:root {
  color-scheme: light;
  --ink: #122940;
  --muted: #49637a;
  --blue: #2141ac;
  --action: #2364e8;
  --line: #d8e5ed;
  --dark: #112d40;
  --white: #fff;
  --container: 1252px;
  --radius-control: 12px;
  --radius-card: 20px;
  --radius-art: 28px;
  --section-space: clamp(44px, 5.8vw, 84px);
  font-family: "Microsoft YaHei", "PingFang SC", "Noto Sans CJK SC", sans-serif;
  color: var(--ink);
}

*, *::before, *::after { box-sizing: border-box; }
body, h1, h2, h3, p, dl, dd, ol { margin: 0; }
a { color: inherit; text-decoration: none; }
button { font: inherit; }
img { display: block; max-width: 100%; }
:focus-visible { outline: 3px solid #1372d1; outline-offset: 5px; }
.container { width: min(calc(100% - 64px), var(--container)); margin-inline: auto; }
.skip-link { position: fixed; z-index: 2; top: 12px; left: 12px; padding: 12px 18px; background: #fff; transform: translateY(-160%); }
.skip-link:focus { transform: none; }

.site-header { min-height: 88px; border-bottom: 1px solid var(--line); }
.header-inner, .footer-inner { display: flex; align-items: center; min-height: 87px; }
.brand { display: inline-flex; align-items: center; gap: 12px; font-size: 28px; font-weight: 700; white-space: nowrap; }
.brand img { flex: none; }
.site-nav { display: flex; align-items: center; gap: clamp(20px, 2.9vw, 42px); margin-left: auto; margin-right: clamp(28px, 6vw, 86px); color: var(--muted); font-size: 17px; font-weight: 700; white-space: nowrap; }
.site-nav a:hover, .site-footer a:hover { text-decoration: underline; text-underline-offset: 4px; }
.button { display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-height: 52px; padding: 10px 22px; border: 1px solid transparent; border-radius: var(--radius-control); background: var(--action); color: #fff; font-size: 17px; line-height: 1.35; font-weight: 700; text-align: center; cursor: pointer; }
.button:hover { background: #1b51c4; }
.button-outline { border-color: #c8ddf4; background: #fff; color: var(--blue); }
.button-outline:hover { background: #eef6ff; }
.header-cta { flex: none; min-height: 46px; font-size: 15px; }

.hero { background: linear-gradient(180deg, #f4f8fe, #edfafa 78%, #fff); }
.hero-main { position: relative; display: grid; grid-template-columns: minmax(0, 573fr) minmax(0, 655fr); align-items: center; gap: clamp(24px, 3vw, 44px); padding-block: 38px 54px; background: radial-gradient(ellipse at 79% 42%, #d7eaff 0, transparent 58%); }
.hero-copy { position: relative; isolation: isolate; }
.hero-copy::before, .learning::before, .contact::before { content: ""; position: absolute; z-index: -1; pointer-events: none; background: radial-gradient(circle, var(--dots) 1.2px, transparent 1.6px) 0 0 / 25px 25px; }
.hero-copy::before { --dots: #d8e8f7; inset: 0 0 103px; mask-image: linear-gradient(120deg, #000 28%, transparent 85%); }
.hero-label { display: inline-flex; align-items: center; min-height: 34px; padding: 4px 14px; border: 1px solid #d8e8fa; border-radius: 999px; background: #fff; color: var(--blue); font-size: 14px; font-weight: 700; }
h1 { margin-top: 26px; font-size: clamp(38px, 4.25vw, 61px); line-height: 1.2; letter-spacing: -.035em; }
h1 span { color: var(--action); }
.hero-description { max-inline-size: 25em; margin-top: 24px; color: var(--muted); font-size: 20px; line-height: 1.8; text-wrap: pretty; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; }
.hero-platforms { display: flex; flex-wrap: wrap; align-items: center; gap: 8px 12px; margin: 22px 0 0; padding: 0; list-style: none; color: var(--muted); font: 600 14px/1.4 "Segoe UI", sans-serif; }
.hero-platforms li + li::before { content: ""; display: inline-block; width: 4px; height: 4px; margin: 0 12px 2px 0; border-radius: 50%; background: #82c7aa; }
.hero-art { width: 100%; height: auto; aspect-ratio: 655 / 532; object-fit: cover; border-radius: var(--radius-art); box-shadow: 0 16px 32px #2141ac14; }
.hero-highlights {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) repeat(3, minmax(0, 1fr));
  align-items: center;
  gap: 16px 24px;
  padding-block: 24px 28px;
  border-top: 1px solid var(--line);
}
.hero-highlights dt { font-size: 18px; font-weight: 700; line-height: 1.4; }
.hero-highlights dd { margin-top: 4px; color: var(--muted); font-size: 14px; line-height: 1.6; }
.partner-highlight { position: relative; padding-left: 122px; }
.partner-count {
  position: absolute;
  top: 50%;
  left: 0;
  translate: 0 -50%;
  color: var(--action);
  font: 800 58px/1 "Segoe UI", sans-serif;
  letter-spacing: -.045em;
}
.partner-count sup { font-size: .54em; vertical-align: super; line-height: 0; }

