:root {
  color-scheme: light;
  --ink: #202321;
  --muted: #767b73;
  --paper: #f7f7f2;
  --line: #dedfd7;
  --green: #cce38d;
  font-synthesis: none;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 30px; }
body {
  margin: 0; background: var(--paper); color: var(--ink);
  font-family: "Microsoft YaHei", "PingFang SC", system-ui, sans-serif;
  -webkit-font-smoothing: antialiased; line-height: 1.7;
}
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; cursor: pointer; }
button, a { -webkit-tap-highlight-color: transparent; }
svg { display: block; }
a:focus-visible, button:focus-visible {
  outline: 3px solid #577b27; outline-offset: 5px; border-radius: 5px;
}
.wrap { width: min(1220px, calc(100% - 100px)); margin-inline: auto; }
.skip { position: absolute; top: -100px; left: 20px; padding: 10px 20px; background: #fff; z-index: 5; }
.skip:focus { top: 10px; }
.preview-note { font-size: 10px; text-align: center; padding: 5px 16px; background: #e9ebdf; color: #7b8170; }
.site-header { min-height: 100px; display: flex; align-items: center; justify-content: space-between; gap: 25px; border-bottom: 1px solid var(--line); }
.brand { display: inline-flex; gap: 11px; align-items: center; }
.brand-symbol { width: 32px; height: 32px; position: relative; }
.brand-symbol::before, .brand-symbol::after { content: ""; position: absolute; width: 23px; height: 23px; background: #202321; border-radius: 50%; top: 2px; left: 0; }
.brand-symbol::after { width: 14px; height: 14px; background: var(--green); top: 16px; left: 17px; border: 3px solid var(--paper); }
.brand-name { font-size: 18px; font-weight: 800; letter-spacing: -.04em; }
.brand-english { margin-top: -2px; font-size: 9px; letter-spacing: .18em; color: #8b8e84; }
.nav { display: flex; align-items: center; gap: 32px; font-size: 12px; }
.nav .current { font-weight: 700; }
.nav .stamp { display: inline-flex; align-items: center; gap: 8px; border: 1px solid #d5d9cd; border-radius: 30px; padding: 7px 13px; font-size: 10px; color: #7b826e; }
.status-dot { width: 5px; height: 5px; background: #79904e; border-radius: 50%; display: inline-block; }
.intro { display: grid; grid-template-columns: 1.32fr 1fr; align-items: end; gap: 70px; padding-block: 64px 58px; }
.overline { display: flex; gap: 13px; align-items: center; font-size: 10px; color: #72796a; letter-spacing: .13em; text-transform: uppercase; }
.overline::before { content: ""; width: 25px; height: 1px; background: #6f7b5e; }
h1 { font-size: clamp(46px, 4.8vw, 70px); line-height: 1.23; letter-spacing: -.055em; margin: 26px 0 0; font-weight: 750; isolation: isolate; }
h1 em { font-style: normal; position: relative; white-space: nowrap; }
h1 em::after { content: ""; height: 10px; position: absolute; background: #d8e4b7; bottom: 3px; left: -3px; right: -3px; z-index: -1; }
.intro-copy { max-width: 385px; justify-self: end; padding-bottom: 4px; }
.intro-copy p { font-size: 14px; line-height: 2; color: #666f5c; margin: 0 0 22px; }
.intro-copy strong { color: #454b40; font-weight: 500; }
.intro-index { display: flex; align-items: center; justify-content: space-between; color: #858b7b; font-size: 10px; letter-spacing: .08em; padding-top: 14px; border-top: 1px solid #d8dcd0; }
.little-arrow { font-family: Arial, sans-serif; font-size: 19px; line-height: 1; }
.section-label { display: flex; justify-content: space-between; align-items: center; font-size: 10px; color: #7a8074; letter-spacing: .12em; margin: 0 0 17px; }
.section-label span:first-child { color: #3f4936; }
