:root {
  color-scheme: light;
  --navy: #10264a;
  --ink: #1b2e4e;
  --muted: #63748e;
  --blue: #2f6df6;
  --pale: #eef4ff;
  --line: #e2e9f2;
  --canvas: #f7f9fc;
  --white: #fff;
  font-family: "Noto Sans JP", -apple-system, BlinkMacSystemFont, "Hiragino Kaku Gothic ProN", "Yu Gothic", sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: var(--canvas); line-height: 1.8; }
a { color: inherit; }
.site-header { min-height: 82px; padding: 16px max(24px, calc((100vw - 1120px) / 2)); display: flex; align-items: center; justify-content: space-between; gap: 24px; background: var(--white); border-bottom: 1px solid var(--line); }
.brand { display: inline-flex; align-items: center; gap: 11px; color: var(--navy); text-decoration: none; font-size: 12px; line-height: 1.4; letter-spacing: .02em; }
.brand strong { font-size: 15px; font-weight: 800; }
.brand-mark { display: inline-flex; flex: 0 0 auto; align-items: center; justify-content: center; min-height: 36px; padding: 0 12px; border: 1px solid #dce8ff; border-radius: 999px; color: #245ed3; background: #eef4ff; font-size: 12px; font-weight: 900; letter-spacing: .07em; white-space: nowrap; }
nav { display: flex; gap: 30px; align-items: center; }
nav a, .footer-links a { text-decoration: none; color: var(--muted); font-size: 13px; font-weight: 600; }
nav a:hover, .footer-links a:hover { color: var(--blue); }
main { max-width: 1120px; margin: 0 auto; padding: 0 24px; }
.hero { display: grid; grid-template-columns: 1.05fr .95fr; align-items: center; gap: 48px; padding: 90px 0 70px; }
.eyebrow { margin: 0 0 14px; color: var(--blue); font-size: 12px; font-weight: 800; letter-spacing: .14em; }
h1, h2, h3, p { margin-top: 0; }
.hero h1 { margin-bottom: 20px; color: var(--navy); font-size: clamp(34px, 5vw, 56px); font-weight: 800; letter-spacing: -.045em; line-height: 1.35; }
.hero h1 span { color: var(--blue); }
.hero-description { max-width: 510px; margin-bottom: 28px; color: var(--muted); font-size: 16px; }
.primary-link { display: inline-flex; align-items: center; gap: 15px; padding: 12px 19px; color: white; background: var(--blue); border-radius: 12px; text-decoration: none; font-size: 14px; font-weight: 700; box-shadow: 0 8px 22px #2f6df62b; }
.primary-link:hover { background: #1f5ee8; }
.release-note { display: inline-flex; align-items: center; gap: 9px; margin: -2px 0 17px; padding: 7px 12px; border: 1px solid #cfe0ff; border-radius: 999px; color: #245ed3; background: #fff; font-size: 12px; font-weight: 700; }
.release-note span { width: 8px; height: 8px; border-radius: 50%; background: #f0a63b; box-shadow: 0 0 0 4px #fff3df; }
.hero-card { padding: 25px; border: 1px solid #e4ebf5; border-radius: 23px; background: var(--white); box-shadow: 0 18px 46px #18396712; transform: rotate(1deg); }
.hero-card-top, .progress-label { display: flex; align-items: center; justify-content: space-between; }
.hero-card-top { margin-bottom: 25px; color: var(--navy); font-weight: 800; }
.dot { width: 9px; height: 9px; border-radius: 50%; background: #36bd83; box-shadow: 0 0 0 5px #e8f8f1; }
.progress-label { margin-bottom: 8px; font-size: 12px; color: var(--muted); }
.progress-label strong { color: var(--navy); font-size: 14px; }
.progress-track { height: 8px; overflow: hidden; border-radius: 9px; background: #edf1f6; }
.progress-track span { display: block; width: 32%; height: 100%; background: var(--blue); border-radius: inherit; }
.lesson-row { display: flex; align-items: center; gap: 13px; margin-top: 18px; padding: 14px; border: 1px solid var(--line); border-radius: 14px; }
.lesson-icon { display: grid; place-items: center; flex: 0 0 34px; width: 34px; height: 34px; border-radius: 11px; color: #16855f; background: #e9f8f1; font-weight: 800; }
.lesson-icon.pale { color: var(--blue); background: var(--pale); }
.lesson-row strong, .lesson-row small { display: block; }
