:root {
  color-scheme: light;
  --bg: #f5f5f7;
  --surface: #ffffff;
  --ink: #1d1d1f;
  --ink-soft: #515154;
  --muted: #6e6e73;
  --line: rgb(29 29 31 / 0.12);
  --blue: #0071e3;
  --blue-hover: #0077ed;
  --dark: #000000;
  --dark-soft: #161617;
  --white-soft: rgb(245 245 247 / 0.78);
  --shadow: 0 38px 90px rgb(0 0 0 / 0.12);
  --max: 1180px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--ink);
  font-family: 'SF Pro Display', 'SF Pro Text', 'PingFang SC', 'Helvetica Neue', Helvetica, Arial, sans-serif;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
  text-decoration: none;
}

button {
  font: inherit;
}

img {
  display: block;
}

h1,
h2,
p {
  margin: 0;
}

h1,
h2 {
  text-wrap: balance;
}

p {
  text-wrap: pretty;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgb(245 245 247 / 0.76);
  backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid transparent;
  transition:
    background 180ms var(--ease),
    border-color 180ms var(--ease);
}

.site-header.is-scrolled {
  background: rgb(245 245 247 / 0.92);
  border-color: var(--line);
}

.header-shell,
.footer-shell {
  width: min(calc(100% - 44px), var(--max));
  margin: 0 auto;
}

.header-shell {
  min-height: 48px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand,
.nav,
.language-switcher {
  display: flex;
  align-items: center;
}

.brand {
  gap: 8px;
  font-size: 0.9rem;
  font-weight: 600;
}

.brand img {
  width: 22px;
  height: 22px;
}

.nav {
  gap: 30px;
  color: var(--ink-soft);
  font-size: 0.78rem;
}

.nav a,
.language-switcher button,
.hero-links a {
  transition:
    color 180ms var(--ease),
    background 180ms var(--ease),
    transform 180ms var(--ease);
}

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

.language-switcher {
  gap: 4px;
}

.language-switcher button {
  min-height: 26px;
  padding: 0 9px;
  border: 0;
  border-radius: 999px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
}

.language-switcher button[aria-pressed='true'] {
  background: rgb(29 29 31 / 0.07);
  color: var(--ink);
}

.hero {
  overflow: hidden;
  padding: clamp(58px, 8vw, 104px) 0 0;
  text-align: center;
}

.hero-copy {
  width: min(calc(100% - 40px), 960px);
  margin: 0 auto;
}

.eyebrow {
  color: var(--ink);
  font-size: clamp(1.05rem, 1.8vw, 1.38rem);
  font-weight: 600;
  line-height: 1.18;
  letter-spacing: -0.02em;
}

h1 {
  margin-top: 10px;
  font-size: clamp(4.2rem, 11vw, 8.5rem);
  line-height: 0.92;
  letter-spacing: -0.04em;
  font-weight: 700;
}

.hero-intro {
  max-width: 720px;
  margin: 28px auto 0;
  color: var(--ink-soft);
  font-size: clamp(1.25rem, 2.3vw, 1.72rem);
  line-height: 1.42;
  letter-spacing: -0.02em;
}

.hero-links {
  display: flex;
  justify-content: center;
  gap: 28px;
  margin-top: 30px;
  color: var(--blue);
  font-size: clamp(1.05rem, 1.4vw, 1.24rem);
}

.hero-links a::after {
  content: ' >';
}

.hero-links a:hover,
.hero-links a:focus-visible {
  color: var(--blue-hover);
  transform: translateY(-1px);
}

.product-stage {
  position: relative;
  width: min(calc(100% - 32px), 1320px);
  min-height: clamp(620px, 72vw, 920px);
  margin: clamp(56px, 7vw, 84px) auto 0;
  overflow: hidden;
  border-radius: clamp(24px, 4vw, 44px) clamp(24px, 4vw, 44px) 0 0;
  background:
    radial-gradient(circle at 50% 88%, rgb(0 113 227 / 0.22), transparent 35%),
    linear-gradient(180deg, #ffffff 0%, #e9edf3 58%, #d9e1ec 100%);
  box-shadow: inset 0 1px 0 rgb(255 255 255 / 0.85);
}

.mac-frame {
  position: absolute;
  left: 50%;
  top: clamp(44px, 6vw, 84px);
  width: min(88%, 980px);
  min-height: clamp(330px, 36vw, 500px);
  padding: clamp(20px, 3vw, 34px);
  border-radius: clamp(20px, 3vw, 34px);
  background: rgb(255 255 255 / 0.9);
  border: 1px solid rgb(255 255 255 / 0.9);
  box-shadow: var(--shadow);
  transform: translateX(-50%);
}

