:root {
  color-scheme: light;
  --paper: #f2f7fa;
  --white: #ffffff;
  --ink: #173246;
  --blue: #285f7e;
  --teal: #2e8791;
  --muted: #667e8d;
  --line: #cbdce4;
  font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans CJK SC", system-ui, sans-serif;
  color: var(--ink);
  background: var(--paper);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  min-width: 320px;
  min-height: 100vh;
  margin: 0;
  background:
    linear-gradient(rgba(40, 95, 126, .045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(40, 95, 126, .045) 1px, transparent 1px),
    var(--paper);
  background-size: 32px 32px;
}

.site-header,
main,
footer {
  width: min(1120px, calc(100% - 48px));
  margin-inline: auto;
}

.site-header {
  min-height: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--line);
}

.site-mark {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--ink);
  font-size: 11px;
  font-weight: 650;
  letter-spacing: .14em;
  text-decoration: none;
}

.mark-lines {
  width: 34px;
  height: 34px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 3px;
  border: 1px solid var(--blue);
  border-radius: 50%;
}

.mark-lines i {
  width: 3px;
  display: block;
  border-radius: 2px;
  background: var(--teal);
}

.mark-lines i:nth-child(1) { height: 9px; }
.mark-lines i:nth-child(2) { height: 20px; }
.mark-lines i:nth-child(3) { height: 13px; }

.site-state {
  color: var(--muted);
  font-size: 12px;
}

.site-state i {
  width: 7px;
  height: 7px;
  display: inline-block;
  margin-right: 8px;
  border-radius: 50%;
  background: var(--teal);
}

.hero {
  min-height: 560px;
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(330px, .8fr);
  align-items: center;
  gap: 64px;
  border-bottom: 1px solid var(--line);
}

.eyebrow,
.section-heading p {
  margin: 0 0 18px;
  color: var(--teal);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .18em;
}

h1 {
  max-width: 700px;
  margin: 0;
  font-family: "STSong", "Songti SC", "Noto Serif CJK SC", serif;
  font-size: clamp(44px, 6vw, 76px);
  font-weight: 600;
  line-height: 1.18;
  letter-spacing: -.045em;
}

.lead {
  max-width: 610px;
  margin: 30px 0 0;
  color: var(--muted);
  font-size: 16px;
  line-height: 1.9;
}

.circuit {
  position: relative;
  width: min(390px, 100%);
  aspect-ratio: 1;
  justify-self: end;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: rgba(255, 255, 255, .54);
}

.circuit::before,
.circuit::after {
  content: "";
  position: absolute;
  inset: 15%;
  border: 1px solid rgba(46, 135, 145, .25);
  border-radius: 50%;
}

.circuit::after { inset: 31%; }

.circuit .symbol {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  color: var(--blue);
  font-family: Georgia, serif;
  font-size: 64px;
  font-style: normal;
}

.circuit small {
  position: absolute;
  left: 50%;
  bottom: 18%;
  transform: translateX(-50%);
  color: var(--muted);
  font: 10px ui-monospace, SFMono-Regular, Menlo, monospace;
  letter-spacing: .16em;
  white-space: nowrap;
}

.node {
  position: absolute;
  z-index: 2;
  width: 11px;
  height: 11px;
  border: 3px solid var(--paper);
  border-radius: 50%;
  background: var(--teal);
  box-shadow: 0 0 0 1px var(--teal);
}

.node-a { top: 13%; left: 49%; }
.node-b { top: 48%; right: 5%; }
.node-c { bottom: 7%; left: 36%; }
.node-d { top: 42%; left: 5%; }

.wire {
  position: absolute;
  z-index: 1;
  display: block;
  height: 1px;
  transform-origin: left center;
  background: var(--teal);
}

.wire-a { width: 37%; top: 14%; left: 51%; transform: rotate(45deg); }
.wire-b { width: 39%; top: 50%; right: 8%; transform: rotate(128deg); transform-origin: right center; }
.wire-c { width: 40%; bottom: 10%; left: 38%; transform: rotate(152deg); }
.wire-d { width: 42%; top: 44%; left: 8%; transform: rotate(-43deg); }

.scope { padding: 82px 0 74px; }

.section-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 30px;
  margin-bottom: 34px;
}

.section-heading p { margin: 0 0 5px; }

.section-heading h2 {
  margin: 0;
  font-size: clamp(25px, 3vw, 36px);
  font-weight: 650;
  letter-spacing: -.03em;
}

.scope-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.scope-grid article {
  min-height: 220px;
  padding: 32px;
  background: rgba(255, 255, 255, .5);
}

.scope-grid article + article { border-left: 1px solid var(--line); }

.scope-grid span {
  color: var(--teal);
  font: 700 11px ui-monospace, SFMono-Regular, Menlo, monospace;
  letter-spacing: .14em;
}

.scope-grid h3 {
  margin: 42px 0 12px;
  font-size: 20px;
}

.scope-grid p {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.8;
}

.note {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 26px 0 64px;
  color: var(--muted);
  font-size: 12px;
}

.note p { margin: 0; }

.note span {
  color: var(--blue);
  letter-spacing: .08em;
  white-space: nowrap;
}

footer {
  min-height: 78px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 11px;
}

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

footer a:hover,
footer a:focus-visible {
  color: var(--blue);
  text-decoration: underline;
  text-underline-offset: 3px;
}

@media (max-width: 820px) {
  .hero {
    min-height: auto;
    grid-template-columns: 1fr;
    gap: 50px;
    padding: 88px 0 70px;
  }

  .circuit {
    width: min(330px, 86vw);
    height: min(330px, 86vw);
    justify-self: center;
  }

  .scope-grid { grid-template-columns: 1fr; }
  .scope-grid article { min-height: auto; }
  .scope-grid article + article { border-top: 1px solid var(--line); border-left: 0; }
}

@media (max-width: 560px) {
  .site-header,
  main,
  footer { width: min(100% - 30px, 1120px); }

  .site-header { min-height: 66px; }
  .site-mark { font-size: 9px; }
  .site-state { display: none; }
  .hero { padding-top: 68px; }
  h1 { font-size: 42px; }
  .lead { margin-top: 22px; font-size: 14px; }
  .scope { padding: 64px 0 54px; }
  .section-heading { display: block; }
  .scope-grid article { padding: 27px 22px; }
  .scope-grid h3 { margin-top: 28px; }
  .note { align-items: flex-start; flex-direction: column; padding-bottom: 48px; }
  footer { align-items: flex-start; flex-direction: column; justify-content: center; gap: 7px; }
}

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