.lesson-row strong { color: var(--navy); font-size: 13px; }
.lesson-row small { margin-top: 2px; color: var(--muted); font-size: 11px; }
.facts { display: grid; grid-template-columns: repeat(5, 1fr); align-items: center; gap: 20px; margin: 0 0 94px; padding: 24px 30px; border: 1px solid var(--line); border-radius: 18px; background: var(--white); }
.facts div { display: flex; align-items: baseline; gap: 8px; }
.facts strong { color: var(--blue); font-size: 30px; line-height: 1; }
.facts span { color: var(--muted); font-size: 13px; font-weight: 600; }
.facts p { grid-column: 1 / -1; margin: 0; color: var(--muted); font-size: 11px; }
.section { padding: 0 0 88px; }
.section h2, .premium-band h2, .note-section h2 { margin-bottom: 12px; color: var(--navy); font-size: clamp(25px, 3vw, 34px); font-weight: 800; letter-spacing: -.03em; line-height: 1.5; }
.section-lead { max-width: 690px; margin-bottom: 30px; color: var(--muted); }
.feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.feature-card { min-height: 190px; padding: 24px; border: 1px solid var(--line); border-radius: 17px; background: var(--white); }
.feature-number { color: var(--blue); font-size: 11px; font-weight: 800; letter-spacing: .12em; }
.feature-card h3 { margin: 8px 0; color: var(--navy); font-size: 18px; }
.feature-card p { margin: 0; color: var(--muted); font-size: 13px; }
.diagram-section { padding-bottom: 86px; }
.diagram-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 18px; align-items: stretch; }
.diagram-card { display: flex; flex-direction: column; overflow: hidden; border: 1px solid var(--line); border-radius: 20px; background: var(--white); box-shadow: 0 12px 32px #1839670b; }
.diagram-image { display: grid; flex: 0 0 520px; place-items: center; height: 520px; min-height: 0; overflow: hidden; padding: 18px; background: linear-gradient(145deg, #f1f6ff, #f7fbfc); }
.diagram-image img { display: block; width: 100%; height: 100%; min-width: 0; min-height: 0; max-width: 100%; object-fit: contain; }
.diagram-caption { position: relative; z-index: 1; flex: 1; min-height: 145px; padding: 22px 22px 25px; background: var(--white); }
.diagram-caption > span { color: var(--blue); font-size: 11px; font-weight: 800; }
.diagram-caption h3 { margin: 6px 0 7px; color: var(--navy); font-size: 17px; }
.diagram-caption p { margin: 0; color: var(--muted); font-size: 12px; line-height: 1.75; }
.diagram-footnote { margin: 15px 0 0; color: var(--muted); font-size: 11px; }
.lesson-preview-heading { margin: 65px 0 22px; }
.lesson-preview-heading .eyebrow { margin-bottom: 8px; }
.lesson-preview-heading h3 { margin: 0 0 8px; color: var(--navy); font-size: clamp(22px, 3vw, 29px); font-weight: 800; line-height: 1.5; }
.lesson-preview-heading > p:last-child { margin: 0; color: var(--muted); font-size: 13px; }
.lesson-preview-grid { display: grid; grid-template-columns: .9fr 1.1fr; gap: 18px; align-items: stretch; }
.lesson-sample, .question-sample { padding: 25px; border: 1px solid var(--line); border-radius: 20px; background: var(--white); box-shadow: 0 12px 32px #1839670b; }
.sample-label { display: flex; justify-content: space-between; gap: 12px; align-items: center; margin-bottom: 14px; color: var(--blue); font-size: 11px; font-weight: 800; }
.sample-label span + span { color: var(--muted); font-weight: 600; }
.lesson-sample h4, .question-sample h4 { margin: 0 0 12px; color: var(--navy); font-size: 17px; line-height: 1.6; }
.lesson-sample > p { margin: 0; color: #52647e; font-size: 13px; line-height: 2; }
.flow-chips { display: flex; flex-wrap: wrap; align-items: center; gap: 7px; margin-top: 19px; }
.flow-chips span { padding: 5px 10px; border-radius: 999px; color: #245ed3; background: var(--pale); font-size: 11px; font-weight: 700; }
.flow-chips i { color: #93a4bc; font-size: 12px; font-style: normal; }