.mac-titlebar {
  display: flex;
  gap: 8px;
}

.mac-titlebar span {
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: rgb(29 29 31 / 0.14);
}

.reader-line {
  margin-top: clamp(54px, 7vw, 92px);
  color: var(--ink);
  font-size: clamp(2rem, 4.8vw, 4.7rem);
  line-height: 1.04;
  letter-spacing: -0.04em;
  text-align: left;
}

mark {
  padding: 0 0.14em;
  border-radius: 0.22em;
  background: rgb(0 113 227 / 0.14);
  color: var(--blue);
}

.floating-actions {
  position: absolute;
  left: 50%;
  bottom: clamp(20px, 3vw, 34px);
  display: flex;
  gap: 8px;
  padding: 8px;
  border-radius: 999px;
  background: rgb(29 29 31 / 0.94);
  box-shadow: 0 24px 60px rgb(0 0 0 / 0.22);
  transform: translateX(-50%);
}

.floating-actions button {
  min-height: 38px;
  padding: 0 15px;
  border: 0;
  border-radius: 999px;
  background: transparent;
  color: rgb(245 245 247 / 0.72);
}

.floating-actions .active {
  background: var(--blue);
  color: #fff;
}

.word-card {
  position: absolute;
  right: clamp(22px, 8vw, 148px);
  bottom: clamp(34px, 8vw, 128px);
  width: min(360px, calc(100% - 44px));
  padding: 28px;
  border-radius: 28px;
  background: rgb(255 255 255 / 0.82);
  border: 1px solid rgb(255 255 255 / 0.86);
  box-shadow: var(--shadow);
  text-align: left;
  backdrop-filter: saturate(160%) blur(18px);
}

.word-card span,
.meaning-showcase span,
.review-screen span {
  color: var(--muted);
  font-size: 0.86rem;
  font-weight: 600;
}

.word-card strong {
  display: block;
  margin-top: 8px;
  font-size: clamp(2.15rem, 4vw, 3.5rem);
  line-height: 0.98;
  letter-spacing: -0.04em;
}

.word-card p {
  margin-top: 14px;
  color: var(--blue);
  font-size: 1.05rem;
  line-height: 1.45;
}

.word-card small {
  display: block;
  margin-top: 14px;
  color: var(--ink-soft);
  font-size: 0.95rem;
  line-height: 1.55;
}

.split-section,
.center-section,
.dark-section {
  width: min(calc(100% - 44px), var(--max));
  margin: 0 auto;
  padding: clamp(90px, 12vw, 160px) 0;
}

.split-section {
  display: grid;
  grid-template-columns: minmax(0, 0.84fr) minmax(0, 1.16fr);
  gap: clamp(28px, 7vw, 92px);
  align-items: center;
}

.section-copy h2,
.center-section h2,
.review-copy h2 {
  margin-top: 10px;
  font-size: clamp(3rem, 7vw, 6.2rem);
  line-height: 0.96;
  letter-spacing: -0.04em;
}

.section-copy p:last-child,
.center-section > p:last-of-type,
.review-copy p:last-child {
  margin-top: 22px;
  color: var(--ink-soft);
  font-size: clamp(1.14rem, 2vw, 1.45rem);
  line-height: 1.48;
  letter-spacing: -0.02em;
}

.panel {
  min-height: clamp(420px, 48vw, 620px);
  border-radius: clamp(24px, 4vw, 38px);
  background:
    radial-gradient(circle at 50% 92%, rgb(0 113 227 / 0.18), transparent 38%),
    linear-gradient(180deg, #ffffff 0%, #edf1f6 100%);
  box-shadow: inset 0 0 0 1px rgb(29 29 31 / 0.08);
}

.selection-panel {
  position: relative;
  overflow: hidden;
  padding: clamp(28px, 5vw, 56px);
}

.selection-text {
  max-width: 12ch;
  color: var(--ink);
  font-size: clamp(2.35rem, 5.5vw, 5rem);
  line-height: 1;
  letter-spacing: -0.04em;
}

.selection-menu {
  position: absolute;
  left: clamp(26px, 5vw, 56px);
  bottom: clamp(26px, 5vw, 56px);
  display: flex;
  gap: 8px;
  padding: 8px;
  border-radius: 999px;
  background: rgb(255 255 255 / 0.9);
  box-shadow: 0 22px 54px rgb(0 0 0 / 0.12);
}

