/* ===== AI 交易实验室 · 币安风（黑+金）+ 现代化 ===== */
:root {
  --bg: #0b0e11;
  --bg-soft: #14171c;
  --bg-card: #181a20;
  --bg-card-hover: #1e2128;
  --border: #2b2f36;
  --border-soft: #1e2128;
  --text: #eaecef;
  --text-soft: #b7bdc6;
  --muted: #707a8a;
  --binance: #F0B90B;
  --binance-dark: #d4a30a;
  --binance-glow: rgba(240, 185, 11, 0.15);
  --accent-2: #fcd535;
  --good: #0ecb81;
  --bad: #f6465d;
  --grad-gold: linear-gradient(135deg, #F0B90B 0%, #fcd535 100%);
  --grad-dark: linear-gradient(180deg, #14171c 0%, #0b0e11 100%);
  --radius: 8px;
  --radius-lg: 16px;
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.4);
  --shadow-gold: 0 8px 32px rgba(240, 185, 11, 0.2);
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', Menlo, monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  font-size: 16px;
}

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

a { color: var(--binance); text-decoration: none; transition: opacity .2s; }
a:hover { opacity: 0.8; }

h1, h2, h3, h4 { font-weight: 700; letter-spacing: -0.02em; line-height: 1.2; margin: 0; color: var(--text); }
h1 { font-size: clamp(2.4rem, 5.5vw, 4.2rem); font-weight: 800; }
h2 { font-size: clamp(1.6rem, 3vw, 2.4rem); margin-bottom: 0.8em; }
h3 { font-size: 1.2rem; margin-bottom: 0.5em; }

p { margin: 0 0 1em 0; color: var(--text-soft); }
strong { color: var(--text); font-weight: 600; }
code, pre { font-family: var(--font-mono); font-size: 0.9em; }
code { background: var(--bg-soft); padding: 2px 6px; border-radius: 4px; color: var(--binance); }
pre { background: var(--bg-soft); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px 20px; overflow-x: auto; font-size: 0.85em; line-height: 1.6; }
pre code { background: none; padding: 0; color: var(--text); }

ul, ol { padding-left: 1.5em; color: var(--text-soft); }
li { margin: 0.5em 0; }

hr { border: 0; border-top: 1px solid var(--border); margin: 48px 0; }

/* ===== 顶部 AD Disclosure Banner（币安风 + CryptoCompass 借鉴）===== */
.ad-banner {
  background: var(--bg-soft);
  border-bottom: 1px solid var(--binance);
  padding: 10px 0;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-soft);
  text-align: center;
}
.ad-banner strong { color: var(--binance); }
.ad-banner a { color: var(--binance); text-decoration: underline; text-underline-offset: 3px; }

/* ===== Header / Nav ===== */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(11, 14, 17, 0.92);
  backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--border-soft);
}
.nav {
  display: flex; align-items: center; justify-content: space-between;
  height: 68px;
}
.brand {
  display: flex; align-items: center; gap: 10px;
  font-weight: 800; font-size: 1.1rem;
  color: var(--text) !important;
  letter-spacing: -0.01em;
}
.brand:hover { opacity: 1; color: var(--binance) !important; }
.brand .logo {
  width: 32px; height: 32px;
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0;
}
.brand .logo svg { width: 100%; height: 100%; display: block; }
.brand-text { display: flex; flex-direction: column; line-height: 1.05; }
.brand-text .main { font-weight: 800; font-size: 1.02rem; letter-spacing: -0.01em; }
.brand-text .sub { font-family: var(--font-mono); font-size: 0.62rem; color: var(--muted); letter-spacing: 0.16em; text-transform: uppercase; margin-top: 1px; }

/* card icon → minimal SVG 线条 */
.card-icon {
  width: 48px; height: 48px;
  background: transparent;
  border: 1px solid var(--binance);
  border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  margin-bottom: 20px;
  color: var(--binance);
}
.card-icon svg { width: 22px; height: 22px; display: block; }
.nav-links { display: flex; gap: 32px; }
.nav-links a {
  color: var(--text-soft); font-size: 0.92rem; font-weight: 500;
}
.nav-links a:hover { color: var(--binance); opacity: 1; }
.nav-cta {
  padding: 10px 18px;
  background: var(--binance);
  color: #0b0e11 !important;
  border-radius: 6px;
  font-size: 0.9rem;
  font-weight: 700;
  transition: background .2s;
}
.nav-cta:hover { background: var(--accent-2); opacity: 1; }