.text-takeaway { display: grid; gap: 3px; margin-top: 19px; padding: 13px 15px; border-left: 3px solid var(--blue); border-radius: 0 11px 11px 0; background: var(--pale); }
.text-takeaway strong { color: #245ed3; font-size: 10px; }
.text-takeaway span { color: var(--navy); font-size: 12px; font-weight: 700; }
.question-sample ol { display: grid; gap: 7px; margin: 15px 0 17px; padding: 0; list-style: none; counter-reset: answer-option; }
.question-sample li { position: relative; padding: 9px 11px 9px 38px; border: 1px solid #e8edf4; border-radius: 10px; color: #52647e; background: #fbfcfe; font-size: 11px; line-height: 1.7; counter-increment: answer-option; }
.question-sample li::before { content: counter(answer-option, katakana); position: absolute; top: 8px; left: 12px; color: var(--blue); font-weight: 800; }
.question-sample li.is-correct { padding-right: 58px; border-color: #8ed6b5; color: #185b46; background: #eaf8f1; }
.question-sample li.is-correct::before { color: #17845c; }
.question-sample li.is-correct::after { content: "正解"; position: absolute; top: 50%; right: 9px; padding: 2px 7px; border-radius: 999px; color: white; background: #17845c; font-size: 9px; font-weight: 800; transform: translateY(-50%); }
.answered-badge { padding: 3px 9px; border-radius: 999px; color: #176f54 !important; background: #eaf8f1; font-size: 10px; }
.answer-feedback { padding: 13px 15px; border: 1px solid #c5ead8; border-radius: 12px; background: #f0faf5; }
.answer-feedback strong { color: #176f54; font-size: 12px; }
.answer-feedback strong span { margin-right: 4px; }
.answer-feedback p { margin: 5px 0 0; color: #3f6557; font-size: 11px; line-height: 1.8; }
.past-question-band { display: grid; grid-template-columns: 170px 1fr; gap: 35px; align-items: center; margin: 0 0 82px; padding: 38px; border: 1px solid #dce8ff; border-radius: 24px; background: linear-gradient(120deg, #edf4ff, #f8fbff 70%); }
.past-question-icon { display: grid; place-items: center; width: 142px; height: 142px; border: 1px solid #d6e4ff; border-radius: 38px; color: white; background: linear-gradient(145deg, #5590ff, #235fe4); box-shadow: 0 18px 35px #2f6df62b; font-size: 24px; font-weight: 800; transform: rotate(-5deg); }
.past-question-copy .eyebrow { margin-bottom: 8px; }
.past-question-copy h2 { margin: 0 0 9px; color: var(--navy); font-size: clamp(23px, 3vw, 31px); line-height: 1.45; }
.past-question-copy > p:not(.eyebrow) { max-width: 720px; margin: 0 0 14px; color: var(--muted); font-size: 14px; }
.past-question-copy > a { display: inline-flex; gap: 12px; align-items: center; color: #245ed3; font-size: 13px; font-weight: 800; text-decoration: none; }
.past-question-copy > a:hover { text-decoration: underline; }
.past-question-copy small { display: block; margin-top: 12px; color: #73839b; font-size: 10px; line-height: 1.7; }
.premium-band { display: grid; grid-template-columns: 1.4fr .8fr; gap: 36px; align-items: center; margin: 0 0 74px; padding: 36px; border-radius: 22px; color: #eaf1ff; background: var(--navy); }
.premium-band .eyebrow { color: #8eb3ff; }
.premium-band h2 { margin-bottom: 10px; color: white; font-size: 26px; }
.premium-band p:not(.eyebrow) { margin: 0; color: #c2cde0; font-size: 14px; }
.premium-note { padding: 17px; border: 1px solid #ffffff2b; border-radius: 14px; color: #d5def0; font-size: 12px; }
.note-section { max-width: 800px; margin: 0 auto 70px; }
.note-section h2 { font-size: 21px; }
.note-section p { margin: 0; color: var(--muted); font-size: 13px; }
.legal-links { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; margin-bottom: 72px; }
.legal-links a { display: flex; align-items: center; gap: 13px; padding: 17px 20px; border: 1px solid var(--line); border-radius: 13px; background: var(--white); text-decoration: none; }
.legal-links a > span:first-child { color: var(--blue); font-size: 11px; font-weight: 800; }
.legal-links strong { flex: 1; color: var(--navy); font-size: 13px; }
