:root {
  --paper: #f4efe5;
  --paper-soft: #faf6ee;
  --ink: #24201b;
  --muted: #716d65;
  --line: rgba(77, 70, 60, 0.17);
  --accent: #7f99af;
}

* {
  box-sizing: border-box;
}

html {
  min-height: 100%;
  background: var(--paper);
  scrollbar-width: none;
}

html::-webkit-scrollbar,
body::-webkit-scrollbar {
  display: none;
}

body {
  min-height: 100vh;
  margin: 0;
  color: var(--ink);
  font-family: Inter, "Noto Serif SC", "Microsoft YaHei", sans-serif;
  -ms-overflow-style: none;
  background:
    url("textures/paper-warm.webp") center / 580px 580px repeat,
    radial-gradient(circle at 22% 20%, rgba(255, 255, 255, 0.55), transparent 34%),
    radial-gradient(circle at 80% 76%, rgba(188, 164, 128, 0.13), transparent 32%),
    linear-gradient(135deg, #f8f3ea 0%, #f0e9de 100%);
}

body[data-topic="product"] {
  --accent: #aeb7a4;
}

body[data-topic="ai"] {
  --accent: #7f99af;
}

body[data-topic="business"] {
  --accent: #c8a083;
}

body[data-topic="system"] {
  --accent: #cfc3a8;
}

body[data-topic="observe"] {
  --accent: #aeb9ac;
}

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

.page {
  width: min(100% - 44px, 764px);
  margin: 0 auto;
  padding: 40px 0 100px;
}

.crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin-bottom: 54px;
  color: var(--muted);
  font-size: 14px;
}

.crumbs a {
  border-bottom: 1px solid rgba(36, 32, 27, 0.28);
}

.hero {
  padding-bottom: 32px;
  border-bottom: 1px solid var(--line);
}

.kicker {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  margin-bottom: 20px;
  color: var(--muted);
  font-size: 13px;
}

.kicker::before {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--accent);
  content: "";
}

.hero h1 {
  margin: 0 0 20px;
  font-family: "Noto Serif SC", "Microsoft YaHei", serif;
  font-size: clamp(30px, 5vw, 44px);
  font-weight: 700;
  line-height: 1.24;
}

.summary {
  max-width: 40rem;
  margin: 0;
  color: #5f5c56;
  font-family: "Noto Serif SC", "Microsoft YaHei", serif;
  font-size: 16px;
  line-height: 1.95;
}

.meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  margin-top: 26px;
}

.state {
  padding: 5px 13px;
  color: #514d45;
  border-radius: 999px;
  background: rgba(219, 211, 191, 0.58);
  font-size: 13px;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tags span {
  padding: 4px 11px;
  color: #6b6760;
  border: 1px solid var(--line);
  border-radius: 999px;
  font-size: 12px;
}

.body {
  padding-top: 48px;
  color: #2b2721;
  font-family: "Noto Serif SC", "Microsoft YaHei", serif;
  font-size: 17px;
  line-height: 1.95;
}

.body h2 {
  margin: 54px 0 18px;
  font-size: 24px;
  font-weight: 700;
  line-height: 1.45;
}

.body h3 {
  margin: 38px 0 14px;
  font-size: 19px;
  font-weight: 700;
  line-height: 1.55;
}

.body p {
  margin: 0 0 22px;
}

.body strong {
  color: #1c1915;
  font-weight: 700;
}

.body ul,
.body ol {
  margin: 0 0 24px;
  padding-left: 1.45em;
}

.body li {
  margin-bottom: 10px;
}

.body li::marker {
  color: var(--muted);
}

.body blockquote {
  margin: 30px 0;
  padding: 2px 0 2px 22px;
  color: #4f4b44;
  border-left: 2px solid var(--accent);
  font-size: 16px;
}

.body blockquote p:last-child {
  margin-bottom: 0;
}

.body hr {
  height: 1px;
  margin: 48px 0;
  border: 0;
  background: var(--line);
}

.body .table-wrap {
  margin: 0 0 28px;
  overflow-x: auto;
}

.body table {
  width: 100%;
  min-width: 560px;
  border-collapse: collapse;
  font-family: Inter, "Noto Serif SC", "Microsoft YaHei", sans-serif;
  font-size: 15px;
}

.body th:first-child,
.body td:first-child {
  width: 1%;
  white-space: nowrap;
}

.body th,
.body td {
  padding: 13px 16px;
  line-height: 1.75;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--line);
}

.body th {
  color: var(--muted);
  font-weight: 500;
  border-bottom-color: rgba(77, 70, 60, 0.3);
}

.body code {
  padding: 2px 6px;
  border-radius: 4px;
  background: rgba(219, 211, 191, 0.45);
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.88em;
}

.body a {
  border-bottom: 1px solid rgba(36, 32, 27, 0.32);
}

.related {
  display: grid;
  gap: 28px;
  margin-top: 76px;
  padding-top: 32px;
  border-top: 1px solid var(--line);
}

.related h2 {
  margin: 0 0 12px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0;
}

.related p {
  margin: 0;
  color: #5f5c56;
  font-size: 15px;
  line-height: 1.88;
}

.related a {
  border-bottom: 1px solid rgba(36, 32, 27, 0.32);
}

.foot {
  margin-top: 64px;
  color: var(--muted);
  font-size: 14px;
}

.reveal {
  opacity: 0;
  transform: translateY(22px);
  transition:
    opacity 720ms cubic-bezier(0.22, 1, 0.36, 1),
    transform 720ms cubic-bezier(0.22, 1, 0.36, 1);
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
}

@media (max-width: 720px) {
  .page {
    width: min(100% - 32px, 764px);
    padding: 28px 0 72px;
  }

  .crumbs {
    margin-bottom: 36px;
  }

  .body {
    padding-top: 36px;
    font-size: 16px;
  }

  .body h2 {
    margin-top: 44px;
    font-size: 21px;
  }

  .body h3 {
    font-size: 18px;
  }
}