/* Sandbox Platform — Shared Guide Styles */
:root {
    --canvas: #FFFFFF;
    --ink-primary: #111111;
    --ink-secondary: #555555;
    --ink-tertiary: #999999;
    --highlight: #FAFAFA;
    --surface: #F5F5F5;
    --border-color: #E0E0E0;
    --border-thin: 1px solid #E0E0E0;
    --border-thick: 3px solid #111111;
    --font-ui: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-code: 'JetBrains Mono', monospace;
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --status-success: #059669;
    --status-error: #DC2626;
    --status-warning: #D97706;
    --max-w: 740px;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    font-family: var(--font-ui);
    background: var(--canvas);
    color: var(--ink-primary);
    line-height: 1.75;
    -webkit-font-smoothing: antialiased;
}

/* Nav */
.nav {
    position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
    background: rgba(255,255,255,0.95);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: var(--border-thick);
}
.nav-inner {
    max-width: 1100px; margin: 0 auto; padding: 0 32px;
    height: 64px; display: flex; align-items: center; justify-content: space-between;
}
.nav-left { display: flex; align-items: center; gap: 16px; }
.nav-left a { text-decoration: none; color: var(--ink-primary); font-weight: 700; font-size: 15px; }
.nav-left .sep { color: var(--ink-tertiary); font-size: 14px; }
.nav-left .section-label { color: var(--ink-secondary); font-weight: 500; font-size: 14px; }
.nav-right { display: flex; align-items: center; gap: 16px; }
.nav-right a {
    padding: 10px 24px; background: var(--ink-primary); color: var(--canvas);
    border-radius: var(--radius-sm); text-decoration: none; font-weight: 600; font-size: 14px;
}
.nav-right a:hover { background: #333; }
.nav-right .ghost { background: transparent; color: var(--ink-secondary); padding: 10px 16px; }
.nav-right .ghost:hover { color: var(--ink-primary); background: var(--highlight); }

/* Hero */
.hero { margin-top: 64px; padding: 80px 32px 64px; border-bottom: var(--border-thin); }
.hero-inner { max-width: var(--max-w); margin: 0 auto; }
.hero-meta {
    display: flex; align-items: center; gap: 16px; flex-wrap: wrap;
    font-size: 13px; color: var(--ink-tertiary); margin-bottom: 28px;
}
.hero-tag {
    padding: 4px 12px; border: 1px solid var(--border-color);
    border-radius: 100px; font-weight: 600; font-size: 11px;
    text-transform: uppercase; letter-spacing: 0.5px;
}
.hero-tag-green { border-color: var(--status-success); color: var(--status-success); }
.hero h1 { font-size: 44px; font-weight: 800; line-height: 1.12; letter-spacing: -1.8px; margin-bottom: 24px; }
.hero .lead { font-size: 19px; color: var(--ink-secondary); line-height: 1.7; max-width: 640px; }
.hero .lead strong { color: var(--ink-primary); }

/* Page layout */
.page-layout { display: flex; gap: 48px; max-width: 1100px; margin: 0 auto; padding: 56px 32px 100px; }
.page-main { flex: 1; min-width: 0; }
.page-toc {
    width: 240px; flex-shrink: 0;
    position: sticky; top: 88px; align-self: flex-start;
    max-height: calc(100vh - 100px); overflow-y: auto;
}
.page-toc h4 {
    font-size: 11px; font-weight: 700; text-transform: uppercase;
    letter-spacing: 1px; color: var(--ink-tertiary); margin-bottom: 14px;
}
.page-toc a {
    display: block; padding: 5px 0; color: var(--ink-secondary);
    text-decoration: none; font-size: 13px; font-weight: 500;
    border-left: 2px solid transparent; padding-left: 14px; transition: all 0.15s;
}
.page-toc a:hover { color: var(--ink-primary); }
.page-toc a.active { color: var(--ink-primary); font-weight: 600; border-left-color: var(--ink-primary); }
.page-toc .toc-sub { font-size: 12px; padding-left: 28px; color: var(--ink-tertiary); }
@media (max-width: 920px) {
    .page-layout { flex-direction: column; }
    .page-toc { display: none; }
    .hero h1 { font-size: 32px; letter-spacing: -1px; }
}

