/* Product presentation. Experiment source files retain their own visual language. */
:root {
  --ink: #172435;
  --muted: #596778;
  --blue: #245cda;
  --blue-hover: #194ab8;
  --pale: #f5f6f8;
  --line: #dfe3e9;
  --lab: #080f19;
  --cyan: #35c9dc;
  --font: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
}
html { scroll-padding-top: 28px; }
body { font-size: 17px; background: #fff; }
.container { width: min(1280px, calc(100% - 96px)); }
.section { padding-block: 104px; }
h1, h2, h3 { font-weight: 650; }
h2 { font-size: 40px; line-height: 1.4; letter-spacing: -1.2px; }
h3 { font-size: 23px; }
.section-label { font-size: 15px; color: var(--muted); font-weight: 500; letter-spacing: 0; margin-bottom: 16px; }
.section-heading { gap: 48px; margin-bottom: 48px; align-items: flex-end; }
.section-heading > p { font-size: 17px; line-height: 1.8; max-width: 370px; }
.button { font-size: 16px; min-height: 52px; border-radius: 9px; padding: 13px 22px; font-weight: 600; box-shadow: none; gap: 12px; }
.button-small { font-size: 14px; min-height: 40px; padding: 9px 16px; }
.text-link { color: var(--blue); font-size: 16px; font-weight: 500; min-height: 44px; }
a:focus-visible, button:focus-visible, input:focus-visible, summary:focus-visible { outline: 3px solid var(--blue); outline-offset: 5px; }
.site-header { position: relative; background: #fff; border-bottom: 1px solid #edf0f3; }
.header-inner { height: 80px; }
.header-brand { gap: 13px; min-width: 250px; font-size: 18px; line-height: 1.25; }
.header-brand > img { width: 50px; height: 50px; object-fit: contain; flex: 0 0 50px; }
.header-brand-copy { display: flex; flex-direction: column; justify-content: center; min-width: 0; gap: 3px; }
.header-brand-name { display: flex; align-items: baseline; gap: 7px; white-space: nowrap; color: var(--ink); }
.header-brand-name strong { font-size: 21px; font-weight: 750; letter-spacing: -.3px; }
.header-brand-name > span { font-size: 17px; font-weight: 450; letter-spacing: .1px; }
.header-brand-tagline { display: block; color: var(--muted); font-size: 12px; font-weight: 400; line-height: 1.3; letter-spacing: .2px; }
.header-inner nav { font-size: 14px; gap: 32px; }
.nav-price { display: none; }
.hero { grid-template-columns: minmax(0, .82fr) minmax(0, 1.18fr); gap: 44px; padding-block: 68px 56px; align-items: center; }
.hero-kicker { display: block; color: var(--muted); font-size: 15px; letter-spacing: 0; margin-bottom: 22px; }
.hero h1 { font-size: clamp(44px, 3.85vw, 56px); line-height: 1.24; letter-spacing: -2px; font-weight: 650; margin-bottom: 24px; white-space: normal; }
.hero-question { font-size: 18px; line-height: 1.8; font-weight: 400; margin-bottom: 22px; }
.hero-question strong, .hero-description strong { font-weight: 650; }
.hero-empathy { font-size: 16px; line-height: 1.8; color: var(--muted); margin-bottom: 22px; }
.hero-description { font-size: 18px; line-height: 1.8; color: var(--blue); }
.hero-question, .hero-empathy, .hero-description { text-wrap: pretty; }
.hero-actions { flex-wrap: wrap; gap: 14px 24px; margin-block: 28px 16px; }
.hero-note { font-size: 14px; color: var(--muted); }
.hero-note span { margin: 0; white-space: nowrap; }
.engine-visual { background: none; border: 0; border-radius: 0; box-shadow: none; transform: none; overflow: visible; margin: 0; min-width: 0; }
.engine-window { border-radius: 18px; overflow: hidden; background: var(--lab); box-shadow: 0 18px 42px -28px #17243566; }
.engine-visual .experiment-chrome { height: 48px; padding-inline: 22px; background: var(--lab); border: 0; gap: 10px; }
.engine-visual .experiment-chrome .engine-name { margin: 0; color: #f1f5fa; font-size: 15px; line-height: 1.5; }
.engine-grade { color: #a8b9cc; font-size: 14px; }
.status-light { flex: 0 0 6px; background: var(--cyan); }
.engine-visual iframe { display: block; width: 100%; height: 480px; border: 0; background: var(--lab); }
.engine-visual figcaption { display: block; background: none; border: 0; padding: 16px 0 0; color: var(--muted); font-size: 14px; line-height: 1.7; text-align: center; }
