:root {
  --jade: #285f45;
  --jade-dark: #173b2c;
  --jade-soft: #dbeadd;
  --coral: #e66f4e;
  --coral-dark: #a82e39;
  --gold: #f2b948;
  --cream: #fff7e4;
  --ink: #1e2621;
  --muted: rgba(30, 38, 33, .62);
  --soft: #f5f1e8;
  --paper: #fffdf8;
  --line: rgba(23, 59, 44, .12);
  --shadow: rgba(71, 44, 31, .16) 0 20px 60px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; color: var(--ink); background: radial-gradient(circle at 15% 5%, #fff9e9 0, transparent 28%), var(--soft); letter-spacing: -.25px; }
button, input, a { font: inherit; }
button { cursor: pointer; }
a { color: var(--jade); }
[hidden] { display: none !important; }

.nav { position: sticky; top: 0; z-index: 20; min-height: 54px; display: flex; align-items: center; justify-content: space-between; padding: 7px clamp(16px, 4vw, 48px); background: rgba(23, 59, 44, .92); color: white; backdrop-filter: saturate(150%) blur(18px); -webkit-backdrop-filter: saturate(150%) blur(18px); }
.nav__brand { display: inline-flex; gap: 9px; align-items: center; color: white; text-decoration: none; font-weight: 780; letter-spacing: -.4px; }
.nav__brand img { filter: drop-shadow(0 3px 8px rgba(0,0,0,.2)); }
.nav__links { display: flex; align-items: center; gap: 14px; color: rgba(255,255,255,.78); font-size: 12px; }
.nav__button { border: 1px solid rgba(255,255,255,.18); color: white; background: rgba(255,255,255,.1); border-radius: 999px; padding: 7px 11px; }
.nav__button--signed-in { color: #123b2b; background: #e2f5de; border-color: rgba(255,255,255,.45); font-weight: 800; box-shadow: 0 0 0 2px rgba(226,245,222,.12); }
.nav__button--plan { background: var(--coral); border-color: transparent; font-weight: 750; }
.nav__button--quiet { color: rgba(255,255,255,.7); }

.language-banner { display: flex; justify-content: center; gap: 18px; align-items: center; min-height: 34px; padding: 7px 18px; font-size: 12px; letter-spacing: .03em; }
.language-banner--chinese { color: #fff8e7; background: linear-gradient(90deg, #7e2931, #bd3e3c 45%, #8f2b32); box-shadow: inset 0 -1px rgba(255,255,255,.14); }
.language-banner__brand { font-weight: 800; }
.language-banner__native { color: #ffd583; }
.language-banner__promise { color: rgba(255,255,255,.75); }

main { max-width: 1160px; margin: 0 auto; padding: 0 20px 64px; }
.hero { min-height: 520px; display: grid; grid-template-columns: minmax(280px, .82fr) minmax(440px, 1.18fr); gap: clamp(18px, 5vw, 70px); align-items: center; padding: 56px 0 44px; }
.hero__content { position: relative; z-index: 1; }
.bloom-stage { display: grid; place-items: center; min-height: 420px; border-radius: 48% 52% 45% 55% / 55% 42% 58% 45%; background: radial-gradient(circle at 48% 42%, #fff7d3 0 13%, #ffd9a7 14% 30%, rgba(235,121,76,.24) 31% 51%, rgba(40,95,69,.12) 52% 68%, transparent 69%); }
.hero-bloom { width: min(100%, 430px); overflow: visible; animation: float-bloom 7s ease-in-out infinite; }
@keyframes float-bloom { 0%,100% { transform: translateY(0) rotate(-1deg); } 50% { transform: translateY(-9px) rotate(1deg); } }
.eyebrow { margin: 0 0 12px; color: var(--coral-dark); font-size: 13px; font-weight: 760; text-transform: uppercase; letter-spacing: .08em; }
h1 { margin: 0; max-width: 720px; font-family: "Helvetica Neue", Arial, system-ui, sans-serif; font-size: clamp(48px, 7.6vw, 86px); line-height: .98; letter-spacing: -2.8px; font-weight: 750; }
.hero__copy { max-width: 650px; margin: 22px 0 0; font-size: clamp(18px, 2.2vw, 24px); line-height: 1.34; color: var(--muted); }
.hero__actions, .controls, .account-actions { display: flex; align-items: center; gap: 11px; margin-top: 28px; flex-wrap: wrap; }
.migration-notice { display: inline-block; margin: 16px 0 0; padding: 8px 12px; border-radius: 999px; color: var(--jade); background: var(--jade-soft); font-size: 13px; }

