:root {
  --primary: #087f73;
  --primary-strong: #075e57;
  --primary-soft: #ddf5f0;
  --secondary: #ffb84d;
  --secondary-soft: #fff2d7;
  --background: #f6faf9;
  --surface: #ffffff;
  --surface-muted: #edf5f3;
  --ink: #17312e;
  --muted: #607773;
  --outline: #d8e5e2;
  --shadow-low: 0 12px 34px rgba(11, 64, 56, .07);
  --shadow-medium: 0 24px 64px rgba(11, 64, 56, .11);
  --shadow-float: 0 34px 90px rgba(11, 64, 56, .16);
  --ease-out: cubic-bezier(.23, 1, .32, 1);
  --radius-small: 12px;
  --radius-control: 16px;
  --radius-card: 22px;
  --radius-large: 32px;
  --shell: 1180px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: var(--background); font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "PingFang SC", "Microsoft YaHei", "Noto Sans CJK SC", sans-serif; font-size: 17px; line-height: 1.72; -webkit-font-smoothing: antialiased; }
body.nav-open { overflow: hidden; }
img { display: block; max-width: 100%; height: auto; }
a { color: inherit; text-decoration: none; }
button { font: inherit; }
h1, h2, h3, p { margin-top: 0; }
:focus-visible { outline: 3px solid var(--secondary); outline-offset: 4px; }
.shell { width: min(calc(100% - 44px), var(--shell)); margin-inline: auto; }
.skip-link { position: fixed; z-index: 100; top: 10px; left: 10px; padding: 9px 14px; border-radius: var(--radius-small); color: #fff; background: var(--primary-strong); transform: translateY(-160%); transition: transform .18s ease; }
.skip-link:focus { transform: translateY(0); }

.site-header { position: sticky; z-index: 50; top: 0; border-bottom: 1px solid rgba(216, 229, 226, .72); background: rgba(246, 250, 249, .84); backdrop-filter: blur(20px) saturate(130%); }
.nav-wrap { min-height: 76px; display: flex; align-items: center; gap: 28px; }
.brand { display: inline-flex; align-items: center; gap: 12px; font-weight: 850; letter-spacing: -.03em; }
.brand img { width: 44px; height: 44px; border-radius: 13px; box-shadow: 0 10px 24px rgba(8, 127, 115, .16); }
.nav-links { display: flex; align-items: center; gap: 28px; margin-left: auto; }
.nav-links a, .language-link { color: var(--muted); font-size: 14px; font-weight: 700; transition: color .18s ease; }
.nav-links a:hover, .language-link:hover { color: var(--primary); }
.nav-actions { display: flex; align-items: center; gap: 14px; }
.nav-download { min-height: 44px; display: inline-flex; align-items: center; padding: 0 18px; border-radius: 999px; color: #fff; background: var(--primary); font-size: 14px; font-weight: 800; box-shadow: 0 10px 22px rgba(8, 127, 115, .16); transition: transform .18s ease, background .18s ease; }
.nav-download:hover { transform: translateY(-2px); background: var(--primary-strong); }
.nav-toggle { display: none; width: 44px; height: 44px; border: 1px solid var(--outline); border-radius: var(--radius-small); background: var(--surface); }
.nav-toggle span { display: block; width: 18px; height: 2px; margin: 5px auto; border-radius: 2px; background: var(--ink); }