.engine-visual figcaption span { display: inline; margin-left: 8px; }
.proof-strip { background: #fff; border: 0; }
.proof-inner { grid-template-columns: 1fr 1fr; padding-block: 30px 36px; border-block: 1px solid var(--line); }
.proof-inner p { padding-inline: 48px 0; gap: 8px; border: 0; }
.proof-inner p:first-child { border-right: 1px solid var(--line); }
.proof-inner strong { font-size: 25px; letter-spacing: -.5px; font-weight: 600; }
.proof-inner span { font-size: 16px; }
.trial-grid { gap: 48px 28px; }
.trial-card, .trial-card:hover { border: 0; border-radius: 0; background: transparent; box-shadow: none; }
.trial-image { border-radius: 12px; background: var(--lab); }
.trial-image img { object-fit: contain; aspect-ratio: 1.6; }
.trial-image span { display: none; }
.trial-body { padding: 22px 0 0; }
.trial-body h3 { font-size: 22px; margin-bottom: 10px; }
.trial-body p { font-size: 16px; min-height: 56px; line-height: 1.75; }
.trial-cta { width: fit-content; min-height: 44px; border: 0; margin-top: 12px; padding: 5px 0; gap: 14px; font-size: 16px; font-weight: 500; }
.trial-cta span:last-child { font-size: inherit; }
.trial-cta .trial-device { display: none; }
.mobile-notice { padding: 0 0 22px; background: none; border: 0; font-size: 14px; color: var(--muted); }
.learning-section { background: var(--pale); }
.learning-grid { gap: 42px; }
.learning-grid article { border-top: 1px solid #c6cdd6; padding-top: 28px; }
.small-subject { font-size: 15px; margin-bottom: 14px; }
.learning-grid h3 { font-size: 23px; line-height: 1.5; }
.learning-grid p { font-size: 17px; line-height: 1.85; }
.learning-grid a { display: inline-flex; align-items: center; min-height: 44px; font-size: 16px; font-weight: 500; }
.outcome-note { margin-top: 44px; padding: 0; background: none; border: 0; }
.outcome-note strong { display: block; font-size: 21px; font-weight: 500; line-height: 1.7; }
.study-flow { gap: 14px; margin-top: 32px; padding-top: 28px; font-size: 16px; flex-wrap: wrap; justify-content: flex-start; }
.study-flow strong { width: 100%; font-size: 15px; font-weight: 500; color: var(--muted); }
.study-flow b { font-weight: 400; color: var(--muted); }
.manual-section { display: grid; grid-template-columns: 1.1fr 1fr; align-items: start; gap: 72px; padding-block: 104px; }
.manual-visual { margin: 0; min-width: 0; }
.manual-preview-frame { overflow: hidden; border: 1px solid #2c3d54; border-radius: 14px; background: var(--lab); }
.manual-preview-scroll { height: 590px; overflow-x: hidden; overflow-y: scroll; overscroll-behavior: contain; scrollbar-gutter: stable; scrollbar-width: thin; scrollbar-color: #8298b4 #0a1321; background: var(--lab); }
.manual-preview-scroll::-webkit-scrollbar { width: 10px; }
.manual-preview-scroll::-webkit-scrollbar-track { background: #0a1321; }
.manual-preview-scroll::-webkit-scrollbar-thumb { background: #8298b4; border: 2px solid #0a1321; border-radius: 999px; }
.manual-preview-scroll::-webkit-scrollbar-thumb:hover { background: #a1b3c9; }
.manual-preview-link { display: block; width: 100%; cursor: pointer; }
.manual-preview-link:focus-visible, .manual-preview-scroll:focus-visible { outline: 3px solid var(--blue); outline-offset: -3px; }
.manual-visual img { width: 100%; height: auto; }
.manual-visual figcaption { font-size: 14px; color: var(--muted); margin-top: 14px; line-height: 1.75; }
.manual-preview-cta { color: var(--blue); }
.manual-preview-cta:hover { text-decoration: underline; text-underline-offset: 3px; }
.manual-mobile-copy { display: none; }
.manual-copy h2 { font-size: 38px; line-height: 1.4; letter-spacing: -1px; }
.manual-copy > p:not(.section-label) { font-size: 17px; line-height: 1.85; color: var(--muted); margin-top: 22px; }
.manual-points { list-style: none; padding: 0; margin: 30px 0 18px; display: grid; gap: 22px; }
.manual-points li { display: block; }
.manual-points li > span { display: none; }
.manual-points strong { display: block; font-size: 19px; font-weight: 600; margin-bottom: 5px; }
