/* LazyZCode docs — "The Verified Mark" design system
   dark + light themes, system-follow default; devtool-doc restraint */

:root {
  color-scheme: dark;
  --bg: #0a0c10;
  --surface: #10141a;
  --surface-2: #141922;
  --line: #1e2530;
  --line-strong: #2a3340;
  --text: #dce5ef;
  --text-strong: #ffffff;
  --muted: #8595a8;
  --faint: #5c6c80;
  --accent: #4fd6b8;
  --accent-strong: #74e6cb;
  --accent-dim: rgba(79, 214, 184, 0.10);
  --header-bg: rgba(10, 12, 16, 0.82);
  --code-bg: #0c0f14;
  --code-inline-text: #b8e8d8;
  --code-block-text: #a9c7bd;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", sans-serif;
  --mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
  --ease: cubic-bezier(0.32, 0.72, 0, 1);
  --maxw: 1180px;
  --selection: rgba(79, 214, 184, 0.25);
}

:root[data-theme="light"] {
  color-scheme: light;
  --bg: #f6f8fa;
  --surface: #ffffff;
  --surface-2: #eef1f5;
  --line: #e2e7ee;
  --line-strong: #cdd6e0;
  --text: #182230;
  --text-strong: #000000;
  --muted: #55677a;
  --faint: #8595a8;
  --accent: #0c8f76;
  --accent-strong: #0a7a64;
  --accent-dim: rgba(12, 143, 118, 0.10);
  --header-bg: rgba(246, 248, 250, 0.86);
  --code-bg: #f2f5f8;
  --code-inline-text: #0b6e5c;
  --code-block-text: #33475c;
  --selection: rgba(12, 143, 118, 0.18);
}

/* no-JS fallback: follow the system preference */
@media (prefers-color-scheme: light) {
  :root:not([data-theme]) {
    color-scheme: light;
    --bg: #f6f8fa;
    --surface: #ffffff;
    --surface-2: #eef1f5;
    --line: #e2e7ee;
    --line-strong: #cdd6e0;
    --text: #182230;
    --text-strong: #000000;
    --muted: #55677a;
    --faint: #8595a8;
    --accent: #0c8f76;
    --accent-strong: #0a7a64;
    --accent-dim: rgba(12, 143, 118, 0.10);
    --header-bg: rgba(246, 248, 250, 0.86);
    --code-bg: #f2f5f8;
    --code-inline-text: #0b6e5c;
    --code-block-text: #33475c;
  --selection: rgba(12, 143, 118, 0.18);
  }
}

* { box-sizing: border-box; }

@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
  a, button, .nav-group a, .lang-card, .feature, .theme-toggle button {
    transition: color 0.25s var(--ease), background-color 0.25s var(--ease), border-color 0.25s var(--ease), transform 0.25s var(--ease);
  }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 15.5px/1.75 var(--sans);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
html[lang="zh"] body { line-height: 1.85; }

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-strong); text-decoration: underline; text-underline-offset: 3px; }

::selection { background: var(--selection); }

/* ---------- header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 40;
  background: var(--header-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; height: 56px; gap: 12px; }
.brand {
  display: inline-flex; align-items: center; gap: 10px;
  color: var(--text); font-weight: 650; font-size: 15.5px; letter-spacing: -0.02em;
}
.brand:hover { text-decoration: none; color: var(--text-strong); }
.brand img { width: 22px; height: 22px; display: block; }
.header-nav { display: flex; align-items: center; gap: 20px; font-size: 13.5px; }
.header-nav .nav-link { color: var(--muted); }
.header-nav .nav-link:hover { color: var(--text); text-decoration: none; }

/* language toggle: pill sibling of .theme-toggle; shows the TARGET language, no JS needed */
.lang-toggle {
  display: inline-flex; align-items: center; gap: 6px; height: 30px; padding: 0 12px;
  border: 1px solid var(--line-strong); border-radius: 999px;
  background: var(--surface); color: var(--muted);
  font-size: 12.5px; font-weight: 600; line-height: 1;
}
.lang-toggle svg { width: 14px; height: 14px; }
.lang-toggle:hover { color: var(--accent-strong); border-color: var(--accent); text-decoration: none; }
.lang-toggle span { letter-spacing: 0.02em; }
.btn {
  display: inline-flex; align-items: center; gap: 6px; height: 30px; padding: 0 14px;
  border: 1px solid var(--line-strong); border-radius: 999px;
  color: var(--text) !important; background: var(--surface);
  font-size: 13px; font-weight: 550;
}
.btn:hover { border-color: var(--accent); color: var(--accent-strong) !important; text-decoration: none; }