/* Language switcher dropdown */
.nav-tail {
  display: flex;
  align-items: center;
  gap: 10px;
}
.lang-switch {
  background: rgba(240, 185, 11, 0.06);
  color: #e8e8ed;
  border: 1.5px solid rgba(240, 185, 11, 0.45);
  border-radius: 8px;
  padding: 8px 28px 8px 32px;
  font-size: 0.9rem;
  font-weight: 500;
  font-family: inherit;
  cursor: pointer;
  transition: all .2s ease;
  background-image:
    url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23F0B90B' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'><circle cx='12' cy='12' r='10'/><line x1='2' y1='12' x2='22' y2='12'/><path d='M12 2a15.3 15.3 0 0 1 4 10 15.3 15.3 0 0 1-4 10 15.3 15.3 0 0 1-4-10 15.3 15.3 0 0 1 4-10z'/></svg>"),
    url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23F0B90B' stroke-width='2.5' stroke-linecap='round' stroke-linejoin='round'><polyline points='6 9 12 15 18 9'/></svg>");
  background-repeat: no-repeat, no-repeat;
  background-position: 8px center, right 8px center;
  background-size: 16px 16px, 12px 12px;
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
  min-width: 130px;
}
.lang-switch:hover {
  border-color: var(--binance);
  background-color: rgba(240, 185, 11, 0.12);
  color: #fff;
}
.lang-switch:focus {
  outline: none;
  border-color: var(--binance);
  box-shadow: 0 0 0 3px rgba(240, 185, 11, 0.18);
}
.lang-switch option {
  background: #0b0e11;
  color: #e8e8ed;
  font-weight: 500;
  padding: 8px;
}
.lang-switch option:checked {
  background: rgba(240, 185, 11, 0.18);
  color: var(--binance);
}
@media (max-width: 720px) {
  .nav-tail { gap: 6px; }
  .lang-switch {
    padding: 7px 24px 7px 28px;
    font-size: 0.82rem;
    min-width: 110px;
    background-size: 14px 14px, 10px 10px;
    background-position: 7px center, right 7px center;
  }
}

/* ===== Hero ===== */
.hero {
  position: relative;
  padding: 80px 0 60px;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 15% 30%, rgba(240, 185, 11, 0.08), transparent 50%),
    radial-gradient(circle at 85% 70%, rgba(240, 185, 11, 0.04), transparent 50%);
  pointer-events: none;
}
.hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 64px;
  align-items: center;
  position: relative;
}
.hero-eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 6px 14px;
  border: 1px solid var(--binance);
  background: var(--binance-glow);
  border-radius: 999px;
  font-size: 0.78rem;
  color: var(--binance);
  font-family: var(--font-mono);
  font-weight: 600;
  margin-bottom: 24px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}
.hero-eyebrow .dot {
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--good);
  box-shadow: 0 0 8px var(--good);
}
.hero h1 {
  margin-bottom: 24px;
}
.hero h1 .accent {
  color: var(--binance);
  background: var(--grad-gold);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}
.hero-sub {
  font-size: 1.15rem;
  color: var(--text-soft);
  margin-bottom: 40px;
  max-width: 540px;
}
.hero-ctas { display: flex; gap: 16px; flex-wrap: wrap; }

/* Hero 右侧数据卡 */
.hero-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
  position: relative;
  overflow: hidden;
}
.hero-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0; height: 3px;
  background: var(--grad-gold);
}
.hero-card-title {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--muted);
  margin-bottom: 20px;
}
.hero-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-bottom: 24px;
}
.hero-stat .num {
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 700;
  color: var(--binance);
  display: block;
  line-height: 1.1;
}
.hero-stat .label {
  font-size: 0.82rem;
  color: var(--muted);
  margin-top: 4px;
}

.binance-badge {
  display: flex; align-items: center; gap: 12px;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 16px;
  margin-top: 8px;
}
.binance-badge .binance-mark {
  flex-shrink: 0;
  width: 32px; height: 32px;
}
.binance-badge .txt {
  font-size: 0.82rem;
  color: var(--text-soft);
  line-height: 1.5;
}
.binance-badge strong { color: var(--binance); }

