:root {
  --rt-bg: #F4F6F7;
  --rt-surface: #FFFFFF;
  --rt-ink: #15202B;
  --rt-sub: #4B5966;
  --rt-mute: #6B7884;
  --rt-rule: #D3DAE0;
  --rt-control: #8A96A1;
  --rt-line: #0B7894;
  --rt-line-tint: #E0F0F4;
  --rt-font-en: "Atkinson Hyperlegible Next", "Arial", sans-serif;
  color-scheme: light;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--rt-bg); color: var(--rt-ink); font-family: "Hiragino Sans", "Yu Gothic UI", YuGothic, "Noto Sans JP", Meiryo, sans-serif; line-height: 1.7; }
button, select, textarea { font: inherit; }
button, a, select { -webkit-tap-highlight-color: transparent; }
.wrap { width: min(100% - 40px, 1080px); margin-inline: auto; }
.hero { background: #fff; border-bottom: 1px solid var(--rt-rule); }
.hero__inner { min-height: 450px; display: grid; grid-template-columns: 1.15fr .85fr; align-items: center; gap: clamp(32px, 7vw, 88px); padding-block: 64px 72px; }
.eyebrow, .section-kicker { margin: 0 0 12px; color: var(--rt-sub); font: 700 12px/1.4 var(--rt-font-en); letter-spacing: .08em; }
.eyebrow { display: flex; align-items: center; gap: 9px; }
.eyebrow__dot, .route-dot { width: 10px; height: 10px; display: inline-block; border: 2px solid var(--rt-line); border-radius: 50%; background: #fff; }
.tool-label { margin: 0 0 8px; color: var(--rt-line); font-size: 13px; font-weight: 700; }
h1 { margin: 0; font-size: clamp(38px, 5vw, 58px); line-height: 1.25; letter-spacing: -.045em; }
h1 span { color: var(--rt-line); }
.hero__lead { max-width: 540px; margin: 20px 0; color: var(--rt-sub); font-size: 16px; }
.facts { display: flex; flex-wrap: wrap; gap: 8px 20px; margin: 0 0 28px; padding: 0; list-style: none; color: var(--rt-sub); font-size: 13px; }
.facts li { display: flex; gap: 7px; align-items: center; }
.facts li span { color: var(--rt-line); font-weight: 700; }
.hero__actions { display: flex; flex-wrap: wrap; gap: 10px; }
.button { min-height: 50px; display: inline-flex; align-items: center; justify-content: center; gap: 10px; padding: 0 20px; border: 1.5px solid var(--rt-control); border-radius: 9px; color: var(--rt-ink); background: #fff; text-decoration: none; font-size: 14px; font-weight: 700; cursor: pointer; }
.button:focus-visible, .play-button:focus-visible, select:focus-visible, textarea:focus-visible { outline: 3px solid #5dabbc; outline-offset: 3px; }
.button--primary { border-color: var(--rt-line); color: #fff; background: var(--rt-line); }
.button--primary:hover { background: #08657c; }
.button--secondary:hover { border-color: var(--rt-line); color: var(--rt-line); }
.button--text { border-color: transparent; color: var(--rt-sub); padding-inline: 12px; }
.hero-card { padding: 22px; border: 1px solid var(--rt-rule); border-radius: 10px; background: var(--rt-bg); }
.hero-card__top, .hero-card__foot { display: flex; align-items: center; gap: 9px; color: var(--rt-sub); font: 700 11px/1.5 var(--rt-font-en); letter-spacing: .06em; }
.hero-card__step { margin-left: auto; font-variant-numeric: tabular-nums; }
.hero-card__hint { margin: 27px 0 12px; font-size: 14px; font-weight: 700; }
.wave { height: 58px; display: flex; align-items: center; justify-content: space-between; gap: 4px; padding: 0 2px; }
.wave span { width: 4px; height: 16px; border-radius: 5px; background: #0B7894; opacity: .78; }
.wave span:nth-child(3n) { height: 34px; }.wave span:nth-child(4n) { height: 45px; }.wave span:nth-child(5n) { height: 25px; }.wave span:nth-child(7n) { height: 52px; }
.hero-card__input { min-height: 58px; display: flex; align-items: center; margin: 14px 0 18px; padding: 0 15px; border: 1px solid var(--rt-control); border-radius: 8px; color: var(--rt-mute); background: #fff; font: 16px var(--rt-font-en); }
.hero-card__foot { justify-content: space-between; letter-spacing: .02em; }
.practice { padding-block: 64px 74px; }
.practice__intro { max-width: 680px; }
h2 { margin: 0; font-size: clamp(24px, 3vw, 32px); line-height: 1.4; letter-spacing: -.025em; }
.practice__intro > p:last-child { margin: 12px 0 24px; color: var(--rt-sub); font-size: 14px; }
.level-panel { display: grid; grid-template-columns: 140px minmax(180px, 360px); align-items: center; gap: 12px; max-width: 560px; padding: 16px; border: 1px solid var(--rt-rule); border-radius: 9px; background: #fff; }
.level-panel label { font-size: 13px; font-weight: 700; }
.level-panel select { min-height: 44px; padding: 0 34px 0 12px; border: 1px solid var(--rt-control); border-radius: 7px; color: var(--rt-ink); background: #fff; }
.level-panel__note { grid-column: 1 / -1; margin: 0; color: var(--rt-sub); font-size: 12px; }
.player { max-width: 820px; margin-top: 22px; padding: clamp(18px, 4vw, 30px); border: 1px solid var(--rt-rule); border-radius: 10px; background: #fff; }