.arrow { color: var(--muted); }
.site-footer { display: grid; grid-template-columns: 1fr auto; align-items: center; gap: 16px 30px; padding: 28px max(24px, calc((100vw - 1120px) / 2)); border-top: 1px solid var(--line); background: var(--white); }
.footer-brand img.brand-mark { width: 36px; height: 36px; min-height: 36px; padding: 0; border: 0; border-radius: 12px; object-fit: cover; }
.footer-brand strong { font-size: 13px; }
.footer-links { display: flex; gap: 20px; }
.site-footer > small { grid-column: 1 / -1; color: #8794a8; font-size: 11px; }
.document-page { max-width: 850px; padding-top: 52px; padding-bottom: 76px; }
.back-link { display: inline-block; margin-bottom: 38px; color: var(--muted); font-size: 13px; text-decoration: none; }
.back-link:hover { color: var(--blue); }
.document-page h1 { margin-bottom: 15px; color: var(--navy); font-size: clamp(30px, 4vw, 42px); font-weight: 800; letter-spacing: -.035em; }
.document-intro { margin-bottom: 12px; color: var(--muted); }
.updated { margin-bottom: 38px; color: #8290a4; font-size: 12px; }
.policy-content { padding: 34px; border: 1px solid var(--line); border-radius: 18px; background: var(--white); }
.policy-content section + section { margin-top: 30px; padding-top: 25px; border-top: 1px solid #edf0f5; }
.policy-content h2 { margin-bottom: 10px; color: var(--navy); font-size: 18px; }
.policy-content p { margin-bottom: 11px; color: #52647e; font-size: 14px; }
.policy-content p:last-child { margin-bottom: 0; }
.policy-content a { color: #245ed3; overflow-wrap: anywhere; }
.document-end { margin: 20px 10px 0; color: var(--muted); font-size: 13px; text-align: right; }

@media (max-width: 760px) {
  .site-header { min-height: 72px; padding: 13px 18px; }
  .brand { font-size: 10px; }
  .brand-mark { min-height: 33px; padding: 0 10px; font-size: 11px; }
  .brand strong { font-size: 13px; }
  nav { gap: 12px; }
  nav a { font-size: 11px; }
  main { padding-right: 18px; padding-left: 18px; }
  .hero { grid-template-columns: 1fr; gap: 35px; padding: 57px 0 42px; }
  .hero h1 { font-size: 38px; }
  .hero-card { max-width: 500px; width: 100%; justify-self: center; transform: none; }
  .facts { grid-template-columns: repeat(3, 1fr); gap: 14px 8px; margin-bottom: 66px; padding: 20px; }
  .facts strong { font-size: 26px; }
  .facts p { grid-column: 1 / -1; }
  .section { padding-bottom: 65px; }
  .feature-grid { grid-template-columns: 1fr; }
  .diagram-grid { grid-template-columns: 1fr; }
  .diagram-image { flex-basis: 560px; height: 560px; padding: 14px; }
  .diagram-caption { min-height: auto; padding: 18px 20px 22px; }
  .diagram-caption h3 { font-size: 17px; }
  .diagram-caption p { font-size: 12px; }
  .lesson-preview-grid { grid-template-columns: 1fr; }
  .lesson-sample, .question-sample { padding: 21px; }
  .lesson-preview-heading { margin-top: 48px; }
  .past-question-band { grid-template-columns: 1fr; gap: 22px; margin-bottom: 62px; padding: 26px 22px; }
  .past-question-icon { width: 100px; height: 100px; border-radius: 29px; font-size: 19px; }
  .feature-card { min-height: auto; }
  .premium-band { grid-template-columns: 1fr; gap: 20px; margin-bottom: 60px; padding: 26px 22px; }
  .premium-band h2 { font-size: 23px; }
  .note-section { margin-bottom: 54px; }
  .legal-links { grid-template-columns: 1fr; margin-bottom: 55px; }
  .site-footer { grid-template-columns: 1fr; padding: 25px 18px; }
  .footer-links { gap: 17px; }
  .site-footer > small { grid-column: auto; }
  .document-page { padding-top: 32px; padding-bottom: 54px; }
  .back-link { margin-bottom: 25px; }
  .policy-content { padding: 24px 20px; }
}

@media (max-width: 390px) {
  .site-header { align-items: flex-start; flex-direction: column; gap: 12px; }
  nav { width: 100%; justify-content: space-between; }
}

@media (max-width: 420px) {
  .diagram-image { flex-basis: 500px; height: 500px; }
}