:root {
  color-scheme: light;
  --paper: #fffaf0;
  --paper-deep: #fbf1df;
  --surface: rgba(255, 255, 255, 0.72);
  --ink: #1c1917;
  --muted: #625d57;
  --line: rgba(120, 53, 15, 0.14);
  --accent: #c6570a;
  --accent-dark: #963d08;
  --selection: #dcecff;
  --shadow: 0 28px 72px rgba(92, 45, 14, 0.13);
  --sans: "Avenir Next", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --mono: "SFMono-Regular", "Cascadia Code", Consolas, monospace;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: var(--paper); font-family: var(--sans); -webkit-font-smoothing: antialiased; }
a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }
button, input, select, textarea { font: inherit; }

.site-header,
.site-footer,
main { width: min(1400px, calc(100% - 64px)); margin-inline: auto; }

.site-header {
  position: relative;
  z-index: 20;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  min-height: 104px;
  gap: 28px;
}

.brand { display: inline-flex; align-items: center; gap: 12px; width: fit-content; }
.brand-mark { width: 48px; height: 48px; }
.brand-name { font-size: 1.25rem; font-weight: 800; letter-spacing: -0.03em; }
.site-nav { display: flex; gap: 42px; color: var(--muted); font-size: .98rem; font-weight: 650; }
.site-nav a:hover { color: var(--accent-dark); }
.site-header > .button { justify-self: end; }

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 52px;
  padding: 0 22px;
  border: 1px solid var(--line);
  border-radius: 12px;
  font-weight: 750;
  line-height: 1;
  transition: transform 160ms ease, background-color 160ms ease, box-shadow 160ms ease;
}
.button:hover { transform: translateY(-2px); }
.button-primary { color: #fff; border-color: transparent; background: var(--accent); box-shadow: 0 14px 30px rgba(198, 87, 10, .2); }
.button-primary:hover { background: var(--accent-dark); box-shadow: 0 18px 38px rgba(198, 87, 10, .26); }
.button-quiet { background: rgba(255,255,255,.5); }
.button-quiet:hover { background: #fff; }
.button-small { min-height: 44px; padding-inline: 18px; font-size: .9rem; }

.hero {
  min-height: calc(100svh - 104px);
  display: grid;
  grid-template-columns: minmax(420px, .82fr) minmax(620px, 1.18fr);
  align-items: center;
  gap: clamp(36px, 6vw, 92px);
  padding: 50px 0 90px;
}
.hero-copy { display: grid; gap: 28px; align-content: center; }
.hero h1 { margin: 0; font-size: clamp(3.45rem, 4.65vw, 4.8rem); line-height: .98; letter-spacing: -.065em; }
.hero h1 span { display: block; white-space: nowrap; }
.hero-copy > p { margin: 0; max-width: 34em; color: var(--muted); font-size: clamp(1.04rem, 1.5vw, 1.3rem); line-height: 1.8; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; }
kbd { min-width: 38px; padding: 9px 11px; border: 1px solid var(--line); border-bottom-width: 3px; border-radius: 9px; background: rgba(255,255,255,.78); color: var(--ink); font: 700 .8rem/1 var(--mono); text-align: center; box-shadow: 0 5px 12px rgba(92,45,14,.06); }

