:root {
  color-scheme: light dark;
  --page: #f6f4f8;
  --surface: #fcfbfd;
  --surface-soft: #eeeaf3;
  --surface-strong: #e3dcec;
  --ink: #231f29;
  --ink-soft: #625d69;
  --ink-faint: #817b88;
  --accent: #8356bd;
  --accent-strong: #674091;
  --accent-wash: #e8dcf5;
  --line: rgba(47, 37, 57, 0.12);
  --shadow: rgba(66, 48, 82, 0.16);
  --max: 1240px;
  --radius-panel: 22px;
  --radius-media: 26px;
  --ease: cubic-bezier(0.16, 1, 0.3, 1);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text",
    "PingFang SC", "PingFang HK", "Microsoft YaHei", sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --page: #17141b;
    --surface: #1e1a22;
    --surface-soft: #27212d;
    --surface-strong: #33293d;
    --ink: #f0ebf3;
    --ink-soft: #c7becd;
    --ink-faint: #9d93a5;
    --accent: #b792e0;
    --accent-strong: #c8a8e9;
    --accent-wash: #3a2b48;
    --line: rgba(236, 224, 244, 0.13);
    --shadow: rgba(4, 2, 7, 0.42);
  }
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-width: 320px;
  overflow-x: clip;
  background: var(--page);
  color: var(--ink);
  font-size: 16px;
  line-height: 1.65;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

h1,
h2,
h3 {
  text-wrap: balance;
}

p {
  text-wrap: pretty;
}

a {
  color: inherit;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

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

[data-lang="en"] {
  display: none;
}

body.lang-en [data-lang="zh"] {
  display: none;
}

body.lang-en [data-lang="en"] {
  display: block;
}

body.lang-en span[data-lang="en"] {
  display: inline;
}

.shell {
  width: min(calc(100% - 48px), var(--max));
  margin: 0 auto;
}

.topbar-wrap {
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid transparent;
  background: color-mix(in srgb, var(--page) 84%, transparent);
  backdrop-filter: blur(18px) saturate(1.12);
  -webkit-backdrop-filter: blur(18px) saturate(1.12);
}

.topbar {
  min-height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  font-size: 17px;
  font-weight: 660;
  letter-spacing: -0.02em;
}

.brand img {
  width: 28px;
  height: 28px;
  object-fit: contain;
}

.topbar-actions,
.topbar-links,
.language-switch {
  display: flex;
  align-items: center;
}

.topbar-actions {
  gap: 22px;
}

.topbar-links {
  gap: 24px;
}

.topbar-links a {
  color: var(--ink-soft);
  font-size: 13px;
  font-weight: 560;
  text-decoration: none;
  transition: color 180ms ease;
}

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

.language-switch {
  gap: 4px;
  padding: 3px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
}

.language-switch button {
  min-width: 58px;
  border: 0;
  border-radius: 999px;
  padding: 6px 10px;
  background: transparent;
  color: var(--ink-soft);
  font: inherit;
  font-size: 12px;
  font-weight: 620;
  cursor: pointer;
}

.language-switch button[aria-pressed="true"] {
  background: var(--ink);
  color: var(--page);
}

.hero {
  min-height: calc(100dvh - 68px);
  display: grid;
  grid-template-columns: minmax(400px, 0.92fr) minmax(0, 1.28fr);
  align-items: center;
  gap: clamp(40px, 5vw, 80px);
  padding: clamp(56px, 7vh, 76px) 0;
}

.eyebrow {
  margin: 0 0 22px;
  color: var(--accent-strong);
  font-size: 12px;
  font-weight: 720;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

.hero h1 {
  max-width: none;
  margin: 0;
  font-size: clamp(42px, 3.65vw, 56px);
  font-weight: 660;
  letter-spacing: -0.048em;
  line-height: 1.08;
}

.lang-en .hero h1 {
  font-size: clamp(32px, 3.25vw, 46px);
  letter-spacing: -0.04em;
}

.semantic-lines > span,
.hero-summary > span {
  display: block;
}

.copy-phrase {
  display: inline-block;
  white-space: nowrap;
}

.zh-lines > span {
  white-space: nowrap;
}

.hero h1.zh-lines,
.manifesto h2.zh-lines,
.feature h2.zh-lines,
.writing h2.zh-lines,
.privacy-band h2.zh-lines,
.final h2.zh-lines,
.story h3.zh-lines {
  letter-spacing: -0.025em;
  line-height: 1.22;
}

.hero-copy > p:not(.eyebrow) {
  max-width: 42ch;
  margin: 26px 0 0;
  color: var(--ink-soft);
  font-size: clamp(17px, 1.45vw, 20px);
  line-height: 1.62;
}

.hero-copy,
.feature-copy {
  min-width: 0;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 34px;
}

.button {
  min-height: 48px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0 21px;
  background: var(--surface);
  color: var(--ink);
  font-size: 14px;
  font-weight: 660;
  line-height: 1;
  text-decoration: none;
  white-space: nowrap;
  transition: transform 180ms var(--ease), background 180ms ease,
    border-color 180ms ease;
}