.hero { position: relative; overflow: hidden; padding: 90px 0 86px; }
.hero-glow { position: absolute; pointer-events: none; border-radius: 50%; filter: blur(2px); animation: drift 12s ease-in-out infinite alternate; }
.hero-glow-one { width: 520px; height: 520px; top: -320px; right: 8%; background: radial-gradient(circle, rgba(8,127,115,.16), rgba(8,127,115,0) 68%); }
.hero-glow-two { width: 420px; height: 420px; bottom: -280px; left: -100px; background: radial-gradient(circle, rgba(255,184,77,.20), rgba(255,184,77,0) 68%); animation-delay: -4s; }
.hero-grid { position: relative; display: grid; grid-template-columns: minmax(0, .94fr) minmax(480px, 1.06fr); align-items: center; gap: 76px; }
.eyebrow, .section-kicker { color: var(--primary); font-size: 13px; font-weight: 850; letter-spacing: .13em; text-transform: uppercase; }
.eyebrow { display: inline-flex; align-items: center; gap: 9px; margin-bottom: 20px; padding: 7px 12px; border: 1px solid rgba(8,127,115,.18); border-radius: 999px; background: rgba(221,245,240,.7); letter-spacing: .08em; }
.eyebrow::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: var(--primary); box-shadow: 0 0 0 5px rgba(8,127,115,.10); }
h1 { margin-bottom: 24px; font-size: clamp(44px, 5.4vw, 72px); line-height: 1.08; letter-spacing: -.062em; font-weight: 900; }
h1 em { display: block; color: var(--primary); font-style: normal; }
h2 { margin-bottom: 18px; font-size: clamp(32px, 4vw, 50px); line-height: 1.17; letter-spacing: -.045em; font-weight: 880; }
h3 { margin-bottom: 10px; font-size: 22px; line-height: 1.35; letter-spacing: -.025em; }
.hero-lead { max-width: 640px; margin-bottom: 30px; color: var(--muted); font-size: 19px; }
.button-row { display: flex; flex-wrap: wrap; gap: 12px; }
.button { min-height: 54px; display: inline-flex; align-items: center; justify-content: center; padding: 0 22px; border: 1px solid transparent; border-radius: var(--radius-control); font-weight: 820; transition: transform .18s ease, box-shadow .18s ease, background .18s ease; }
.button:hover { transform: translateY(-2px); }
.button-primary { color: #fff; background: var(--primary); box-shadow: 0 15px 32px rgba(8,127,115,.2); }
.button-primary:hover { background: var(--primary-strong); box-shadow: 0 18px 38px rgba(8,127,115,.24); }
.button-secondary { border-color: var(--outline); background: rgba(255,255,255,.72); }
.button-secondary:hover { background: #fff; box-shadow: var(--shadow-low); }
.support-line { display: flex; flex-wrap: wrap; gap: 8px 22px; margin: 24px 0 0; padding: 0; color: var(--muted); font-size: 14px; list-style: none; }
.support-line li { position: relative; padding-left: 15px; }
.support-line li::before { content: ""; position: absolute; top: .68em; left: 0; width: 6px; height: 6px; border-radius: 50%; background: var(--secondary); }

