:root {
  --bg: #f7f9fc;
  --bg-soft: #eef4ff;
  --panel: rgba(255, 255, 255, 0.92);
  --panel-strong: #ffffff;
  --text: #1d2129;
  --muted: #646a73;
  --line: #dce3ea;
  --brand: #0064fa;
  --brand-strong: #0052d9;
  --accent: #0064fa;
  --code-bg: #f4f7fb;
  --shadow: 0 12px 36px rgba(29, 33, 41, 0.07);
  --shadow-soft: 0 4px 18px rgba(29, 33, 41, 0.04);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at 0% 0%, rgba(0, 100, 250, 0.08), transparent 28%),
    radial-gradient(circle at 100% 0%, rgba(0, 100, 250, 0.05), transparent 24%),
    radial-gradient(circle at 50% 100%, rgba(0, 100, 250, 0.05), transparent 30%),
    linear-gradient(180deg, #fbfdff 0%, var(--bg) 100%);
  line-height: 1.7;
}

a {
  color: var(--brand-strong);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

code,
pre {
  font-family: "IBM Plex Mono", "SFMono-Regular", Consolas, monospace;
}

pre {
  position: relative;
  margin: 0;
  padding: 18px 20px;
  overflow: auto;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--code-bg);
  font-size: 14px;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.65);
}

.code-block {
  padding-top: 48px;
}

.copy-button {
  position: absolute;
  top: 12px;
  right: 12px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  padding: 0;
  border: 1px solid rgba(220, 227, 234, 0.95);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.96);
  color: var(--muted);
  cursor: pointer;
  transition: all 0.14s ease;
}

.copy-button svg {
  width: 16px;
  height: 16px;
  fill: currentColor;
}

.copy-button:hover {
  color: var(--brand);
  border-color: rgba(0, 100, 250, 0.18);
  background: rgba(234, 245, 255, 0.9);
}

.copy-button.copied {
  color: var(--brand-strong);
  border-color: rgba(0, 100, 250, 0.24);
  background: rgba(234, 245, 255, 1);
}

.copy-button.error {
  color: #d14343;
  border-color: rgba(209, 67, 67, 0.2);
  background: rgba(255, 244, 244, 0.98);
}

code.inline {
  padding: 2px 6px;
  border-radius: 6px;
  background: var(--code-bg);
  border: 1px solid rgba(15, 23, 42, 0.06);
  font-size: 0.95em;
}

.shell::before {
  content: "$ ";
  color: var(--accent);
}

.layout {
  max-width: 1180px;
  margin: 0 auto;
  padding: 24px 20px 72px;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  margin-bottom: 20px;
  padding: 12px 16px;
  border: 1px solid rgba(220, 227, 234, 0.9);
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.82);
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-soft);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  color: var(--text);
}

.brand-mark {
  width: 42px;
  height: 42px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 12px;
  background: linear-gradient(135deg, #1b7cff 0%, var(--brand) 60%, var(--brand-strong) 100%);
  color: #fff;
  font-weight: 700;
  letter-spacing: 0.04em;
  box-shadow: 0 10px 20px rgba(0, 100, 250, 0.22);
}

.brand-copy {
  display: flex;
  flex-direction: column;
}

.brand-copy strong {
  font-size: 18px;
  line-height: 1.1;
}

.brand-copy span {
  color: var(--muted);
  font-size: 13px;
}

.topnav {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.topnav a {
  padding: 9px 14px;
  border-radius: 999px;
  color: var(--muted);
  background: rgba(244, 247, 251, 0.92);
  border: 1px solid rgba(220, 227, 234, 0.9);
  transition: all 0.16s ease;
}

.topnav a:hover {
  text-decoration: none;
  color: var(--brand-strong);
  border-color: rgba(0, 100, 250, 0.18);
  background: rgba(234, 245, 255, 0.9);
}

.topnav a.active {
  color: var(--brand-strong);
  border-color: rgba(0, 100, 250, 0.22);
  background: rgba(234, 245, 255, 0.95);
  font-weight: 600;
}

.hero {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 24px;
  margin-bottom: 24px;
}

