: var(--accent);
    color: white;
}
.btn-primary:hover {
    background: var(--accent-hover);
    color: white;
    text-decoration: none;
    transform: translateY(-2px);
    box-shadow: 0 4px 16px rgba(var(--accent-rgb), 0.4);
}
.btn-secondary {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border);
}
.btn-secondary:hover {
    background: var(--border);
    color: white;
    text-decoration: none;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

/* ── Feature grid ── */
.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.25rem;
    margin: 2rem 0;
}
.feature-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.5rem;
    transition: transform 0.3s ease, border-color 0.3s, box-shadow 0.3s;
    cursor: default;
}
.feature-card:hover {
    transform: translateY(-4px);
    border-color: var(--accent);
    box-shadow: 0 8px 24px rgba(var(--accent-rgb), 0.15);
}
.feature-card h3 {
    font-size: 1rem;
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}
.feature-card p {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* ── Guide pages ── */
.guide-content {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 2.5rem;
    margin: 2rem 0;
    animation: fadeInUp 0.5s ease-out;
}
.guide-content h1 { font-size: 1.75rem; margin-bottom: 1.5rem; }
.guide-content h2 {
    font-size: 1.3rem;
    margin: 2rem 0 0.75rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--border);
    cursor: pointer;
    user-select: none;
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.guide-content h2::after {
    content: '';
    width: 0;
    height: 0;
    border-left: 5px solid transparent;
    border-right: 5px solid transparent;
    border-top: 6px solid var(--text-muted);
    transition: transform 0.3s;
    flex-shrink: 0;
    margin-left: 0.5rem;
}
.guide-content h2.collapsed::after {
    transform: rotate(-90deg);
}
.guide-content .section-content {
    overflow: hidden;
    transition: max-height 0.4s ease, opacity 0.3s ease;
    max-height: 5000px;
    opacity: 1;
}
.guide-content .section-content.collapsed {
    max-height: 0;
    opacity: 0;
}
.guide-content h3 { font-size: 1.1rem; margin: 1.5rem 0 0.5rem; }
.guide-content p { margin-bottom: 1rem; color: var(--text-secondary); }
.guide-content ul, .guide-content ol {
    margin-bottom: 1rem;
    padding-left: 1.5rem;
    color: var(--text-secondary);
}
.guide-content li { margin-bottom: 0.4rem; }
.guide-content strong { color: var(--text-primary); }
.guide-content code {
    background: var(--code-bg);
    padding: 0.15rem 0.4rem;
    border-radius: 4px;
    font-size: 0.85em;
    color: var(--accent);
    border: 1px solid var(--border);
}
.guide-content table {
    width: 100%;
    border-collapse: collapse;
    margin: 1rem 0;
    font-size: 0.9rem;
}
.guide-content th, .guide-content td {
    padding: 0.6rem 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
    transition: background 0.2s;
}
.guide-content th { color: var(--text-primary); font-weight: 600; }
.guide-content td { color: var(--text-secondary); }
.guide-content tr:hover td { background: rgba(255, 255, 255, 0.03); }

/* ── Tip/Note/Warning boxes ── */
.tip, .note, .warning {
    padding: 1rem 1.25rem;
    border-radius: 8px;
    margin: 1rem 0;
    font-size: 0.9rem;
    animation: fadeIn 0.4s ease-out;
}
.tip { background: rgba(16, 185, 129, 0.1); border-left: 3px solid var(--accent-green); }
.note { background: rgba(59, 130, 246, 0.1); border-left: 3px solid #3b82f6; }
.warning { background: rgba(245, 158, 11, 0.1); border-left: 3px solid #f59e0b; }

/* ── Guide nav cards ── */
.guide-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1rem;
    margin: 2rem 0;
}
.guide-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.5rem;
    transition: transform 0.3s ease, border-color 0.3s, box-shadow 0.3s;
    display: block;
    position: relative;
    overflow: hidden;
}
.guide-card::after {
    content: '\2192';
    position: absolute;
    right: 1.5rem;
    top: 50%;
    transform: translateY(-50%) translateX(-5px);
    opacity: 0;
    font-size: 1.2rem;
    color: var(--accent);
    transition: all 0.3s ease;
}
.guide-card:hover {
    transform: translateY(-4px);
    border-color: var(--accent);
    box-shadow: 0 8px 24px rgba(var(--accent-rgb), 0.15);
    text-decoration: none;
}
.guide-card:hover::after {
    opacity: 1;
    transform: translateY(-50%) translateX(0);
}
.guide-card h3 { margin-bottom: 0.5rem; color: var(--text-primary); }
.guide-card p { color: var(--text-secondary); font-size: 0.875rem; margin: 0; }