/* theme toggle */
.theme-toggle {
  display: inline-flex; align-items: center; gap: 2px;
  padding: 2px; border: 1px solid var(--line-strong); border-radius: 999px;
  background: var(--surface);
}
.theme-toggle button {
  display: grid; place-items: center; width: 26px; height: 26px;
  border: none; border-radius: 999px; background: none;
  color: var(--faint); cursor: pointer; padding: 0;
}
.theme-toggle button svg { width: 14px; height: 14px; }
.theme-toggle button:hover { color: var(--text); }
.theme-toggle button.active { background: var(--accent-dim); color: var(--accent); }

/* ---------- layout ---------- */
.layout { display: grid; grid-template-columns: 248px minmax(0, 1fr); gap: 52px; padding-top: 40px; padding-bottom: 80px; }

/* ---------- sidebar ---------- */
.sidebar { position: sticky; top: 80px; align-self: start; max-height: calc(100vh - 104px); overflow-y: auto; scrollbar-width: thin; }
.nav-group { margin-bottom: 26px; }
.nav-heading {
  display: flex; align-items: center; gap: 8px;
  margin: 0 0 6px; padding: 0 10px;
  font-family: var(--mono); font-size: 10.5px; font-weight: 600;
  text-transform: uppercase; letter-spacing: 0.14em; color: var(--faint);
}
.nav-heading svg { width: 14px; height: 14px; stroke: var(--faint); flex: none; }
.nav-group ul { list-style: none; margin: 0; padding: 0; border-left: 1px solid var(--line); }
.nav-group li { margin: 1px 0; }
.nav-group a {
  display: block; margin-left: -1px; padding: 4px 12px;
  border-left: 2px solid transparent;
  color: var(--muted); font-size: 13.5px; line-height: 1.55;
}
.nav-group a:hover { color: var(--text); background: var(--surface); text-decoration: none; }
.nav-group a.active { color: var(--accent); border-left-color: var(--accent); background: var(--accent-dim); }

.menu-toggle { display: none; }

/* ---------- content ---------- */
.content { max-width: 800px; min-width: 0; }
.content { overflow-wrap: break-word; }
.content > h1:first-of-type {
  font-size: 2.3em; font-weight: 700; letter-spacing: -0.03em;
  line-height: 1.15; margin: 0.1em 0 0.35em;
}
.content h2 {
  font-size: 1.38em; font-weight: 650; letter-spacing: -0.02em;
  margin-top: 2.4em; padding-top: 1.3em;
  border-top: 1px solid var(--line);
}
.content h2:first-of-type { margin-top: 1.6em; }
.content h3 { font-size: 1.1em; font-weight: 650; margin-top: 1.9em; }
.content p { color: var(--text); }
.content li { margin: 0.25em 0; }
.content strong { color: var(--text-strong); font-weight: 620; }
.content hr { border: none; border-top: 1px solid var(--line); margin: 2.6em 0; }
.content blockquote {
  margin: 1.4em 0; padding: 2px 20px;
  border-left: 2px solid var(--accent); border-radius: 4px 10px 10px 4px;
  background: linear-gradient(90deg, var(--accent-dim), transparent 70%), var(--surface);
}
.content blockquote p { color: var(--muted); }
.content blockquote strong { color: var(--text); }
.content img { max-width: 100%; }

code {
  font-family: var(--mono); font-size: 0.86em;
  background: var(--code-bg); border: 1px solid var(--line);
  border-radius: 5px; padding: 0.12em 0.4em; color: var(--code-inline-text);
}
pre {
  background: var(--code-bg); border: 1px solid var(--line);
  border-radius: 10px; padding: 16px 18px; overflow-x: auto; line-height: 1.6;
  -webkit-overflow-scrolling: touch;
}
pre code { background: none; border: none; padding: 0; font-size: 0.84em; color: var(--code-block-text); }

table { border-collapse: separate; border-spacing: 0; width: 100%; margin: 1.3em 0; font-size: 0.93em; border: 1px solid var(--line); border-radius: 10px; overflow: hidden; }
th, td { border-bottom: 1px solid var(--line); padding: 9px 14px; text-align: left; vertical-align: top; }
tr:last-child td { border-bottom: none; }
th { background: var(--surface-2); font-weight: 620; color: var(--text); font-size: 0.95em; }
td { color: var(--muted); }
td strong { color: var(--text); }

/* ---------- single page (no sidebar) ---------- */
.page { padding-top: 48px; padding-bottom: 88px; }
.page .content { max-width: 820px; margin: 0 auto; }

