/* built4.fun shared visual system */

:root {
  --paper: #f5efe4;
  --paper-soft: #fbf7ef;
  --paper-warm: #efe2ce;
  --ink: #17211c;
  --ink-soft: rgba(23, 33, 28, 0.74);
  --ink-mute: rgba(23, 33, 28, 0.54);
  --ink-dim: rgba(23, 33, 28, 0.34);
  --text: var(--ink);
  --text-soft: var(--ink-soft);
  --text-mute: var(--ink-mute);
  --text-dim: var(--ink-dim);
  --line: rgba(23, 33, 28, 0.12);
  --line-strong: rgba(23, 33, 28, 0.2);

  --moss: #57623d;
  --moss-dark: #38402b;
  --ochre: #d68115;
  --clay: #a94f2d;
  --cream: #fffaf1;
  --radius-card: 8px;
  --radius-sm: 4px;
  --radius-pill: 999px;

  --max-w: 1160px;
  --max-w-prose: 720px;

  --font-display: "Fraunces", "Noto Serif SC", Georgia, serif;
  --font-sans: "Manrope", "Noto Sans", system-ui, -apple-system, sans-serif;
  --font-cjk: "Noto Serif SC", "Source Han Serif SC", "Songti SC", serif;
  --font-mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  overflow-x: clip;
}

body {
  min-height: 100vh;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.65;
  color: var(--ink);
  background:
    repeating-linear-gradient(90deg, rgba(23, 33, 28, 0.018) 0 1px, transparent 1px 5px),
    linear-gradient(180deg, var(--paper-soft), var(--paper) 38%, #efe4d4 100%);
  -webkit-font-smoothing: antialiased;
  overflow-x: clip;
}

:lang(zh-Hans) h1,
:lang(zh-Hans) h2,
:lang(zh-Hans) .pc-name,
:lang(zh-Hans) .sell-title { font-family: var(--font-cjk); font-weight: 700; }

img { display: block; max-width: 100%; height: auto; }

a {
  color: var(--moss-dark);
  text-decoration: none;
  transition: color 0.15s ease, border-color 0.15s ease, background 0.15s ease, transform 0.15s ease;
}
a:hover { color: var(--clay); text-decoration: underline; text-underline-offset: 3px; }

.skip-link {
  position: absolute;
  left: -10000px;
  top: auto;
  width: 1px;
  height: 1px;
  overflow: hidden;
}
.skip-link:focus {
  position: static;
  width: auto;
  height: auto;
  padding: 8px 12px;
  background: var(--ink);
  color: var(--cream);
}

/* Header */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  padding: 28px clamp(28px, 5vw, 80px) 14px;
  isolation: isolate;
}
.site-header::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  opacity: 0;
  pointer-events: none;
  background:
    linear-gradient(90deg, rgba(255, 250, 241, 0), rgba(255, 250, 241, 0.34) 16%, rgba(255, 250, 241, 0.38) 84%, rgba(255, 250, 241, 0)),
    linear-gradient(180deg, rgba(251, 247, 239, 0.62), rgba(245, 239, 228, 0.38) 72%, rgba(245, 239, 228, 0.05));
  border-bottom: 1px solid rgba(23, 33, 28, 0.06);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.5),
    0 20px 48px rgba(61, 48, 32, 0.055);
  backdrop-filter: blur(18px) saturate(1.18);
  -webkit-backdrop-filter: blur(18px) saturate(1.18);
  transition: opacity 0.22s ease;
}
.site-header.is-scrolled::before {
  opacity: 0.86;
}
.site-header-inner {
  position: relative;
  z-index: 1;
  max-width: 1420px;
  min-height: 58px;
  margin: 0 auto;
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: clamp(24px, 5vw, 84px);
}
.site-header-brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 800;
  letter-spacing: 0;
}
.site-header-brand::before {
  content: "";
  width: 28px;
  height: 28px;
  border-radius: 7px;
  background:
    linear-gradient(135deg, var(--ink) 0 46%, transparent 46% 54%, var(--moss) 54%),
    var(--ochre);
  transform: rotate(-8deg);
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.24);
}
.site-header-brand:hover { color: var(--ink); text-decoration: none; }
.site-header-brand .dot { color: var(--ochre); }
.site-header-nav {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: clamp(24px, 4vw, 64px);
  flex-wrap: wrap;
}
.site-header-link {
  color: var(--ink-soft);
  font-size: 14px;
  font-weight: 600;
  line-height: 1;
  padding: 8px 0;
  border-radius: var(--radius-pill);
}
.site-header-link:hover {
  color: var(--ink);
  text-decoration: none;
}
.site-header-cta {
  margin-left: clamp(6px, 2vw, 28px);
  padding: 14px 27px;
  color: var(--cream);
  background: var(--moss);
}
.site-header-cta:hover {
  color: var(--cream);
  background: var(--moss-dark);
}
.site-header-lang {
  background: transparent;
  color: var(--ink-soft);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 5px 8px;
  font-size: 13px;
  font-family: inherit;
}

