/* pangu.skill — landing page
   Aesthetic: minimalist editorial / typographic (native CSS, no framework).
   One accent (vermilion / 朱紅, a nod to CJK seal ink) used only to mark the
   spaces pangu inserts and on the primary CTA. One radius scale (10px); tags
   are the documented pill exception. Light + dark locked at page level. */

:root {
  --font-sans: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, "Noto Sans TC", "PingFang TC", "Microsoft JhengHei",
    sans-serif;
  --font-mono: ui-monospace, "SF Mono", "JetBrains Mono", "Cascadia Code",
    Menlo, Consolas, "Noto Sans TC", monospace;

  --bg: #f7f7f8;
  --surface: #ffffff;
  --surface-2: #f1f1f3;
  --text: #18181b;
  --text-soft: #5b5b63;
  --text-faint: #8a8a92;
  --border: #e5e5e8;
  --border-strong: #d6d6da;
  --accent: #df372b;
  --accent-ink: #ffffff;
  --space-mark: rgba(223, 55, 43, 0.16);

  --radius: 10px;
  --maxw: 1080px;
  --ease: cubic-bezier(0.16, 1, 0.3, 1);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0d0d0f;
    --surface: #161619;
    --surface-2: #1c1c20;
    --text: #f4f4f5;
    --text-soft: #aeaeb6;
    --text-faint: #76767e;
    --border: #27272b;
    --border-strong: #34343a;
    --accent: #f0594d;
    --accent-ink: #150a09;
    --space-mark: rgba(240, 89, 77, 0.24);
  }
}

/* Manual override beats system preference */
:root[data-theme="light"] {
  --bg: #f7f7f8; --surface: #fff; --surface-2: #f1f1f3;
  --text: #18181b; --text-soft: #5b5b63; --text-faint: #8a8a92;
  --border: #e5e5e8; --border-strong: #d6d6da;
  --accent: #df372b; --accent-ink: #fff; --space-mark: rgba(223,55,43,.16);
}
:root[data-theme="dark"] {
  --bg: #0d0d0f; --surface: #161619; --surface-2: #1c1c20;
  --text: #f4f4f5; --text-soft: #aeaeb6; --text-faint: #76767e;
  --border: #27272b; --border-strong: #34343a;
  --accent: #f0594d; --accent-ink: #150a09; --space-mark: rgba(240,89,77,.24);
}

*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  margin: 0;
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: inherit; text-decoration: none; }

.wrap { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

/* ---------- nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  height: 64px;
  display: flex; align-items: center;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav .wrap { display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.brand { display: inline-flex; align-items: center; gap: 9px; font-weight: 640; letter-spacing: -0.02em; font-size: 1.02rem; }
.brand .mark { width: 18px; height: 18px; border-radius: 5px; flex: none; }
.nav-links { display: flex; align-items: center; gap: 28px; }
.nav-links a { color: var(--text-soft); font-size: 0.92rem; transition: color 0.2s var(--ease); }
.nav-links a:hover { color: var(--text); }
.nav-right { display: flex; align-items: center; gap: 10px; }

.icon-btn {
  width: 34px; height: 34px; display: inline-grid; place-items: center;
  border: 1px solid var(--border); border-radius: var(--radius);
  background: var(--surface); color: var(--text-soft); cursor: pointer;
  transition: color 0.2s, border-color 0.2s, transform 0.1s;
}
.icon-btn:hover { color: var(--text); border-color: var(--border-strong); }
.icon-btn:active { transform: translateY(1px); }
.icon-btn svg { width: 17px; height: 17px; }
.theme-icon-dark { display: none; }
:root[data-theme="dark"] .theme-icon-light,
:root:not([data-theme="light"]) .theme-icon-light { }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .theme-icon-light { display: none; } :root:not([data-theme="light"]) .theme-icon-dark { display: block; } }
:root[data-theme="dark"] .theme-icon-light { display: none; }
:root[data-theme="dark"] .theme-icon-dark { display: block; }
:root[data-theme="light"] .theme-icon-light { display: block; }
:root[data-theme="light"] .theme-icon-dark { display: none; }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  height: 44px; padding: 0 20px; border-radius: var(--radius);
  font-size: 0.95rem; font-weight: 560; white-space: nowrap; cursor: pointer;
  border: 1px solid transparent; transition: transform 0.1s, background 0.2s, border-color 0.2s, color 0.2s;
}
.btn:active { transform: translateY(1px); }
.btn-primary { background: var(--accent); color: var(--accent-ink); }
.btn-primary:hover { background: color-mix(in srgb, var(--accent) 88%, #000); }
.btn-ghost { background: var(--surface); color: var(--text); border-color: var(--border-strong); }
.btn-ghost:hover { border-color: var(--text-faint); }

