:root {
  --paper: #f3efe6;
  --ink: #1d1916;
  --muted: #5e564e;
  --line: #ddd4c6;
  --clay: #c4512c;
  --clay-deep: #8d3418;
  --moss: #2f5d4a;
  --card: #fffaf3;
  --shadow: 0 18px 40px rgba(60, 36, 18, 0.08);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at top left, rgba(196, 81, 44, 0.08), transparent 28rem),
    var(--paper);
  font-family: "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", sans-serif;
  line-height: 1.7;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem 6vw;
  background: rgba(243, 239, 230, 0.92);
  border-bottom: 1px solid transparent;
  backdrop-filter: blur(10px);
}

.brand {
  font-family: "Songti SC", "Noto Serif SC", serif;
  font-size: 1.6rem;
  letter-spacing: 0.12em;
}

.site-nav {
  display: flex;
  gap: 1.5rem;
}

.site-nav a {
  color: var(--muted);
}

.site-nav a:hover,
.site-nav a:focus-visible {
  color: var(--ink);
}

.nav-toggle {
  display: none;
  border: 1px solid var(--line);
  background: transparent;
  padding: 0.35rem 0.75rem;
  font: inherit;
}

.hero,
.preview,
.feature-band,
.split,
.mall,
.archive,
.rules {
  width: min(1080px, calc(100% - 12vw));
  margin: 0 auto;
}

#preview,
#community,
#nearby,
#mall,
#archive,
#rules,
#intro,
#features,
#notice,
#company {
  scroll-margin-top: 5.5rem;
}

.hero {
  display: grid;
  grid-template-columns: 1.3fr 0.7fr;
  gap: 4rem;
  align-items: end;
  padding: 5.5rem 0 4rem;
}

.hero-plain {
  grid-template-columns: 1fr;
  align-items: start;
  padding-bottom: 2rem;
}

.feature-plain {
  grid-template-columns: 1fr;
}

.company,
.document {
  width: min(1080px, calc(100% - 12vw));
  margin: 0 auto;
}

.company {
  padding: 3.2rem 0;
  border-top: 1px solid var(--line);
}

.company-list {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin: 0;
}

.company-list div {
  padding: 1.2rem 1.3rem;
  background: var(--card);
}

.company-list dt {
  color: var(--muted);
  font-size: 0.92rem;
}

.company-list dd {
  margin: 0.35rem 0 0;
  font-size: 1.05rem;
}

.company-list a,
.footer-links a,
.document a {
  text-decoration: underline;
  text-underline-offset: 0.18em;
}

.document {
  width: min(760px, calc(100% - 12vw));
  padding: 3.5rem 0 4rem;
}

.document h1 {
  font-size: clamp(2rem, 4vw, 3rem);
}

.document h2 {
  margin-top: 2rem;
  font-size: 1.35rem;
}

.document-meta {
  color: var(--muted);
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem 1.4rem;
  align-items: center;
}

.eyebrow {
  margin: 0 0 0.6rem;
  color: var(--clay-deep);
  letter-spacing: 0.16em;
  font-size: 0.82rem;
}

h1,
h2,
h3 {
  font-family: "Songti SC", "Noto Serif SC", serif;
  font-weight: 500;
  line-height: 1.25;
}

h1 {
  margin: 0;
  font-size: clamp(2.4rem, 5vw, 4.4rem);
}

h2 {
  margin: 0 0 0.8rem;
  font-size: clamp(1.8rem, 3vw, 2.6rem);
}

.lede {
  max-width: 38rem;
  color: var(--muted);
  font-size: 1.08rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem;
  margin-top: 1.6rem;
}

.button {
  display: inline-flex;
  align-items: center;
  min-height: 2.8rem;
  padding: 0.45rem 1rem;
  border: 1px solid var(--ink);
}

.button-primary {
  background: var(--ink);
  color: #f7f3ec;
}

.button-ghost {
  background: transparent;
}

.hero-stage {
  position: relative;
  height: 360px;
}

.paper-card {
  position: absolute;
  width: 210px;
  padding: 1.1rem 1rem 1.25rem;
  background: var(--card);
  box-shadow: var(--shadow);
}

.paper-card span,
.feed-item small {
  color: var(--moss);
  font-size: 0.82rem;
}

.paper-card strong,
.feed-item b {
  display: block;
  margin-top: 0.45rem;
  font-family: "Songti SC", "Noto Serif SC", serif;
  font-size: 1.35rem;
  font-weight: 500;
}

.paper-card em {
  display: block;
  margin-top: 0.4rem;
  color: var(--muted);
  font-style: normal;
}