.product-tabs { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 8px; padding: 7px; background: #eeefe7; border: 1px solid #e2e4d9; border-radius: 15px; }
.product-tab { border: 0; background: transparent; display: flex; justify-content: center; align-items: center; gap: 12px; border-radius: 10px; padding: 17px 10px; font-size: 13px; font-weight: 600; transition: background .2s, color .2s; }
.tab-number { font-family: Arial, sans-serif; font-size: 10px; color: #939887; }
.product-tab[aria-selected="true"] { background: #252b23; color: white; box-shadow: 0 4px 9px #26312312; }
.product-tab[aria-selected="true"] .tab-number { color: #d0dfb9; }
.product-tab:hover:not([aria-selected="true"]) { background: #e0e4d4; }
.product-panel { display: grid; grid-template-columns: .94fr 1.16fr; gap: 50px; padding-top: 31px; align-items: stretch; min-height: 470px; }
.product-panel[hidden] { display: none; }
.product-copy { padding: 22px 0 5px; display: flex; flex-direction: column; align-items: flex-start; }
.product-type { font-size: 10px; letter-spacing: .11em; color: #838978; text-transform: uppercase; display: flex; align-items: center; gap: 10px; }
.product-type .index { font-family: Georgia, serif; font-size: 16px; color: #37442a; }
.product-name { margin: 12px 0 0; font-size: 13px; font-weight: 600; color: #69715e; }
.product-copy h2 { font-size: clamp(28px, 2.65vw, 38px); line-height: 1.45; letter-spacing: -.04em; margin: 13px 0 17px; }
.product-summary { font-size: 13px; line-height: 1.9; margin: 0; max-width: 420px; color: #67705f; }
.feature-list { display: grid; grid-template-columns: 1fr 1fr; gap: 11px 12px; margin: 22px 0 25px; padding: 0; list-style: none; width: 100%; }
.feature-list li { display: flex; gap: 8px; font-size: 11px; color: #5a6550; align-items: center; }
.feature-list li::before { content: ""; width: 4px; height: 4px; border-radius: 50%; background: #899d69; flex-shrink: 0; }
.product-action { display: inline-flex; align-items: center; justify-content: center; gap: 24px; background: #252b23; color: white; padding: 11px 18px; font-size: 11px; min-height: 43px; border-radius: 7px; border: 1px solid #252b23; font-weight: 500; }
.product-action:hover { background: #405035; }
.product-action.unavailable { background: transparent; color: #6b755f; border-color: #cfd5c5; cursor: default; }
.domain-note { font-size: 10px; color: #939788; margin-top: 11px; word-break: break-word; }
.product-disclaimer { font-size: 10px; color: #93988a; margin: 10px 0 0; max-width: 420px; line-height: 1.8; }
.visual { min-height: 426px; border-radius: 17px; position: relative; overflow: hidden; }
.visual-head { display: flex; align-items: center; justify-content: space-between; font-size: 9px; letter-spacing: .12em; color: #b2c0a7; position: absolute; top: 23px; left: 25px; right: 25px; z-index: 2; }
.visual-foot { display: flex; align-items: center; justify-content: space-between; gap: 12px; font-size: 9px; color: #9da995; letter-spacing: .04em; position: absolute; bottom: 20px; left: 25px; right: 25px; z-index: 2; }
.physics-visual { background: #202923; }
.physics-art { width: 100%; height: 100%; position: absolute; inset: 0; }
.english-visual { background: #e7ebdd; padding: 78px 45px 65px; }
.english-visual .visual-head, .english-visual .visual-foot { color: #7f8d70; }
.english-card { background: #fafbf7; padding: 26px 27px 22px; max-width: 330px; margin: auto; border-radius: 13px; border: 1px solid #dce3ce; box-shadow: 8px 14px 0 #d3dbc4; transform: rotate(-4deg); }
