:root {
  --bg: #101416;
  --bg-raise: #171d1f;
  --ink: #f4f7f6;
  --muted: rgba(244, 247, 246, 0.72);
  --line: rgba(244, 247, 246, 0.14);
  --accent: #8ed4c2;
  --accent-dim: rgba(142, 212, 194, 0.14);
  --warn: #f0b4a8;
  --max: 980px;
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, "Songti SC", serif;
  --sans: "Avenir Next", "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.6;
  background:
    linear-gradient(rgba(142, 212, 194, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(142, 212, 194, 0.05) 1px, transparent 1px),
    var(--bg);
  background-size: 28px 28px, 28px 28px, auto;
}

a { color: var(--accent); }
a:hover { color: #d7fff4; }

.skip {
  position: absolute;
  left: 12px;
  top: -120px;
  background: var(--ink);
  color: var(--bg);
  padding: 8px 12px;
  z-index: 2;
}
.skip:focus { top: 12px; }

.wrap {
  width: min(var(--max), calc(100% - 32px));
  margin: 0 auto;
}

header.site {
  border-bottom: 1px solid var(--line);
  background: rgba(16, 20, 22, 0.92);
  position: sticky;
  top: 0;
  z-index: 1;
}

.bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  padding: 16px 0;
}

.brand {
  color: var(--ink);
  text-decoration: none;
  font-weight: 650;
  letter-spacing: 0.04em;
}

.brand small {
  display: block;
  font-weight: 450;
  letter-spacing: 0;
  color: var(--muted);
  font-size: 12px;
}

nav { display: flex; gap: 16px; flex-wrap: wrap; }
nav a { color: var(--ink); text-decoration: none; font-size: 15px; }
nav a[aria-current="page"] { color: var(--accent); }

main { padding: 36px 0 64px; }

.hero {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 28px;
  align-items: center;
  margin-bottom: 28px;
}

.kicker {
  margin: 0 0 8px;
  color: var(--accent);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-size: 12px;
}

h1, h2, h3 { line-height: 1.25; font-weight: 620; }
h1 { font-family: var(--serif); font-size: clamp(34px, 5vw, 52px); margin: 0 0 12px; }
h2 { font-size: 26px; margin: 0 0 12px; }
h3 { font-size: 18px; margin: 0 0 6px; }

.lede, .zh { color: var(--muted); }
.zh { margin-top: 8px; }

.plan {
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--accent-dim);
  padding: 18px;
}

.shapes {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px 18px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.shapes li {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0;
}

.mark {
  width: 28px;
  height: 28px;
  flex: none;
}

.mark.circle { border-radius: 50%; background: #8ed4c2; }
.mark.triangle {
  width: 0;
  height: 0;
  border-left: 14px solid transparent;
  border-right: 14px solid transparent;
  border-bottom: 24px solid #e2c27a;
  background: transparent;
}
.mark.square { background: #e7a39a; }
.mark.dashed {
  border-radius: 50%;
  border: 2px dashed rgba(244, 247, 246, 0.8);
  background: transparent;
}

.notice, .card, .module, .contact {
  border: 1px solid var(--line);
  border-radius: 16px;
  background: rgba(23, 29, 31, 0.88);
  padding: 16px 18px;
}

.notice { margin: 18px 0; }
.notice strong { color: var(--warn); }

.grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin: 14px 0 8px;
}

.module h3 span {
  display: block;
  color: var(--muted);
  font-weight: 450;
  font-size: 14px;
}

section { margin: 34px 0; }

.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px 28px;
}

.split .zh { margin-top: 0; }

ol, ul { margin: 8px 0 0; padding-left: 1.2em; }
li + li { margin-top: 6px; }

.contact a { word-break: break-all; }

footer.site {
  border-top: 1px solid var(--line);
  padding: 22px 0 36px;
  color: var(--muted);
  font-size: 14px;
}

footer.site p { margin: 6px 0; }

@media (max-width: 800px) {
  .hero, .grid, .split { grid-template-columns: 1fr; }
  .bar { align-items: flex-start; flex-direction: column; }
}