/* Hero */

.hero {
  --hero-copy-y: 0px;
  --hero-copy-opacity: 1;
  --hero-art-top: 430px;
  --hero-art-height: 760px;
  --hero-art-y: 0px;
  --hero-art-scale: 1.03;
  --hero-proof-y: 0px;
  max-width: var(--max-w);
  min-height: calc(var(--hero-art-top) + var(--hero-art-height) + 80px);
  margin: 0 auto;
  padding: 72px 20px 520px;
  text-align: center;
  position: relative;
}
.hero-copy {
  max-width: 900px;
  margin: 0 auto;
  position: sticky;
  top: 124px;
  z-index: 3;
  opacity: var(--hero-copy-opacity);
  transform: translate3d(0, var(--hero-copy-y), 0);
  will-change: transform, opacity;
}
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-bottom: 20px;
  padding: 6px;
  color: var(--ink-mute);
  background: rgba(255, 250, 241, 0.72);
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  box-shadow: 0 12px 36px rgba(61, 48, 32, 0.06);
  font-size: 13px;
  font-weight: 700;
  line-height: 1;
}
.eyebrow span:first-child {
  color: var(--cream);
  background: var(--ochre);
  border-radius: var(--radius-pill);
  padding: 8px 12px;
}
.eyebrow span:last-child { padding: 8px 10px 8px 4px; }
.hero h1 {
  font-family: var(--font-display);
  font-size: 92px;
  line-height: 0.96;
  letter-spacing: 0;
  font-weight: 700;
  color: var(--ink);
  text-wrap: balance;
}
.tagline {
  max-width: 670px;
  margin: 24px auto 0;
  color: var(--ink-soft);
  font-size: 18px;
  line-height: 1.78;
  text-wrap: balance;
}
.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 14px;
  flex-wrap: wrap;
  margin-top: 30px;
}
.hero-art {
  position: absolute;
  left: 50%;
  top: var(--hero-art-top);
  width: 100vw;
  height: var(--hero-art-height);
  min-height: var(--hero-art-height);
  margin: 0;
  overflow: hidden;
  background: transparent;
  -webkit-mask-image: linear-gradient(to bottom, transparent 0, #000 92px, #000 100%);
  mask-image: linear-gradient(to bottom, transparent 0, #000 92px, #000 100%);
  pointer-events: none;
  transform: translate3d(-50%, var(--hero-art-y), 0);
  will-change: transform;
}
.hero-art img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
  transform: scale(var(--hero-art-scale));
  transform-origin: center top;
  will-change: transform;
}
.hero-proof {
  width: min(920px, calc(100% - 48px));
  margin: 0;
  position: absolute;
  left: 50%;
  bottom: 48px;
  z-index: 2;
  display: flex;
  justify-content: center;
  gap: 0;
  flex-wrap: wrap;
  overflow: hidden;
  color: rgba(255, 250, 241, 0.94);
  background: rgba(23, 33, 28, 0.9);
  border-radius: var(--radius-pill);
  box-shadow: 0 20px 60px rgba(31, 23, 14, 0.22);
  transform: translate3d(-50%, var(--hero-proof-y), 0);
  will-change: transform;
}
.hero-proof span {
  padding: 15px 20px;
  font-size: 13px;
  font-weight: 700;
  border-right: 1px solid rgba(255, 250, 241, 0.16);
}
.hero-proof span:last-child { border-right: 0; }

/* Sections */

.section {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 66px 20px;
}
.section-prose {
  max-width: var(--max-w-prose);
}
.section h2 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 44px;
  line-height: 1.04;
  letter-spacing: 0;
  margin-bottom: 18px;
}
.section .lede {
  max-width: 650px;
  margin-bottom: 30px;
  color: var(--ink-soft);
  font-size: 17px;
}