.button { border: 1px solid transparent; text-decoration: none; border-radius: 999px; padding: 11px 18px; min-height: 44px; display: inline-flex; align-items: center; justify-content: center; gap: 8px; font-weight: 680; transition: transform .18s ease, background .18s ease, border-color .18s ease, box-shadow .18s ease; }
.button:hover { transform: translateY(-1px); }
.button:active { transform: translateY(1px) scale(.99); }
.button:disabled { opacity: .48; cursor: not-allowed; transform: none; }
.button--primary { background: var(--jade); color: white; box-shadow: rgba(40,95,69,.18) 0 8px 20px; }
.button--primary:hover { background: var(--jade-dark); }
.button--ghost { color: var(--jade); border-color: rgba(40,95,69,.35); background: rgba(255,253,248,.7); }
.button--secondary { color: var(--ink); background: var(--paper); border-color: var(--line); }
.button--google { width: 100%; color: #202124; background: white; border-color: #dadce0; }
.button--google::before { content: "G"; display: grid; place-items: center; width: 22px; height: 22px; border-radius: 50%; color: #4285f4; font-weight: 850; background: #f8fbff; }
.shortcut { opacity: .68; font-size: 12px; }

.dashboard { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin-bottom: 18px; }
.metric-card { background: var(--paper); border: 1px solid var(--line); border-radius: 26px; padding: 22px; min-height: 150px; display: flex; flex-direction: column; justify-content: space-between; box-shadow: rgba(67,47,32,.04) 0 2px 3px; }
.metric-card--dark { color: white; background: linear-gradient(145deg, var(--jade-dark), #245a40); }
.metric-card--account { background: linear-gradient(145deg, #fffdf8, #eef6ed); }
.metric-card__label { color: var(--muted); font-size: 13px; font-weight: 700; }
.metric-card strong { font-size: clamp(28px, 3.2vw, 38px); line-height: 1; letter-spacing: -1.5px; }
.metric-card span:last-child { color: var(--muted); font-size: 13px; }
.metric-card--dark .metric-card__label, .metric-card--dark span:last-child { color: rgba(255,255,255,.7); }
.progress { height: 9px; background: rgba(40,95,69,.1); border-radius: 999px; overflow: hidden; }
.progress span { display: block; width: 0; height: 100%; background: linear-gradient(90deg, var(--jade), #61a467, var(--gold)); border-radius: inherit; transition: width .32s ease; }

.study { position: relative; background: var(--paper); border: 1px solid var(--line); border-radius: 36px; padding: clamp(18px, 4vw, 36px); box-shadow: var(--shadow); overflow: hidden; }
.study::before { content: ""; position: absolute; width: 250px; height: 250px; right: -110px; top: -120px; border-radius: 50%; background: radial-gradient(circle, rgba(242,185,72,.2), transparent 65%); pointer-events: none; }
.deck-strip { position: relative; z-index: 1; display: flex; justify-content: space-between; color: var(--muted); font-size: 14px; font-weight: 680; margin-bottom: 14px; }
.flashcard { min-height: 430px; border-radius: 29px; background: radial-gradient(circle at 50% 12%, #fffdf7 0, #faf6ea 48%, #f0eadb 100%); border: 1px solid rgba(40,95,69,.09); display: grid; place-items: center; padding: clamp(22px, 5vw, 56px); text-align: center; }
.prompt, .label { display: block; color: var(--muted); font-size: 12px; font-weight: 760; text-transform: uppercase; letter-spacing: .08em; }
#targetWord { margin: 8px 0 0; font-size: clamp(96px, 17vw, 190px); line-height: .94; letter-spacing: -8px; font-weight: 720; color: #263d30; text-shadow: 0 9px 30px rgba(40,95,69,.08); }
#targetHint { color: var(--muted); font-size: 17px; margin-top: 18px; }
.flashcard__answer { width: min(720px, 100%); margin-top: 28px; animation: rise .24s ease both; }
@keyframes rise { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: translateY(0); } }
.answer-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.answer-grid > div, .sentence { background: #fffefb; border-radius: 20px; padding: 18px; text-align: left; border: 1px solid var(--line); }
.answer-big { font-size: 24px; font-weight: 680; margin: 8px 0 0; }
.sentence { margin-top: 14px; }
.sentence__zh { font-size: 34px; margin: 10px 0 4px; font-weight: 680; letter-spacing: -1px; }
#examplePinyin, #exampleEnglish { margin: 6px 0 0; color: var(--muted); font-size: 17px; }
.controls { justify-content: center; }
.session-end { margin-top: 16px; text-align: center; }
.session-end small { display: block; margin-top: 7px; color: var(--muted); }
.ratings { display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px; margin-top: 16px; }
.ratings button { border: 1px solid rgba(40,95,69,.08); border-radius: 18px; min-height: 66px; background: #f5f1e8; color: var(--ink); font-weight: 730; transition: transform .16s ease, background .16s ease; }
.ratings button:hover { background: var(--jade-soft); transform: translateY(-1px); }
.ratings span { display: block; color: var(--muted); margin-top: 3px; font-size: 12px; }
.sponsor-card { margin-top: 18px; display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 18px; border: 1px solid rgba(230,111,78,.24); background: linear-gradient(135deg, #fff4df, #fffdf8); border-radius: 24px; }
.sponsor-card h3 { margin: 6px 0 4px; font-size: 22px; }
.sponsor-card p { margin: 0; color: var(--muted); line-height: 1.45; }