.selection-menu span {
  padding: 10px 16px;
  border-radius: 999px;
  color: var(--blue);
  background: rgb(0 113 227 / 0.1);
  font-weight: 600;
}

.selection-menu span:last-child {
  background: var(--blue);
  color: #fff;
}

.center-section {
  text-align: center;
}

.center-section > p:last-of-type {
  max-width: 760px;
  margin-inline: auto;
}

.meaning-showcase {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
  margin-top: clamp(42px, 6vw, 72px);
  text-align: left;
}

.meaning-showcase article {
  min-height: 260px;
  padding: 28px;
  border-radius: 28px;
  background: #fff;
  box-shadow: inset 0 0 0 1px var(--line);
}

.meaning-showcase strong {
  display: block;
  margin-top: 18px;
  color: var(--ink);
  font-size: clamp(1.35rem, 2.5vw, 2.1rem);
  line-height: 1.12;
  letter-spacing: -0.035em;
}

.dark-section {
  width: 100%;
  margin: 0;
  padding-inline: max(22px, calc((100% - var(--max)) / 2));
  color: #f5f5f7;
  background:
    radial-gradient(circle at 68% 42%, rgb(0 113 227 / 0.28), transparent 24%),
    linear-gradient(180deg, #151517 0%, #050505 100%);
  display: grid;
  grid-template-columns: minmax(0, 0.95fr) minmax(300px, 0.7fr);
  gap: clamp(32px, 8vw, 116px);
  align-items: center;
}

.dark-section .eyebrow,
.review-copy p:last-child {
  color: var(--white-soft);
}

.review-device {
  display: grid;
  place-items: center;
}

.review-screen {
  width: min(100%, 390px);
  min-height: 520px;
  padding: 34px;
  border-radius: 44px;
  background:
    linear-gradient(180deg, rgb(255 255 255 / 0.12), rgb(255 255 255 / 0.04)),
    #0d0d0f;
  box-shadow:
    inset 0 0 0 1px rgb(255 255 255 / 0.14),
    0 42px 100px rgb(0 0 0 / 0.46);
}

.review-screen span {
  color: var(--white-soft);
}

.review-screen strong {
  display: block;
  margin-top: 28px;
  color: #fff;
  font-size: 9rem;
  line-height: 0.8;
  letter-spacing: -0.06em;
}

.review-screen p {
  margin-top: 28px;
  color: var(--white-soft);
  font-size: 1.32rem;
}

.review-screen div {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  margin-top: 120px;
}

.review-screen b {
  display: grid;
  min-height: 46px;
  place-items: center;
  border-radius: 999px;
  color: #fff;
  background: rgb(255 255 255 / 0.12);
  font-size: 0.94rem;
}

.review-screen b:nth-child(3) {
  background: var(--blue);
}

.site-footer {
  background: #f5f5f7;
  color: var(--muted);
  border-top: 1px solid var(--line);
}

.footer-shell {
  min-height: 82px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  font-size: 0.86rem;
}

.footer-shell span:first-child {
  color: var(--ink);
  font-weight: 600;
}

a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 3px;
}

@media (max-width: 900px) {
  .header-shell {
    flex-wrap: wrap;
    justify-content: center;
    padding: 10px 0;
  }

  .nav {
    order: 3;
    width: 100%;
    justify-content: center;
  }

  .split-section,
  .dark-section {
    grid-template-columns: 1fr;
  }

  .meaning-showcase {
    grid-template-columns: 1fr;
  }

  .word-card {
    left: 50%;
    right: auto;
    transform: translateX(-50%);
  }
}

@media (max-width: 620px) {
  .header-shell,
  .footer-shell,
  .split-section,
  .center-section {
    width: min(calc(100% - 32px), var(--max));
  }

  .nav {
    gap: 18px;
    overflow-x: auto;
  }

  h1 {
    font-size: clamp(3.35rem, 17vw, 5rem);
  }

  .hero-links {
    flex-direction: column;
    gap: 12px;
  }

  .product-stage {
    min-height: 720px;
  }

  .mac-frame {
    width: calc(100% - 28px);
  }

  .floating-actions,
  .selection-menu {
    width: calc(100% - 40px);
    flex-wrap: wrap;
    justify-content: center;
  }

  .floating-actions button,
  .selection-menu span {
    flex: 1 1 auto;
  }

  .word-card {
    bottom: 28px;
  }

  .footer-shell {
    flex-direction: column;
    align-items: flex-start;
    justify-content: center;
  }
}

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

  *,
  *::before,
  *::after {
    transition: none !important;
  }
}