/* diagrams */
.diagram { margin: 30px 0; padding: 22px 20px 14px; background: var(--surface); border: 1px solid var(--line); border-radius: 14px; }
.diagram svg { width: 100%; height: auto; display: block; }
.diagram figcaption { margin-top: 12px; padding: 0 4px; color: var(--faint); font-size: 13px; line-height: 1.6; }
.diagram text { font-family: var(--sans); }
.diagram .mono { font-family: var(--mono); }

/* ---------- home ---------- */
.home { padding-top: 88px; padding-bottom: 96px; max-width: 880px; }
.hero-mark { width: 68px; height: 68px; display: block; margin-bottom: 30px; }
.hero h1 { font-size: 3em; font-weight: 700; letter-spacing: -0.035em; line-height: 1.05; margin: 0 0 16px; }
.hero .tagline { font-size: 17px; color: var(--muted); max-width: 56ch; margin: 0 0 40px; }
.lang-cards { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; max-width: 640px; }
.lang-card {
  display: flex; align-items: center; justify-content: space-between; gap: 14px;
  padding: 20px 22px;
  background: var(--surface); border: 1px solid var(--line); border-radius: 14px;
  color: var(--text);
}
.lang-card:hover { border-color: var(--accent); text-decoration: none; transform: translateY(-2px); }
.lang-card b { display: block; font-size: 15.5px; font-weight: 640; margin-bottom: 3px; }
.lang-card span { display: block; color: var(--muted); font-size: 13px; line-height: 1.5; }
.lang-card .arrow { flex: none; width: 30px; height: 30px; border-radius: 999px; background: var(--accent-dim); display: grid; place-items: center; }
.lang-card .arrow svg { width: 14px; height: 14px; stroke: var(--accent); }
.lang-card:hover .arrow { transform: translate(2px, -2px); }

.features { display: grid; grid-template-columns: 1fr 1fr; margin-top: 72px; border-top: 1px solid var(--line); }
.feature { padding: 30px 34px 34px 0; border-bottom: 1px solid var(--line); }
.feature:nth-child(even) { padding-left: 34px; border-left: 1px solid var(--line); }
.feature svg { width: 20px; height: 20px; stroke: var(--accent); display: block; margin-bottom: 14px; }
.feature b { display: block; font-size: 14.5px; font-weight: 640; margin-bottom: 6px; }
.feature p { margin: 0; color: var(--muted); font-size: 13.5px; line-height: 1.65; }

/* ---------- footer ---------- */
.site-footer { border-top: 1px solid var(--line); padding: 30px 0 44px; color: var(--faint); font-size: 13px; }
.site-footer p { margin: 4px 0; }
.site-footer a { color: var(--muted); }
.site-footer a:hover { color: var(--text); }

/* ---------- responsive ---------- */
@media (max-width: 960px) {
  .layout { grid-template-columns: 1fr; gap: 20px; padding-top: 24px; }
  .sidebar { position: static; max-height: none; border: 1px solid var(--line); border-radius: 12px; padding: 16px 14px 6px; background: var(--surface); display: none; }
  .sidebar.open { display: block; }
  .menu-toggle {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 8px 14px; margin: 2px 0 14px;
    border: 1px solid var(--line-strong); border-radius: 999px;
    background: var(--surface); color: var(--text);
    font-size: 13px; font-weight: 550; cursor: pointer;
  }
  .menu-toggle svg { width: 14px; height: 14px; stroke: currentColor; }
  .menu-toggle:hover { border-color: var(--accent); color: var(--accent); }
  .nav-group ul { border-left: none; }
  .nav-group a { margin-left: 0; border-left-width: 0; border-radius: 6px; padding: 8px 10px; }
  .nav-group a.active { border-left-width: 0; background: var(--accent-dim); }
  .content > h1:first-of-type { font-size: 1.8em; }
  .hero h1 { font-size: 2.2em; }
  .home { padding-top: 56px; }
  .lang-cards { grid-template-columns: 1fr; }
  .features { grid-template-columns: 1fr; }
  .feature { padding-right: 0; }
  .feature:nth-child(even) { padding-left: 0; border-left: none; }
  /* wide figures and tables scroll instead of shrinking into illegibility */
  .diagram { overflow-x: auto; -webkit-overflow-scrolling: touch; }
  .diagram svg { min-width: 640px; }
  table { display: block; overflow-x: auto; -webkit-overflow-scrolling: touch; }
}

@media (max-width: 720px) {
  .wrap { padding: 0 16px; }
  /* narrow header keeps: brand + language toggle + theme toggle; section links and GitHub live in content/footer */
  .header-nav { gap: 10px; }
  .header-nav .nav-link { display: none; }
  .header-nav .btn { display: none; }
  .lang-toggle { height: 28px; padding: 0 10px; }
  body { font-size: 15px; }
  th, td { padding: 8px 10px; }
}