.upgrade { margin-top: 36px; color: white; background: radial-gradient(circle at 90% 5%, rgba(242,185,72,.2), transparent 28%), linear-gradient(145deg, #173b2c, #2c6245); border-radius: 36px; padding: clamp(24px, 5vw, 46px); }
.upgrade .eyebrow { color: #ffd47f; }
.upgrade h2 { margin: 0; max-width: 790px; font-size: clamp(34px, 5vw, 62px); line-height: 1.02; letter-spacing: -1.8px; }
.pricing-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin-top: 26px; }
.pricing-card { background: rgba(255,255,255,.08); border: 1px solid rgba(255,255,255,.13); border-radius: 27px; padding: 22px; }
.pricing-card--featured { background: var(--cream); color: var(--ink); }
.pricing-card .label { color: rgba(255,255,255,.67); }
.pricing-card--featured .label { color: var(--coral-dark); }
.pricing-card strong { display: block; margin-top: 10px; font-size: 42px; line-height: 1; letter-spacing: -1.5px; }
.pricing-card strong span { font-size: 17px; letter-spacing: 0; color: var(--muted); }
.pricing-card:not(.pricing-card--featured) strong span { color: rgba(255,255,255,.58); }
.pricing-card p, .pricing-card li, .upgrade__note { color: rgba(255,255,255,.68); line-height: 1.45; }
.pricing-card--featured p, .pricing-card--featured li { color: var(--muted); }
.pricing-card ul { padding-left: 20px; min-height: 90px; }
.pricing-card .button { width: 100%; margin-top: 8px; }
.upgrade__note { margin: 18px 0 0; font-size: 13px; }

.footer { max-width: 1000px; margin: 0 auto; padding: 12px 20px 36px; color: var(--muted); font-size: 13px; text-align: center; }
.footer__brand { display: flex; justify-content: center; align-items: center; gap: 8px; color: var(--ink); margin-bottom: 10px; }
.footer nav { display: flex; gap: 15px; justify-content: center; flex-wrap: wrap; }
.footer nav a { text-decoration: none; font-weight: 650; }

.auth-dialog { width: min(590px, calc(100vw - 28px)); max-height: calc(100vh - 30px); overflow: auto; color: var(--ink); background: #fffdf8; border: 1px solid var(--line); border-radius: 30px; padding: 30px; box-shadow: rgba(23,59,44,.25) 0 30px 100px; }
.auth-dialog::backdrop { background: rgba(15,34,25,.62); backdrop-filter: blur(7px); }
.mock-interstitial { width: min(520px, calc(100vw - 28px)); color: var(--ink); background: var(--cream); border: 2px solid var(--jade); border-radius: 24px; padding: 26px; box-shadow: rgba(23,59,44,.25) 0 30px 100px; }
.mock-interstitial::backdrop { background: rgba(15,34,25,.62); }
.mock-interstitial h2 { margin: 8px 0; }
.mock-interstitial .button { width: 100%; margin-top: 10px; }
.auth-dialog h2 { margin: 10px 0 8px; font-size: clamp(30px, 5vw, 44px); letter-spacing: -1.5px; }
.auth-dialog > p { color: var(--muted); line-height: 1.5; }
.dialog-close { position: absolute; top: 16px; right: 16px; width: 34px; height: 34px; border-radius: 50%; border: 0; color: var(--muted); background: #f1ede4; font-size: 24px; line-height: 1; }
.auth-bloom { width: 68px; height: 68px; }
.auth-divider { display: flex; align-items: center; gap: 12px; color: var(--muted); font-size: 12px; margin: 18px 0; }
.auth-divider::before, .auth-divider::after { content: ""; height: 1px; flex: 1; background: var(--line); }
.auth-form label { display: block; font-size: 13px; font-weight: 700; margin-bottom: 7px; }
.auth-form__hint { margin: 8px 0 0; color: var(--muted); font-size: 12px; line-height: 1.45; }
.auth-form__code-toggle { margin-top: 10px; }
.auth-form--code { margin-top: 14px; padding-top: 14px; border-top: 1px solid var(--line); }
.auth-form__row { display: grid; grid-template-columns: 1fr auto; gap: 8px; }
.auth-form input { min-width: 0; width: 100%; min-height: 46px; border: 1px solid rgba(40,95,69,.22); border-radius: 13px; padding: 10px 13px; color: var(--ink); background: white; }
.auth-form input:focus { outline: 3px solid rgba(242,185,72,.28); border-color: var(--jade); }
.auth-status { min-height: 22px; padding: 9px 0 0; color: var(--jade) !important; font-weight: 630; }
.auth-privacy { font-size: 12px; }
.account-card { display: flex; flex-direction: column; gap: 7px; padding: 18px; border-radius: 18px; background: #eff6ed; border: 1px solid var(--line); }
.account-card strong { font-size: 20px; }
.account-card span:last-child { color: var(--muted); font-size: 13px; }
.account-actions { margin-top: 14px; }