.manual-points p { font-size: 16px; line-height: 1.8; color: var(--muted); }
.manual-copy .manual-source { font-size: 14px !important; margin-top: 14px !important; }
.manual-section-wrap { background: var(--pale); border-top: 1px solid var(--line); }
.grade-line { margin-block: 40px 56px; gap: 36px; }
.grade-line article { gap: 18px; }
.grade-line article > span { width: auto; height: auto; padding-top: 2px; background: none; border-radius: 0; font-size: 16px; color: var(--muted); font-weight: 400; }
.grade-line h3 { font-size: 20px; }
.grade-line p { font-size: 16px; }
.catalog-heading { margin-bottom: 22px; gap: 12px; }
.catalog-heading h3 { font-size: 22px; }
.catalog-heading > span { font-size: 14px; }
.catalog { display: block; border-top: 1px solid var(--line); }
.catalog details { border: 0; border-bottom: 1px solid var(--line); border-radius: 0; padding: 0; background: none; }
.catalog summary { padding: 23px 0; font-size: 22px; font-weight: 600; gap: 20px; }
.catalog summary .subject-dot { display: none; }
.catalog summary small { font-size: 15px; margin-left: auto; color: var(--muted); }
.catalog summary::after { margin-left: 22px; color: var(--muted); font-size: 24px; }
.catalog ul { margin: 0; padding: 0 0 28px; border: 0; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 14px 32px; }
.catalog li { font-size: 16px; color: var(--muted); }
.catalog-note { font-size: 14px; margin-top: 24px; line-height: 1.85; max-width: 900px; }
.purchase-section { color: var(--ink); background: #fff; padding-block: 0 104px; }
.purchase-inner { padding-top: 96px; border-top: 1px solid var(--line); }
.purchase-heading { max-width: 800px; margin-bottom: 48px; }
.purchase-heading > p { color: var(--muted); font-size: 18px; margin-top: 20px; }
.purchase-layout { grid-template-columns: .9fr 1.1fr; gap: 96px; align-items: start; }
.price-card { padding: 0; border: 0; border-radius: 0; box-shadow: none; background: none; }
.price-top { color: var(--muted); font-size: 16px; font-weight: 400; }
.price { margin: 10px 0 12px; gap: 6px; }
.price strong { font-size: 80px; font-weight: 600; line-height: 1.1; letter-spacing: -3px; }
.price > span:first-child { font-size: 34px; font-weight: 500; }
.price > span:last-child { font-size: 16px; margin-left: 12px; }
.price-description { font-size: 18px; color: var(--ink); font-weight: 500; }
.price-card > .button { margin-top: 28px; min-width: 250px; }
.inline-wechat { justify-content: flex-start; margin-top: 18px; font-size: 16px; gap: 5px; }
.copy-link { font-size: 14px; min-height: 44px; }
.purchase-delivery { font-size: 14px; color: var(--muted); margin-top: 12px; line-height: 1.8; }
.purchase-copy .section-label { font-size: 16px; color: var(--muted); margin-bottom: 20px; }
.benefits { padding: 0; margin: 0; border: 0; gap: 0; list-style: none; }
.benefits li { display: block; padding: 19px 0; border-bottom: 1px solid var(--line); }
.benefits li:first-child { padding-top: 0; }
.benefits li::before { display: none; }
.benefits strong { display: block; font-size: 22px; font-weight: 600; margin-bottom: 6px; }
.benefits span { display: block; font-size: 16px; color: var(--muted); line-height: 1.8; }
.faq-wrap { background: var(--pale); }
.faq-section { grid-template-columns: .7fr 1.3fr; gap: 80px; }
.faq-list summary { font-size: 18px; font-weight: 500; gap: 22px; }
.faq-list summary::after { flex-shrink: 0; }
.faq-list p { font-size: 16px; line-height: 1.85; }
.faq-list details:last-child { border-bottom: 0; }
.faq-section { padding-bottom: 60px; }
.faq-aside { font-size: 16px; }
.site-footer { border: 0; padding-block: 40px; background: var(--pale); }
.site-footer .container { border-top: 1px solid var(--line); padding-top: 32px; }
.site-footer .brand img { mix-blend-mode: multiply; }
.site-footer p, .footer-meta { font-size: 14px; }
.contact-dialog { padding: 36px; border-radius: 16px; }
.contact-dialog > p { font-size: 16px; }
.contact-dialog .section-label, .contact-dialog label, .contact-steps { font-size: 14px !important; }
