:root {
  color-scheme: light;
  --paper: #fff4dd;
  --ink: #26201a;
  --muted: #5c5347;
  --soft: #877b6b;
  --card: #fffdf7;
  --accent: #ff5c2b;
  --accent-hover: #ed4618;
  --sun: #ffd84d;
  --rose: #ffb9cc;
  --sky: #a5dcff;
  --mint: #b9e6a6;
  --line: 2px solid var(--ink);
  --shadow: 5px 5px 0 var(--ink);
  --shadow-small: 3px 3px 0 var(--ink);
  --radius: 16px;
  --page: 1080px;
  --font-display: "Arial Rounded MT Bold", "Microsoft YaHei", "PingFang SC", system-ui, sans-serif;
  --font-body: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", sans-serif;
  --font-mono: "Cascadia Code", "SFMono-Regular", Consolas, monospace;
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --paper: #17130f;
  --ink: #f7ead2;
  --muted: #c9bba5;
  --soft: #a2927d;
  --card: #252019;
  --accent: #ff6a3d;
  --accent-hover: #ff805b;
  --sun: #d9ad2f;
  --rose: #c97d96;
  --sky: #6aa8cb;
  --mint: #81b970;
  --shadow: 5px 5px 0 #050403;
  --shadow-small: 3px 3px 0 #050403;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    color-scheme: dark;
    --paper: #17130f;
    --ink: #f7ead2;
    --muted: #c9bba5;
    --soft: #a2927d;
    --card: #252019;
    --accent: #ff6a3d;
    --accent-hover: #ff805b;
    --sun: #d9ad2f;
    --rose: #c97d96;
    --sky: #6aa8cb;
    --mint: #81b970;
    --shadow: 5px 5px 0 #050403;
    --shadow-small: 3px 3px 0 #050403;
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background:
    radial-gradient(circle at 1px 1px, color-mix(in srgb, var(--ink) 8%, transparent) 1px, transparent 1px),
    var(--paper);
  background-size: 20px 20px;
  color: var(--ink);
  font-family: var(--font-body);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; }
a { color: inherit; text-decoration-color: var(--accent); text-decoration-thickness: 2px; text-underline-offset: 3px; }
a:hover { color: var(--accent); }
button, a { -webkit-tap-highlight-color: transparent; }
:focus-visible { outline: 3px solid var(--ink); outline-offset: 3px; }
::selection { background: var(--sun); color: #26201a; }

.shell { width: min(var(--page), calc(100% - 40px)); margin: 0 auto; }
.skip-link {
  position: fixed; top: 8px; left: 8px; z-index: 100;
  transform: translateY(-160%); background: var(--sun); border: var(--line);
  border-radius: 10px; padding: 8px 12px; font-weight: 800;
}
.skip-link:focus { transform: none; }

.site-header { padding: 26px 0 8px; }
.header-row { display: flex; align-items: center; gap: 18px; }
.brand { display: inline-flex; align-items: center; gap: 11px; min-width: 0; text-decoration: none; }
.brand:hover { color: inherit; }
.brand img {
  width: 46px; height: 46px; border: var(--line); border-radius: 13px;
  box-shadow: var(--shadow-small); transform: rotate(-3deg); transition: transform .18s ease;
}
.brand:hover img { transform: rotate(3deg) scale(1.04); }
.brand-copy { display: grid; line-height: 1.1; }
.brand-name { font-family: var(--font-display); font-size: clamp(18px, 2.8vw, 25px); font-weight: 900; }
.brand-sub { color: var(--soft); font: 700 9px/1.4 var(--font-mono); letter-spacing: .09em; text-transform: uppercase; }
.desktop-nav { display: flex; align-items: center; gap: 18px; margin-left: auto; }
.desktop-nav a { font-size: 13px; font-weight: 800; text-decoration: none; }
.header-tools { display: flex; align-items: center; gap: 7px; }
.round-control {
  display: inline-grid; place-items: center; width: 38px; height: 38px;
  border: var(--line); border-radius: 50%; background: var(--card); color: var(--ink);
  box-shadow: 2px 2px 0 var(--ink); cursor: pointer; font: 800 14px/1 var(--font-body);
  text-decoration: none; transition: transform .1s, box-shadow .1s;
}
.round-control:active { transform: translate(2px, 2px); box-shadow: none; }
.mobile-menu { display: none; position: relative; }
.mobile-menu summary { list-style: none; }
.mobile-menu summary::-webkit-details-marker { display: none; }
.mobile-menu-panel {
  position: absolute; right: 0; top: 48px; z-index: 20; min-width: 210px;
  display: grid; gap: 4px; padding: 8px; border: var(--line); border-radius: 14px;
  background: var(--card); box-shadow: var(--shadow);
}
.mobile-menu-panel a { padding: 10px 12px; border-radius: 8px; text-decoration: none; font-weight: 800; }
.mobile-menu-panel a:hover { background: var(--sun); color: #26201a; }