.browser-demo { overflow: hidden; border: 1px solid var(--line); border-radius: 24px; background: #fffdf8; box-shadow: var(--shadow); }
.browser-bar { display: grid; grid-template-columns: auto 1fr auto; align-items: center; gap: 16px; min-height: 58px; padding: 0 18px; border-bottom: 1px solid var(--line); background: #fbf5ea; color: #8d857d; font-size: .75rem; }
.browser-bar > img { width: 28px; height: 28px; }
.window-dots { display: flex; gap: 6px; }
.window-dots i { width: 9px; height: 9px; border-radius: 50%; background: #d8cfc2; }
.window-dots i:first-child { background: #ef7d62; }
.window-dots i:nth-child(2) { background: #eebc52; }
.window-dots i:last-child { background: #62b96d; }
.address { overflow: hidden; padding: 9px 14px; border-radius: 999px; background: #f5efe6; white-space: nowrap; text-overflow: ellipsis; }
.article-page { position: relative; min-height: 610px; padding: 44px 42% 36px 34px; background: linear-gradient(145deg,#fffdf9,#fbf5ea); }
.article-copy { font-family: Georgia, "Songti SC", serif; }
.article-source { margin: 0 0 12px; color: #8d857d; font: 700 .72rem var(--sans); text-transform: uppercase; letter-spacing: .12em; }
.article-copy h2 { margin: 0 0 24px; font-size: 2rem; }
.article-copy p { margin: 0 0 18px; font-size: 1rem; line-height: 1.9; }
mark { padding: 2px 3px; background: var(--selection); box-decoration-break: clone; }
.print-illustration { display: grid; grid-template-columns: repeat(3,1fr); gap: 8px; min-height: 170px; margin-top: 32px; padding: 16px; border: 1px solid #d8ccbc; background: #e8ddcd; }
.print-illustration span { display: grid; place-items: center; border: 1px solid #9e8d78; background: #f7f0e5; color: #675b4d; font-size: 1.5rem; }
.explain-popover { position: absolute; top: 34px; right: 22px; width: 38%; overflow: hidden; border: 1px solid var(--line); border-radius: 17px; background: rgba(255,253,249,.96); box-shadow: 0 22px 50px rgba(65,35,16,.15); backdrop-filter: blur(12px); }
.popover-title { display: grid; grid-template-columns: auto 1fr auto; align-items: center; gap: 8px; padding: 14px; border-bottom: 1px solid var(--line); font-size: .82rem; }
.popover-title img { width: 24px; height: 24px; }
.popover-title span { color: #93877c; font-size: .7rem; }
.popover-section { padding: 16px; border-bottom: 1px solid var(--line); }
.popover-section b, .translation-row b { color: var(--accent); font-size: .76rem; }
.popover-section p, .popover-section li { color: #4f4943; font-size: .78rem; line-height: 1.7; }
.popover-section ul { margin: 8px 0 0; padding-left: 18px; }
.popover-section.compact { padding-block: 12px; }
.translation-row { display: grid; gap: 7px; padding: 14px 16px; font-size: .76rem; }

.feature-section,
.flow-section,
.privacy-band,
.final-section { padding: 120px 0; border-top: 1px solid var(--line); }
.section-intro { display: grid; grid-template-columns: minmax(0,.8fr) minmax(280px,.5fr); align-items: end; gap: 40px; margin-bottom: 76px; }
.section-intro h2,
.privacy-heading h2,
.final-section h2 { margin: 0; font-size: clamp(2.8rem, 5vw, 5rem); line-height: 1.05; letter-spacing: -.055em; }
.section-intro p,
.privacy-heading p,
.final-section > p { margin: 0; color: var(--muted); line-height: 1.8; }
.feature-layout { display: grid; grid-template-columns: minmax(340px,.7fr) minmax(560px,1.3fr); gap: 72px; align-items: center; }
.feature-list { list-style: none; margin: 0; padding: 0; }
.feature-list li { display: grid; grid-template-columns: 56px 1fr; gap: 20px; padding: 25px 8px; border-bottom: 1px solid var(--line); cursor: pointer; transition: color 160ms ease, padding-left 160ms ease; }
.feature-list li:first-child { border-top: 1px solid var(--line); }
.feature-list li > span { color: var(--accent); font: 700 1rem var(--mono); }
.feature-list h3 { margin: 0 0 7px; font-size: 1.3rem; }
.feature-list p { margin: 0; color: var(--muted); line-height: 1.65; }
.feature-list li.is-active { padding-left: 18px; color: var(--accent-dark); }
.feature-preview { overflow: hidden; min-height: 570px; border: 1px solid var(--line); border-radius: 20px; background: #fffdf9; box-shadow: var(--shadow); }
.preview-toolbar { display: flex; align-items: center; gap: 7px; height: 48px; padding: 0 16px; border-bottom: 1px solid var(--line); background: #f8f1e7; }
.preview-toolbar span { width: 8px; height: 8px; border-radius: 50%; background: #d8cfc2; }
.preview-toolbar em { margin-left: auto; color: #918980; font-size: .72rem; font-style: normal; }
.preview-canvas { position: relative; min-height: 520px; padding: 64px; }
.preview-copy { display: grid; gap: 20px; width: 64%; }
.preview-copy i { display: block; height: 12px; border-radius: 3px; background: #ddd3c6; }
.preview-copy i:nth-child(2) { width: 86%; }
.preview-copy i:nth-child(4) { width: 92%; }
.preview-copy i:nth-child(5) { width: 70%; }
.preview-copy i.selected { width: 78%; background: var(--selection); }
.preview-result { position: absolute; right: 42px; bottom: 54px; width: 52%; padding: 24px; border: 1px solid rgba(198,87,10,.22); border-radius: 15px; background: #fffaf2; box-shadow: 0 18px 40px rgba(92,45,14,.12); }
.preview-result small { color: var(--accent); font-weight: 800; }
.preview-result strong { display: block; margin: 12px 0 8px; font-size: 1.15rem; }
.preview-result p { margin: 0; color: var(--muted); line-height: 1.7; }