.device-composition { position: relative; min-height: 620px; perspective: 1200px; }
.device-float { animation: deviceFloat 7s ease-in-out infinite; }
.tablet-frame, .phone-frame { position: absolute; box-sizing: content-box; padding: 0; background: #101918; box-shadow: var(--shadow-float); }
.tablet-frame { width: 430px; height: auto; aspect-ratio: 2048 / 2732; top: 10px; right: 0; border: 10px solid #101918; border-radius: 30px; transform: rotate(2deg); }
.phone-frame { z-index: 2; width: 214px; height: auto; aspect-ratio: 1170 / 2532; bottom: 0; left: 0; border: 8px solid #101918; border-radius: 32px; animation-delay: -2.5s; transform: rotate(-4deg); }
.tablet-camera { position: absolute; z-index: 2; top: 50%; left: 4px; width: 4px; height: 4px; border-radius: 50%; background: #4b5a57; }
.phone-island { position: absolute; z-index: 3; top: 8px; left: 50%; width: 56px; height: 14px; border-radius: 999px; background: #10211e; transform: translateX(-50%); }
.screen-placeholder { position: relative; overflow: hidden; width: 100%; height: 100%; border-radius: inherit; background: linear-gradient(150deg, #fff 0%, #f0f8f6 100%); }
.screen-image { display: block; width: 100%; height: 100%; object-fit: cover; object-position: center; }
.phone-screen { padding: 0; border-radius: 24px; }
.tablet-screen { padding: 0; border-radius: 20px; }
.placeholder-label { position: absolute; z-index: 2; top: 16px; right: 16px; padding: 4px 9px; border: 1px solid rgba(8,127,115,.18); border-radius: 999px; color: var(--primary); background: rgba(255,255,255,.82); font-size: 10px; font-weight: 800; letter-spacing: .04em; }
.mock-toolbar { display: flex; gap: 8px; margin-bottom: 26px; }
.mock-toolbar i { width: 72px; height: 28px; border-radius: 9px; background: var(--surface-muted); }
.mock-toolbar i:first-child { background: var(--primary-soft); }
.copy-grid, .layout-demo > div { display: grid; grid-template-columns: repeat(4, 1fr); }
.copy-grid b, .layout-demo b { position: relative; display: grid; aspect-ratio: 1; place-items: center; border: 1px solid rgba(8,127,115,.34); color: var(--ink); font-size: 28px; font-weight: 600; }
.copy-grid b::before, .copy-grid b::after, .layout-demo b::before, .layout-demo b::after { content: ""; position: absolute; background: rgba(8,127,115,.16); }
.copy-grid b::before, .layout-demo b::before { width: 100%; height: 1px; }
.copy-grid b::after, .layout-demo b::after { width: 1px; height: 100%; }
.copy-grid .trace, .layout-demo .trace { color: rgba(23,49,46,.22); }
.mock-title { margin-bottom: 22px; font-size: 21px; font-weight: 850; }
.mock-card { display: flex; align-items: center; gap: 11px; margin-bottom: 12px; padding: 14px; border: 1px solid var(--outline); border-radius: 16px; background: #fff; box-shadow: 0 7px 20px rgba(11,64,56,.05); }
.mock-card i { width: 38px; height: 38px; display: grid; flex: 0 0 auto; place-items: center; border-radius: 12px; color: var(--primary); background: var(--primary-soft); font-style: normal; font-weight: 800; }
.mock-card span { display: flex; flex-direction: column; line-height: 1.3; }
.mock-card strong { font-size: 13px; }
.mock-card small { margin-top: 4px; color: var(--muted); font-size: 10px; }
.mock-button { position: absolute; right: 18px; bottom: 24px; left: 18px; padding: 11px; border-radius: 13px; color: #fff; background: var(--primary); text-align: center; font-size: 12px; font-weight: 800; }
.paper-card { position: absolute; z-index: 1; display: flex; gap: 4px; padding: 12px; border: 1px solid var(--outline); border-radius: 16px; background: rgba(255,255,255,.88); box-shadow: var(--shadow-low); backdrop-filter: blur(12px); }
.paper-card-a { top: 30px; left: 5px; transform: rotate(-8deg); }
.paper-card span { width: 42px; height: 42px; display: grid; place-items: center; border: 1px solid rgba(8,127,115,.24); color: var(--primary-strong); font-weight: 800; }

.quiet-strip { border-block: 1px solid var(--outline); background: rgba(255,255,255,.58); }
.strip-grid { display: grid; grid-template-columns: repeat(3, 1fr); }
.strip-grid > .strip-feature { display: flex; flex-direction: row; align-items: center; gap: 14px; min-height: 114px; justify-content: flex-start; padding: 22px 30px; border-right: 1px solid var(--outline); }
.strip-feature > img { flex: 0 0 42px; width: 42px; height: 42px; object-fit: contain; }
.strip-feature > div { display: flex; flex-direction: column; gap: 3px; }
.strip-grid div:last-child { border-right: 0; }
.strip-grid strong { color: var(--primary-strong); font-size: 15px; }
.strip-grid span { color: var(--muted); font-size: 14px; }

.section { padding: 112px 0; }
.section-mint { background: var(--primary-soft); }
.section-head { max-width: 720px; margin-bottom: 50px; }
.section-head.center { margin-inline: auto; text-align: center; }
.section-kicker { margin-bottom: 12px; }
.section-head > p:last-child, .bento-card p, .practice-copy > p, .privacy-panel p, .faq-item p { color: var(--muted); }
.steps-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.step-card { min-height: 260px; padding: 30px; border: 1px solid var(--outline); border-radius: var(--radius-card); background: var(--surface); box-shadow: var(--shadow-low); transition: transform .28s ease, box-shadow .28s ease; }
.step-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-medium); }
.step-card > span { display: inline-grid; width: 46px; height: 46px; margin-bottom: 34px; place-items: center; border-radius: 14px; color: var(--primary); background: var(--primary-soft); font-size: 13px; font-weight: 900; }
.step-card p { margin-bottom: 0; color: var(--muted); }