/* ── Video page ── */
.video-page-header {
    margin-bottom: 1.5rem;
    animation: fadeInUp 0.5s ease-out;
}
.video-page-header h1 {
    font-size: 1.75rem;
    margin-bottom: 0.5rem;
}
.video-page-header p {
    color: var(--text-secondary);
}

/* ── Video cards ── */
.video-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-top: 1rem;
}
.video-card {
    display: flex;
    flex-direction: row;
    align-items: stretch;
    gap: 1.25rem;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1rem;
    transition: transform 0.3s ease, border-color 0.3s, box-shadow 0.3s;
    text-decoration: none !important;
    color: inherit;
    overflow: hidden;
    animation: fadeInUp 0.5s ease-out backwards;
}
.video-card:hover {
    transform: translateY(-4px);
    border-color: var(--accent);
    box-shadow: 0 8px 24px rgba(var(--accent-rgb), 0.15);
    text-decoration: none !important;
    color: inherit;
}
.video-thumbnail {
    position: relative;
    flex-shrink: 0;
    width: 240px;
    height: 135px;
    border-radius: 8px;
    overflow: hidden;
    background: var(--bg-primary);
}
.video-thumbnail img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
    transition: transform 0.3s;
}
.video-card:hover .video-thumbnail img {
    transform: scale(1.05);
}
.video-play-icon {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(0, 0, 0, 0.3);
    opacity: 0;
    transition: opacity 0.3s;
    pointer-events: none;
}
.video-card:hover .video-play-icon {
    opacity: 1;
}
.video-play-icon svg {
    width: 44px;
    height: 44px;
    color: white;
    filter: drop-shadow(0 2px 8px rgba(0, 0, 0, 0.5));
}
.video-duration {
    position: absolute;
    bottom: 6px;
    right: 6px;
    background: rgba(0, 0, 0, 0.8);
    color: white;
    font-size: 0.75rem;
    font-weight: 600;
    padding: 0.15rem 0.4rem;
    border-radius: 4px;
    line-height: 1.3;
}
.video-info {
    display: flex;
    flex-direction: column;
    justify-content: center;
    min-width: 0;
    flex: 1;
}
.video-info h3 {
    font-size: 1.05rem;
    font-weight: 700;
    margin: 0 0 0.4rem 0;
    color: var(--text-primary);
}
.video-info p {
    color: var(--text-secondary);
    font-size: 0.875rem;
    margin: 0 0 0.75rem 0;
    line-height: 1.5;
}
.video-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
}
.video-tag {
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.03em;
    padding: 0.15rem 0.5rem;
    border-radius: 4px;
    background: rgba(var(--accent-rgb), 0.15);
    color: var(--accent);
}

@media (max-width: 700px) {
    .video-card {
        flex-direction: column;
    }
    .video-thumbnail {
        width: 100%;
        height: auto;
        aspect-ratio: 16 / 9;
    }
}

/* ── Back to top button ── */
.back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--accent);
    color: white;
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 16px rgba(var(--accent-rgb), 0.4);
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: all 0.3s ease;
    z-index: 99;
}
.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}
.back-to-top:hover {
    background: var(--accent-hover);
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(var(--accent-rgb), 0.5);
}
.back-to-top svg { width: 20px; height: 20px; }

/* ── FAQ Search ── */
.faq-search {
    position: relative;
    margin-bottom: 1.5rem;
}
.faq-search input {
    width: 100%;
    padding: 0.75rem 1rem 0.75rem 2.75rem;
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: 10px;
    color: var(--text-primary);
    font-size: 0.95rem;
    outline: none;
    transition: border-color 0.3s, box-shadow 0.3s;
}
.faq-search input:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(var(--accent-rgb), 0.15);
}
.faq-search input::placeholder { color: var(--text-muted); }
.faq-search svg {
    position: absolute;
    left: 0.85rem;
    top: 50%;
    transform: translateY(-50%);
    width: 18px;
    height: 18px;
    color: var(--text-muted);
    pointer-events: none;
}
.faq-no-results {
    text-align: center;
    color: var(--text-muted);
    padding: 2rem;
    display: none;
}