.button-primary {
  border-color: var(--accent-strong);
  background: var(--accent-strong);
  color: #f8f3fb;
}

.button:hover,
.button:focus-visible {
  transform: translateY(-2px);
  border-color: var(--accent);
}

.button:active {
  transform: translateY(1px) scale(0.98);
}

.hero-visual {
  position: relative;
  isolation: isolate;
}

.hero-visual::before {
  content: "";
  position: absolute;
  inset: 13% 10% -8% 18%;
  z-index: -1;
  border-radius: 42%;
  background: var(--accent-wash);
  filter: blur(60px);
  opacity: 0.7;
}

.screen {
  overflow: hidden;
  border: 1px solid color-mix(in srgb, var(--line) 76%, transparent);
  border-radius: var(--radius-media);
  background: var(--surface);
  box-shadow: 0 30px 80px -38px var(--shadow);
}

.screen img {
  width: 100%;
  height: auto;
}

.hero .screen {
  transform: rotate(1.15deg);
}

.manifesto {
  padding: clamp(104px, 13vw, 180px) 0;
  text-align: center;
}

.manifesto h2 {
  max-width: 14ch;
  margin: 0 auto;
  font-size: clamp(38px, 5vw, 68px);
  font-weight: 620;
  letter-spacing: -0.05em;
  line-height: 1.08;
}

.manifesto p {
  max-width: 49ch;
  margin: 28px auto 0;
  color: var(--ink-soft);
  font-size: 18px;
}

.feature {
  min-height: 720px;
  display: grid;
  grid-template-columns: minmax(0, 0.72fr) minmax(0, 1.28fr);
  align-items: center;
  gap: clamp(48px, 8vw, 120px);
  padding: clamp(80px, 9vw, 132px) 0;
}

.feature-reverse {
  grid-template-columns: minmax(0, 1.28fr) minmax(0, 0.72fr);
}

.feature-reverse .feature-copy {
  order: 2;
}

.feature h2,
.writing h2,
.privacy-band h2,
.final h2 {
  margin: 0;
  font-size: clamp(34px, 4vw, 56px);
  font-weight: 620;
  letter-spacing: -0.045em;
  line-height: 1.1;
}

.feature-copy p,
.writing-head p,
.privacy-band p,
.final p {
  max-width: 42ch;
  margin: 24px 0 0;
  color: var(--ink-soft);
  font-size: 17px;
}

.privacy-band .security-lede {
  max-width: 31ch;
  color: var(--ink);
  font-size: clamp(19px, 1.9vw, 24px);
  font-weight: 560;
  line-height: 1.62;
}

.privacy-band .security-note {
  margin-top: 18px;
  font-size: 15px;
}

.text-link {
  display: inline-flex;
  margin-top: 26px;
  color: var(--accent-strong);
  font-size: 14px;
  font-weight: 680;
  text-decoration: none;
}

.text-link:hover,
.text-link:focus-visible {
  text-decoration: underline;
  text-underline-offset: 5px;
}

.writing {
  padding: clamp(96px, 11vw, 156px) 0;
}

.writing-head {
  max-width: 720px;
  margin-bottom: 54px;
}

.writing-grid {
  display: grid;
  grid-template-columns: 1.22fr 0.78fr;
  align-items: start;
  gap: 24px;
}

.story {
  min-width: 0;
}

.story:last-child {
  margin-top: 88px;
}

.story .screen {
  border-radius: var(--radius-panel);
}

.story h3 {
  margin: 24px 0 0;
  font-size: clamp(23px, 2.4vw, 32px);
  font-weight: 620;
  letter-spacing: -0.035em;
  line-height: 1.18;
}

.story p {
  max-width: 40ch;
  margin: 12px 0 0;
  color: var(--ink-soft);
}

.privacy-band {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(340px, 0.74fr);
  gap: clamp(52px, 9vw, 130px);
  align-items: start;
  margin: clamp(76px, 9vw, 132px) auto;
  padding: clamp(52px, 7vw, 88px);
  border-radius: var(--radius-media);
  background: var(--surface-soft);
}

.privacy-points {
  display: grid;
  gap: 0;
  border-top: 1px solid var(--line);
}

.privacy-point {
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
}

.privacy-point strong {
  display: block;
  font-size: 15px;
}

.privacy-point > span {
  display: block;
  margin-top: 5px;
  color: var(--ink-soft);
  font-size: 14px;
}

.privacy-band .security-runtime {
  max-width: none;
  margin: 22px 0 0;
  color: var(--ink-soft);
  font-size: 13px;
  line-height: 1.65;
}

.final {
  padding: clamp(110px, 14vw, 190px) 0;
  text-align: center;
}

.final h2,
.final p {
  margin-left: auto;
  margin-right: auto;
}

.final .hero-actions {
  justify-content: center;
}

.site-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
  padding: 30px 0 42px;
  border-top: 1px solid var(--line);
  color: var(--ink-soft);
  font-size: 12px;
}