.bento-grid { display: grid; grid-template-columns: repeat(12, 1fr); gap: 18px; }
.bento-card { min-height: 320px; grid-column: span 4; display: flex; flex-direction: column; overflow: hidden; padding: 30px; border: 1px solid rgba(8,127,115,.13); border-radius: var(--radius-card); background: rgba(255,255,255,.86); box-shadow: var(--shadow-low); }
.bento-large { grid-column: span 8; display: grid; grid-template-columns: .9fr 1.1fr; gap: 30px; }
.bento-wide { min-height: 240px; grid-column: span 8; }
.bento-warm { background: var(--secondary-soft); }
.feature-index { display: block; margin-bottom: 22px; color: var(--primary); font-size: 12px; font-weight: 850; letter-spacing: .1em; text-transform: uppercase; }
.layout-demo { align-self: end; padding: 18px; border-radius: 18px; background: #f8fcfb; box-shadow: inset 0 0 0 1px var(--outline); transform: rotate(2deg); }
.layout-demo > div + div { margin-top: 8px; }
.layout-demo b { font-size: 34px; font-weight: 700; background: #fff; }
.grid-icons { display: flex; gap: 10px; margin-top: auto; }
.grid-icons i { position: relative; width: 58px; height: 58px; border: 2px solid var(--primary); background: rgba(221,245,240,.6); }
.grid-icons i::before, .grid-icons i::after { content: ""; position: absolute; background: var(--primary); opacity: .55; }
.grid-icons i::before { top: 50%; left: 0; width: 100%; height: 1px; }
.grid-icons i::after { top: 0; left: 50%; width: 1px; height: 100%; }
.grid-icons .mi { background: linear-gradient(45deg, transparent 49%, rgba(8,127,115,.45) 50%, transparent 51%), linear-gradient(-45deg, transparent 49%, rgba(8,127,115,.45) 50%, transparent 51%), rgba(221,245,240,.6); }
.grid-icons .hui::before { inset: 13px; width: auto; height: auto; border: 1px solid rgba(8,127,115,.55); background: none; }
.grid-icons .hui::after { display: none; }
.pinyin-demo { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; margin-top: auto; padding: 18px; border-radius: 16px; background: rgba(255,255,255,.62); text-align: center; }
.pinyin-pair { display: grid; justify-items: center; gap: 4px; min-width: 0; }
.pinyin-demo small { color: var(--primary); font-size: 13px; line-height: 1.3; letter-spacing: .02em; }
.pinyin-demo strong { font-size: 38px; line-height: 1.15; letter-spacing: 0; }
.character-demo { display: flex; align-items: end; gap: 18px; margin-top: auto; }
.character-demo strong { width: 88px; height: 88px; display: grid; place-items: center; border: 2px solid var(--primary); color: var(--primary-strong); font-size: 48px; }
.character-demo span { color: var(--muted); font-size: 14px; }
.export-chip { width: fit-content; display: inline-flex; align-items: center; gap: 10px; margin-top: auto; padding: 10px 14px; border: 1px solid var(--outline); border-radius: 14px; background: var(--surface); color: var(--primary-strong); font-size: 14px; font-weight: 800; }
.export-chip i { width: 28px; height: 34px; border: 2px solid var(--primary); border-radius: 4px; background: linear-gradient(var(--primary-soft), var(--surface)); }