.word-category { font-size: 8px; color: #8d9a7d; letter-spacing: .12em; display: flex; justify-content: space-between; }
.word { font-family: Georgia, serif; font-size: 54px; line-height: 1.4; color: #384630; margin: 14px 0 0; }
.pronunciation { font-family: Arial, sans-serif; font-size: 11px; color: #8b957f; letter-spacing: .02em; }
.word-meaning { margin: 16px 0 21px; font-size: 13px; color: #707d63; }
.word-line { height: 1px; background: #e3e9da; margin-bottom: 14px; }
.word-tools { display: flex; gap: 8px; }
.word-tools span { border: 1px solid #dce5cd; border-radius: 4px; padding: 4px 12px; color: #82916f; font-size: 9px; }
.word-note { position: absolute; right: 38px; bottom: 80px; background: #c8dc95; color: #4b5c36; padding: 8px 14px; font-size: 10px; border-radius: 5px; transform: rotate(5deg); box-shadow: 3px 4px 0 #a6bb7240; }
.exam-visual { background: #e6e8ec; padding: 83px 39px 65px; }
.exam-visual .visual-head, .exam-visual .visual-foot { color: #858d9d; }
.exam-board { background: #fafbfc; border-radius: 11px; padding: 22px 26px; border: 1px solid #d9dee6; box-shadow: 0 15px 30px #5d6a8312; }
.exam-top { display: flex; align-items: center; justify-content: space-between; font-size: 9px; color: #7c879c; padding-bottom: 12px; border-bottom: 1px solid #e3e7ee; }
.exam-status { text-align: center; font-size: 11px; color: #6b7a90; margin-top: 17px; }
.exam-clock { text-align: center; font-family: Arial, sans-serif; font-variant-numeric: tabular-nums; font-weight: 600; font-size: clamp(36px, 4vw, 55px); letter-spacing: .035em; line-height: 1.45; color: #29354c; }
.exam-caption { text-align: center; font-size: 8px; color: #9ba5b6; }
.exam-stats { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-top: 20px; }
.exam-stats span { padding: 9px; background: #edf1f6; border-radius: 5px; color: #8290a5; font-size: 9px; text-align: center; }
.music-visual { background: #e9e5ee; padding: 76px 42px 62px; }
.music-visual .visual-head, .music-visual .visual-foot { color: #9786a8; }
.music-score { padding: 18px 22px; background: #fbf9fe; border: 1px solid #dfd6e8; border-radius: 11px; transform: rotate(-2deg); box-shadow: 6px 8px 0 #d9cfe3; }
.music-score-head { font-size: 9px; color: #a395b1; display: flex; justify-content: space-between; margin-bottom: 18px; }
.staff { display: grid; grid-template-columns: 36px 1fr; align-items: center; gap: 14px; }
.staff + .staff { margin-top: 15px; }
.staff-label { font-size: 9px; color: #ad9dbb; border-right: 1px solid #e9dff1; }
.staff-notes { font-size: 20px; font-family: Georgia, serif; letter-spacing: .21em; color: #7b638d; display: flex; justify-content: space-between; }
.staff-notes small { font-size: 15px; }
.music-tracks { position: relative; display: grid; grid-template-columns: 1fr 1fr; gap: 11px; margin-top: 25px; }
.music-track { background: #faf7ff; border: 1px solid #d8cbe4; border-radius: 8px; padding: 16px 13px; box-shadow: 0 7px 14px #b4a0c21a; }
.music-track:nth-child(2) { background: #e0d6eb; }
.track-title { display: flex; align-items: center; justify-content: space-between; font-size: 10px; color: #89729d; }
.wave { display: flex; gap: 3px; align-items: center; height: 24px; margin-top: 12px; }
.wave i { width: 3px; background: #aa90bd; border-radius: 2px; height: var(--h); }
.track-play { border: 1px solid #cfc1da; width: 20px; height: 20px; border-radius: 50%; display: grid; place-items: center; font-size: 7px; }