main { padding-bottom: 30px; }
.hero { display: grid; grid-template-columns: minmax(0, 1.08fr) minmax(330px, .92fr); gap: 54px; align-items: center; padding: 82px 0 62px; }
.eyebrow {
  display: inline-flex; align-items: center; gap: 8px; margin: 0 0 18px;
  border: var(--line); border-radius: 999px; background: var(--sun); color: #26201a;
  box-shadow: var(--shadow-small); padding: 7px 13px; font: 800 11px/1.2 var(--font-mono);
  letter-spacing: .06em; text-transform: uppercase; transform: rotate(-1deg);
}
.eyebrow::before { content: ""; width: 8px; height: 8px; border: 1.5px solid #26201a; border-radius: 50%; background: var(--accent); }
h1, h2, h3 { font-family: var(--font-display); text-wrap: balance; }
.hero h1 { max-width: 760px; margin: 0; font-size: clamp(46px, 7.4vw, 82px); letter-spacing: -.045em; line-height: .99; }
.hero h1 em { color: var(--accent); font-style: normal; }
.hero-lead { max-width: 650px; margin: 24px 0 0; color: var(--muted); font-size: clamp(16px, 2vw, 20px); text-wrap: pretty; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 13px; margin-top: 30px; }
.button {
  display: inline-flex; align-items: center; justify-content: center; gap: 9px; min-height: 48px;
  border: var(--line); border-radius: 12px; background: var(--card); color: var(--ink);
  box-shadow: var(--shadow-small); padding: 10px 18px; font-family: var(--font-display);
  font-size: 15px; font-weight: 900; text-decoration: none; transition: transform .1s, box-shadow .1s, background .15s;
}
.button:hover { color: var(--ink); transform: translate(-1px, -1px); box-shadow: var(--shadow); }
.button:active { transform: translate(3px, 3px); box-shadow: none; }
.button-primary { background: var(--accent); color: #fffdf7; }
.button-primary:hover { background: var(--accent-hover); color: #fffdf7; }
.button-secondary { background: var(--sun); color: #26201a; }
.button-disabled { opacity: .58; cursor: not-allowed; box-shadow: none; }
.button-disabled:hover { transform: none; box-shadow: none; }
.hero-note { margin: 15px 0 0; color: var(--soft); font: 600 11px/1.5 var(--font-mono); }