.player__head { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-bottom: 20px; }
.player__head .section-kicker { margin-bottom: 3px; }
.player__head h3 { margin: 0; font-size: 16px; }
.separator { color: var(--rt-mute); }
.audio-panel { display: flex; justify-content: space-between; align-items: center; gap: 16px; padding: 14px; border: 1px solid var(--rt-rule); border-radius: 8px; background: var(--rt-bg); }
.play-button { min-height: 56px; display: flex; align-items: center; gap: 12px; padding: 0 14px; border: 0; border-radius: 8px; color: #fff; background: var(--rt-line); text-align: left; cursor: pointer; }
.play-button:hover { background: #08657c; }
.play-icon { font-size: 17px; }
.play-button strong, .play-button small { display: block; }
.play-button strong { font-size: 14px; }.play-button small { color: #e5f5f8; font-size: 11px; }
.audio-panel__note { color: var(--rt-sub); font-size: 12px; }
.answer-label { display: block; margin: 22px 0 8px; font-size: 14px; font-weight: 700; }
#answerInput { width: 100%; min-height: 108px; resize: vertical; padding: 14px; border: 1.5px solid var(--rt-control); border-radius: 8px; color: var(--rt-ink); background: #fff; font: 18px/1.55 var(--rt-font-en); }
#answerInput::placeholder { color: #6b7884; }
.keyboard-hint { margin: 5px 0 0; color: var(--rt-mute); font-size: 11px; }
.feedback { margin-top: 17px; padding: 12px 14px; border: 2px solid var(--rt-line); border-radius: 8px; color: var(--rt-ink); background: var(--rt-line-tint); font-weight: 700; }
.feedback--retry { border-style: dashed; border-width: 1.5px; background: #fff; font-weight: 400; }
.answer-reveal { margin-top: 12px; padding: 12px 14px; border: 1px solid var(--rt-rule); border-radius: 8px; background: #fff; }
.answer-reveal__label { margin: 0 0 4px; color: var(--rt-sub); font-size: 12px; font-weight: 700; }
.answer-reveal p:last-child { margin: 0; font: 18px/1.55 var(--rt-font-en); }
.translation { display: grid; grid-template-columns: 90px 1fr; gap: 12px; margin-top: 12px; padding: 12px 14px; border: 1px solid var(--rt-rule); border-radius: 8px; }
.translation__label { margin: 0; color: var(--rt-sub); font-size: 12px; font-weight: 700; }.translation p:last-child { margin: 0; font-size: 14px; }
.player__actions { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 18px; }
.player__actions .button--primary { min-width: 190px; }.player__actions .button--secondary { margin-left: auto; }
.loading, .error-message { margin: 14px 0 0; color: var(--rt-sub); font-size: 13px; }.error-message { color: #15202b; }
.how { padding-block: 30px 72px; border-top: 1px solid var(--rt-rule); }
.how h2 { margin-bottom: 24px; }
.steps { display: grid; grid-template-columns: repeat(3, 1fr); border-top: 1px solid var(--rt-rule); border-bottom: 1px solid var(--rt-rule); }
.step { padding: 22px 20px 24px 0; }.step + .step { padding-left: 20px; border-left: 1px solid var(--rt-rule); }
.step__number { color: var(--rt-line); font: 700 12px/1.5 var(--rt-font-en); letter-spacing: .08em; }
.step h3 { margin: 8px 0 5px; font-size: 16px; }.step p { margin: 0; color: var(--rt-sub); font-size: 13px; }
.site-footer { border-top: 1px solid var(--rt-rule); background: #fff; }.site-footer .wrap { min-height: 68px; display: flex; align-items: center; gap: 18px; color: var(--rt-sub); font-size: 12px; }.site-footer a { color: var(--rt-ink); font-weight: 700; text-decoration: none; }.site-footer a:last-child { margin-left: auto; }
[hidden] { display: none !important; }
@media (max-width: 760px) {
  .wrap { width: min(100% - 32px, 600px); }
  .hero__inner { min-height: 0; grid-template-columns: 1fr; gap: 30px; padding-block: 42px 44px; }
  h1 { font-size: clamp(38px, 11vw, 52px); }
  .hero__lead { font-size: 15px; }
  .hero-card { max-width: 480px; }
  .practice { padding-block: 44px 52px; }
  .level-panel { grid-template-columns: 1fr; gap: 8px; }
  .level-panel select { width: 100%; }
  .level-panel__note { grid-column: auto; margin-top: 2px; }
  .player__head { align-items: flex-start; }
  .audio-panel__note { max-width: 120px; text-align: right; }
  .player__actions { display: grid; grid-template-columns: 1fr; }
  .player__actions .button, .player__actions .button--primary { width: 100%; margin-left: 0; }
  .steps { grid-template-columns: 1fr; }
  .step, .step + .step { padding: 17px 0; border-left: 0; }
  .step + .step { border-top: 1px solid var(--rt-rule); }
  .site-footer .wrap { min-height: 76px; flex-wrap: wrap; gap: 0 14px; padding-block: 12px; }
  .site-footer .wrap span { flex-basis: calc(100% - 130px); order: 1; }
  .site-footer a:last-child { margin-left: auto; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; } }