.dialog-close { width: 44px; height: 44px; top: 10px; right: 10px; }
.contact-dialog .dialog-close { line-height: 1; }
.copy-status { margin: 10px 0 0 !important; padding: 9px 12px; border: 1px solid #b9cff6; border-radius: 8px; background: #f2f6ff; color: #1856c7 !important; font-size: 15px !important; font-weight: 600; line-height: 1.6 !important; filter: none; opacity: 1; text-rendering: optimizeLegibility; }
.copy-status.copy-error { border-color: #f0c98d; background: #fff8e9; color: #9a5a00 !important; }
.engine-in-view .mobile-bar { visibility: hidden; pointer-events: none; }
@media (max-width: 1150px) {
  .container { width: calc(100% - 64px); }
  .hero { grid-template-columns: minmax(0, .8fr) minmax(0, 1.2fr); gap: 28px; padding-block: 48px; }
  .hero h1 { font-size: clamp(36px, 4.05vw, 46px); }
  .hero-question { font-size: 18px; }
  .hero-description { font-size: 17px; }
  .hero-actions { gap: 10px 18px; }
  .hero-actions .button { font-size: 15px; padding-inline: 18px; }
  .engine-visual iframe { height: 465px; }
  .engine-visual .experiment-chrome { padding-inline: 16px; }
  .engine-visual figcaption span { display: block; margin: 0; }
  h2, .manual-copy h2 { font-size: 36px; }
  .manual-section { gap: 44px; }
  .purchase-layout { gap: 64px; }
  .learning-grid { gap: 28px; }
}
@media (max-width: 900px) {
  .hero { grid-template-columns: 1fr; gap: 32px; }
  .hero-copy { max-width: 680px; }
  .hero h1 { font-size: 52px; }
  .engine-visual { width: 100%; max-width: 760px; margin-inline: auto; }
  .engine-visual iframe { height: 480px; }
  .engine-visual figcaption span { display: inline; margin-left: 8px; }
  .header-inner nav { gap: 18px; }
  .section-heading { display: block; }
  .section-heading > p { margin-top: 22px; max-width: 600px; }
  .trial-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .mobile-notice { display: block; }
  .trial-cta > span:first-child { display: none; }
  .trial-cta .trial-device { display: inline; }
  .learning-grid { grid-template-columns: 1fr; gap: 30px; }
  .learning-grid p { max-width: 650px; }
  .manual-section { grid-template-columns: 1fr; gap: 32px; }
  .manual-copy { order: -1; max-width: 680px; }
  .manual-visual { max-width: 650px; }
  .catalog ul { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .purchase-layout { gap: 44px; }
  .faq-section { grid-template-columns: 1fr; gap: 30px; }
  .faq-aside { display: none; }
}
@media (max-width: 600px) {
  .container { width: calc(100% - 40px); }
  body { font-size: 16px; }
  .section { padding-block: 60px; }
  .header-inner { height: 68px; gap: 12px; }
  .header-brand { min-width: 0; flex: 1 1 auto; gap: 10px; font-size: 16px; }
  .header-brand > img { width: 38px; height: 38px; flex-basis: 38px; }
  .header-brand-copy { gap: 1px; }
  .header-brand-name { display: flex; flex-direction: column; align-items: flex-start; gap: 0; line-height: 1.12; }
  .header-brand-name strong { font-size: 17px; letter-spacing: -.2px; }
  .header-brand-name > span { font-size: 15px; letter-spacing: 0; }
  .header-brand-tagline { font-size: 11px; line-height: 1.25; letter-spacing: 0; white-space: nowrap; }
  .header-brand-tagline { display: none; }
  .header-inner nav { display: none; }
  .header-inner > .button { flex: 0 0 auto; font-size: 13px; min-height: 40px; padding: 8px 12px; }
  .hero { padding-block: 32px 30px; gap: 26px; }
  .hero-kicker { font-size: 14px; line-height: 1.7; margin-bottom: 18px; }
  .hero h1 { font-size: clamp(32px, 8.9vw, 36px); line-height: 1.3; letter-spacing: -1px; margin-bottom: 20px; }
  .hero-question, .hero-description { font-size: 17px; line-height: 1.75; }
  .hero-question, .hero-empathy { margin-bottom: 20px; }
  .hero-empathy { font-size: 16px; line-height: 1.75; }
  .hero-actions { gap: 8px 20px; margin-block: 22px 12px; }
  .hero-actions .button { min-height: 48px; font-size: 15px; padding-inline: 16px; }
  .hero-actions .text-link { font-size: 15px; }
  .hero-note { font-size: 14px; }
  .engine-window { border-radius: 12px; }