/* ---------- hero ---------- */
.hero { padding: clamp(48px, 9vw, 104px) 0 clamp(40px, 7vw, 88px); }
.hero .wrap { display: grid; grid-template-columns: 1.05fr 0.95fr; gap: clamp(32px, 5vw, 64px); align-items: center; }
.hero-copy { max-width: 36ch; }
.hero h1 {
  margin: 0 0 18px;
  font-size: clamp(2.1rem, 5.4vw, 3.7rem);
  line-height: 1.16; letter-spacing: -0.018em; font-weight: 720;
}
.hero h1 .q { color: var(--accent); }
.hero-sub { margin: 0 0 28px; font-size: clamp(1rem, 1.4vw, 1.12rem); color: var(--text-soft); max-width: 30ch; }
.hero-cta { display: flex; flex-wrap: wrap; gap: 12px; }
.hero-note { margin-top: 18px; font-size: 0.85rem; color: var(--text-faint); }
.hero-note code { font-family: var(--font-mono); font-size: 0.82em; }

/* ---------- demo card ---------- */
.demo {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 16px; padding: 20px;
  box-shadow: 0 1px 2px color-mix(in srgb, var(--text) 6%, transparent),
              0 24px 48px -24px color-mix(in srgb, var(--text) 18%, transparent);
}
.demo-row + .demo-row { margin-top: 14px; }
.demo-label {
  display: flex; align-items: center; gap: 7px;
  font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.12em;
  color: var(--text-faint); margin-bottom: 8px; font-weight: 600;
}
.demo-label .dot { width: 6px; height: 6px; border-radius: 999px; background: var(--border-strong); }
.demo-label.is-out .dot { background: var(--accent); }
.demo-io {
  width: 100%; min-height: 84px; resize: vertical;
  font-family: var(--font-sans); font-size: 1.06rem; line-height: 1.7;
  color: var(--text); background: var(--surface-2);
  border: 1px solid var(--border); border-radius: var(--radius);
  padding: 12px 14px;
}
.demo-io:focus { outline: 2px solid var(--accent); outline-offset: 1px; border-color: transparent; }
.demo-out {
  font-family: var(--font-sans); font-size: 1.06rem; line-height: 1.7;
  background: var(--surface-2); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 12px 14px; min-height: 84px;
  white-space: pre-wrap; word-break: break-word;
}
.demo-out .sp {
  background: var(--space-mark);
  border-radius: 3px;
  box-shadow: inset 0 -1px 0 var(--accent);
}
.demo-foot { margin-top: 14px; font-size: 0.82rem; color: var(--text-faint); display: flex; align-items: center; gap: 8px; }
.demo-foot .pip { width: 14px; height: 8px; border-radius: 2px; background: var(--space-mark); box-shadow: inset 0 -1px 0 var(--accent); flex: none; }

/* ---------- generic section ---------- */
section { scroll-margin-top: 80px; }
.band { padding: clamp(56px, 8vw, 100px) 0; border-top: 1px solid var(--border); }
.band-head { max-width: 52ch; margin-bottom: clamp(28px, 4vw, 48px); }
.eyebrow { font-size: 0.74rem; text-transform: uppercase; letter-spacing: 0.14em; color: var(--accent); font-weight: 650; margin: 0 0 12px; }
.band h2 { margin: 0 0 12px; font-size: clamp(1.55rem, 3.2vw, 2.3rem); letter-spacing: -0.015em; line-height: 1.18; font-weight: 680; }
.band h2 + p { margin: 0; color: var(--text-soft); font-size: 1.04rem; }

/* ---------- rules / examples ---------- */
.rules { display: grid; gap: 0; border-top: 1px solid var(--border); }
.rule {
  display: grid; grid-template-columns: 150px 1fr; gap: 20px; align-items: baseline;
  padding: 20px 0; border-bottom: 1px solid var(--border);
}
.rule-k { font-size: 0.9rem; color: var(--text-soft); font-weight: 560; }
.rule-k small { display: block; color: var(--text-faint); font-weight: 400; font-size: 0.82rem; margin-top: 2px; }
.rule-v { font-size: 1.12rem; line-height: 1.75; }
.rule-v .from { color: var(--text-faint); }
.rule-v .arrow { color: var(--text-faint); margin: 0 12px; }
.rule-v .sp { background: var(--space-mark); border-radius: 3px; box-shadow: inset 0 -1px 0 var(--accent); }
.rule-v.keep .to { color: var(--text-soft); }
.rule-tag { font-family: var(--font-mono); font-size: 0.78rem; color: var(--text-faint); }