.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 14px 28px;
  border-radius: 6px;
  font-weight: 700;
  font-size: 0.95rem;
  border: none;
  cursor: pointer;
  transition: all .2s;
  text-decoration: none;
  letter-spacing: -0.01em;
}
.btn-primary {
  background: var(--binance);
  color: #0b0e11;
}
.btn-primary:hover { background: var(--accent-2); transform: translateY(-1px); box-shadow: var(--shadow-gold); opacity: 1; }
.btn-secondary {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
}
.btn-secondary:hover { border-color: var(--binance); color: var(--binance); opacity: 1; }

/* ===== Ticker / 实时数据条 ===== */
.ticker {
  background: #0a0c10;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  padding: 14px 0;
  overflow: hidden;
}
.ticker-inner {
  display: flex;
  gap: 48px;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  white-space: nowrap;
  animation: tickerMove 60s linear infinite;
}
.ticker-inner:hover { animation-play-state: paused; }
.ticker .ticker-item { display: inline-flex; align-items: center; gap: 8px; }
.ticker .sym { color: var(--text); font-weight: 700; }
.ticker .price { color: var(--text-soft); }
.ticker .chg { font-weight: 600; }
.ticker .chg.up { color: var(--good); }
.ticker .chg.dn { color: var(--bad); }
.ticker .live-dot {
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--good); margin-right: 6px;
  animation: livePulse 1.5s ease-in-out infinite;
}
@keyframes livePulse {
  0%, 100% { opacity: 1; box-shadow: 0 0 0 0 rgba(14, 203, 129, 0.6); }
  50% { opacity: 0.7; box-shadow: 0 0 0 6px rgba(14, 203, 129, 0); }
}
@keyframes tickerMove {
  from { transform: translateX(0); }
  to { transform: translateX(-50%); }
}

/* ===== Section ===== */
.section { padding: 80px 0; }
.section-title {
  text-align: center;
  margin-bottom: 56px;
}
.section-title .eyebrow {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--binance);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 14px;
  font-weight: 600;
}
.section-title h2 { max-width: 720px; margin: 0 auto; }
.section-title .desc {
  max-width: 600px; margin: 16px auto 0;
  color: var(--text-soft);
}

/* ===== Card grid ===== */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
  transition: all .2s;
  position: relative;
}
.card:hover { transform: translateY(-3px); border-color: var(--binance); background: var(--bg-card-hover); }
.card-icon {
  width: 48px; height: 48px;
  background: var(--binance-glow);
  border: 1px solid var(--binance);
  border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.4rem;
  margin-bottom: 20px;
}
.card h3 { margin-bottom: 12px; }
.card p { margin: 0; font-size: 0.95rem; }
.card-link {
  display: inline-block;
  margin-top: 20px;
  color: var(--binance);
  font-size: 0.9rem;
  font-weight: 600;
}
.card-link:hover { color: var(--accent-2); }

/* ===== Binance section ===== */
.binance-section {
  background: linear-gradient(135deg, rgba(240, 185, 11, 0.06) 0%, rgba(240, 185, 11, 0.01) 100%);
  border: 1px solid rgba(240, 185, 11, 0.2);
  border-radius: var(--radius-lg);
  padding: 64px 56px;
  position: relative;
  overflow: hidden;
}
.binance-section::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 50% 0%, rgba(240, 185, 11, 0.1), transparent 60%);
  pointer-events: none;
}
.binance-section .binance-logo-large {
  display: inline-flex; align-items: center; gap: 12px;
  margin-bottom: 24px;
}
.binance-section .binance-logo-large svg { width: 44px; height: 44px; }
.binance-section .binance-logo-large .name {
  font-weight: 800; font-size: 1.8rem;
  color: var(--binance);
  letter-spacing: -0.02em;
}

/* ===== Tag / Pill ===== */
.tag {
  display: inline-block;
  padding: 3px 10px;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 0.78rem;
  color: var(--text-soft);
  font-family: var(--font-mono);
}
.tag.warm { color: var(--binance); border-color: rgba(240, 185, 11, 0.4); }
.tag.good { color: var(--good); border-color: rgba(14, 203, 129, 0.3); }
.tag.bad { color: var(--bad); border-color: rgba(246, 70, 93, 0.3); }