.demo-board {
  position: relative; min-height: 438px; border: var(--line); border-radius: 22px;
  background: var(--card); box-shadow: 9px 9px 0 var(--ink); padding: 24px;
  transform: rotate(1.1deg); overflow: hidden;
}
.demo-board::before {
  content: ""; position: absolute; width: 170px; height: 170px; right: -58px; top: -58px;
  border: var(--line); border-radius: 50%; background: var(--sky);
}
.demo-top { position: relative; display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-bottom: 22px; }
.demo-title { font-family: var(--font-display); font-size: 18px; font-weight: 900; }
.demo-badge { border: 1.5px solid var(--ink); border-radius: 999px; background: var(--mint); color: #26201a; padding: 3px 9px; font: 800 9px var(--font-mono); }
.demo-flow { position: relative; display: grid; grid-template-columns: 1fr 52px 1fr; align-items: center; gap: 10px; }
.demo-column { display: grid; gap: 9px; }
.demo-column-title { color: var(--soft); font: 800 9px var(--font-mono); letter-spacing: .09em; text-transform: uppercase; }
.chat-chip, .group-card { border: 1.5px solid var(--ink); border-radius: 10px; color: #26201a; box-shadow: 2px 2px 0 var(--ink); }
.chat-chip { background: #fff4dd; padding: 9px 10px; font-size: 11px; font-weight: 800; }
.chat-chip:nth-child(3) { background: var(--rose); transform: rotate(-1.5deg); }
.chat-chip:nth-child(4) { background: var(--sky); transform: rotate(1deg); }
.chat-chip:nth-child(5) { background: var(--sun); }
.demo-arrow { text-align: center; font-family: var(--font-display); font-size: 28px; animation: nudge 1.8s ease-in-out infinite; }
.group-card { background: var(--sun); padding: 11px; }
.group-card:nth-child(3) { background: var(--sky); transform: rotate(1deg); }
.group-card:nth-child(4) { background: var(--mint); transform: rotate(-1deg); }
.group-name { display: block; font-family: var(--font-display); font-size: 13px; font-weight: 900; }
.group-count { font: 700 9px var(--font-mono); opacity: .68; }
.demo-approval { position: absolute; left: 50%; bottom: 23px; transform: translateX(-50%) rotate(-1deg); width: calc(100% - 48px); border: var(--line); border-radius: 12px; background: var(--accent); color: #fff; box-shadow: var(--shadow-small); padding: 10px 14px; text-align: center; font-family: var(--font-display); font-size: 13px; font-weight: 900; }
@keyframes nudge { 50% { transform: translateX(5px); } }

.section { padding: 62px 0; }
.section-head { max-width: 720px; margin-bottom: 28px; }
.section-kicker { color: var(--accent); font: 900 11px var(--font-mono); letter-spacing: .1em; text-transform: uppercase; }
.section h2 { margin: 8px 0 0; font-size: clamp(32px, 5vw, 48px); line-height: 1.06; letter-spacing: -.025em; }
.section-intro { margin: 14px 0 0; color: var(--muted); font-size: 17px; }
.platform-section { padding-top: 28px; }
.platform-panel {
  display: grid; grid-template-columns: minmax(0, 1fr) minmax(310px, .72fr); gap: 28px; align-items: center;
  border: var(--line); border-radius: 22px; background: var(--sky); color: #26201a;
  box-shadow: var(--shadow); padding: 30px;
}
.platform-copy h2 { margin: 7px 0 10px; font-size: clamp(30px, 4vw, 43px); }
.platform-copy p { max-width: 620px; margin: 0; color: #344853; }
.platform-card {
  display: grid; grid-template-columns: 52px minmax(0, 1fr) auto; gap: 13px; align-items: center;
  border: var(--line); border-radius: 16px; background: #fffdf7; box-shadow: var(--shadow-small); padding: 16px;
  transform: rotate(.5deg);
}
.platform-mark {
  display: grid; place-items: center; width: 52px; height: 52px; border: var(--line); border-radius: 14px;
  background: #fff; box-shadow: 2px 2px 0 var(--ink); border-radius: 50%; object-fit: cover;
}
.platform-name { display: grid; line-height: 1.25; }
.platform-name strong { font-family: var(--font-display); font-size: 19px; }
.platform-name small { margin-top: 4px; color: #6a5b49; font-size: 11px; }
.platform-status { border: 1.5px solid var(--ink); border-radius: 999px; background: var(--mint); padding: 5px 9px; font: 900 9px var(--font-mono); white-space: nowrap; }
.card-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 20px; }
.feature-card, .step-card, .trust-card, .info-card {
  border: var(--line); border-radius: var(--radius); background: var(--card); box-shadow: var(--shadow);
  padding: 24px; transition: transform .18s ease;
}
.feature-card:nth-child(2), .step-card:nth-child(2) { transform: rotate(.7deg); }
.feature-card:nth-child(3), .step-card:nth-child(3) { transform: rotate(-.6deg); }
.feature-card:hover, .step-card:hover { transform: translateY(-4px) rotate(0); }
.card-icon { display: grid; place-items: center; width: 44px; height: 44px; border: var(--line); border-radius: 12px; background: var(--sun); color: #26201a; box-shadow: 2px 2px 0 var(--ink); font-size: 21px; }
.feature-card:nth-child(2) .card-icon { background: var(--sky); }
.feature-card:nth-child(3) .card-icon { background: var(--rose); }
.feature-card h3, .step-card h3, .trust-card h3 { margin: 18px 0 8px; font-size: 21px; }
.feature-card p, .step-card p, .trust-card p { margin: 0; color: var(--muted); font-size: 14px; }
.step-number { color: var(--ink); font: 900 34px/1 var(--font-display); }
.step-card:nth-child(1) { background: var(--sun); color: #26201a; }
.step-card:nth-child(2) { background: var(--sky); color: #26201a; }
.step-card:nth-child(3) { background: var(--mint); color: #26201a; }
.step-card p { color: #473f35; }