.eyebrow { color: var(--action); font-size: 14px; font-weight: 700; line-height: 1.4; }
h2 { margin-top: 12px; font-size: clamp(27px, 3.5vw, 48px); line-height: 1.24; letter-spacing: -.025em; text-wrap: balance; }
.section-description { max-inline-size: 42em; margin-top: 12px; color: var(--muted); font-size: clamp(16px, 1.5vw, 20px); line-height: 1.7; }
.about-inner { display: grid; grid-template-columns: minmax(0, 47fr) minmax(0, 53fr); align-items: center; gap: 28px; padding-block: var(--section-space); }
.about-copy { border-left: 3px solid #82c7aa; padding: 6px 0 6px 24px; color: var(--muted); font-size: clamp(16px, 1.65vw, 22px); line-height: 1.75; }
.about-copy p + p { margin-top: 6px; }
.about-copy h3 { margin-bottom: 8px; color: var(--ink); font-size: 1em; }

.features, .learning, .learning-details, .audience, .partners, .platforms, .faq, .contact { padding-block: var(--section-space); }
.features { background: #f2f7fa; }
.feature-grid, .audience-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px; }
.feature-grid { margin-top: 30px; }
.feature-card { --chip: #eaf4fe; --accent: var(--action); display: flex; flex-direction: column; padding: 24px; border: 1px solid #e2ebf2; border-radius: var(--radius-card); background: #fff; }
.feature-card.grammar { --chip: #e8f6ee; --accent: #266a55; }
.feature-card.text { --chip: #fff3d9; --accent: #885409; }
.feature-card.sounds { --chip: #fff0e8; --accent: #a44730; }
.feature-card h3 { display: flex; align-items: center; gap: 14px; font-size: clamp(22px, 2.2vw, 30px); line-height: 1.2; }
.module-label { display: grid; flex: 0 0 56px; height: 56px; place-items: center; border-radius: var(--radius-control); background: var(--chip); color: var(--accent); font: 700 26px/1 "Segoe UI", sans-serif; }
.feature-card p { flex: 1; margin-top: 16px; padding-top: 14px; border-top: 1px solid var(--line); color: var(--muted); font-size: clamp(16px, 1.4vw, 19px); line-height: 1.75; }
.module-en { margin-top: 12px; color: var(--accent); font: 700 12px/1.4 "Segoe UI", sans-serif; letter-spacing: .08em; }
.guide-inline { color: var(--blue); font-size: .9em; font-weight: 700; text-decoration: underline; text-underline-offset: .2em; }
.feature-card .guide-inline { align-self: flex-start; margin-top: 9px; }
.reading-note { display: flex; align-items: baseline; gap: 24px; margin-top: 18px; padding: 18px 24px; border-radius: var(--radius-card); background: #e5f3ec; }
.reading-note h3 { color: #266a55; font-size: 22px; white-space: nowrap; }
.reading-note p { font-size: 18px; line-height: 1.65; }