.site-footer nav {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
}

.site-footer a {
  text-decoration: none;
}

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

.legal-page {
  padding: 62px 0 120px;
}

.legal-hero {
  max-width: 900px;
  padding: 48px 0 64px;
}

.legal-hero h1 {
  max-width: 13ch;
  margin: 0;
  font-size: clamp(45px, 6vw, 76px);
  font-weight: 640;
  letter-spacing: -0.055em;
  line-height: 1.05;
}

.legal-lede {
  max-width: 66ch;
  margin: 28px 0 0;
  color: var(--ink-soft);
  font-size: 18px;
}

.legal-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 24px;
  margin-top: 28px;
  color: var(--ink-faint);
  font-size: 12px;
}

.legal-highlights {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin: 0 0 58px;
}

.legal-highlight {
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius-panel);
  background: var(--surface);
}

.legal-highlight strong,
.legal-highlight span {
  display: block;
}

.legal-highlight span {
  margin-top: 8px;
  color: var(--ink-soft);
  font-size: 13px;
}

.legal-toc {
  margin: 0 0 70px;
  padding: 28px 30px;
  border-radius: var(--radius-panel);
  background: var(--surface-soft);
}

.legal-toc > p {
  margin: 0 0 14px;
  font-size: 13px;
  font-weight: 700;
}

.legal-toc ol {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 7px 36px;
  margin: 0;
  padding-left: 20px;
  color: var(--ink-soft);
  font-size: 13px;
}

.legal-toc a {
  text-decoration: none;
}

.legal-toc a:hover,
.legal-toc a:focus-visible {
  color: var(--accent-strong);
  text-decoration: underline;
  text-underline-offset: 4px;
}

.legal-article {
  max-width: 820px;
}

.legal-article section {
  margin-top: 70px;
  scroll-margin-top: 92px;
}

.legal-article h2 {
  margin: 0 0 20px;
  font-size: clamp(25px, 3vw, 34px);
  font-weight: 650;
  letter-spacing: -0.035em;
  line-height: 1.2;
}

.legal-article p,
.legal-article li {
  color: var(--ink-soft);
}

.legal-article p {
  margin: 0 0 16px;
}

.legal-article ul {
  margin: 16px 0 0;
  padding-left: 22px;
}

.legal-article li + li {
  margin-top: 9px;
}

.legal-note,
.legal-contact {
  margin: 24px 0;
  padding: 22px 24px;
  border-radius: var(--radius-panel);
  background: var(--surface-soft);
}

.legal-note strong,
.legal-contact strong {
  color: var(--ink);
}

.legal-contact p {
  margin: 8px 0 0;
}

.legal-article a,
.legal-contact a {
  color: var(--accent-strong);
  text-underline-offset: 4px;
}

:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--accent) 70%, transparent);
  outline-offset: 4px;
}

@media (max-width: 920px) {
  .topbar-links {
    display: none;
  }

  .hero,
  .feature,
  .feature-reverse,
  .privacy-band {
    grid-template-columns: 1fr;
  }

  .hero {
    min-height: auto;
    gap: 52px;
    padding: 72px 0 92px;
  }

  .hero h1 {
    max-width: none;
  }

  .feature,
  .feature-reverse {
    min-height: auto;
    gap: 44px;
  }

  .feature-reverse .feature-copy {
    order: 0;
  }

  .privacy-band {
    min-width: 0;
  }

  .legal-highlights {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 680px) {
  .shell {
    width: min(calc(100% - 32px), var(--max));
  }

  .topbar {
    min-height: 62px;
  }

  .topbar-actions {
    gap: 10px;
  }

  .language-switch button {
    min-width: 47px;
    padding: 6px 8px;
  }

  .hero {
    padding: 54px 0 78px;
  }

  .hero h1 {
    font-size: clamp(32px, 10vw, 46px);
  }

  .privacy-band h2 {
    font-size: clamp(40px, 9vw, 48px);
  }

  .hero-actions {
    align-items: stretch;
    flex-direction: column;
  }

  .button {
    width: 100%;
  }

  .manifesto,
  .feature,
  .writing,
  .final {
    padding: 82px 0;
  }

  .writing-grid {
    grid-template-columns: 1fr;
  }

  .story:last-child {
    margin-top: 44px;
  }

  .privacy-band {
    margin: 62px auto;
    padding: 34px 24px;
    border-radius: var(--radius-panel);
  }

  .site-footer {
    align-items: flex-start;
    flex-direction: column;
  }

  .legal-page {
    padding: 28px 0 86px;
  }

  .legal-hero {
    padding: 38px 0 50px;
  }

  .legal-hero h1 {
    font-size: clamp(41px, 12vw, 56px);
  }

  .legal-toc {
    padding: 24px;
  }

  .legal-toc ol {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

@media (prefers-reduced-transparency: reduce) {
  .topbar-wrap {
    background: var(--page);
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
    border-color: var(--line);
  }
}

@media print {
  .topbar-wrap,
  .language-switch {
    position: static;
  }

  body {
    background: #fdfcfd;
    color: #242127;
  }

  .legal-article section {
    break-inside: avoid;
  }
}