/* 紹介ページ。濃青は既存の Brand.blue、赤はカレンダーの --sun と揃える。 */
:root { color-scheme: light; --blue: #00205b; --red: #c8102e; --white: #fff; --muted: #425578; --line: #dce2eb; --wash: #f5f7fb; }
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 32px; }
body { margin: 0; background: var(--white); color: var(--blue); font-family: -apple-system, BlinkMacSystemFont, "Helvetica Neue", "Noto Sans", "Hiragino Kaku Gothic ProN", "Yu Gothic", sans-serif; font-size: 16px; line-height: 1.8; -webkit-font-smoothing: antialiased; }
a { color: inherit; text-underline-offset: .25em; }
a:focus-visible, summary:focus-visible { outline: 3px solid var(--red); outline-offset: 5px; }
.wrap { width: min(1120px, calc(100% - 96px)); margin-inline: auto; }
.skip { position: absolute; top: 8px; left: 8px; z-index: 2; padding: 8px 16px; background: var(--white); transform: translateY(-150%); }
.skip:focus { transform: none; }
.header { display: flex; justify-content: space-between; align-items: center; gap: 24px; padding-block: 26px; }
.logo { display: inline-flex; align-items: center; gap: 10px; font-size: 22px; font-weight: 750; letter-spacing: .05em; text-decoration: none; }
.logo img { display: block; }
.header nav { display: flex; align-items: center; gap: 32px; }
.nav-link { font-size: 14px; text-decoration: none; }
.nav-link:hover { text-decoration: underline; }
.button { display: inline-flex; align-items: center; justify-content: center; gap: 24px; min-height: 54px; padding: 13px 25px; border-radius: 8px; background: var(--blue); color: var(--white); font-size: 16px; font-weight: 650; text-decoration: none; transition: background-color .18s ease; }
.button:hover { background: #163a78; }
.button.small { min-height: 44px; padding: 9px 17px; gap: 16px; font-size: 14px; }
.hero { display: grid; grid-template-columns: 1.1fr 1fr; align-items: center; gap: 64px; padding-block: 76px 116px; }
p { margin: 0; }
.eyebrow { margin-bottom: 22px; color: var(--red); font-size: 13px; font-weight: 700; letter-spacing: .08em; }
h1, h2, h3 { margin: 0; font-weight: 700; line-height: 1.5; letter-spacing: -.03em; }
h1 { font-size: clamp(34px, 3.8vw, 50px); line-height: 1.45; }
.lead { margin-block: 26px 30px; color: var(--muted); font-size: 17px; line-height: 1.95; }
.caption { margin-top: 12px; font-size: 12px; color: var(--muted); }
.mobile-break { display: none; }
.preview { margin: 0; padding: 28px; border: 1px solid var(--line); border-radius: 16px; }
.preview-heading { display: flex; justify-content: space-between; align-items: center; margin-bottom: 10px; font-size: 18px; font-weight: 700; }
.preview table { width: 100%; table-layout: fixed; border-spacing: 5px; margin-left: -5px; }
.preview th { font-size: 12px; font-weight: 600; text-align: center; }
.preview th:first-child, .preview thead td { width: 34px; }
.preview tbody th span { display: block; color: var(--muted); font-size: 10px; font-weight: 400; }
.preview td { padding: 0; height: 78px; background: var(--wash); border-radius: 5px; vertical-align: top; }
.preview thead td { height: auto; background: none; }
.class-cell { height: 100%; padding: 12px 8px; background: var(--blue); color: var(--white); border-radius: 5px; font-size: 12px; font-weight: 650; line-height: 1.6; }
.class-cell span { display: block; margin-top: 5px; font-size: 10px; font-weight: 400; }
.class-cell.accent { background: var(--red); }
.preview-task { display: flex; align-items: center; gap: 10px; padding-top: 20px; margin-top: 14px; border-top: 1px solid var(--line); font-size: 12px; }
.task-label { color: var(--muted); }
.deadline { margin-left: auto; color: var(--red); font-weight: 650; white-space: nowrap; }
figcaption { margin-top: 16px; color: var(--muted); font-size: 10px; }
.features { border-top: 1px solid var(--line); padding-block: 72px 96px; }
.section-heading { margin-bottom: 48px; }
h2 { font-size: clamp(26px, 3vw, 34px); }
.section-heading > p:last-child { margin-top: 20px; color: var(--muted); }
.feature-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); column-gap: 80px; }
.feature-grid article { padding-block: 30px 34px; border-top: 1px solid var(--line); }
.number { margin-bottom: 12px; color: var(--red); font-size: 12px; font-variant-numeric: tabular-nums; }
h3 { font-size: 21px; }
.feature-grid article > p:last-child { margin-top: 14px; color: var(--muted); font-size: 15px; line-height: 1.95; }
.start { background: var(--blue); color: var(--white); }
.start-inner { display: flex; align-items: center; justify-content: space-between; gap: 48px; padding-block: 64px; }
.start .eyebrow { color: var(--white); margin-bottom: 16px; }
.start p:last-child { margin-top: 20px; font-size: 15px; }
.button.light { background: var(--white); color: var(--blue); flex-shrink: 0; }
.button.light:hover { background: #e9edf5; }
.notes { padding-block: 80px; max-width: 840px; }
.notes h2 { font-size: 24px; margin-bottom: 30px; }
details { border-bottom: 1px solid var(--line); }
summary { padding-block: 22px; cursor: pointer; font-size: 16px; font-weight: 600; }
details > div { padding: 0 0 24px; color: var(--muted); font-size: 14px; }
details p + p { margin-top: 12px; }
.footer { display: flex; align-items: center; gap: 24px; padding-block: 32px; border-top: 1px solid var(--line); }
.footer .logo { font-size: 16px; }
.footer p, .footer nav { font-size: 12px; color: var(--muted); }
.footer nav { display: flex; gap: 24px; margin-left: auto; }
@media (max-width: 900px) {
  .wrap { width: calc(100% - 48px); }
  .hero { gap: 32px; padding-block: 56px 80px; }
  .preview { padding: 20px; }
  .feature-grid { column-gap: 40px; }
  .start-inner { gap: 28px; }
  .footer { flex-wrap: wrap; }
  .footer nav { width: 100%; margin-left: 0; }
}
@media (max-width: 640px) {
  .header { padding-block: 20px; gap: 12px; }
  .logo { font-size: 18px; gap: 6px; }
  .logo img { width: 32px; height: 32px; }
  .header nav { gap: 0; }
  .nav-link { display: none; }
  .button.small { font-size: 12px; padding-inline: 12px; gap: 10px; }
  .hero { grid-template-columns: 1fr; gap: 40px; padding-block: 40px 64px; }
  h1 { font-size: clamp(30px, 8vw, 44px); }
  .eyebrow { margin-bottom: 18px; font-size: 12px; }
  .lead { font-size: 15px; margin-block: 22px 26px; }
  .mobile-break { display: block; }
  .preview { max-width: 420px; width: 100%; }
  .features { padding-block: 48px; }
  .section-heading { margin-bottom: 30px; }
  .section-heading > p:last-child { font-size: 14px; }
  .feature-grid { grid-template-columns: 1fr; }
  h3 { font-size: 20px; }
  .feature-grid article { padding-block: 26px; }
  .start-inner { flex-direction: column; align-items: flex-start; padding-block: 48px; }
  .start h2 { font-size: 26px; }
  .notes { padding-block: 48px; }
  .notes h2 { font-size: 21px; }
  summary { font-size: 15px; }
  .footer { gap: 12px 20px; padding-block: 24px; }
  .footer nav { gap: 20px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .button { transition: none; }
}