.info-main { max-width: 900px; padding-top: 54px; }
.info-hero { padding: 38px 0 28px; }
.info-hero h1 { font-size: clamp(42px, 7vw, 76px); }
.info-section { margin: 16px 0; padding: clamp(22px, 4vw, 34px); border: 1px solid var(--line); border-radius: 27px; background: var(--paper); }
.info-section h2 { margin: 0 0 10px; font-size: 28px; }
.info-section p, .info-section li { color: var(--muted); line-height: 1.65; }
.info-section strong { color: var(--ink); }
.info-callout { border-left: 5px solid var(--coral); }

@media (prefers-reduced-motion: reduce) { *, *::before, *::after { scroll-behavior: auto !important; animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; } }
@media (max-width: 900px) { .hero { grid-template-columns: 1fr; text-align: center; padding-top: 28px; } .hero__content { display: flex; flex-direction: column; align-items: center; } .bloom-stage { min-height: 300px; order: 2; margin-top: -26px; } .hero-bloom { width: min(360px, 86vw); } .dashboard { grid-template-columns: 1fr 1fr; } .pricing-grid { grid-template-columns: 1fr; } .pricing-card ul { min-height: auto; } }
@media (max-width: 650px) {
  html, body { max-width: 100%; overflow-x: hidden; }
  .nav { gap: 8px; padding-inline: 12px; }
  .nav__brand { flex: 0 0 auto; }
  .nav__links { min-width: 0; margin-left: auto; gap: 6px; }
  .nav__links > span, .nav__button--quiet, .nav__button--plan { display: none; }
  #accountBtn { max-width: 112px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; padding-inline: 10px; }
  .language-banner { gap: 8px; justify-content: center; }
  .language-banner__native, .language-banner__promise { display: none; }
  main { width: 100%; padding-left: 14px; padding-right: 14px; }
  .hero, .hero > *, .hero__content { min-width: 0; width: 100%; max-width: 100%; }
  .hero { min-height: auto; overflow: hidden; }
  .hero__content { padding-inline: 2px; }
  .eyebrow { max-width: 100%; font-size: 11px; line-height: 1.4; }
  h1 { max-width: 100%; font-size: clamp(43px, 13vw, 56px); letter-spacing: -1.2px; overflow-wrap: break-word; }
  .hero__copy { max-width: 100%; font-size: 18px; }
  .hero__actions { width: 100%; justify-content: center; gap: 8px; }
  .hero__actions .button { padding-inline: 14px; }
  .bloom-stage { width: 100%; max-width: 100%; overflow: hidden; }
  .dashboard { grid-template-columns: 1fr; }
  .metric-card { min-height: 132px; }
  .answer-grid { grid-template-columns: 1fr; }
  .ratings { grid-template-columns: 1fr 1fr; }
  .flashcard { min-height: 390px; }
  #targetWord { letter-spacing: -4px; }
  .sponsor-card { align-items: stretch; flex-direction: column; }
  .auth-dialog { padding: 24px 18px; border-radius: 24px; }
  .auth-form__row { grid-template-columns: 1fr; }
  .auth-form__row .button { width: 100%; }
}