/* Product cards */

.products {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}
.product-card {
  min-height: 100%;
  padding: 28px;
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  background: rgba(255, 250, 241, 0.68);
  box-shadow: 0 18px 64px rgba(61, 48, 32, 0.07);
  transition: border-color 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
}
.product-card:hover {
  border-color: var(--line-strong);
  transform: translateY(-3px);
  box-shadow: 0 22px 72px rgba(61, 48, 32, 0.1);
}
.product-card .pc-name {
  color: var(--ink);
  font-family: var(--font-display);
  font-size: 30px;
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: 0;
  margin-bottom: 4px;
}
.product-card .pc-name .cn {
  margin-left: 8px;
  color: var(--ink-mute);
  font-size: 20px;
}
.product-card .pc-domain {
  margin-bottom: 16px;
  color: var(--ochre);
  font-family: var(--font-mono);
  font-size: 13px;
}
.product-card .pc-desc {
  margin-bottom: 18px;
  color: var(--ink-soft);
  font-size: 15px;
}
.product-card .pc-meta {
  margin-bottom: 20px;
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}
.product-card .pc-meta span {
  color: var(--moss-dark);
  background: rgba(87, 98, 61, 0.09);
  border: 1px solid rgba(87, 98, 61, 0.12);
  border-radius: var(--radius-pill);
  padding: 6px 10px;
  font-size: 12px;
  font-weight: 700;
}
.product-card .pc-links {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

/* Buttons */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 11px 18px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--line);
  background: rgba(255, 250, 241, 0.72);
  color: var(--ink-soft);
  font-size: 14px;
  font-weight: 700;
  line-height: 1.1;
  cursor: pointer;
}
.btn:hover {
  border-color: var(--line-strong);
  color: var(--ink);
  text-decoration: none;
  box-shadow: inset 0 0 0 1px rgba(23, 33, 28, 0.06);
}
.btn-primary {
  background: linear-gradient(180deg, #2b2c29, #141815);
  border-color: rgba(23, 33, 28, 0.9);
  color: var(--cream);
  box-shadow: 0 14px 34px rgba(23, 33, 28, 0.2);
}
.btn-primary:hover {
  background: var(--moss-dark);
  border-color: var(--moss-dark);
  color: var(--cream);
  box-shadow: 0 14px 34px rgba(23, 33, 28, 0.22);
}
.btn-ghost {
  background: rgba(255, 250, 241, 0.64);
}

/* Sell section */

.sell {
  margin-top: 28px;
  padding: 34px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 34px;
  align-items: center;
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  background:
    linear-gradient(90deg, rgba(87, 98, 61, 0.09), transparent 42%),
    rgba(255, 250, 241, 0.74);
  box-shadow: 0 20px 70px rgba(61, 48, 32, 0.08);
}
.sell-title {
  margin-bottom: 8px;
  color: var(--ink);
  font-family: var(--font-display);
  font-size: 30px;
  font-weight: 700;
  line-height: 1.12;
}
.sell-desc {
  margin-bottom: 16px;
  color: var(--ink-soft);
  font-size: 15px;
}
.sell-desc strong { color: var(--ink); }
.sell-points {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, minmax(180px, 1fr));
  gap: 8px 18px;
  margin-bottom: 18px;
  color: var(--ink-soft);
  font-size: 14px;
}
.sell-points li::before {
  content: "✓";
  color: var(--moss);
  font-weight: 800;
  margin-right: 8px;
}
.sell-fineprint {
  color: var(--ink-mute);
  font-size: 12px;
}
.sell-price {
  min-width: 190px;
  text-align: center;
  white-space: nowrap;
}
.sell-price .amount {
  display: block;
  color: var(--ink);
  font-family: var(--font-display);
  font-size: 54px;
  font-weight: 800;
  line-height: 1;
}
.sell-price .currency {
  margin-top: 4px;
  margin-bottom: 16px;
  color: var(--ink-mute);
  font-size: 13px;
}

/* Legal / prose pages */

.legal {
  max-width: var(--max-w-prose);
  margin: 0 auto;
  padding: 58px 20px 86px;
}
.legal-header {
  margin-bottom: 36px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--line);
}
.legal-header .back {
  display: inline-block;
  margin-bottom: 16px;
  color: var(--ink-mute);
  font-size: 13px;
  font-weight: 700;
}
.legal-header h1 {
  color: var(--ink);
  font-family: var(--font-display);
  font-size: 42px;
  font-weight: 700;
  line-height: 1.08;
  letter-spacing: 0;
}
.legal-header .subtitle {
  margin-top: 8px;
  color: var(--ink-soft);
  font-size: 16px;
}
.legal-header .effective-date {
  margin-top: 6px;
  color: var(--ink-mute);
  font-size: 13px;
}
.legal-body h2 {
  margin-top: 32px;
  margin-bottom: 12px;
  color: var(--ink);
  font-family: var(--font-display);
  font-size: 24px;
  font-weight: 700;
  letter-spacing: 0;
}
.legal-body h3 {
  margin-top: 20px;
  margin-bottom: 8px;
  color: var(--ink);
  font-size: 16px;
  font-weight: 700;
}
.legal-body p,
.legal-body ul,
.legal-body ol {
  margin-bottom: 14px;
  color: var(--ink-soft);
}
.legal-body ul,
.legal-body ol { padding-left: 22px; }
.legal-body li { margin-bottom: 6px; }
.legal-body strong { color: var(--ink); font-weight: 700; }
.legal-body code {
  padding: 2px 6px;
  border-radius: var(--radius-sm);
  background: rgba(255, 250, 241, 0.72);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 13px;
}

