:root {
  color-scheme: light dark;
  --ink: #14213d;
  --muted: #5e6b84;
  --paper: #f6f8fc;
  --card: rgba(255, 255, 255, 0.72);
  --line: rgba(54, 72, 110, 0.14);
  --accent: #4f6df5;
  --accent-deep: #3851d8;
  --teal: #13a99a;
  --violet: #8a63f6;
  --success: #168a64;
  --shadow: 0 24px 70px rgba(40, 57, 105, 0.13);
  --radius: 28px;
  --page: min(1160px, calc(100vw - 40px));
  font-family: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "SF Pro Display", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-synthesis: none;
  text-rendering: optimizeLegibility;
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  background: var(--paper);
}

body {
  min-width: 320px;
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 12% 8%, rgba(112, 141, 255, 0.20), transparent 28rem),
    radial-gradient(circle at 90% 20%, rgba(26, 202, 178, 0.14), transparent 26rem),
    linear-gradient(180deg, #fbfcff 0%, #f3f6fb 52%, #eef2f9 100%);
}

body::before {
  position: fixed;
  inset: 0;
  z-index: -1;
  content: "";
  opacity: 0.24;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(57, 76, 122, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(57, 76, 122, 0.04) 1px, transparent 1px);
  background-size: 40px 40px;
  mask-image: linear-gradient(to bottom, black, transparent 75%);
}

a { color: inherit; }

.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 100;
  padding: 10px 14px;
  border-radius: 12px;
  color: white;
  background: var(--accent-deep);
  transform: translateY(-150%);
}

.skip-link:focus { transform: translateY(0); }

.site-header {
  position: sticky;
  top: 0;
  z-index: 30;
  border-bottom: 1px solid transparent;
  background: rgba(246, 248, 252, 0.76);
  backdrop-filter: saturate(160%) blur(22px);
  -webkit-backdrop-filter: saturate(160%) blur(22px);
}

.nav-shell {
  width: var(--page);
  min-height: 72px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-size: 1.06rem;
  font-weight: 760;
  letter-spacing: -0.02em;
  text-decoration: none;
}

.brand-mark {
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  border: 1px solid rgba(255, 255, 255, 0.8);
  border-radius: 11px;
  color: white;
  background: linear-gradient(145deg, #7991ff, #4c67ed 56%, #2943b9);
  box-shadow: 0 9px 20px rgba(67, 91, 213, 0.24), inset 0 1px 1px rgba(255, 255, 255, 0.45);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-links a {
  padding: 9px 12px;
  border-radius: 12px;
  color: var(--muted);
  font-size: 0.9rem;
  font-weight: 620;
  text-decoration: none;
}

.nav-links a:hover,
.nav-links a:focus-visible {
  color: var(--accent-deep);
  background: rgba(79, 109, 245, 0.09);
  outline: none;
}

.hero {
  width: var(--page);
  min-height: 720px;
  margin: 0 auto;
  padding: 82px 0 72px;
  display: grid;
  grid-template-columns: minmax(0, 1.03fr) minmax(360px, 0.97fr);
  align-items: center;
  gap: clamp(52px, 7vw, 96px);
}

.eyebrow {
  width: fit-content;
  margin: 0 0 20px;
  padding: 7px 11px;
  border: 1px solid rgba(79, 109, 245, 0.16);
  border-radius: 999px;
  color: var(--accent-deep);
  background: rgba(255, 255, 255, 0.58);
  font-size: 0.78rem;
  font-weight: 760;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.hero h1 {
  max-width: 720px;
  margin: 0;
  font-size: clamp(3rem, 7vw, 5.7rem);
  line-height: 0.98;
  letter-spacing: -0.065em;
}

.hero h1 span {
  color: transparent;
  background: linear-gradient(105deg, #314cd0, #6a66f6 45%, #0d9d91 92%);
  background-clip: text;
  -webkit-background-clip: text;
}

.hero-copy {
  max-width: 620px;
  margin: 28px 0 0;
  color: var(--muted);
  font-size: clamp(1.02rem, 1.8vw, 1.22rem);
  line-height: 1.8;
}

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

.button {
  min-height: 48px;
  padding: 0 18px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: 1px solid var(--line);
  border-radius: 15px;
  color: var(--ink);
  background: rgba(255, 255, 255, 0.65);
  box-shadow: 0 8px 24px rgba(44, 63, 111, 0.08);
  font-size: 0.94rem;
  font-weight: 720;
  text-decoration: none;
}