.trust-panel { display: grid; grid-template-columns: .82fr 1.18fr; border: var(--line); border-radius: 22px; background: var(--ink); color: var(--paper); box-shadow: 8px 8px 0 var(--accent); overflow: hidden; }
.trust-copy { padding: 36px; }
.trust-copy h2 { margin: 8px 0 14px; }
.trust-copy p { color: color-mix(in srgb, var(--paper) 78%, transparent); }
.trust-list { display: grid; gap: 12px; background: var(--card); color: var(--ink); padding: 28px; }
.trust-item { display: grid; grid-template-columns: 32px 1fr; gap: 12px; align-items: start; }
.trust-check { display: grid; place-items: center; width: 28px; height: 28px; border: 1.5px solid var(--ink); border-radius: 50%; background: var(--mint); color: #26201a; font-weight: 900; }
.trust-item strong { display: block; font-family: var(--font-display); }
.trust-item span { color: var(--muted); font-size: 13px; }

.price-strip { display: grid; grid-template-columns: 1fr auto; gap: 24px; align-items: center; border: var(--line); border-radius: var(--radius); background: var(--rose); color: #26201a; box-shadow: var(--shadow); padding: 28px 30px; transform: rotate(-.3deg); }
.price-strip h2 { margin: 0; font-size: 31px; }
.price-strip p { margin: 7px 0 0; color: #4e3a40; }
.price-mark { min-width: 138px; border: var(--line); border-radius: 14px; background: #fffdf7; box-shadow: var(--shadow-small); padding: 12px 17px; text-align: center; font-family: var(--font-display); font-weight: 900; }

.faq-list { display: grid; gap: 13px; }
.faq-list details { border: var(--line); border-radius: 13px; background: var(--card); box-shadow: var(--shadow-small); padding: 0 18px; }
.faq-list summary { cursor: pointer; padding: 16px 28px 16px 0; font-family: var(--font-display); font-weight: 900; position: relative; }
.faq-list summary::after { content: "+"; position: absolute; right: 0; font-size: 22px; line-height: 1; }
.faq-list details[open] summary::after { content: "−"; }
.faq-list details p { margin: 0 0 17px; color: var(--muted); }

.final-cta { border: var(--line); border-radius: 24px; background: var(--sun); color: #26201a; box-shadow: 9px 9px 0 var(--ink); padding: 40px; text-align: center; }
.final-cta h2 { max-width: 780px; margin: 0 auto; font-size: clamp(34px, 6vw, 58px); }
.final-cta p { max-width: 620px; margin: 14px auto 24px; color: #514327; }
.final-cta .hero-actions { justify-content: center; margin-top: 0; }

.content-layout { display: grid; grid-template-columns: 230px minmax(0, 1fr); gap: 44px; align-items: start; padding: 62px 0 70px; }
.side-nav { position: sticky; top: 22px; border: var(--line); border-radius: 14px; background: var(--card); box-shadow: var(--shadow-small); padding: 10px; }
.side-nav a { display: block; border-radius: 8px; padding: 9px 10px; color: var(--muted); font-size: 12px; font-weight: 800; text-decoration: none; }
.side-nav a:hover { background: var(--sun); color: #26201a; }
.article { min-width: 0; border: var(--line); border-radius: 20px; background: var(--card); box-shadow: var(--shadow); padding: clamp(24px, 5vw, 48px); }
.article h1 { margin: 0 0 10px; font-size: clamp(38px, 6vw, 58px); line-height: 1.02; }
.article-meta { color: var(--soft); font: 700 11px var(--font-mono); }
.article h2 { margin: 38px 0 10px; padding-top: 4px; font-size: 27px; }
.article h3 { margin: 26px 0 7px; font-size: 19px; }
.article p, .article li { color: var(--muted); }
.article li + li { margin-top: 6px; }
.article a { overflow-wrap: anywhere; }
.notice { border: var(--line); border-radius: 13px; background: var(--sun); color: #26201a; box-shadow: var(--shadow-small); padding: 15px 17px; }
.notice p { color: #4f4327; margin: 0; }
.notice-danger { background: var(--rose); }
.download-card { display: grid; gap: 16px; border: var(--line); border-radius: 17px; background: var(--sky); color: #26201a; box-shadow: var(--shadow); padding: 24px; margin: 28px 0; }
.download-card p { color: #334750; margin: 0; }
.download-meta { display: flex; flex-wrap: wrap; gap: 9px 18px; font: 700 11px var(--font-mono); }
.checksum { display: block; max-width: 100%; border: 1.5px solid var(--ink); border-radius: 9px; background: #fffdf7; padding: 9px; color: #26201a; font: 600 10px/1.5 var(--font-mono); overflow-wrap: anywhere; }