.paper-back {
  top: 0;
  right: 0;
  transform: rotate(5deg);
}

.paper-front {
  bottom: 0;
  left: 0;
  transform: rotate(-4deg);
}

.preview {
  padding: 2rem 0 4rem;
}

.section-heading {
  max-width: 40rem;
  margin-bottom: 2rem;
}

.preview-layout {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 3rem;
  align-items: center;
}

.phone {
  background: #241c18;
  color: #f6f1e8;
  border-radius: 1.8rem;
  padding: 0.8rem;
  box-shadow: var(--shadow);
}

.phone-bar,
.phone-tabs {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.phone-bar {
  padding: 0.4rem 0.7rem 0.8rem;
  font-size: 0.85rem;
}

.phone-time {
  opacity: 0.7;
}

.phone-screen {
  min-height: 280px;
  padding: 0.4rem;
  background: #f6f1e8;
  color: var(--ink);
}

.feed-item {
  margin-bottom: 0.6rem;
  padding: 0.85rem;
  background: white;
}

.feed-item header {
  display: flex;
  justify-content: space-between;
  gap: 0.5rem;
}

.feed-item p {
  margin: 0.45rem 0 0;
}

.phone-tabs {
  gap: 0.25rem;
  padding-top: 0.55rem;
}

.phone-tabs button {
  flex: 1;
  border: 0;
  background: transparent;
  color: rgba(246, 241, 232, 0.62);
  font: inherit;
  font-size: 0.78rem;
  padding: 0.45rem 0;
  cursor: pointer;
}

.phone-tabs button[aria-selected="true"] {
  color: #f6f1e8;
  box-shadow: inset 0 -2px 0 #e7a08a;
}

.preview-notes {
  color: var(--muted);
}

.preview-notes ul,
.rules ul {
  padding-left: 1.1rem;
}

.feature-band,
.split,
.mall,
.archive,
.rules {
  padding: 3.2rem 0;
  border-top: 1px solid var(--line);
}

.feature-band {
  display: grid;
  grid-template-columns: 1.4fr 0.8fr;
  gap: 2rem;
  align-items: end;
}

.chip-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.chip-list li {
  padding: 0.45rem 0.8rem;
  background: white;
  border: 1px solid var(--line);
}

.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
}

.split article {
  padding: 1.4rem;
  background: rgba(255, 250, 243, 0.7);
}

.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: step;
}

.steps li {
  padding: 1.2rem;
  background: var(--card);
  border-top: 3px solid var(--clay);
}

.steps strong,
.steps span {
  display: block;
}

.steps span {
  margin-top: 0.4rem;
  color: var(--muted);
}

.layers {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
}

.layers article {
  min-height: 180px;
  padding: 1.2rem;
  background: var(--card);
}

.layers article:nth-child(2) {
  background: #efe4d4;
}

.layers article:nth-child(3) {
  background: #e7efe9;
}

/* 功能说明用统一卡片，避免沿用档案三层的底色 */
#features .layers article,
#features .layers article:nth-child(2),
#features .layers article:nth-child(3) {
  background: var(--card);
}

.rules {
  display: grid;
  grid-template-columns: 0.8fr 1.2fr;
  gap: 2rem;
}

.site-footer {
  display: flex;
  justify-content: space-between;
  gap: 2rem;
  width: min(1080px, calc(100% - 12vw));
  margin: 0 auto;
  padding: 2rem 0 3rem;
  color: var(--muted);
  border-top: 1px solid var(--line);
}

.site-footer strong {
  color: var(--ink);
  font-family: "Songti SC", "Noto Serif SC", serif;
  font-size: 1.3rem;
  letter-spacing: 0.12em;
}

.site-footer p {
  margin: 0.3rem 0 0;
  font-size: 0.82rem;
}

@media (max-width: 800px) {
  .nav-toggle {
    display: inline-flex;
  }

  .site-nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    padding: 0.4rem 6vw 1rem;
    background: rgba(243, 239, 230, 0.98);
    border-bottom: 1px solid var(--line);
  }

  .site-nav.is-open {
    display: flex;
  }

  .site-nav a {
    padding: 0.7rem 0;
  }

  .hero,
  .preview-layout,
  .feature-band,
  .split,
  .steps,
  .layers,
  .rules,
  .company-list,
  .site-footer {
    grid-template-columns: 1fr;
  }

  .hero {
    padding-top: 3rem;
  }

  .hero-stage {
    height: 300px;
  }

  .site-footer {
    display: grid;
  }
}