/* ===== Disclosure / Callout ===== */
.disclosure {
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-left: 3px solid var(--binance);
  border-radius: 6px;
  padding: 16px 20px;
  font-size: 0.88rem;
  color: var(--text-soft);
  margin: 32px 0;
}
.disclosure strong { color: var(--binance); }

.callout {
  padding: 20px 24px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--bg-card);
  margin: 24px 0;
}
.callout.warn { border-left: 3px solid var(--binance); }
.callout.danger { border-left: 3px solid var(--bad); }
.callout.info { border-left: 3px solid #5e9eff; }
.callout.success { border-left: 3px solid var(--good); }
.callout strong { color: var(--text); }

/* ===== Table ===== */
.tbl {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.92rem;
}
.tbl th, .tbl td {
  text-align: left;
  padding: 14px 16px;
  border-bottom: 1px solid var(--border);
}
.tbl th {
  background: var(--bg-soft);
  font-weight: 600;
  color: var(--muted);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.tbl tr:hover { background: var(--bg-soft); }
.tbl td.score { font-family: var(--font-mono); font-weight: 700; color: var(--binance); }
.tbl-wrap {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow-x: auto;
  padding: 8px;
}

/* ===== Prompt card ===== */
.prompt-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin: 24px 0;
}
.prompt-card-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 12px; }
.prompt-card-head h3 { margin: 0; font-size: 1.1rem; }
.prompt-card .scene { color: var(--text-soft); font-size: 0.9rem; margin-bottom: 12px; }
.prompt-card pre { margin: 12px 0 0; }

/* ===== Article ===== */
.article {
  max-width: 780px;
  margin: 0 auto;
  padding: 80px 24px;
}
.article header { margin-bottom: 48px; }
.article header .breadcrumb {
  font-family: var(--font-mono); font-size: 0.82rem;
  color: var(--muted); margin-bottom: 16px;
}
.article header h1 { margin-bottom: 16px; }
.article header .meta-row {
  display: flex; gap: 16px; color: var(--muted); font-size: 0.88rem; margin-top: 12px;
}
.article h2 {
  margin-top: 56px;
  padding-top: 32px;
  border-top: 1px solid var(--border-soft);
  scroll-margin-top: 80px;
}
.article h3 { margin-top: 40px; scroll-margin-top: 80px; }
.article p, .article ul, .article ol { font-size: 1.02rem; }
.article h2 .anchor, .article h3 .anchor {
  opacity: 0; margin-left: 8px;
  font-size: 0.7em; color: var(--binance);
  text-decoration: none; font-weight: 400; transition: opacity .2s;
}
.article h2:hover .anchor, .article h3:hover .anchor { opacity: 1; }

/* ===== Article with sidebar TOC ===== */
.article-layout {
  max-width: 1280px;
  margin: 0 auto;
  padding: 64px 24px 80px;
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: 56px;
  align-items: start;
}
.toc {
  position: sticky;
  top: 88px;
  font-size: 0.88rem;
  max-height: calc(100vh - 120px);
  overflow-y: auto;
  padding-right: 8px;
}
.toc::-webkit-scrollbar { width: 6px; }
.toc::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
.toc-title {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  text-transform: uppercase;
  color: var(--muted);
  letter-spacing: 0.1em;
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border-soft);
}
.toc ol, .toc ul { padding-left: 0; list-style: none; margin: 0; }
.toc > ol > li {
  margin: 0;
  padding: 8px 0 8px 14px;
  border-left: 2px solid var(--border-soft);
  transition: border-color .2s;
}
.toc > ol > li:hover { border-left-color: var(--binance); }
.toc a {
  color: var(--text-soft);
  display: block;
  line-height: 1.4;
  font-size: 0.9rem;
  font-weight: 500;
}
.toc a:hover { color: var(--binance); opacity: 1; }
.toc .sub-list { margin-top: 6px; padding-left: 12px; }
.toc .sub-list li {
  padding: 4px 0;
  border-left: 1px solid var(--border-soft);
  padding-left: 10px;
}
.toc .sub-list a { font-size: 0.82rem; color: var(--muted); font-weight: 400; }
.toc .sub-list a:hover { color: var(--text-soft); }

