:root {
  --bg: #08080c;
  --bg-2: #0b0b10;
  --fg: #ecedf1;
  --mute: rgba(236, 237, 241, 0.58);
  --muter: rgba(236, 237, 241, 0.36);
  --mutest: rgba(236, 237, 241, 0.22);
  --line: rgba(236, 237, 241, 0.08);
  --line-strong: rgba(236, 237, 241, 0.16);
  --purple: #8a2be2;
  --cyan: #67e8f9;
  --sans: "IBM Plex Sans", "Noto Sans SC", -apple-system, system-ui, sans-serif;
  --serif: "Newsreader", "Noto Serif SC", Georgia, serif;
  --mono: "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, monospace;
  --cn-sans: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --cn-serif: "Noto Serif SC", "Songti SC", "STSong", serif;
  --col: 920px;
  --gutter: clamp(20px, 5vw, 56px);
}

* { box-sizing: border-box; }
html, body { background: var(--bg); color: var(--fg); }
body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--sans);
  font-weight: 300;
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  font-feature-settings: "kern", "liga", "calt";
}
::selection { background: rgba(138, 43, 226, 0.35); color: var(--fg); }
a { color: var(--fg); text-decoration: none; border-bottom: 1px solid var(--line-strong); transition: border-color .18s ease, color .18s ease; }
a:hover { border-bottom-color: var(--cyan); color: var(--cyan); }

#field {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
  z-index: 0;
  opacity: 0.38;
  pointer-events: none;
}
.vignette {
  position: fixed;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background:
    radial-gradient(ellipse 130% 100% at 50% 24%,
      rgba(11, 11, 18, 0) 0%,
      rgba(9, 9, 14, 0.42) 46%,
      rgba(8, 8, 12, 0.82) 78%,
      rgba(6, 6, 9, 0.95) 100%);
}

.shell { position: relative; z-index: 2; padding: 0 var(--gutter); }
.wrap { max-width: var(--col); margin: 0 auto; }

.topbar {
  max-width: var(--col);
  margin: 0 auto;
  padding: 28px 0;
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 24px;
}
.brand {
  font-family: var(--sans);
  font-weight: 600;
  font-size: 22px;
  letter-spacing: -0.03em;
  color: var(--fg);
  border-bottom: none;
}
.brand .dot { color: var(--purple); }
.nav {
  display: flex;
  align-items: center;
  gap: clamp(16px, 2.6vw, 30px);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}
.nav a { color: var(--mute); border-bottom: none; }
.nav a:hover { color: var(--cyan); }

.pagehead {
  max-width: var(--col);
  margin: 0 auto;
  padding: clamp(64px, 12vh, 128px) 0 clamp(52px, 8vh, 88px);
  text-align: center;
}
.kicker {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--muter);
  margin: 0 0 22px;
}
.hero-title {
  font-family: var(--sans);
  font-style: normal;
  font-weight: 600;
  font-size: clamp(54px, 9vw, 104px);
  line-height: 0.94;
  color: var(--fg);
  margin: 0 auto 28px;
  letter-spacing: -0.045em;
  max-width: none;
  overflow-wrap: normal;
  word-break: keep-all;
}
.hero-cn {
  font-family: var(--cn-serif);
  font-weight: 400;
  font-size: clamp(21px, 2.8vw, 31px);
  line-height: 1.55;
  color: var(--fg);
  max-width: 25ch;
  margin: 0 auto;
  letter-spacing: 0.01em;
  text-wrap: balance;
}
.hero-en {
  font-family: var(--serif);
  font-style: italic;
  font-size: clamp(16px, 1.9vw, 19px);
  color: var(--mute);
  line-height: 1.55;
  margin: 22px auto 0;
  max-width: 48ch;
}