.practice-section { background: var(--primary-strong); color: #fff; }
.practice-grid { display: grid; grid-template-columns: .95fr 1.05fr; align-items: center; gap: 86px; }
.practice-section h2 { color: #fff; }
.practice-section .section-kicker { color: #8de0d4; }
.practice-copy > p { color: rgba(255,255,255,.72); }
.check-list { display: grid; gap: 12px; margin: 28px 0 0; padding: 0; list-style: none; }
.check-list li { position: relative; padding-left: 28px; }
.check-list li::before { content: "✓"; position: absolute; left: 0; color: var(--secondary); font-weight: 900; }
.review-card { width: min(100%, 500px); margin-inline: auto; padding: 30px; border: 1px solid rgba(255,255,255,.16); border-radius: 28px; color: var(--ink); background: #fff; box-shadow: 0 36px 90px rgba(0,0,0,.2); transform: rotate(1.4deg); }
.review-top, .review-result { display: flex; align-items: center; justify-content: space-between; }
.review-top span { font-weight: 850; }
.review-top small { color: var(--muted); }
.dictation-word { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 20px; padding: 50px 20px; text-align: center; }
.dictation-syllable { display: grid; justify-items: center; gap: 8px; min-width: 0; }
.dictation-syllable span { font-size: 60px; line-height: 1.1; font-weight: 850; letter-spacing: 0; }
.dictation-syllable i { color: var(--primary); font-style: normal; line-height: 1.2; letter-spacing: .02em; }
.review-result { padding: 16px; border-radius: 16px; background: var(--secondary-soft); }
.review-result span { color: #9a6416; font-size: 13px; }
.review-result strong { color: #80510e; font-size: 14px; }
.progress { height: 8px; margin-top: 24px; overflow: hidden; border-radius: 999px; background: var(--surface-muted); }
.progress i { display: block; width: 38%; height: 100%; border-radius: inherit; background: var(--primary); }

.privacy-section { padding-block: 84px; }
.privacy-panel { display: grid; grid-template-columns: 104px 1fr auto; align-items: center; gap: 34px; padding: 38px 42px; border: 1px solid var(--outline); border-radius: 28px; background: var(--surface); box-shadow: var(--shadow-low); }
.privacy-panel h2 { margin-bottom: 10px; font-size: clamp(28px, 3.4vw, 42px); }
.privacy-panel p { margin-bottom: 0; }
.privacy-panel > a { color: var(--primary); font-size: 14px; font-weight: 850; white-space: nowrap; }
.privacy-mark { width: 92px; height: 92px; display: grid; place-items: center; border-radius: 26px; background: var(--primary-soft); }
.privacy-mark img { width: 92px; height: 92px; object-fit: contain; }

.faq-layout { display: grid; grid-template-columns: .72fr 1.28fr; gap: 84px; }
.faq-layout .section-head { position: sticky; top: 120px; align-self: start; }
.faq-item { border-bottom: 1px solid rgba(8,127,115,.2); }
.faq-item summary { position: relative; padding: 24px 48px 24px 0; cursor: pointer; font-weight: 820; list-style: none; }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-icon { position: absolute; top: calc(50% - 16px); right: 4px; width: 32px; height: 32px; display: grid; place-items: center; border-radius: 50%; background: rgba(255,255,255,.64); transform: rotate(0deg); transform-origin: center; transition: transform 220ms var(--ease-out), background-color 160ms var(--ease-out); }
.faq-icon::before, .faq-icon::after { content: ""; position: absolute; border-radius: 2px; background: var(--primary); transition: opacity 160ms var(--ease-out), background-color 160ms var(--ease-out); }
.faq-icon::before { width: 2px; height: 14px; }
.faq-icon::after { width: 14px; height: 2px; }
.faq-item[open] .faq-icon { background: rgba(221,245,240,.9); transform: rotate(90deg); }
.faq-item[open] .faq-icon::after { opacity: 0; }
.faq-answer p { margin: 0; padding-right: 42px; padding-bottom: 24px; color: var(--muted); }