.button.primary {
  border-color: transparent;
  color: white;
  background: linear-gradient(135deg, #607af2, #4059d8);
  box-shadow: 0 13px 30px rgba(60, 82, 195, 0.28);
}

.button:hover { transform: translateY(-1px); }
.button:focus-visible { outline: 3px solid rgba(79, 109, 245, 0.28); outline-offset: 3px; }

.hero-notes {
  margin-top: 22px;
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 600;
}

.hero-notes span::before {
  margin-right: 7px;
  color: var(--success);
  content: "●";
  font-size: 0.55rem;
  vertical-align: 0.12em;
}

.app-stage {
  position: relative;
  min-height: 520px;
  display: grid;
  place-items: center;
}

.app-stage::before,
.app-stage::after {
  position: absolute;
  border-radius: 999px;
  content: "";
  filter: blur(2px);
}

.app-stage::before {
  width: 320px;
  height: 320px;
  background: rgba(91, 116, 243, 0.20);
}

.app-stage::after {
  right: 0;
  bottom: 35px;
  width: 190px;
  height: 190px;
  background: rgba(22, 191, 168, 0.20);
}

.phone {
  position: relative;
  z-index: 2;
  width: min(368px, 100%);
  padding: 14px;
  border: 1px solid rgba(255, 255, 255, 0.94);
  border-radius: 44px;
  background: rgba(255, 255, 255, 0.48);
  box-shadow: 0 40px 90px rgba(37, 52, 105, 0.23), inset 0 0 0 1px rgba(40, 53, 95, 0.08);
  transform: rotate(1.8deg);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
}

.phone-screen {
  min-height: 540px;
  padding: 25px 20px 18px;
  overflow: hidden;
  border: 1px solid rgba(71, 87, 130, 0.10);
  border-radius: 33px;
  background:
    radial-gradient(circle at 25% 0%, rgba(114, 140, 255, 0.18), transparent 38%),
    linear-gradient(180deg, rgba(251, 252, 255, 0.97), rgba(240, 244, 252, 0.96));
}

.phone-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  color: var(--muted);
  font-size: 0.74rem;
  font-weight: 700;
}

.phone-title { margin: 42px 0 4px; font-size: 0.82rem; color: var(--muted); }
.phone-meaning { margin: 0; font-size: 1.3rem; font-weight: 760; }

.word-card {
  margin-top: 28px;
  padding: 24px 17px 18px;
  border: 1px solid rgba(255, 255, 255, 0.82);
  border-radius: 24px;
  background: rgba(255, 255, 255, 0.68);
  box-shadow: 0 18px 40px rgba(52, 69, 116, 0.10);
}

.letter-row {
  display: flex;
  justify-content: center;
  gap: 5px;
}

.letter {
  width: 24px;
  padding: 0 0 7px;
  border-bottom: 2px solid rgba(49, 67, 121, 0.18);
  text-align: center;
  font-family: ui-rounded, "SF Pro Rounded", sans-serif;
  font-size: 1.04rem;
  font-weight: 760;
}

.letter.hidden { color: var(--accent); border-color: var(--accent); }

.keyboard-note {
  margin: 17px 0 0;
  color: var(--muted);
  text-align: center;
  font-size: 0.72rem;
}

.phone-stats {
  margin-top: 16px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
}

.stat {
  padding: 11px 6px;
  border-radius: 14px;
  text-align: center;
  background: rgba(86, 108, 214, 0.07);
}

.stat strong { display: block; color: var(--accent-deep); font-size: 0.94rem; }
.stat span { color: var(--muted); font-size: 0.62rem; }

.tab-bar {
  margin-top: 46px;
  padding: 10px 7px;
  display: flex;
  justify-content: space-around;
  border: 1px solid rgba(255, 255, 255, 0.82);
  border-radius: 19px;
  background: rgba(255, 255, 255, 0.62);
  box-shadow: 0 12px 30px rgba(52, 69, 116, 0.09);
}

.tab-bar span { color: var(--muted); font-size: 0.64rem; }
.tab-bar .active { color: var(--accent-deep); font-weight: 760; }