/* Article typography */
.article h2 {
    font-size: 28px; font-weight: 800; letter-spacing: -0.8px;
    margin: 64px 0 16px; padding-top: 32px; border-top: var(--border-thin);
}
.article h2:first-child { border-top: none; margin-top: 0; padding-top: 0; }
.article h3 { font-size: 20px; font-weight: 700; letter-spacing: -0.3px; margin: 40px 0 12px; }
.article h4 { font-size: 16px; font-weight: 700; margin: 28px 0 8px; }
.article p { margin-bottom: 18px; }
.article ul, .article ol { margin: 0 0 18px 28px; }
.article li { margin-bottom: 8px; }
.article li ul { margin-top: 8px; }
.article a { color: var(--ink-primary); font-weight: 500; text-decoration: underline; text-underline-offset: 2px; }
.article a:hover { text-decoration-thickness: 2px; }
.article strong { font-weight: 700; }
.article code {
    font-family: var(--font-code); font-size: 13px;
    background: var(--surface); padding: 2px 7px;
    border-radius: 4px; border: 1px solid var(--border-color);
}
.article hr { border: none; border-top: var(--border-thin); margin: 48px 0; }
.article blockquote {
    border-left: 4px solid var(--border-color);
    padding: 0 0 0 20px; margin: 0 0 18px 0;
    color: var(--ink-secondary); font-style: italic;
}

/* Code blocks */
.code-block {
    background: #0F0F0F; color: #D4D4D4;
    border-radius: var(--radius-md); overflow: hidden;
    margin: 20px 0 28px; border: 1px solid #2A2A2A;
}
.code-block-header {
    display: flex; align-items: center; justify-content: space-between;
    padding: 10px 20px; background: #1A1A1A; border-bottom: 1px solid #2A2A2A;
}
.code-block-lang {
    font-family: var(--font-code); font-size: 11px;
    color: #888; font-weight: 600; text-transform: uppercase; letter-spacing: 0.5px;
}
.code-block-copy {
    background: #2A2A2A; color: #AAA; border: none;
    padding: 4px 12px; border-radius: 4px;
    font-size: 12px; font-weight: 600; cursor: pointer; font-family: var(--font-ui);
}
.code-block-copy:hover { background: #333; color: #DDD; }
.code-block pre {
    padding: 20px 24px; overflow-x: auto;
    font-family: var(--font-code); font-size: 13px; line-height: 1.7; margin: 0;
}
.code-block .cmt { color: #6A9955; }
.code-block .str { color: #CE9178; }
.code-block .kw { color: #569CD6; }
.code-block .fn { color: #DCDCAA; }
.code-block .num { color: #B5CEA8; }
.code-block .typ { color: #4EC9B0; }
.code-block .param { color: #9CDCFE; }
.code-block .dec { color: #DCDCAA; }

/* Callouts */
.callout { border-radius: var(--radius-md); padding: 24px 28px; margin: 28px 0; }
.callout p { margin-bottom: 0; }
.callout p + p { margin-top: 12px; }
.callout strong { display: block; margin-bottom: 6px; font-size: 15px; }
.callout ul { margin: 8px 0 0 20px; }
.callout li { margin-bottom: 4px; }
.callout code { background: rgba(0,0,0,0.06); border-color: rgba(0,0,0,0.1); }
.callout-info { background: #EFF6FF; border-left: 4px solid #3B82F6; }
.callout-warning { background: #FFFBEB; border-left: 4px solid var(--status-warning); }
.callout-success { background: #ECFDF5; border-left: 4px solid var(--status-success); }
.callout-tip { background: var(--surface); border-left: 4px solid var(--ink-primary); }