.article-content { min-width: 0; max-width: 760px; }
.article-content header { margin-bottom: 48px; }
.article-content header .breadcrumb { font-family: var(--font-mono); font-size: 0.82rem; color: var(--muted); margin-bottom: 16px; }
.article-content header h1 { margin-bottom: 16px; }
.article-content header .meta-row {
  display: flex; gap: 16px; color: var(--muted); font-size: 0.88rem; margin-top: 12px;
}
.article-content h2 {
  margin-top: 56px; padding-top: 32px;
  border-top: 1px solid var(--border-soft);
  scroll-margin-top: 80px;
}
.article-content h2:first-of-type { border-top: none; padding-top: 0; margin-top: 32px; }
.article-content h3 { margin-top: 40px; scroll-margin-top: 80px; }
.article-content p, .article-content ul, .article-content ol { font-size: 1.02rem; }
.article-content h2 .anchor, .article-content h3 .anchor {
  opacity: 0; margin-left: 8px;
  font-size: 0.65em; color: var(--binance);
  text-decoration: none; font-weight: 400; transition: opacity .2s;
}
.article-content h2:hover .anchor, .article-content h3:hover .anchor { opacity: 1; }

/* ===== FAQ accordion ===== */
.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin: 12px 0;
  transition: border-color .2s;
  overflow: hidden;
}
.faq-item:hover { border-color: var(--binance); }
.faq-item[open] { border-color: var(--binance); }
.faq-item summary {
  list-style: none;
  cursor: pointer;
  padding: 20px 24px;
  font-weight: 600;
  font-size: 1.02rem;
  color: var(--text);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: '+';
  font-family: var(--font-mono);
  font-size: 1.5rem;
  color: var(--binance);
  transition: transform .2s;
  font-weight: 400;
  line-height: 1;
}
.faq-item[open] summary::after { content: '−'; }
.faq-body {
  padding: 0 24px 22px;
  color: var(--text-soft);
}
.faq-body p:last-child { margin-bottom: 0; }
.faq-body ol, .faq-body ul { padding-left: 1.4em; margin: 8px 0; }
.faq-body code { font-size: 0.88em; }

/* ===== Footer ===== */
.site-footer {
  margin-top: 80px;
  padding: 60px 0 32px;
  border-top: 1px solid var(--border-soft);
  background: var(--bg-soft);
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
}
.footer-grid h4 {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  margin-bottom: 16px;
}
.footer-grid ul { list-style: none; padding: 0; }
.footer-grid li { margin: 8px 0; }
.footer-grid a { color: var(--text-soft); font-size: 0.9rem; }
.footer-grid a:hover { color: var(--binance); }
.footer-bottom {
  border-top: 1px solid var(--border);
  margin-top: 40px; padding-top: 24px;
  text-align: center;
  font-size: 0.85rem;
  color: var(--muted);
}

/* ===== Responsive ===== */
@media (max-width: 980px) {
  .nav-links { display: none; }
  .nav-cta { display: inline-flex; }
  .hero { padding: 56px 0 40px; }
  .hero-grid { grid-template-columns: 1fr; gap: 40px; }
  .hero-card { padding: 24px; }
  .section { padding: 56px 0; }
  .binance-section { padding: 32px 24px; }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 28px; }
  .article-layout { grid-template-columns: 1fr; gap: 24px; padding: 40px 20px 60px; }
  .toc {
    position: static;
    max-height: none;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px 20px;
  }
  .toc-mobile-toggle {
    display: flex; align-items: center; justify-content: space-between;
    cursor: pointer; user-select: none;
    font-family: var(--font-mono); font-size: 0.78rem;
    text-transform: uppercase; color: var(--text);
    letter-spacing: 0.08em;
  }
  .toc-mobile-toggle::after {
    content: '▼'; font-size: 0.7em; transition: transform .2s;
  }
  .toc[open] .toc-mobile-toggle::after { transform: rotate(180deg); }
  .toc-title { display: none; }
  details.toc { padding: 0; }
  details.toc summary { padding: 16px 20px; list-style: none; }
  details.toc summary::-webkit-details-marker { display: none; }
  details.toc[open] > *:not(summary) { padding: 0 20px 16px; }
}
@media (min-width: 981px) {
  details.toc { display: block; }
  details.toc summary { display: none; }
  details.toc > * { display: block; }
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; }
}

/* ===== 404 ===== */
.err-hero { padding: 120px 0; text-align: center; }
.err-code {
  font-family: var(--font-mono); font-size: clamp(80px, 18vw, 200px);
  background: var(--grad-gold);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  font-weight: 800; line-height: 1;
}