/* ── Section tags ── */
.section-tag {
    display: inline-block;
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    padding: 0.15rem 0.5rem;
    border-radius: 4px;
    margin-left: 0.5rem;
    vertical-align: middle;
}
.section-tag.new { background: rgba(16, 185, 129, 0.2); color: var(--accent-green); }
.section-tag.updated { background: rgba(59, 130, 246, 0.2); color: var(--accent-blue); }

/* ── Partner bars ── */
.partner-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    margin: 1rem 0;
}
a.partner-bar {
    display: flex;
    align-items: center;
    gap: 1rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.25rem 1.5rem;
    text-decoration: none !important;
    color: var(--text-primary);
    transition: transform 0.3s ease, border-color 0.3s, box-shadow 0.3s;
    position: relative;
    overflow: hidden;
}
a.partner-bar:hover {
    transform: translateY(-3px);
    border-color: var(--accent);
    box-shadow: 0 6px 20px rgba(var(--accent-rgb), 0.15);
    color: var(--text-primary);
    text-decoration: none !important;
}
.partner-bar::after {
    content: '\2192';
    position: absolute;
    right: 1.5rem;
    font-size: 1.2rem;
    color: var(--accent);
    opacity: 0;
    transform: translateX(-5px);
    transition: all 0.3s ease;
}
.partner-bar:hover::after {
    opacity: 1;
    transform: translateX(0);
}
a.partner-bar h3 {
    font-size: 0.95rem;
    color: var(--text-primary) !important;
    margin: 0;
}
a.partner-bar p {
    font-size: 0.85rem;
    color: var(--text-secondary) !important;
    margin: 0;
}

/* ── Footer ── */
.footer {
    border-top: 1px solid var(--border);
    padding: 2rem;
    text-align: center;
    color: var(--text-muted);
    font-size: 0.85rem;
    margin-top: 3rem;
}
.footer a { transition: color 0.2s; }

/* ── Animations ── */
@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}
@keyframes heroGlow {
    from { box-shadow: 0 8px 32px rgba(var(--accent-rgb), 0.3); }
    to { box-shadow: 0 8px 48px rgba(var(--accent-rgb), 0.5), 0 0 60px rgba(var(--accent-rgb), 0.15); }
}

/* Staggered card entrance */
.feature-card, .guide-card {
    animation: fadeInUp 0.5s ease-out backwards;
}
.feature-card:nth-child(1), .guide-card:nth-child(1) { animation-delay: 0.05s; }
.feature-card:nth-child(2), .guide-card:nth-child(2) { animation-delay: 0.1s; }
.feature-card:nth-child(3), .guide-card:nth-child(3) { animation-delay: 0.15s; }
.feature-card:nth-child(4), .guide-card:nth-child(4) { animation-delay: 0.2s; }
.feature-card:nth-child(5), .guide-card:nth-child(5) { animation-delay: 0.25s; }
.feature-card:nth-child(6) { animation-delay: 0.3s; }

/* ── Mobile hamburger menu ── */
.nav-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--text-primary);
    cursor: pointer;
    padding: 0.5rem;
    margin-left: auto;
}
.nav-toggle svg { width: 24px; height: 24px; }

/* ── Responsive ── */
@media (max-width: 700px) {
    .hero h1 { font-size: 1.75rem; }
    .nav-inner { padding: 0 1rem; gap: 1rem; }
    .nav-toggle { display: flex; }
    .nav-links {
        display: none;
        position: absolute;
        top: 56px;
        left: 0;
        right: 0;
        background: var(--bg-secondary);
        border-bottom: 1px solid var(--border);
        flex-direction: column;
        padding: 1rem 1.5rem;
        gap: 0.5rem;
    }
    .nav-links.open { display: flex; }
    .nav-links a { padding: 0.5rem 0; }
    .container { padding: 1rem; }
    .guide-content { padding: 1.5rem; }
    .back-to-top { bottom: 1rem; right: 1rem; width: 40px; height: 40px; }
}