.section {
  width: var(--page);
  margin: 0 auto;
  padding: 96px 0;
}

.section-heading { max-width: 760px; margin-bottom: 44px; }
.section-kicker { margin: 0 0 12px; color: var(--accent-deep); font-size: 0.78rem; font-weight: 800; letter-spacing: 0.09em; text-transform: uppercase; }
.section h2 { margin: 0; font-size: clamp(2.15rem, 4.8vw, 4rem); line-height: 1.08; letter-spacing: -0.05em; }
.section-intro { margin: 18px 0 0; color: var(--muted); font-size: 1.02rem; line-height: 1.8; }

.feature-grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: 18px;
}

.feature-card {
  min-height: 260px;
  padding: 28px;
  border: 1px solid rgba(255, 255, 255, 0.86);
  border-radius: var(--radius);
  background: var(--card);
  box-shadow: 0 18px 50px rgba(43, 59, 105, 0.08);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
}

.feature-card.wide { grid-column: span 7; }
.feature-card.narrow { grid-column: span 5; }

.feature-icon {
  width: 46px;
  height: 46px;
  display: grid;
  place-items: center;
  border-radius: 15px;
  color: var(--accent-deep);
  background: rgba(79, 109, 245, 0.11);
  font-size: 1rem;
  font-weight: 850;
}

.feature-card:nth-child(2) .feature-icon { color: #087e75; background: rgba(19, 169, 154, 0.12); }
.feature-card:nth-child(3) .feature-icon { color: #7048da; background: rgba(138, 99, 246, 0.12); }
.feature-card:nth-child(4) .feature-icon { color: #b05e20; background: rgba(232, 133, 64, 0.13); }

.feature-card h3 { margin: 30px 0 10px; font-size: 1.35rem; letter-spacing: -0.025em; }
.feature-card p { margin: 0; color: var(--muted); line-height: 1.75; }

.principles {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 64px;
  align-items: center;
}

.principle-list { display: grid; gap: 14px; }

.principle {
  padding: 20px;
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 15px;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.52);
}

.principle-number {
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  border-radius: 11px;
  color: var(--accent-deep);
  background: rgba(79, 109, 245, 0.10);
  font-weight: 800;
}

.principle h3 { margin: 2px 0 5px; font-size: 1rem; }
.principle p { margin: 0; color: var(--muted); font-size: 0.9rem; line-height: 1.65; }

.closing-card {
  position: relative;
  padding: clamp(38px, 8vw, 78px);
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.64);
  border-radius: 34px;
  color: white;
  background:
    radial-gradient(circle at 90% 20%, rgba(33, 221, 189, 0.36), transparent 24rem),
    linear-gradient(135deg, #20337e, #5268e8 58%, #5646b8);
  box-shadow: var(--shadow);
}

.closing-card h2 { max-width: 760px; font-size: clamp(2.15rem, 5vw, 4.4rem); }
.closing-card p { max-width: 660px; margin: 20px 0 0; color: rgba(255, 255, 255, 0.78); font-size: 1.03rem; line-height: 1.8; }
.closing-card .button { margin-top: 28px; color: #243a9a; background: white; }

.site-footer {
  width: var(--page);
  margin: 0 auto;
  padding: 42px 0 50px;
  display: flex;
  justify-content: space-between;
  gap: 28px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.82rem;
}

.footer-links { display: flex; flex-wrap: wrap; gap: 18px; }
.footer-links a { text-decoration: none; }
.footer-links a:hover { color: var(--accent-deep); }

.legal-main {
  width: min(880px, calc(100vw - 40px));
  margin: 0 auto;
  padding: 68px 0 100px;
}

.legal-hero {
  padding: 44px clamp(24px, 6vw, 58px);
  border: 1px solid rgba(255, 255, 255, 0.84);
  border-radius: 30px;
  background: rgba(255, 255, 255, 0.65);
  box-shadow: var(--shadow);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
}

.legal-hero h1 { margin: 0; font-size: clamp(2.35rem, 7vw, 4.8rem); letter-spacing: -0.06em; }
.legal-hero p { margin: 16px 0 0; color: var(--muted); line-height: 1.75; }
.legal-meta { display: flex; flex-wrap: wrap; gap: 10px 20px; font-size: 0.82rem; }

.legal-toc {
  margin: 24px 0;
  padding: 20px 24px;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.48);
}

.legal-toc strong { display: block; margin-bottom: 10px; }
.legal-toc div { display: flex; flex-wrap: wrap; gap: 8px 16px; }
.legal-toc a { color: var(--accent-deep); font-size: 0.88rem; text-decoration: none; }

.legal-document {
  padding: 16px clamp(4px, 4vw, 32px);
}

.legal-section {
  padding: 34px 0;
  border-bottom: 1px solid var(--line);
  scroll-margin-top: 92px;
}