/* Tables */
.data-table { width: 100%; border-collapse: collapse; margin: 20px 0 28px; font-size: 14px; line-height: 1.5; }
.data-table th, .data-table td { padding: 12px 16px; text-align: left; border-bottom: 1px solid var(--border-color); }
.data-table th {
    font-size: 11px; font-weight: 700; text-transform: uppercase;
    letter-spacing: 0.5px; color: var(--ink-tertiary);
    background: var(--surface); border-bottom: 2px solid var(--ink-primary);
}
.data-table tr:hover td { background: var(--highlight); }
.data-table code { font-size: 12px; }

/* Steps */
.step {
    display: flex; gap: 20px; margin: 32px 0; padding: 28px;
    background: var(--surface); border-radius: var(--radius-md); border: var(--border-thin);
}
.step-number {
    width: 40px; height: 40px; flex-shrink: 0;
    background: var(--ink-primary); color: var(--canvas);
    border-radius: 50%; display: flex; align-items: center;
    justify-content: center; font-weight: 800; font-size: 16px;
}
.step-content { flex: 1; }
.step-content h4 { margin-top: 0; margin-bottom: 8px; }
.step-content p { margin-bottom: 0; }
.step-content p + p { margin-top: 8px; }

/* Diagram */
.diagram {
    background: var(--surface); border: var(--border-thin);
    border-radius: var(--radius-md); padding: 40px 32px;
    margin: 28px 0; text-align: center;
    font-family: var(--font-code); font-size: 13px;
    line-height: 2.2; color: var(--ink-secondary);
}
.diagram .box {
    display: inline-block; padding: 10px 24px;
    border: 2px solid var(--ink-primary); border-radius: var(--radius-sm);
    background: var(--canvas); font-weight: 600; color: var(--ink-primary); margin: 4px;
}
.diagram .box-highlight { background: var(--ink-primary); color: var(--canvas); }
.diagram .arrow { color: var(--ink-tertiary); margin: 0 8px; font-size: 16px; }
.diagram .label { display: block; font-size: 11px; color: var(--ink-tertiary); margin-top: 4px; font-weight: 400; }

/* Comparison */
.comparison { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin: 28px 0; }
.comparison-card { border: var(--border-thin); border-radius: var(--radius-md); padding: 24px; background: var(--canvas); }
.comparison-card h4 { margin-top: 0; }
.comparison-card.before { border-top: 4px solid var(--status-error); }
.comparison-card.after { border-top: 4px solid var(--status-success); }
.comparison-card ul { margin: 8px 0 0 18px; font-size: 14px; }
.comparison-card li { margin-bottom: 4px; }
@media (max-width: 700px) { .comparison { grid-template-columns: 1fr; } }

/* CTA */
.cta-section {
    background: var(--ink-primary); color: var(--canvas);
    border-radius: var(--radius-lg); padding: 56px 48px;
    margin: 64px 0 0; text-align: center;
}
.cta-section h2 { color: var(--canvas); border: none; margin: 0 0 12px; font-size: 30px; padding: 0; }
.cta-section p { color: #AAA; margin-bottom: 28px; max-width: 480px; margin-left: auto; margin-right: auto; }
.cta-section .btn-cta {
    display: inline-block; padding: 16px 36px;
    background: var(--canvas); color: var(--ink-primary);
    border-radius: var(--radius-sm); font-weight: 700;
    text-decoration: none; font-size: 16px;
}
.cta-section .btn-cta:hover { background: #F0F0F0; text-decoration: none; }

/* Next guides */
.next-guides { margin: 56px 0 0; padding-top: 32px; border-top: var(--border-thin); }
.next-guides h3 { margin-top: 0; }
.guide-card {
    display: block; padding: 16px 20px;
    border: var(--border-thin); border-radius: var(--radius-sm);
    margin: 10px 0; text-decoration: none; color: var(--ink-primary);
    transition: border-color 0.15s, background 0.15s;
}
.guide-card:hover { border-color: var(--ink-primary); background: var(--highlight); text-decoration: none; }
.guide-card-title { font-weight: 700; font-size: 15px; }
.guide-card-desc { font-size: 13px; color: var(--ink-secondary); margin-top: 2px; }