.download-section { background: var(--background); }
.download-panel { position: relative; display: grid; grid-template-columns: 1fr auto; align-items: center; gap: 50px; overflow: hidden; padding: 52px; border-radius: 32px; color: #fff; background: linear-gradient(135deg, var(--primary-strong), #0b8f81); box-shadow: var(--shadow-medium); }
.download-panel::after { content: "词"; position: absolute; right: 27%; bottom: -100px; color: rgba(255,255,255,.05); font-family: serif; font-size: 300px; line-height: 1; transform: rotate(-8deg); }
.download-copy { position: relative; z-index: 1; display: flex; align-items: center; gap: 24px; }
.download-copy img { flex: 0 0 auto; border-radius: 22px; box-shadow: 0 18px 40px rgba(0,0,0,.18); }
.download-copy .section-kicker { color: #a7e9df; }
.download-copy h2 { margin-bottom: 8px; color: #fff; }
.download-copy p { margin-bottom: 0; color: rgba(255,255,255,.72); }
.download-action { position: relative; z-index: 1; text-align: center; }
.app-store-button { display: grid; grid-template-columns: 30px auto; grid-template-rows: auto auto; align-items: center; min-width: 232px; padding: 10px 18px; border-radius: 15px; color: #fff; background: #0f1716; text-align: left; box-shadow: 0 14px 30px rgba(0,0,0,.18); transition: transform .18s ease; }
.app-store-button:hover { transform: translateY(-2px); }
.app-store-button .apple-logo { grid-row: 1 / 3; width: 22px; height: 22px; color: #fff; }
.app-store-button small { font-size: 10px; line-height: 1.2; }
.app-store-button strong { font-size: 16px; line-height: 1.35; }
.download-action p { margin: 10px 0 0; color: rgba(255,255,255,.6); font-size: 11px; }

.site-footer { padding: 64px 0 28px; border-top: 1px solid var(--outline); background: var(--surface); }
.footer-grid { display: grid; grid-template-columns: 1fr auto; gap: 50px; padding-bottom: 42px; }
.footer-brand { margin-bottom: 16px; }
.footer-grid > div > p { max-width: 500px; margin-bottom: 0; color: var(--muted); font-size: 14px; }
.footer-grid nav { display: grid; grid-template-columns: repeat(2, auto); gap: 10px 28px; align-content: start; color: var(--muted); font-size: 14px; }
.footer-grid nav a:hover { color: var(--primary); }
.footer-bottom { display: flex; justify-content: space-between; padding-top: 22px; border-top: 1px solid var(--outline); color: var(--muted); font-size: 12px; }

.error-page { min-height: 100svh; display: grid; place-items: center; padding: 48px 0; background: radial-gradient(circle at 78% 18%, rgba(8,127,115,.12), transparent 30%), radial-gradient(circle at 18% 82%, rgba(255,184,77,.16), transparent 28%), var(--background); }
.error-card { width: min(100%, 720px); padding: clamp(32px, 7vw, 76px); border: 1px solid var(--outline); border-radius: var(--radius-large); background: rgba(255,255,255,.84); box-shadow: var(--shadow-medium); text-align: center; }
.error-card .brand { margin-bottom: 34px; }
.error-card .brand span { font-size: 18px; }
.error-code { margin: 0 0 6px; color: var(--primary); font-size: clamp(110px, 22vw, 190px); font-weight: 950; letter-spacing: -.12em; line-height: .78; opacity: .14; }
.error-card h1 { margin-bottom: 14px; font-size: clamp(32px, 5vw, 52px); }
.error-card > .error-description { max-width: 420px; margin: 0 auto 28px; color: var(--muted); }
.error-actions { justify-content: center; }
.error-meta { margin: 24px 0 0; color: var(--muted); font-size: 14px; }
.error-meta a { color: var(--primary); font-weight: 800; }

.reveal { opacity: 0; transform: translateY(18px); transition: opacity .65s ease, transform .65s cubic-bezier(.2,.8,.2,1); }
.reveal.is-visible { opacity: 1; transform: translateY(0); }
@keyframes drift { to { transform: translate3d(20px, 18px, 0) scale(1.04); } }
@keyframes deviceFloat { 0%,100% { translate: 0 0; } 50% { translate: 0 -9px; } }