.hero-home {
  grid-template-columns: 1fr;
}

.hero-home .hero-card {
  max-width: 760px;
}

.hero-card,
.meta-card,
.content-card,
.toc-card,
.callout,
.mini-card {
  border: 1px solid var(--line);
  background: var(--panel);
  border-radius: 18px;
  box-shadow: var(--shadow);
}

.hero-card {
  padding: 30px;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.99), rgba(249, 251, 255, 0.98));
}

.hero h1 {
  margin: 14px 0 10px;
  font-size: clamp(28px, 3.4vw, 40px);
  line-height: 1.14;
  letter-spacing: -0.025em;
}

.hero p {
  margin: 0;
  max-width: 56ch;
  color: var(--muted);
  font-size: 15px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 18px;
  border-radius: 10px;
  font-weight: 600;
  transition: transform 0.14s ease, box-shadow 0.14s ease, background-color 0.14s ease;
}

.button.primary {
  background: var(--brand);
  color: #fff;
  box-shadow: 0 6px 14px rgba(0, 100, 250, 0.14);
}

.button.secondary {
  border: 1px solid var(--line);
  background: #fff;
  color: var(--muted);
}

.button:hover {
  text-decoration: none;
  transform: translateY(-1px);
}

.meta-card {
  padding: 28px;
  display: grid;
  gap: 20px;
  align-content: start;
}

.meta-card h2 {
  margin: 0;
  font-size: 18px;
}

.meta-section {
  display: grid;
  gap: 12px;
}

.meta-list {
  display: grid;
  gap: 12px;
}

.meta-list.compact {
  gap: 10px;
}

.meta-item {
  padding: 14px 16px;
  border-radius: 12px;
  background: linear-gradient(180deg, #ffffff, #fafcff);
  border: 1px solid rgba(220, 227, 234, 0.95);
}

.meta-item strong {
  display: block;
  font-size: 13px;
  color: var(--muted);
  margin-bottom: 2px;
}

.link-item {
  transition: border-color 0.14s ease, background-color 0.14s ease, transform 0.14s ease;
}

.link-item:hover {
  text-decoration: none;
  transform: translateY(-1px);
  border-color: rgba(0, 100, 250, 0.18);
  background: #f7faff;
}

.link-item span {
  color: var(--text);
  font-size: 14px;
}

.main-grid {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 24px;
}

.toc-card {
  position: sticky;
  top: 24px;
  align-self: start;
  padding: 24px;
  box-shadow: var(--shadow-soft);
}

.toc-card h2 {
  margin: 0 0 12px;
  font-size: 18px;
}

.toc-card ul {
  margin: 0;
  padding-left: 18px;
  color: var(--muted);
}

.toc-card li + li {
  margin-top: 8px;
}

.toc-card a {
  color: var(--muted);
  transition: color 0.14s ease;
}

.toc-card a:hover {
  color: var(--brand);
}

.toc-card a.active {
  color: var(--brand);
  font-weight: 600;
}

.content-stack {
  display: grid;
  gap: 20px;
}

.content-card {
  padding: 30px;
  box-shadow: var(--shadow-soft);
}

.content-card h2 {
  margin: 0 0 12px;
  font-size: 26px;
  letter-spacing: -0.02em;
}

.content-card h3 {
  margin: 24px 0 10px;
  font-size: 20px;
}

.content-card p,
.content-card li {
  color: var(--text);
}

.content-card p {
  margin: 0 0 12px;
}

.content-card ul,
.content-card ol {
  margin: 12px 0 0;
  padding-left: 22px;
}

.content-card li + li {
  margin-top: 8px;
}

.callout {
  padding: 18px 20px;
  border-radius: 14px;
  background: linear-gradient(180deg, rgba(234, 245, 255, 0.92), rgba(248, 251, 255, 0.96));
  border-color: rgba(0, 100, 250, 0.12);
}

.cards {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.mini-card {
  padding: 20px;
  box-shadow: none;
}

.mini-card h3 {
  margin: 0 0 8px;
  font-size: 19px;
}

.mini-card p {
  margin: 0;
  color: var(--muted);
}

.footer {
  margin-top: 28px;
  padding: 24px 0 0;
  color: var(--muted);
  font-size: 14px;
  border-top: 1px solid rgba(220, 227, 234, 0.9);
}

.table-wrap {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  border-radius: 16px;
  margin-top: 14px;
}