.principles { margin-top: 65px; border-top: 1px solid var(--line); padding-top: 31px; display: grid; grid-template-columns: 1.15fr 1fr 1fr 1fr; gap: 32px; }
.principles-label { color: #818775; font-size: 10px; letter-spacing: .1em; padding-top: 5px; }
.principle-number { color: #969d8a; font-size: 9px; font-family: Arial, sans-serif; }
.principle h3 { margin: 8px 0; font-size: 14px; font-weight: 600; }
.principle p { margin: 0; font-size: 11px; color: #8b9082; line-height: 1.9; }
.about { margin-top: 76px; background: #ebece3; border-radius: 16px; padding: 35px 38px; display: grid; grid-template-columns: .9fr 1.5fr; gap: 80px; align-items: center; }
.about h2 { font-size: 24px; line-height: 1.5; font-weight: 600; letter-spacing: -.035em; margin: 0; }
.about h2 span { display: block; font-size: 9px; color: #8c9480; letter-spacing: .15em; margin-bottom: 10px; font-weight: 400; }
.about p { margin: 0; font-size: 12px; line-height: 2; color: #68725e; }
.rollout { display: flex; align-items: center; gap: 15px; font-size: 10px; color: #9b9f92; margin-top: 17px; }
.rollout .label { color: #6b765d; white-space: nowrap; }
.footer { margin-top: 60px; border-top: 1px solid var(--line); padding-block: 25px 30px; }
.footer-top { display: flex; justify-content: space-between; align-items: center; gap: 20px; font-size: 10px; color: #9a9d92; }
.footer-top strong { color: #5e6656; font-weight: 500; }
.footer-bottom { display: flex; justify-content: space-between; gap: 20px; margin-top: 12px; font-size: 9px; color: #9da194; }
.footer a:hover { color: #4e6533; text-decoration: underline; }
.mini-brand { font-family: Arial, sans-serif; letter-spacing: .15em; font-size: 10px; }
.no-js-note { border: 1px solid var(--line); padding: 12px 15px; color: #677359; font-size: 12px; }
@media (min-width: 1600px) {
  .wrap { width: min(1320px, calc(100% - 140px)); }
  .product-panel { gap: 80px; min-height: 485px; }
  .visual { min-height: 450px; }
}
@media (max-width: 1000px) {
  .wrap { width: calc(100% - 56px); }
  .intro { gap: 35px; }
  h1 { font-size: 53px; }
  .intro-copy p { font-size: 12px; }
  .product-panel { gap: 27px; grid-template-columns: 1fr 1.1fr; }
  .visual { min-height: 425px; }
  .product-copy h2 { font-size: 29px; }
  .feature-list { grid-template-columns: 1fr; gap: 7px; margin-block: 16px 20px; }
  .english-visual { padding-inline: 22px; }
  .exam-visual { padding: 83px 24px 65px; }
  .exam-board { padding: 22px 16px; }
  .music-visual { padding: 85px 22px 65px; }
  .staff-notes { font-size: 18px; letter-spacing: .1em; }
  .principles { gap: 22px; grid-template-columns: .8fr 1fr 1fr 1fr; }
  .about { gap: 35px; }
}
@media (max-width: 650px) {
  .wrap { width: calc(100% - 40px); }
  .preview-note { font-size: 9px; }
  .site-header { min-height: 83px; gap: 12px; }
  .brand-name { font-size: 16px; }
  .brand-english { font-size: 8px; }
  .brand-symbol { width: 29px; transform: scale(.85); transform-origin: left center; }
  .brand { gap: 3px; }
  .nav { gap: 17px; font-size: 11px; }
  .nav .stamp { display: none; }
  .intro { grid-template-columns: 1fr; gap: 27px; padding-block: 39px 35px; }
  .overline { font-size: 9px; }
  h1 { font-size: clamp(38px, 10.9vw, 58px); margin-top: 20px; line-height: 1.3; letter-spacing: -.06em; }
  h1 em::after { height: 7px; }
  .intro-copy { justify-self: start; max-width: none; }
  .intro-copy p { margin-bottom: 14px; font-size: 12px; line-height: 1.9; }
  .intro-index { font-size: 9px; padding-top: 12px; }
  .section-label { font-size: 9px; letter-spacing: .06em; }