.flow-section { display: grid; grid-template-columns: .65fr 1.35fr; gap: 80px; }
.flow-section .section-intro { display: block; margin: 0; }
.flow-steps { display: grid; grid-template-columns: repeat(3,1fr); gap: 28px; list-style: none; margin: 0; padding: 0; }
.flow-steps li { display: flex; flex-direction: column; min-width: 0; padding-top: 12px; border-top: 1px solid var(--line); }
.flow-steps li > span { color: var(--accent); font: 700 .95rem var(--mono); }
.flow-steps h3 { margin: 24px 0 6px; }
.flow-steps p { margin: 0; color: var(--muted); }
.selection-sample,
.key-sample,
.answer-sample { min-height: 150px; display: flex; align-items: center; justify-content: center; margin-top: 20px; border-radius: 14px; background: rgba(255,255,255,.62); }
.selection-sample { padding: 18px; text-decoration: underline; text-decoration-color: #9dc8ff; text-decoration-thickness: 7px; text-underline-offset: -2px; font-family: Georgia, serif; }
.key-sample { gap: 7px; flex-wrap: wrap; }
.answer-sample { flex-direction: column; gap: 8px; padding: 20px; border: 1px solid var(--line); align-items: flex-start; }
.answer-sample b { color: var(--accent); }
.answer-sample small { color: var(--muted); line-height: 1.6; }

.privacy-band { display: grid; grid-template-columns: minmax(420px,.9fr) minmax(520px,1.1fr); gap: 100px; width: 100vw; margin-left: calc(50% - 50vw); padding-inline: max(32px, calc((100vw - 1400px)/2)); background: var(--paper-deep); }
.privacy-heading { align-self: start; }
.privacy-heading p { max-width: 38em; margin-top: 24px; }
.trust-list { list-style: none; margin: 0; padding: 0; }
.trust-list li { display: grid; grid-template-columns: 50px 1fr; gap: 18px; padding: 22px 0; border-bottom: 1px solid var(--line); }
.trust-list li:first-child { border-top: 1px solid var(--line); }
.trust-icon { display: grid; place-items: center; width: 38px; height: 38px; color: var(--accent); font: 700 1.1rem var(--mono); }
.trust-list strong { font-size: 1.08rem; }
.trust-list p { margin: 7px 0 0; color: var(--muted); line-height: 1.65; }
.final-section { display: grid; gap: 24px; }
.final-section h2 { max-width: 15ch; }
.final-section > p { max-width: 48em; }
.site-footer { display: grid; grid-template-columns: 1fr auto auto; gap: 36px; align-items: center; min-height: 120px; border-top: 1px solid var(--line); color: var(--muted); font-size: .88rem; }
.site-footer strong { color: var(--ink); }
.site-footer nav { display: flex; gap: 28px; }
.site-footer a:hover { color: var(--accent-dark); }

.reveal { opacity: 0; transform: translateY(18px); transition: opacity 650ms ease, transform 650ms ease; }
.reveal.delay-1 { transition-delay: 100ms; }
.reveal.is-visible { opacity: 1; transform: none; }