.table-wrap table {
  margin-top: 0;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 14px;
  overflow: hidden;
  border-radius: 16px;
  border-style: hidden;
  box-shadow: 0 0 0 1px var(--line);
}

th,
td {
  padding: 12px 14px;
  text-align: left;
  vertical-align: top;
  border: 1px solid var(--line);
}

th {
  background: #f7faff;
}

@media (max-width: 980px) {
  .hero,
  .main-grid {
    grid-template-columns: 1fr;
  }

  .toc-card {
    position: static;
  }
}

@media (max-width: 640px) {
  .layout {
    padding: 18px 14px 48px;
  }

  .topbar {
    align-items: flex-start;
    flex-direction: column;
  }

  .hero-card,
  .meta-card,
  .content-card,
  .toc-card {
    padding: 22px;
    border-radius: 20px;
  }

  .cards {
    grid-template-columns: 1fr;
  }
}

/* ── Dark mode ────────────────────────────────────── */

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1117;
    --bg-soft: #1a1d2e;
    --panel: rgba(30, 33, 45, 0.92);
    --panel-strong: #1e2130;
    --text: #e1e4ea;
    --muted: #9098a6;
    --line: #2a2e3e;
    --brand: #4d9cff;
    --brand-strong: #6db3ff;
    --accent: #4d9cff;
    --code-bg: #1a1d28;
    --shadow: 0 12px 36px rgba(0, 0, 0, 0.25);
    --shadow-soft: 0 4px 18px rgba(0, 0, 0, 0.15);
  }

  body {
    background:
      radial-gradient(circle at 0% 0%, rgba(0, 100, 250, 0.12), transparent 28%),
      radial-gradient(circle at 100% 0%, rgba(0, 100, 250, 0.08), transparent 24%),
      radial-gradient(circle at 50% 100%, rgba(0, 100, 250, 0.06), transparent 30%),
      linear-gradient(180deg, #0d0f16 0%, var(--bg) 100%);
  }

  .topbar {
    border-color: rgba(60, 65, 85, 0.9);
    background: rgba(30, 33, 45, 0.82);
  }

  .topnav a {
    background: rgba(30, 35, 50, 0.92);
    border-color: rgba(60, 65, 85, 0.9);
  }

  .topnav a:hover {
    color: var(--brand);
    border-color: rgba(77, 156, 255, 0.2);
    background: rgba(20, 35, 60, 0.9);
  }

  .topnav a.active {
    color: var(--brand);
    border-color: rgba(77, 156, 255, 0.25);
    background: rgba(20, 35, 60, 0.95);
  }

  .hero-card {
    background: linear-gradient(180deg, rgba(30, 33, 45, 0.99), rgba(25, 28, 40, 0.98));
  }

  .meta-item {
    background: linear-gradient(180deg, #1e2130, #1a1d28);
    border-color: rgba(60, 65, 85, 0.95);
  }

  .link-item:hover {
    border-color: rgba(77, 156, 255, 0.2);
    background: rgba(20, 35, 60, 0.6);
  }

  .callout {
    background: linear-gradient(180deg, rgba(20, 35, 60, 0.92), rgba(15, 25, 45, 0.96));
    border-color: rgba(0, 100, 250, 0.2);
  }

  code.inline {
    border-color: rgba(255, 255, 255, 0.08);
  }

  pre {
    box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.04);
  }

  .copy-button {
    border-color: rgba(60, 65, 85, 0.95);
    background: rgba(30, 33, 45, 0.96);
  }

  .copy-button:hover {
    color: var(--brand);
    border-color: rgba(77, 156, 255, 0.2);
    background: rgba(20, 35, 60, 0.9);
  }

  .copy-button.copied {
    color: var(--brand);
    border-color: rgba(77, 156, 255, 0.3);
    background: rgba(20, 35, 60, 1);
  }

  th {
    background: #1a1d28;
  }

  .button.primary {
    background: var(--brand);
    box-shadow: 0 6px 14px rgba(0, 80, 200, 0.3);
  }

  .button.secondary {
    border-color: var(--line);
    background: var(--panel-strong);
    color: var(--muted);
  }

  .mini-card {
    background: var(--panel-strong);
    border-color: var(--line);
  }
}