.learning { position: relative; z-index: 0; background: var(--dark); color: #fff; }
.learning::before { --dots: #335265; top: 32px; right: max(36px, calc((100vw - var(--container)) / 2)); width: 275px; height: 240px; background-size: 21px 21px; }
.learning .eyebrow { color: #85c9fe; }
.learning .section-description { color: #b6cdd9; }
.learning-steps, .partner-steps { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 16px; padding: 0; list-style: none; }
.learning-steps { margin-top: 34px; }
.learning-steps li { position: relative; min-width: 0; }
.learning-steps li:not(:last-child)::after { content: ""; position: absolute; top: 22px; left: 52px; right: -16px; border-top: 2px solid #426274; }
.step-index { display: grid; width: 46px; height: 46px; place-items: center; border: 2px solid #527d91; border-radius: 50%; background: #284b61; color: #bde5ff; font: 700 16px/1 "Segoe UI", sans-serif; }
.learning-steps h3 { margin-top: 16px; font-size: 24px; }
.learning-steps p { margin-top: 6px; color: #b6cdd9; font-size: 17px; line-height: 1.6; }
.learning-example { display: grid; grid-template-columns: 27% minmax(0, 1fr) auto; align-items: center; gap: 24px; margin-top: 36px; padding: 24px; border-radius: var(--radius-card); background: #e6f5ef; color: var(--ink); }
.example-word { border-right: 2px solid #b9d8cd; }
.example-word p { color: #266a55; font-size: 22px; font-weight: 700; }
.example-word strong { display: block; margin-top: 7px; font: 700 48px/1.15 "Segoe UI", sans-serif; }
.example-sentence p:first-child { font: italic 42px/1.25 Georgia, serif; }
.example-sentence p + p { margin-top: 8px; color: #266a55; font-size: 18px; }
.example-tag { justify-self: start; align-self: start; padding: 5px 10px; border: 1px solid #b9d8cd; border-radius: 999px; color: #266a55; font-size: 13px; font-weight: 700; white-space: nowrap; }

.detail-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px 28px;
  margin: 30px 0 0;
  padding: 0;
  list-style: none;
}
.detail-grid li { display: grid; grid-template-columns: 2em minmax(0, 1fr); gap: 6px 10px; align-content: start; padding-top: 14px; border-top: 1px solid var(--line); }
.detail-grid li > span { grid-row: span 2; color: var(--action); font: 600 23px/1.2 "Segoe UI", sans-serif; }
.detail-grid h3 { font-size: clamp(16px, 1.5vw, 21px); }
.detail-grid p { grid-column: 2; color: var(--muted); font-size: 15px; line-height: 1.65; }
.section-lead { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 300px); align-items: end; gap: 16px 28px; }
.section-lead > p { color: var(--muted); font-size: 16px; line-height: 1.7; }
.eyebrow [lang="en"] { letter-spacing: .08em; }
.audience { background: #f2f7fa; }
.audience-grid { margin-top: 30px; }
.audience-grid article { padding: clamp(20px, 3vw, 38px); border-radius: var(--radius-card); background: #eaf4fe; }
.audience-grid article + article { background: #e8f6ee; }
.audience-tag { color: var(--blue); font: 700 13px/1.4 "Segoe UI", sans-serif; letter-spacing: .1em; }
.audience-grid article + article .audience-tag { color: #266a55; }
.audience-grid h3 { margin-top: 14px; font-size: clamp(22px, 2.2vw, 30px); line-height: 1.35; }
.audience-grid ul { margin: 14px 0 0; padding-inline-start: 1.1em; color: var(--muted); font-size: clamp(15px, 1.3vw, 18px); line-height: 1.7; }
.audience-grid li + li { margin-top: 6px; }
.audience-note { margin-top: 16px; color: var(--muted); font-size: 14px; line-height: 1.55; }
.partners { border-bottom: 1px solid var(--line); }
.partner-steps { margin-top: 34px; gap: 28px; }
.partner-steps li { padding-top: 18px; border-top: 1px solid var(--line); }
.partner-steps li > span { color: #527fa9; font: 700 35px/1.2 "Segoe UI", sans-serif; }
.partner-steps h3 { margin-top: 8px; font-size: clamp(19px, 1.8vw, 24px); }
.partner-steps p { margin-top: 6px; color: var(--muted); font-size: 17px; line-height: 1.65; }

.platform-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 1px; margin-top: 30px; overflow: hidden; border: 1px solid var(--line); border-radius: var(--radius-card); background: var(--line); }
.platform-grid > div { padding: 24px 12px; background: #fff; text-align: center; }
.platform-grid dt { display: grid; justify-items: center; gap: 10px; font: 700 clamp(16px, 1.55vw, 22px)/1.25 "Segoe UI", sans-serif; }
.platform-icon { display: grid; width: 38px; height: 38px; place-items: center; color: var(--action); fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.platform-grid dd { margin-top: 8px; color: var(--muted); font-size: 15px; line-height: 1.55; }
.faq { background: #f2f7fa; }
.faq-inner { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.8fr); gap: 24px 48px; }
.faq-list > div { padding-block: 16px; border-top: 1px solid var(--line); }
.faq-list > div:first-child { padding-top: 0; border-top: 0; }
.faq-list dt { font-size: 19px; font-weight: 700; }
.faq-list dd { margin-top: 6px; color: var(--muted); font-size: 17px; line-height: 1.65; }