/* Privacy policy */
.privacy-page .page-shell { width: min(1040px, calc(100% - 48px)); margin: 0 auto; }
.privacy-page .topbar { display: flex; align-items: center; justify-content: space-between; gap: 24px; min-height: 96px; border-bottom: 1px solid var(--line); }
.privacy-page .brand-copy { display: grid; gap: 2px; }
.privacy-page .brand-tag { color: var(--muted); font-size: .75rem; }
.privacy-page .topnav { display: flex; gap: 24px; color: var(--muted); font-size: .86rem; }
.privacy-page .privacy-main { width: auto; }
.privacy-page .hero { min-height: auto; display: block; padding: 90px 0 70px; }
.privacy-page .hero-copy { display: grid; gap: 22px; }
.privacy-page .eyebrow { color: var(--accent); font-size: .75rem; font-weight: 800; letter-spacing: .12em; text-transform: uppercase; }
.privacy-page h1 { margin: 0; max-width: 14ch; font-size: clamp(3rem,7vw,5.7rem); line-height: .98; letter-spacing: -.06em; }
.privacy-page .lead { margin: 0; max-width: 58em; color: var(--muted); font-size: 1.05rem; line-height: 1.8; }
.privacy-page .section-block { padding: 72px 0; border-top: 1px solid var(--line); }
.privacy-page .section-heading h2 { margin: 10px 0 16px; font-size: clamp(2rem,4vw,3.5rem); line-height: 1.08; letter-spacing: -.045em; }
.privacy-page .section-heading p { margin: 0; color: var(--muted); line-height: 1.8; }
.privacy-page .split-grid { display: grid; grid-template-columns: repeat(2,1fr); gap: 24px; margin-top: 38px; }
.flow-list { padding: 26px; border: 1px solid var(--line); border-radius: 16px; background: rgba(255,255,255,.55); }
.flow-list h3 { margin-top: 0; }
.flow-list ul { list-style: none; margin: 0; padding: 0; }
.flow-list li { display: grid; gap: 5px; padding: 15px 0; border-bottom: 1px solid var(--line); }
.flow-list li:last-child { border-bottom: 0; }
.flow-list li span:first-child { font-weight: 750; }
.flow-list li span:last-child { color: var(--muted); font-size: .9rem; line-height: 1.6; }
.command-grid { display: grid; grid-template-columns: repeat(2,1fr); gap: 18px; margin-top: 36px; }
.command-block { padding: 24px; border-top: 2px solid var(--accent); background: rgba(255,255,255,.45); }
.command-block code { color: var(--accent); font: 700 .8rem var(--mono); }
.command-block p { color: var(--muted); line-height: 1.7; }
.final-cta { display: grid; gap: 28px; padding: 42px; background: var(--paper-deep); }
.privacy-page .footer { display: flex; justify-content: space-between; gap: 20px; padding: 32px 0; border-top: 1px solid var(--line); color: var(--muted); font-size: .82rem; }

@media (max-width: 1050px) {
  .site-header { grid-template-columns: 1fr auto; }
  .site-nav { display: none; }
  .hero { grid-template-columns: 1fr; min-height: auto; }
  .hero h1 { max-width: 13ch; }
  .browser-demo { width: min(820px,100%); }
  .feature-layout, .flow-section, .privacy-band { grid-template-columns: 1fr; }
  .feature-layout, .flow-section, .privacy-band { gap: 56px; }
}

@media (max-width: 720px) {
  .site-header, .site-footer, main { width: min(100% - 32px, 1400px); }
  .site-header { min-height: 82px; }
  .brand-mark { width: 40px; height: 40px; }
  .brand-name { font-size: 1.05rem; }
  .site-header .button { min-height: 40px; padding-inline: 12px; font-size: .76rem; }
  .hero { padding: 54px 0 72px; gap: 52px; }
  .hero h1 { font-size: clamp(2.35rem,9vw,3.4rem); }
  .browser-demo { border-radius: 16px; }
  .article-page { min-height: 540px; padding: 30px 26px; }
  .article-copy { padding-right: 10%; }
  .explain-popover { top: auto; right: 16px; bottom: 18px; width: 82%; }
  .print-illustration { display: none; }
  .feature-section, .flow-section, .privacy-band, .final-section { padding-block: 78px; }
  .section-intro { grid-template-columns: 1fr; margin-bottom: 46px; }
  .section-intro h2, .privacy-heading h2, .final-section h2 { font-size: clamp(2.5rem,12vw,4rem); }
  .feature-layout { gap: 40px; }
  .feature-preview { min-height: 420px; }
  .preview-canvas { min-height: 370px; padding: 42px 30px; }
  .preview-result { right: 20px; bottom: 30px; width: 76%; }
  .flow-steps { grid-template-columns: 1fr; }
  .flow-steps li { display: grid; grid-template-columns: 44px 1fr; column-gap: 16px; }
  .flow-steps li > span { grid-row: 1 / span 3; }
  .selection-sample, .key-sample, .answer-sample { grid-column: 2; min-height: 110px; }
  .flow-steps h3, .flow-steps p { grid-column: 2; }
  .privacy-band { width: 100vw; margin-left: calc(50% - 50vw); padding-inline: 24px; }
  .site-footer { grid-template-columns: 1fr auto; min-height: 110px; }
  .site-footer nav { order: 3; grid-column: 1 / -1; }
  .privacy-page .page-shell { width: min(100% - 32px,1040px); }
  .privacy-page .topnav { display: none; }
  .privacy-page .topbar .button { display: none; }
  .privacy-page .split-grid, .command-grid { grid-template-columns: 1fr; }
  .privacy-page .hero { padding: 64px 0 50px; }
  .final-cta { padding: 28px; }
}

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