.legal-section:last-child { border-bottom: 0; }
.legal-section h2 { margin: 0 0 14px; font-size: 1.42rem; letter-spacing: -0.025em; }
.legal-section h3 { margin: 24px 0 9px; font-size: 1rem; }
.legal-section p,
.legal-section li { color: #46536d; line-height: 1.82; }
.legal-section p { margin: 10px 0; }
.legal-section ul,
.legal-section ol { margin: 10px 0; padding-left: 1.3rem; }
.legal-section li + li { margin-top: 7px; }
.legal-section a { color: var(--accent-deep); text-underline-offset: 3px; }

.data-table-wrap { margin: 18px 0; overflow-x: auto; border: 1px solid var(--line); border-radius: 16px; }
.data-table { width: 100%; border-collapse: collapse; min-width: 640px; font-size: 0.88rem; }
.data-table th,
.data-table td { padding: 14px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; line-height: 1.65; }
.data-table th { color: var(--ink); background: rgba(79, 109, 245, 0.07); }
.data-table td { color: #46536d; }
.data-table tr:last-child td { border-bottom: 0; }

.legal-callout {
  margin: 18px 0;
  padding: 16px 18px;
  border-left: 4px solid var(--accent);
  border-radius: 4px 14px 14px 4px;
  color: #34415e;
  background: rgba(79, 109, 245, 0.08);
  line-height: 1.72;
}

@media (max-width: 860px) {
  .nav-shell { min-height: 66px; }
  .nav-links a:not(.legal-link) { display: none; }
  .hero { min-height: auto; padding-top: 58px; grid-template-columns: 1fr; }
  .hero-copy { max-width: 700px; }
  .app-stage { min-height: 570px; }
  .feature-card.wide,
  .feature-card.narrow { grid-column: span 12; }
  .principles { grid-template-columns: 1fr; gap: 36px; }
}

@media (max-width: 560px) {
  :root { --page: min(100% - 28px, 1160px); }
  .nav-shell { gap: 12px; }
  .nav-links { gap: 2px; }
  .nav-links a { padding-inline: 8px; font-size: 0.8rem; }
  .hero { padding: 50px 0 46px; gap: 28px; }
  .hero h1 { font-size: clamp(2.75rem, 15vw, 4.4rem); }
  .hero-actions { display: grid; }
  .button { width: 100%; }
  .hero-notes { gap: 9px 14px; }
  .app-stage { min-height: 520px; }
  .phone { width: 326px; transform: none; }
  .phone-screen { min-height: 500px; }
  .section { padding: 72px 0; }
  .feature-card { min-height: 0; padding: 23px; }
  .site-footer { flex-direction: column; padding-bottom: 36px; }
  .legal-main { width: min(100% - 28px, 880px); padding-top: 36px; }
  .legal-hero { padding: 30px 22px; }
  .legal-document { padding-inline: 4px; }
}

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

@media (prefers-color-scheme: dark) {
  :root {
    --ink: #f3f5ff;
    --muted: #aab3c9;
    --paper: #0b1020;
    --card: rgba(24, 31, 54, 0.76);
    --line: rgba(188, 200, 234, 0.14);
    --shadow: 0 24px 70px rgba(0, 0, 0, 0.30);
  }
  body {
    background:
      radial-gradient(circle at 12% 8%, rgba(76, 101, 214, 0.25), transparent 28rem),
      radial-gradient(circle at 90% 20%, rgba(15, 134, 122, 0.18), transparent 26rem),
      linear-gradient(180deg, #0e1425 0%, #0a1020 100%);
  }
  .site-header { background: rgba(11, 16, 32, 0.78); }
  .eyebrow,
  .button,
  .principle,
  .legal-hero,
  .legal-toc { background: rgba(25, 33, 58, 0.70); }
  .phone { border-color: rgba(255, 255, 255, 0.16); background: rgba(25, 34, 64, 0.6); }
  .phone-screen { background: linear-gradient(180deg, #171f39, #10182d); }
  .word-card,
  .tab-bar { border-color: rgba(255, 255, 255, 0.12); background: rgba(28, 37, 65, 0.72); }
  .legal-section p,
  .legal-section li,
  .data-table td { color: #bdc5d8; }
  .data-table th { background: rgba(91, 117, 235, 0.13); }
  .legal-callout { color: #d5dcf0; }
}