.contact { position: relative; isolation: isolate; background: #e9f5f8; }
.contact::before { --dots: #c9e3eb; top: 28px; right: max(36px, calc((100vw - var(--container)) / 2)); width: 305px; height: 252px; background-size: 24px 24px; }
.contact-inner { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 405px); align-items: center; gap: 28px; }
.contact-inner > div:first-child > p:last-child { max-inline-size: 31em; margin-top: 14px; color: var(--muted); font-size: clamp(16px, 1.4vw, 19px); line-height: 1.75; }
.contact-card { padding: 24px; border: 1px solid #dce9ef; border-radius: var(--radius-card); background: #fff; }
.contact-card h3 { font-size: 21px; }
.contact-card p { margin-top: 8px; color: var(--muted); font-size: 15px; line-height: 1.6; }
.contact-card .button { width: 100%; margin-top: 16px; }
.site-footer { min-height: 129px; background: var(--dark); color: #fff; }
.footer-inner { min-height: 129px; justify-content: space-between; gap: 24px; }
.site-footer nav { display: flex; flex-wrap: wrap; gap: 24px; color: #b6cdd9; font-size: 17px; }

dialog { width: min(calc(100% - 32px), 480px); max-height: calc(100% - 32px); padding: 28px; border: 1px solid var(--line); border-radius: var(--radius-card); color: var(--ink); }
dialog::backdrop { background: #112d4066; }
dialog h2 { margin-top: 8px; font-size: 28px; }
dialog p:not(.eyebrow) { margin-top: 14px; color: var(--muted); line-height: 1.7; }
dialog form { margin-top: 20px; }
dialog .button { min-height: 44px; font-size: 16px; }

.feature-card, .audience-grid article, .contact-card { box-shadow: 0 5px 18px #112d4009; }
.learning-example { box-shadow: 0 10px 30px #081b2a40; }

@media (hover: hover) and (pointer: fine) {
  .feature-card:hover { border-color: #b8d4eb; }
  .feature-card:hover, .audience-grid article:hover { box-shadow: 0 10px 24px #112d4016; }
  .button:not(.button-outline):hover { box-shadow: 0 6px 16px #2141ac33; }
}

@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
  .hero-copy > *, .hero-art, .is-entering, dialog[open] {
    animation: enter 520ms cubic-bezier(.22, 1, .36, 1) backwards;
  }
  .hero-copy h1 { animation-delay: 60ms; }
  .hero-description { animation-delay: 110ms; }
  .hero-actions { animation-delay: 160ms; }
  .hero-platforms { animation-delay: 210ms; }
  .hero-art { animation-duration: 700ms; animation-delay: 90ms; --entry-offset: 22px; }
  dialog[open] { animation-duration: 250ms; --entry-offset: 8px; }

  @keyframes enter {
    from { opacity: .58; transform: translateY(var(--entry-offset, 14px)); }
    to { opacity: 1; transform: translateY(0); }
  }
}

@media (prefers-reduced-motion: no-preference) and (hover: hover) and (pointer: fine) {
  .button, .feature-card, .audience-grid article {
    transition: translate 180ms ease-out, box-shadow 180ms ease-out, border-color 180ms ease-out, background-color 180ms ease-out;
  }
  .feature-card:hover, .audience-grid article:hover { translate: 0 -4px; }
  .button:hover { translate: 0 -2px; }
  .button:active { translate: 0 0; }
}

@media (max-width: 1180px) {
  .site-nav { margin-right: 36px; }
}

@media (max-width: 960px) {
  .header-inner { flex-wrap: wrap; justify-content: space-between; gap: 14px 24px; padding-block: 14px; }
  .site-nav { order: 3; width: 100%; justify-content: space-between; margin: 0; gap: 12px; }
  .hero-main { grid-template-columns: repeat(2, minmax(0, 1fr)); padding-block: 32px 40px; }
  h1 { font-size: clamp(32px, 4.5vw, 44px); }
  .hero-description { margin-top: 18px; font-size: 17px; }
  .hero-actions { margin-top: 20px; }
  .hero-actions .button { padding-inline: 14px; font-size: 15px; }
  .hero-highlights { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .contact-inner { grid-template-columns: 1fr minmax(240px, 35%); }
  .example-sentence p:first-child { font-size: 34px; }
}

