:root {
  color-scheme: dark;
  --bg: #0b0f14;
  --bg-2: #10161d;
  --line: #1e2a35;
  --text: #d6dee6;
  --muted: #8a99a8;
  --teal: #2dd4bf;
  --teal-dim: #14b8a6;
  --mono: ui-monospace, SFMono-Regular, "JetBrains Mono", Menlo, Consolas, monospace;
  --glow: rgba(45, 212, 191, 0.08);
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto, "Helvetica Neue", Arial, sans-serif;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  background:
    radial-gradient(1200px 600px at 85% -10%, var(--glow), transparent 60%),
    linear-gradient(var(--bg), var(--bg));
  color: var(--text);
  font: 17px/1.7 var(--sans);
}
a { color: var(--teal); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }
.wrap { max-width: 960px; margin: 0 auto; padding: 0 24px; }

header.top { border-bottom: 1px solid var(--line); }
header.top .wrap { display: flex; align-items: center; justify-content: space-between; height: 68px; }
.logo { font: 700 20px/1 var(--mono); color: var(--text); letter-spacing: 0.5px; }
.logo span { color: var(--teal); }
.logo:hover { text-decoration: none; }
nav.top a { font: 14px var(--mono); color: var(--muted); margin-left: 22px; }
nav.top a:hover { color: var(--teal); text-decoration: none; }

section { padding: 56px 0; border-bottom: 1px solid var(--line); }
section:last-of-type { border-bottom: 0; }
.kicker { font: 13px var(--mono); color: var(--teal); letter-spacing: 1px; margin: 0 0 18px; }
.kicker::before { content: "## "; color: var(--teal-dim); opacity: .7; }
h1 { font: 700 clamp(34px, 6vw, 56px)/1.12 var(--sans); margin: 0 0 28px; letter-spacing: -0.5px; }
h1 em { font-style: normal; color: var(--teal); }
h2 { font: 700 clamp(24px, 3.4vw, 32px)/1.25 var(--sans); margin: 0 0 22px; }
p.lead { font-size: clamp(17px, 2vw, 20px); color: var(--text); max-width: 720px; margin: 0 0 18px; }
p.muted { color: var(--muted); max-width: 720px; }

.services { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: 1fr 1fr; gap: 0 48px; }
.services li { padding: 18px 0; border-top: 1px dashed var(--line); }
.services li b { display: block; font: 600 17px var(--sans); margin-bottom: 4px; }
.services li b::before { content: "- "; font-family: var(--mono); color: var(--teal); }
.services li span { color: var(--muted); font-size: 15px; }

.team { display: grid; grid-template-columns: 1fr 1fr; gap: 28px; }
.card { background: var(--bg-2); border: 1px solid var(--line); border-radius: 10px; padding: 32px; }
.card:hover { border-color: rgba(45, 212, 191, 0.45); }
.card .name { font: 700 22px var(--sans); margin: 0; }
.card .role { font: 13px var(--mono); color: var(--teal); margin: 6px 0 20px; }
.card p { margin: 0 0 14px; color: var(--text); font-size: 16px; }
.card p:last-child { margin-bottom: 0; }

.contact-box { font: 15px var(--mono); background: var(--bg-2); border: 1px solid var(--line); border-left: 3px solid var(--teal); border-radius: 6px; padding: 22px 24px; display: inline-block; }
.contact-box .k { color: var(--muted); }
.contact-box a { font-size: 18px; }

footer { border-top: 1px solid var(--line); padding: 36px 0 48px; color: var(--muted); font-size: 14px; }
footer .wrap { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 12px; }
footer nav a { color: var(--muted); margin-left: 20px; }
footer nav a:first-child { margin-left: 0; }
footer nav a:hover { color: var(--teal); }

.doc h2 { margin-top: 48px; font-size: 22px; }
.doc p, .doc li { color: var(--text); max-width: 760px; }

@media (max-width: 860px) {
  section { padding: 48px 0; }
  .services { grid-template-columns: 1fr; }
}
@media (max-width: 680px) {
  body { font-size: 16px; }
  section { padding: 40px 0; }
  .team { grid-template-columns: 1fr; gap: 20px; }
  .card { padding: 24px; }
  nav.top a { margin-left: 14px; }
  nav.top a.hide-sm { display: none; }
}

.lang {
  margin-left: 22px; padding: 4px 10px; background: transparent; color: var(--teal);
  border: 1px solid rgba(45, 212, 191, 0.5); border-radius: 4px; font: 13px var(--mono); cursor: pointer;
}
.lang:hover { background: rgba(45, 212, 191, 0.1); }
html[lang="zh-CN"] body { font-family: var(--sans), "PingFang SC", "Noto Sans SC", "Microsoft YaHei", sans-serif; }
@media (max-width: 680px) { .lang { margin-left: 14px; } }

/* 亮色主题（右上角切换，记在 localStorage tc-theme） */
:root[data-theme="light"] {
  color-scheme: light;
  --bg: #f6f8fa;
  --bg-2: #ffffff;
  --line: #dde4ea;
  --text: #15212c;
  --muted: #5a6977;
  --teal: #0f8f83;
  --teal-dim: #0f766e;
  --glow: rgba(20, 184, 166, 0.10);
}
:root[data-theme="light"] .card { box-shadow: 0 1px 2px rgba(16, 24, 40, 0.04); }

.theme {
  margin-left: 10px; width: 30px; height: 27px; padding: 0; background: transparent; color: var(--teal);
  border: 1px solid var(--line); border-radius: 4px; font: 14px/1 var(--mono); cursor: pointer; vertical-align: middle;
}
.theme:hover { border-color: var(--teal); }
.logo, nav.top { white-space: nowrap; }
@media (max-width: 420px) {
  .wrap { padding: 0 18px; }
  nav.top a { margin-left: 10px; }
  .lang { margin-left: 10px; }
}