/* Contact card */

.contact-card {
  margin: 24px 0;
  padding: 30px;
  text-align: center;
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  background: rgba(255, 250, 241, 0.72);
  box-shadow: 0 18px 60px rgba(61, 48, 32, 0.08);
}
.contact-card .label {
  margin-bottom: 8px;
  color: var(--ink-mute);
  font-size: 13px;
  font-weight: 800;
  text-transform: uppercase;
}
.contact-card .email {
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 22px;
}

/* Footer */

.site-footer {
  max-width: var(--max-w);
  margin: 56px auto 0;
  padding: 32px 20px 48px;
  display: flex;
  flex-direction: column;
  gap: 14px;
  align-items: center;
  text-align: center;
  border-top: 1px solid var(--line);
}
.footer-links {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  justify-content: center;
  font-size: 14px;
}
.footer-links a {
  color: var(--ink-mute);
  font-weight: 700;
  padding: 6px 8px;
  border-radius: var(--radius-pill);
}
.footer-links a:hover {
  color: var(--ink);
  background: rgba(87, 98, 61, 0.09);
  text-decoration: none;
}
.footer-copy {
  color: var(--ink-dim);
  font-size: 13px;
}

@media (max-width: 860px) {
  .site-header { padding: 20px 20px 14px; }
  .site-header-inner {
    align-items: flex-start;
    flex-direction: column;
    gap: 14px;
  }
  .site-header-nav {
    width: 100%;
    justify-content: flex-start;
    gap: 20px;
  }
  .hero {
    --hero-art-top: 535px;
    --hero-art-height: 560px;
    padding-top: 56px;
    padding-bottom: 450px;
  }
  .hero h1 { font-size: 64px; }
  .products,
  .sell {
    grid-template-columns: 1fr;
  }
  .sell-price {
    text-align: left;
    white-space: normal;
  }
}

@media (max-width: 560px) {
  body { font-size: 15px; }
  .site-header-link { padding: 9px 10px; }
  .site-header-cta { padding: 10px 16px; }
  .hero {
    --hero-art-top: 540px;
    --hero-art-height: 430px;
    padding: 44px 14px 420px;
  }
  .eyebrow {
    display: flex;
    width: 100%;
    justify-content: center;
    flex-wrap: wrap;
    border-radius: 18px;
  }
  .eyebrow span:first-child,
  .eyebrow span:last-child { padding: 8px 10px; }
  .hero-copy,
  .tagline,
  .hero-actions {
    width: 100%;
    max-width: 340px;
    margin-left: auto;
    margin-right: auto;
  }
  .hero h1 {
    max-width: 330px;
    margin-left: auto;
    margin-right: auto;
    font-size: 40px;
    line-height: 1.05;
  }
  .tagline { font-size: 16px; }
  .hero-actions .btn {
    width: auto;
    min-width: 260px;
    max-width: 100%;
    justify-self: center;
  }
  .hero-actions {
    display: grid;
    grid-template-columns: minmax(0, 1fr);
    width: calc(100vw - 28px);
  }
  .hero-art {
    min-height: 430px;
  }
  .hero-proof {
    width: calc(100% - 20px);
    bottom: 42px;
    border-radius: 18px;
  }
  .hero-proof span {
    width: 100%;
    border-right: 0;
    border-bottom: 1px solid rgba(255, 250, 241, 0.16);
  }
  .hero-proof span:last-child { border-bottom: 0; }
  .section {
    padding: 48px 14px;
  }
  .section h2,
  .legal-header h1 { font-size: 34px; }
  .product-card,
  .sell,
  .contact-card { padding: 22px; }
  .sell-points { grid-template-columns: 1fr; }
  .sell-price .amount { font-size: 44px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}