@media (max-width: 700px) {
  :root { --radius-card: 16px; --radius-art: 22px; }
  .container { width: calc(100% - 32px); }
  .brand { gap: 7px; font-size: 19px; }
  .brand img { width: 35px; height: 35px; }
  .header-inner { gap: 10px; }
  .header-cta { min-height: 44px; padding-inline: 10px; font-size: 13px; }
  .site-nav { gap: 6px; font-size: 13px; }
  .site-nav a { display: inline-flex; min-height: 44px; align-items: center; }
  .hero-main, .about-inner, .contact-inner, .feature-grid, .audience-grid, .section-lead, .faq-inner { grid-template-columns: 1fr; }
  .hero-main { gap: 24px; padding-top: 16px; padding-bottom: 28px; background: radial-gradient(ellipse closest-side at 65% 57%, #d7eaff 0, transparent 100%); }
  .hero-copy { padding-top: 8px; }
  .hero-label { min-height: 30px; padding-inline: 11px; font-size: 13px; }
  h1 { margin: 22px 0 0; font-size: clamp(33px, 7.7vw, 49px); }
  .hero-description { margin-top: 19px; font-size: 16px; line-height: 1.7; }
  .hero-actions { gap: 8px; margin-top: 20px; }
  .hero-actions .button { min-width: 0; min-height: 44px; padding: 8px 12px; font-size: 15px; }
  .hero-platforms { margin-top: 16px; font-size: 14px; }
  .hero-highlights { padding-block: 18px 24px; gap: 14px 12px; }
  .partner-highlight { padding-left: 0; }
  .partner-count { position: static; display: block; margin-bottom: 3px; translate: none; font-size: 44px; }
  .hero-highlights dt { font-size: 14px; }
  .hero-highlights dd { font-size: 12px; line-height: 1.5; }
  .about-inner { gap: 20px; }
  .about-copy { padding: 3px 0 3px 12px; }
  h2 { margin-top: 10px; font-size: clamp(27px, 6.6vw, 40px); }
  .eyebrow { font-size: 13px; }
  .feature-grid, .audience-grid, .platform-grid, .partner-steps { margin-top: 22px; }
  .feature-card, .audience-grid article { padding: 18px; }
  .module-label { flex-basis: 46px; height: 46px; font-size: 22px; }
  .feature-card p { margin-top: 12px; padding-top: 12px; }
  .reading-note { display: block; padding: 16px; }
  .reading-note h3 { font-size: 20px; }
  .reading-note p { margin-top: 6px; font-size: 16px; }
  .learning-steps, .partner-steps { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 23px 14px; }
  .learning-steps li::after { display: none; }
  .learning-steps h3, .partner-steps h3 { margin-top: 7px; font-size: 21px; }
  .learning-steps p, .partner-steps p { margin-top: 5px; font-size: 15px; line-height: 1.55; }
  .learning-example { grid-template-columns: 1fr; gap: 12px; margin-top: 25px; padding: 17px; }
  .example-word { border-right: 0; border-bottom: 1px solid #b9d8cd; padding-bottom: 12px; }
  .example-word p { font-size: 17px; }
  .example-word strong { font-size: 33px; }
  .example-sentence p:first-child { font-size: 28px; }
  .example-sentence p + p { font-size: 14px; }
  .detail-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px 12px; margin-top: 22px; }
  .detail-grid li { grid-template-columns: 1fr; gap: 5px; }
  .detail-grid li > span { grid-row: auto; }
  .detail-grid p { grid-column: 1; }
  .platform-grid > div { padding: 16px 8px; }
  .platform-grid dd { font-size: 14px; }
  .faq-list > div { padding: 13px 0; }
  .faq-list dt { font-size: 17px; }
  .faq-list dd { margin-top: 6px; font-size: 15px; }
  .contact-inner { gap: 22px; }
  .contact-card { padding: 18px; }
  .contact-card .button { margin-top: 12px; }
  .site-footer, .footer-inner { min-height: 0; }
  .footer-inner { flex-wrap: wrap; gap: 14px; padding-block: 24px; }
  .site-footer nav { gap: 14px; font-size: 14px; }
}