:root {
  --navy: #0a0a23;
  --ink: #1b1b32;
  --muted: #4f4f5f;
  --blue: #002ead;
  --line: #d6d6dc;
  --soft: #f5f6f7;
  --sans: Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  min-width: 320px;
  background: #fff;
}

body {
  margin: 0;
  color: var(--ink);
  background: #fff;
  font-family: var(--sans);
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--blue);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.15em;
}

a:hover,
a:focus-visible {
  color: #001a66;
}

.topbar {
  min-height: 58px;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0 24px;
  color: #fff;
  background: var(--navy);
  border-bottom: 3px solid #d0d0d5;
}

.topbar p {
  margin: 0;
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: 0.12em;
}

.article {
  width: min(760px, calc(100% - 40px));
  margin: 0 auto;
  padding: 72px 0 90px;
}

.category {
  margin: 0 0 18px;
  color: var(--blue);
  font-size: 0.9rem;
  font-weight: 700;
}

h1 {
  margin: 0;
  font-size: clamp(2.6rem, 7vw, 4rem);
  font-weight: 700;
  line-height: 1.17;
  letter-spacing: -0.045em;
}

.summary {
  margin: 30px 0 0;
  color: var(--muted);
  font-size: 1.35rem;
  line-height: 1.65;
}

.divider {
  height: 1px;
  margin: 42px 0;
  background: var(--line);
}

.article-body p {
  margin: 0 0 1.55em;
  font-size: 1.18rem;
  line-height: 1.82;
}

.article-body .lead {
  font-size: 1.3rem;
  line-height: 1.75;
}

.article-body section {
  margin-top: 54px;
}

h2 {
  margin: 0 0 22px;
  font-size: 1.85rem;
  line-height: 1.3;
}

blockquote {
  margin: 52px 0;
  padding: 24px 28px;
  color: var(--ink);
  background: var(--soft);
  border-left: 5px solid var(--navy);
  font-size: 1.25rem;
  font-weight: 600;
  line-height: 1.7;
}

.timeline {
  margin: 52px 0;
  padding: 30px;
  background: var(--soft);
  border: 1px solid var(--line);
}

.timeline h2 {
  font-size: 1.45rem;
}

.timeline dl {
  margin: 0;
}

.timeline dl div {
  display: grid;
  grid-template-columns: 110px 1fr;
  gap: 18px;
  padding: 13px 0;
  border-top: 1px solid var(--line);
}

.timeline dl div:last-child {
  border-bottom: 1px solid var(--line);
}

.timeline dt {
  color: var(--blue);
  font-weight: 700;
}

.timeline dd {
  margin: 0;
  color: var(--muted);
}

.references {
  padding-top: 34px;
  border-top: 1px solid var(--line);
}

.references ul {
  margin: 0;
  padding-left: 1.35rem;
}

.references li {
  margin: 13px 0;
  font-size: 1rem;
  line-height: 1.65;
}

.page-footer {
  padding: 30px 20px;
  color: #fff;
  background: var(--navy);
  text-align: center;
}

.page-footer p {
  margin: 0;
  font-size: 0.82rem;
  letter-spacing: 0.08em;
}

@media (max-width: 600px) {
  .article {
    width: min(100% - 32px, 760px);
    padding-top: 52px;
  }

  h1 {
    font-size: 2.45rem;
  }

  .summary {
    font-size: 1.15rem;
  }

  .article-body p,
  .article-body .lead {
    font-size: 1.08rem;
  }

  .timeline {
    padding: 22px;
  }

  .timeline dl div {
    grid-template-columns: 1fr;
    gap: 5px;
  }
}