  .engine-visual .experiment-chrome { height: auto; min-height: 44px; padding: 10px 14px; gap: 8px; }
  .engine-visual .experiment-chrome .engine-name { font-size: 14px; }
  .engine-grade { font-size: 13px; }
  .engine-visual iframe { height: 640px; }
  .engine-visual figcaption { font-size: 14px; text-align: left; padding-top: 12px; }
  .engine-visual figcaption span { display: block; margin: 0; }
  .proof-inner { grid-template-columns: 1fr; gap: 24px; padding-block: 28px; }
  .proof-inner p, .proof-inner p:first-child { padding: 0; border: 0; gap: 6px; }
  .proof-inner strong { font-size: 24px; }
  .proof-inner span { font-size: 16px; }
  h2, .manual-copy h2 { font-size: 28px; line-height: 1.45; letter-spacing: -.6px; }
  .section-label { font-size: 14px; margin-bottom: 12px; }
  .section-heading { margin-bottom: 30px; }
  .section-heading > p { font-size: 16px; margin-top: 18px; }
  .trial-grid { grid-template-columns: 1fr; gap: 34px; }
  .trial-body { padding: 18px 0 0; }
  .trial-body h3 { font-size: 22px; }
  .trial-body p { font-size: 16px; min-height: 0; }
  .trial-cta { font-size: 16px; margin-top: 8px; }
  .learning-grid h3 { font-size: 22px; }
  .learning-grid p { font-size: 16px; }
  .small-subject { font-size: 14px; }
  .outcome-note { margin-top: 32px; }
  .outcome-note strong { font-size: 18px; }
  .study-flow { font-size: 15px; gap: 10px 12px; margin-top: 24px; }
  .manual-section { padding-block: 60px; gap: 28px; }
  .manual-preview-scroll { height: 360px; }
  .manual-desktop-copy { display: none; }
  .manual-mobile-copy { display: inline; }
  .manual-copy > p:not(.section-label) { font-size: 16px; margin-top: 18px; }
  .manual-points { margin-top: 24px; }
  .manual-points strong { font-size: 20px; }
  .manual-points p { font-size: 16px; }
  .manual-visual figcaption { font-size: 14px; }
  .grade-line { grid-template-columns: 1fr; gap: 24px; margin-block: 32px 40px; }
  .grade-line h3 { font-size: 20px; }
  .grade-line p { font-size: 16px; }
  .catalog-heading { align-items: flex-start; flex-direction: column; gap: 5px; }
  .catalog-heading h3 { font-size: 20px; }
  .catalog-heading > span { font-size: 14px; }
  .catalog summary { font-size: 20px; padding-block: 21px; gap: 12px; }
  .catalog summary small { font-size: 14px; }
  .catalog summary::after { margin-left: 4px; }
  .catalog ul { grid-template-columns: 1fr; gap: 12px; }
  .catalog li { font-size: 16px; }
  .catalog-note { font-size: 14px; }
  .purchase-section { padding-bottom: 60px; }
  .purchase-inner { padding-top: 56px; }
  .purchase-heading { margin-bottom: 30px; }
  .purchase-heading > p { font-size: 16px; margin-top: 18px; }
  .purchase-layout { grid-template-columns: 1fr; gap: 36px; }
  .price strong { font-size: 64px; }
  .price > span:first-child { font-size: 28px; }
  .price > span:last-child { font-size: 16px; }
  .price-description { font-size: 17px; }
  .price-card > .button { width: 100%; }
  .benefits strong { font-size: 20px; }
  .benefits span { font-size: 16px; }
  .faq-list summary { font-size: 17px; }
  .faq-list p { font-size: 16px; }
  .faq-section { padding-bottom: 40px; }
  .site-footer { padding-block: 0 108px; }
  .site-footer > .container { display: block; }
  .site-footer > .container { text-align: center; }
  .site-footer .brand { justify-content: center; }
  .site-footer p { text-align: center; }
  .footer-meta { text-align: center; margin-top: 24px; }
  .mobile-bar { display: flex; padding: 10px 20px max(10px, env(safe-area-inset-bottom)); gap: 12px; background: #fff; }
  .mobile-bar > a { font-size: 14px; }
  .mobile-bar .button { font-size: 14px; min-height: 44px; padding-inline: 14px; }
  .contact-dialog { padding: 28px 24px; }
  .contact-dialog h2 { font-size: 24px; padding-right: 18px; }
  .contact-dialog > p { font-size: 16px; }
}
@media (pointer: coarse) {
  .mobile-notice { display: block; }
  .trial-cta > span:first-child { display: none; }
  .trial-cta .trial-device { display: inline; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }