:root {
  color-scheme: light;
  --canvas: #e9f1f2;
  --surface: #f8fcfb;
  --ink: #102b34;
  --muted: #587078;
  --line: #b9cdd0;
  --blue: #155f9b;
  --aqua: #1ca9a1;
  --signal: #f06035;
  --night: #102730;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-width: 320px;
  min-height: 100vh;
  background-color: var(--canvas);
  background-image:
    linear-gradient(rgba(16, 43, 52, 0.045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(16, 43, 52, 0.045) 1px, transparent 1px);
  background-size: 32px 32px;
  color: var(--ink);
  font-family: "Microsoft YaHei", "PingFang SC", sans-serif;
}

button, a { -webkit-tap-highlight-color: transparent; }

.skip-link {
  position: fixed;
  top: -60px;
  left: 12px;
  z-index: 10;
  padding: 10px 14px;
  background: var(--night);
  color: #fff;
  transition: top 160ms ease;
}

.skip-link:focus { top: 12px; }

.site-header,
main,
.site-footer {
  width: min(1180px, calc(100% - 48px));
  margin-inline: auto;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 82px;
  border-bottom: 1px solid var(--line);
}

.brand {
  display: inline-flex;
  gap: 10px;
  align-items: center;
  color: var(--ink);
  font-size: 14px;
  font-weight: 800;
  letter-spacing: 0.04em;
  text-decoration: none;
}

.brand-mark {
  width: 17px;
  height: 17px;
  border: 5px solid var(--blue);
  border-right-color: var(--signal);
  border-radius: 50%;
}

.version-badge {
  padding: 7px 11px;
  border: 1px solid var(--line);
  background: rgba(248, 252, 251, 0.5);
  color: var(--muted);
  font: 12px/1.3 Consolas, monospace;
}

.version-badge strong { color: var(--signal); }

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(390px, 0.75fr);
  gap: clamp(48px, 8vw, 112px);
  align-items: center;
  padding: clamp(64px, 9vw, 118px) 0 90px;
}

.eyebrow {
  margin: 0 0 18px;
  color: var(--blue);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

h1, h2, p { margin-top: 0; }

h1 {
  max-width: 720px;
  margin-bottom: 26px;
  font-family: "STZhongsong", "SimSun", serif;
  font-size: clamp(48px, 6.5vw, 86px);
  font-weight: 700;
  letter-spacing: -0.07em;
  line-height: 1.03;
}

h1 em {
  display: block;
  margin-top: 0.12em;
  color: var(--signal);
  font-style: normal;
}

.lede {
  max-width: 620px;
  margin-bottom: 0;
  color: var(--muted);
  font-size: clamp(17px, 2vw, 21px);
  line-height: 1.8;
}

.address-trace {
  position: relative;
  overflow: hidden;
  padding: 28px;
  background: var(--night);
  color: #eaf8f7;
  box-shadow: 16px 16px 0 rgba(21, 95, 155, 0.14);
}

.address-trace::after {
  content: "";
  position: absolute;
  right: -58px;
  bottom: -58px;
  width: 150px;
  height: 150px;
  border: 28px solid rgba(28, 169, 161, 0.12);
  border-radius: 50%;
}

.trace-heading {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  padding-bottom: 20px;
  border-bottom: 1px solid rgba(234, 248, 247, 0.18);
  font-size: 13px;
  font-weight: 700;
}

.trace-status { color: #9ec0c4; font: 11px/1.4 Consolas, monospace; }
.trace-status i { display: inline-block; width: 7px; height: 7px; margin-right: 5px; border-radius: 50%; background: var(--aqua); }

.address-trace ol {
  position: relative;
  z-index: 1;
  margin: 0;
  padding: 26px 0 8px;
  list-style: none;
}

.address-trace li {
  position: relative;
  padding: 0 0 28px 28px;
  border-left: 1px solid rgba(234, 248, 247, 0.2);
}

.address-trace li:last-child { padding-bottom: 10px; border-color: transparent; }

.address-trace li::before {
  content: "";
  position: absolute;
  top: 2px;
  left: -5px;
  width: 9px;
  height: 9px;
  border: 1px solid var(--night);
  border-radius: 50%;
  background: var(--aqua);
  box-shadow: 0 0 0 4px rgba(28, 169, 161, 0.14);
}

.address-trace li:last-child::before { background: var(--signal); box-shadow: 0 0 0 4px rgba(240, 96, 53, 0.14); }

.trace-label {
  display: block;
  margin-bottom: 7px;
  color: #91aeb2;
  font-size: 11px;
}

.address-trace code { font: 600 clamp(13px, 1.3vw, 16px)/1.5 Consolas, monospace; overflow-wrap: anywhere; }
.address-trace > p { position: relative; z-index: 1; margin: 14px 0 0; color: #86a4a8; font-size: 11px; line-height: 1.6; }