.section {
  max-width: var(--col);
  margin: 0 auto;
  padding: clamp(42px, 7vh, 78px) clamp(22px, 4vw, 42px);
  border-top: 1px solid var(--line-strong);
  background: rgba(6, 6, 9, 0.74);
  backdrop-filter: blur(2px);
}
.section + .section { margin-top: 1px; }
.section-grid {
  display: grid;
  grid-template-columns: minmax(120px, 0.28fr) 1fr;
  gap: clamp(28px, 5vw, 72px);
}
.section-tag {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--fg);
  line-height: 1.5;
  border-left: 1px solid var(--cyan);
  padding-left: 14px;
}
.section-title {
  font-family: var(--cn-serif);
  font-weight: 500;
  font-size: clamp(26px, 3.3vw, 38px);
  line-height: 1.3;
  color: var(--fg);
  margin: 0 0 18px;
  letter-spacing: 0.01em;
}
.section-body {
  font-family: var(--cn-sans);
  font-size: 16px;
  line-height: 1.9;
  color: rgba(236, 237, 241, 0.72);
  margin: 0;
  letter-spacing: 0.012em;
}
.muted-en {
  font-family: var(--serif);
  font-style: italic;
  font-size: 15px;
  color: var(--mute);
  margin: 14px 0 0;
}

.line-list, .tile-list {
  list-style: none;
  padding: 0;
  margin: 28px 0 0;
  border: 1px solid var(--line);
  background: var(--line);
  display: grid;
  gap: 1px;
}
.line-list { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.line-list li, .tile-list li {
  background: var(--bg);
  padding: 22px 24px;
}
.line-list span, .tile-list span {
  display: block;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muter);
  margin-bottom: 8px;
}
.line-list strong, .tile-list strong {
  font-family: var(--cn-serif);
  font-size: 18px;
  font-weight: 400;
  color: var(--fg);
}
.tile-list { grid-template-columns: repeat(3, minmax(0, 1fr)); }

.code {
  margin: 28px 0 0;
  padding: 28px;
  border: 1px solid var(--line);
  background: rgba(8, 8, 12, 0.72);
  overflow-x: auto;
}
.code pre {
  margin: 0;
  font-family: var(--mono);
  font-size: 13px;
  line-height: 1.75;
  color: rgba(236, 237, 241, 0.78);
}
.text-link {
  display: inline-flex;
  margin-top: 24px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--mute);
  border-bottom: 1px solid var(--line-strong);
  padding-bottom: 3px;
}

footer {
  max-width: var(--col);
  margin: 0 auto;
  padding: 48px 0 56px;
  border-top: 1px solid var(--line);
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 16px;
  font-family: var(--mono);
  font-size: 12px;
  color: var(--mute);
  letter-spacing: 0.04em;
}
footer a { border-bottom: none; color: var(--mute); }
footer a:hover { color: var(--cyan); }
.foot-cn { font-family: var(--cn-sans); letter-spacing: 0.02em; font-size: 12px; }

html[data-locale="en"] .hero-cn,
html[data-locale="en"] .section-title,
html[data-locale="en"] .section-body,
html[data-locale="en"] .line-list strong,
html[data-locale="en"] .tile-list strong,
html[data-locale="en"] .foot-cn {
  font-family: var(--sans);
  letter-spacing: 0;
}

html[data-locale="en"] .hero-cn {
  max-width: 42ch;
}

html[data-locale="zh"] .hero-title {
  font-family: var(--cn-serif);
  font-style: normal;
  font-weight: 500;
  font-size: clamp(54px, 8vw, 92px);
  line-height: 1.05;
  letter-spacing: 0.02em;
  max-width: none;
}

html[data-locale="zh"] .hero-en,
html[data-locale="en"] .hero-en,
html[data-locale="zh"] .muted-en {
  display: none;
}

@media (max-width: 760px) {
  .topbar { align-items: flex-start; flex-direction: column; }
  .nav { flex-wrap: wrap; row-gap: 10px; }
  .section-grid { grid-template-columns: 1fr; gap: 16px; }
  .line-list, .tile-list { grid-template-columns: 1fr; }
}