.site-footer { margin-top: 36px; border-top: var(--line); padding: 24px 0 calc(30px + env(safe-area-inset-bottom)); color: var(--muted); font-size: 12px; }
.footer-grid { display: grid; grid-template-columns: 1fr auto; gap: 24px; align-items: start; }
.footer-links { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 9px 16px; }
.footer-links a { font-weight: 800; }
.disclaimer { max-width: 680px; margin: 10px 0 0; color: var(--soft); }

@media (max-width: 860px) {
  .desktop-nav { display: none; }
  .mobile-menu { display: block; margin-left: auto; }
  .hero { grid-template-columns: 1fr; gap: 42px; padding-top: 58px; }
  .hero-copy { text-align: center; }
  .hero-lead { margin-left: auto; margin-right: auto; }
  .hero-actions { justify-content: center; }
  .platform-panel { grid-template-columns: 1fr; }
  .demo-board { width: min(560px, 100%); margin: 0 auto; transform: rotate(.5deg); }
  .card-grid { grid-template-columns: 1fr; }
  .feature-card:nth-child(n), .step-card:nth-child(n) { transform: none; }
  .trust-panel { grid-template-columns: 1fr; }
  .price-strip { grid-template-columns: 1fr; text-align: center; }
  .price-mark { justify-self: center; }
  .content-layout { grid-template-columns: 1fr; }
  .side-nav { display: none; }
}

@media (max-width: 600px) {
  .shell { width: min(100% - 28px, var(--page)); }
  .site-header { padding-top: calc(18px + env(safe-area-inset-top)); }
  .brand img { width: 38px; height: 38px; border-radius: 10px; }
  .brand-sub { display: none; }
  .header-tools { gap: 3px; }
  .round-control { width: 36px; height: 36px; }
  .hero { padding: 44px 0 40px; }
  .hero h1 { font-size: clamp(42px, 13vw, 60px); }
  .hero-lead { font-size: 16px; }
  .hero-actions { display: grid; grid-template-columns: 1fr; }
  .button { width: 100%; min-height: 50px; }
  .demo-board { min-height: 410px; padding: 18px; }
  .demo-flow { grid-template-columns: 1fr 36px 1fr; gap: 5px; }
  .chat-chip, .group-card { padding: 8px; font-size: 9px; }
  .demo-arrow { font-size: 22px; }
  .section { padding: 46px 0; }
  .section h2 { font-size: 34px; }
  .platform-section { padding-top: 18px; }
  .platform-panel { padding: 22px; }
  .platform-card { grid-template-columns: 48px minmax(0, 1fr); }
  .platform-mark { width: 48px; height: 48px; }
  .platform-status { grid-column: 2; justify-self: start; }
  .feature-card, .step-card, .trust-copy, .trust-list { padding: 22px; }
  .price-strip { padding: 24px 18px; }
  .final-cta { padding: 31px 18px; }
  .article { padding: 24px 19px; }
  .article h1 { font-size: 38px; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-links { justify-content: flex-start; }
}

@media (max-width: 420px) {
  .header-row { gap: 8px; }
  .brand { flex: 1; gap: 7px; }
  .brand-name { font-size: 14px; line-height: 1.05; }
  .mobile-menu { margin-left: 0; }
  .header-tools .round-control { width: 34px; height: 34px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
}