  .section-label .selection-hint { font-size: 9px; }
  .product-tabs { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 5px; padding: 6px; border-radius: 12px; }
  .product-tab { padding: 13px 8px; font-size: 11px; gap: 8px; min-height: 47px; border-radius: 8px; }
  .tab-number { font-size: 9px; }
  .product-panel { grid-template-columns: 1fr; gap: 22px; padding-top: 24px; min-height: auto; }
  .product-copy { padding: 0; }
  .product-type { font-size: 9px; }
  .product-name { margin-top: 7px; font-size: 12px; }
  .product-copy h2 { font-size: 29px; margin: 12px 0 14px; }
  .product-summary { font-size: 12px; }
  .feature-list { grid-template-columns: 1fr 1fr; gap: 10px; margin-block: 18px; }
  .feature-list li { font-size: 10px; gap: 6px; }
  .product-action { min-height: 44px; font-size: 11px; padding: 11px 16px; }
  .product-disclaimer { font-size: 9px; line-height: 1.8; }
  .domain-note { font-size: 9px; margin-top: 9px; }
  .visual { min-height: 340px; border-radius: 13px; }
  .visual-head { top: 18px; left: 19px; right: 19px; font-size: 8px; }
  .visual-foot { left: 19px; right: 19px; font-size: 8px; bottom: 15px; }
  .english-visual { padding: 63px 30px 55px; }
  .english-card { max-width: 275px; padding: 18px 22px; }
  .word { font-size: 44px; }
  .word-meaning { margin: 12px 0 15px; }
  .word-note { bottom: 58px; right: 22px; font-size: 9px; }
  .exam-visual { padding: 64px 26px 51px; }
  .exam-board { padding: 15px 20px; }
  .exam-clock { font-size: 38px; }
  .exam-status { margin-top: 10px; }
  .exam-stats { margin-top: 14px; gap: 8px; }
  .music-visual { padding: 65px 26px 50px; }
  .music-score { padding: 14px 17px; }
  .music-score-head { font-size: 8px; margin-bottom: 13px; }
  .staff { gap: 9px; grid-template-columns: 31px 1fr; }
  .staff-notes { font-size: 17px; }
  .music-tracks { margin-top: 20px; }
  .music-track { padding: 12px 10px; }
  .principles { margin-top: 39px; padding-top: 22px; grid-template-columns: 1fr; gap: 24px; }
  .principles-label { font-size: 9px; }
  .principle { display: grid; grid-template-columns: 25px 1fr; gap: 0 9px; }
  .principle-number { grid-row: span 2; margin-top: 3px; font-size: 0; }
  .principle-number::before { content: attr(data-step); font-size: 10px; }
  .principle h3 { margin: 0 0 4px; font-size: 13px; }
  .principle p { font-size: 11px; }
  .about { margin-top: 35px; padding: 25px; grid-template-columns: 1fr; gap: 17px; border-radius: 12px; }
  .about h2 { font-size: 22px; }
  .about h2 span { font-size: 8px; margin-bottom: 8px; }
  .about p { font-size: 11px; }
  .rollout { font-size: 9px; display: block; line-height: 1.9; margin-top: 13px; }
  .rollout .label { display: block; margin-bottom: 3px; }
  .footer { margin-top: 34px; padding-block: 20px; }
  .footer-top, .footer-bottom { flex-direction: column; align-items: flex-start; gap: 8px; font-size: 9px; }
  .footer-bottom { margin-top: 8px; font-size: 8px; }
}
@media (max-width: 360px) {
  .wrap { width: calc(100% - 32px); }
  .nav { gap: 12px; }
  .brand-name { font-size: 14px; }
  .product-tab { font-size: 10px; gap: 6px; }
  .product-copy h2 { font-size: 27px; }
  .feature-list { column-gap: 6px; }
  .feature-list li { font-size: 9px; }
  .visual-head { font-size: 7px; left: 16px; right: 16px; }
  .music-visual { padding-inline: 19px; }
  .staff-notes { font-size: 16px; }
  .exam-visual { padding-inline: 20px; }
  .exam-board { padding-inline: 14px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; }
}