@media (max-width: 980px) {
  .nav-links { position: fixed; top: 76px; right: 0; left: 0; display: grid; gap: 0; padding: 12px 22px 22px; border-bottom: 1px solid var(--outline); background: rgba(246,250,249,.98); box-shadow: var(--shadow-medium); opacity: 0; pointer-events: none; transform: translateY(-10px); transition: opacity .18s ease, transform .18s ease; }
  .nav-links a { min-height: 50px; display: flex; align-items: center; border-bottom: 1px solid var(--outline); }
  .nav-open .nav-links { opacity: 1; pointer-events: auto; transform: translateY(0); }
  .nav-toggle { display: block; }
  .hero { padding-top: 64px; }
  .hero-grid { grid-template-columns: 1fr; gap: 60px; }
  .hero-copy { max-width: 740px; }
  .device-composition { width: min(100%, 650px); margin-inline: auto; }
  .steps-grid { grid-template-columns: 1fr; }
  .step-card { min-height: auto; display: grid; grid-template-columns: 54px 1fr; gap: 22px; }
  .step-card > span { margin-bottom: 0; }
  .bento-card { grid-column: span 6; }
  .bento-large, .bento-wide { grid-column: span 12; }
  .practice-grid, .faq-layout { grid-template-columns: 1fr; gap: 54px; }
  .faq-layout .section-head { position: static; margin-bottom: 0; }
  .privacy-panel { grid-template-columns: 92px 1fr; }
  .privacy-panel > a { grid-column: 2; }
  .download-panel { grid-template-columns: 1fr; }
  .download-action { justify-self: start; }
}

@media (max-width: 680px) {
  body { font-size: 16px; }
  .shell { width: min(calc(100% - 32px), var(--shell)); }
  .site-header .brand span { display: none; }
  .language-link { display: none; }
  .nav-download { padding-inline: 14px; }
  .hero { padding: 50px 0 62px; }
  h1 { font-size: clamp(39px, 12vw, 54px); }
  .hero-lead { font-size: 17px; }
  .button { width: 100%; }
  .device-composition { min-height: 540px; }
  .tablet-frame { width: min(calc(88vw - 20px), 370px); height: auto; right: -34px; }
  .phone-frame { width: min(calc(190px - 16px), 174px); height: auto; left: -8px; }
  .phone-screen { padding: 0; border-radius: 24px; }
  .paper-card-a { display: none; }
  .tablet-screen { padding: 0; border-radius: 20px; }
  .copy-grid b { font-size: 22px; }
  .strip-grid { grid-template-columns: 1fr; padding-block: 12px; }
  .strip-grid > .strip-feature { min-height: 88px; padding: 16px 4px; border-right: 0; border-bottom: 1px solid var(--outline); }
  .strip-grid div:last-child { border-bottom: 0; }
  .section { padding: 80px 0; }
  .section-head { margin-bottom: 36px; }
  .step-card { display: block; padding: 24px; }
  .step-card > span { margin-bottom: 22px; }
  .bento-card, .bento-large, .bento-wide { min-height: auto; grid-column: span 12; }
  .bento-large { display: flex; }
  .layout-demo, .grid-icons, .pinyin-demo, .character-demo, .export-chip { margin-top: 26px; }
  .practice-grid { gap: 44px; }
  .review-card { padding: 22px; transform: none; }
  .dictation-word { padding-block: 38px; }
  .dictation-syllable span { font-size: 48px; }
  .privacy-panel { grid-template-columns: 1fr; padding: 28px; }
  .privacy-panel > a { grid-column: 1; }
  .privacy-mark { width: 72px; height: 72px; border-radius: 20px; }
  .privacy-mark img { width: 72px; height: 72px; }
  .faq-item summary { padding-right: 42px; }
  .download-panel { padding: 30px 24px; }
  .download-copy { align-items: flex-start; }
  .download-copy img { width: 64px; height: 64px; border-radius: 18px; }
  .download-copy h2 { font-size: 30px; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-grid nav { grid-template-columns: repeat(2, 1fr); }
  .footer-bottom { flex-direction: column; gap: 6px; }
  .error-page { padding: 24px 0; }
  .error-card { padding: 32px 22px; }
  .error-card .brand { margin-bottom: 28px; }
  .error-code { font-size: clamp(96px, 30vw, 150px); }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
  .reveal { opacity: 1; transform: none; }
}