/* ---------- install ---------- */
.tier + .tier { margin-top: 44px; }
.tier-h { display: flex; align-items: baseline; gap: 12px; margin-bottom: 20px; }
.tier-h h3 { margin: 0; font-size: 1.16rem; letter-spacing: -0.01em; font-weight: 640; }
.tier-h span { font-size: 0.86rem; color: var(--text-faint); }
.cmd-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; }
.cmd.span2 { grid-column: 1 / -1; }
.cmd {
  min-width: 0;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 16px 16px 14px;
}
.cmd-name { display: flex; align-items: center; justify-content: space-between; gap: 10px; margin-bottom: 10px; }
.cmd-name b { font-weight: 600; font-size: 0.95rem; }
.cmd pre {
  margin: 0; font-family: var(--font-mono); font-size: 0.82rem; line-height: 1.6;
  color: var(--text); background: var(--surface-2); border: 1px solid var(--border);
  border-radius: 8px; padding: 11px 12px;
}
.cmd .ln {
  display: block; white-space: pre-wrap; overflow-wrap: anywhere;
  padding-left: 1.6ch; text-indent: -1.6ch; /* hanging indent keeps wrapped commands readable */
}
.copy {
  font-family: var(--font-mono); font-size: 0.72rem; color: var(--text-faint);
  background: transparent; border: 1px solid var(--border); border-radius: 6px;
  padding: 3px 8px; cursor: pointer; transition: color 0.2s, border-color 0.2s;
}
.copy:hover { color: var(--text); border-color: var(--border-strong); }
.copy.ok { color: var(--accent); border-color: var(--accent); }

.files { border-top: 1px solid var(--border); margin-top: 4px; }
.file-row {
  display: grid; grid-template-columns: 160px 1fr; gap: 18px; align-items: center;
  padding: 14px 0; border-bottom: 1px solid var(--border);
}
.file-row b { font-weight: 560; font-size: 0.96rem; }
.file-row code { font-family: var(--font-mono); font-size: 0.82rem; color: var(--text-soft); background: var(--surface-2); padding: 2px 7px; border-radius: 6px; }

/* ---------- community ---------- */
.fam-lead { max-width: 56ch; color: var(--text-soft); margin: 0 0 24px; }
.fam { display: flex; flex-wrap: wrap; gap: 10px; }
.fam a {
  display: inline-flex; align-items: center; gap: 8px;
  border: 1px solid var(--border); border-radius: 999px;
  padding: 7px 15px; font-size: 0.9rem; color: var(--text-soft);
  background: var(--surface); transition: color 0.2s, border-color 0.2s, transform 0.1s;
}
.fam a:hover { color: var(--text); border-color: var(--border-strong); transform: translateY(-1px); }
.fam a .lang { color: var(--text-faint); font-size: 0.8rem; }
.fam a.up { border-color: var(--accent); color: var(--text); }
.fam a.up .lang { color: var(--accent); }
.fam-thanks { margin-top: 24px; color: var(--text-soft); font-size: 0.96rem; }
.fam-thanks a { color: var(--accent); }

/* ---------- footer ---------- */
.foot { border-top: 1px solid var(--border); padding: 40px 0 56px; }
.foot .wrap { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 18px; align-items: center; }
.foot .brand { font-size: 0.98rem; }
.foot-links { display: flex; flex-wrap: wrap; gap: 22px; font-size: 0.9rem; color: var(--text-soft); }
.foot-links a:hover { color: var(--text); }
.foot-meta { width: 100%; color: var(--text-faint); font-size: 0.84rem; }

/* ---------- reveal ---------- */
.js .reveal { opacity: 0; transform: translateY(18px); transition: opacity 0.6s var(--ease), transform 0.6s var(--ease); }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  .icon-btn, .btn, .fam a { transition: none; }
}

/* ---------- responsive ---------- */
@media (max-width: 860px) {
  .hero .wrap { grid-template-columns: 1fr; }
  .hero-copy { max-width: none; }
  .nav-links { display: none; }
  .cmd-grid { grid-template-columns: 1fr; }
}
@media (max-width: 560px) {
  .rule { grid-template-columns: 1fr; gap: 6px; }
  .file-row { grid-template-columns: 1fr; gap: 4px; }
  .rule-v { font-size: 1rem; }
}