.terms { padding: 0 0 96px; }

.section-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 36px;
  margin-bottom: 30px;
  padding-top: 32px;
  border-top: 1px solid var(--line);
}

.section-heading h2 {
  margin-bottom: 0;
  font-family: "STZhongsong", "SimSun", serif;
  font-size: clamp(30px, 4vw, 48px);
  letter-spacing: -0.045em;
}

.section-heading > p { max-width: 260px; margin-bottom: 5px; color: var(--muted); line-height: 1.7; }

.term-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; align-items: start; }

.term-card {
  border: 1px solid var(--line);
  background: rgba(248, 252, 251, 0.78);
  transition: border-color 180ms ease, box-shadow 180ms ease, transform 180ms ease;
}

.term-card:hover { border-color: #789ba2; transform: translateY(-2px); }
.term-card.is-open { border-color: var(--blue); box-shadow: 0 12px 30px rgba(16, 43, 52, 0.08); }

.term-trigger {
  width: 100%;
  padding: 25px;
  border: 0;
  background: transparent;
  color: var(--ink);
  font: inherit;
  text-align: left;
  cursor: pointer;
}

.term-trigger:focus-visible { outline: 3px solid var(--signal); outline-offset: -5px; }

.term-meta,
.term-name,
.term-summary,
.term-action { display: flex; }

.term-meta { align-items: center; justify-content: space-between; color: var(--blue); font: 11px/1.2 Consolas, monospace; letter-spacing: 0.08em; }
.term-meta b { font-weight: 500; }
.term-meta code { color: var(--muted); }

.term-name {
  margin-top: 44px;
  font-family: "STZhongsong", "SimSun", serif;
  font-size: clamp(35px, 4vw, 50px);
  font-weight: 700;
  letter-spacing: -0.05em;
}

.term-summary { min-height: 76px; margin-top: 14px; color: var(--muted); font-size: 15px; line-height: 1.75; }

.term-action {
  align-items: center;
  justify-content: space-between;
  margin-top: 22px;
  padding-top: 17px;
  border-top: 1px solid var(--line);
  color: var(--blue);
  font-size: 13px;
  font-weight: 700;
}

.term-action i {
  display: grid;
  width: 27px;
  height: 27px;
  place-items: center;
  border: 1px solid currentColor;
  border-radius: 50%;
  font: normal 19px/1 Consolas, monospace;
  transition: transform 180ms ease;
}

.term-trigger[aria-expanded="true"] .term-action i { transform: rotate(45deg); }

.term-detail { padding: 0 25px 25px; border-top: 1px solid var(--line); }
.term-detail[hidden] { display: none; }
.detail-label { margin: 22px 0 8px; color: var(--signal); font-size: 11px; font-weight: 800; letter-spacing: 0.14em; }
.term-detail > p:not(.detail-label) { min-height: 92px; margin-bottom: 22px; color: var(--ink); font-size: 14px; line-height: 1.75; }
.term-detail dl { margin: 0; }
.term-detail dl div { display: grid; grid-template-columns: 44px 1fr; gap: 10px; padding: 10px 0; border-top: 1px solid rgba(185, 205, 208, 0.7); }
.term-detail dt { color: var(--muted); font-size: 11px; }
.term-detail dd { margin: 0; font-size: 12px; line-height: 1.6; }
.term-detail code { color: var(--blue); font: 600 12px/1.5 Consolas, monospace; overflow-wrap: anywhere; }

.site-footer {
  display: flex;
  justify-content: space-between;
  gap: 30px;
  padding: 26px 0 40px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 12px;
}

.site-footer p { margin: 0; }
.site-footer span { margin-right: 8px; color: var(--signal); font: 700 11px/1 Consolas, monospace; }

@media (max-width: 900px) {
  .hero { grid-template-columns: 1fr; gap: 48px; }
  .address-trace { width: min(100%, 610px); }
  .term-grid { grid-template-columns: 1fr; }
  .term-summary, .term-detail > p:not(.detail-label) { min-height: auto; }
  .term-name { margin-top: 30px; }
}

@media (max-width: 560px) {
  .site-header, main, .site-footer { width: min(calc(100% - 28px), 1180px); }
  .site-header { min-height: 70px; }
  .brand { font-size: 13px; }
  .version-badge { padding: 6px 8px; font-size: 10px; }
  .hero { padding: 52px 0 68px; }
  h1 { font-size: clamp(43px, 14vw, 64px); }
  .address-trace { padding: 23px; box-shadow: 8px 8px 0 rgba(21, 95, 155, 0.14); }
  .section-heading { display: block; }
  .section-heading > p { margin-top: 14px; }
  .term-trigger, .term-detail { padding-right: 21px; padding-left: 21px; }
  .site-footer { display: block; }
  .site-footer p + p { margin-top: 10px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: 0.01ms !important; }
}