:root {
  --navy: #003a73;
  --navy-dark: #002a54;
  --blue: #009fe6;
  --blue-soft: #e3f4fd;
  --ink: #1c2b36;
  --gray: #5b6b78;
  --line: #dde5ec;
  --bg: #f5f8fa;
  --white: #ffffff;
  --accent: #ff7a45;
  --green: #2bb673;
  --red: #e0443a;
  --radius: 14px;
  --shadow: 0 2px 12px rgba(0, 42, 84, 0.08);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: 'Noto Sans JP', 'Inter', sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.8;
}

.container { max-width: 980px; margin: 0 auto; padding: 0 20px; }

/* ---------- header / hero(シリーズ共通) ---------- */
.site-header { position: sticky; top: 0; z-index: 100; background: var(--navy); box-shadow: 0 2px 8px rgba(0,0,0,.15); }
.header-inner { max-width: 980px; margin: 0 auto; padding: 0 20px; display: flex; align-items: center; justify-content: space-between; height: 58px; }
.logo { color: #fff; font-weight: 900; font-size: 17px; display: flex; align-items: center; gap: 10px; }
.logo-mark { display: inline-flex; align-items: center; justify-content: center; width: 30px; height: 30px; border-radius: 8px; background: var(--blue); color: #fff; font-weight: 800; font-size: 15px; flex-shrink: 0; }
.nav { display: flex; gap: 4px; flex-wrap: wrap; align-items: center; }
.nav a { color: #cfe3f5; text-decoration: none; font-size: 13px; font-weight: 500; padding: 6px 12px; border-radius: 999px; transition: .15s; }
.nav a:hover { background: rgba(255,255,255,.14); color: #fff; }
.nav .nav-home { background: rgba(255,255,255,.14); color: #fff; font-weight: 700; border: 1px solid rgba(255,255,255,.25); }
.nav .nav-home:hover { background: var(--blue); border-color: var(--blue); }

.hero { background: linear-gradient(135deg, var(--navy) 0%, #00518f 70%, #0070b8 100%); color: #fff; padding: 64px 0 52px; }
.hero-eyebrow { font-family: 'Inter', sans-serif; font-weight: 600; font-size: 12px; letter-spacing: .2em; color: #7fd0f5; margin: 0 0 10px; }
.hero h1 { font-size: 40px; font-weight: 900; margin: 0 0 16px; letter-spacing: .02em; }
.hero-lead { font-size: 15px; color: #d7e7f5; margin: 0 0 28px; }
.hero-lead strong { color: #fff; }
.hero-steps { display: flex; gap: 10px; flex-wrap: wrap; }
.step-chip { background: rgba(255,255,255,.12); border: 1px solid rgba(255,255,255,.3); color: #fff; text-decoration: none; font-size: 13px; font-weight: 700; padding: 8px 16px; border-radius: 999px; transition: .15s; }
.step-chip:hover { background: var(--blue); border-color: var(--blue); }
.hero-disc { font-size: 11.5px; color: #a9c8e2; margin: 18px 0 0; }

/* ---------- lesson(共通) ---------- */
.lesson { background: var(--white); border-radius: var(--radius); box-shadow: var(--shadow); padding: 36px 36px 32px; margin: 36px 0; }
.lesson-head { display: flex; align-items: center; gap: 14px; margin-bottom: 8px; }
.step-badge { background: var(--blue); color: #fff; font-family: 'Inter', sans-serif; font-weight: 800; font-size: 12px; letter-spacing: .08em; padding: 4px 12px; border-radius: 999px; }
.lesson h2 { font-size: 24px; font-weight: 900; color: var(--navy); margin: 0; }
.lesson-desc { color: var(--gray); font-size: 14.5px; margin: 10px 0 20px; }
.lesson-desc strong { color: var(--navy); }
.sub-head { color: var(--navy); font-size: 17px; margin: 32px 0 12px; }

.term-grid, .tips-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); gap: 14px; margin-top: 20px; }
.term-card, .tip-card { background: var(--bg); border-radius: 10px; padding: 18px 18px 14px; border: 1px solid var(--line); }
.term-card h3, .tip-card h3 { font-size: 14.5px; color: var(--navy); margin: 6px 0 6px; }
.term-card p, .tip-card p { font-size: 13px; color: var(--gray); margin: 0; line-height: 1.7; }
.term-card p strong, .tip-card p strong { color: var(--navy); }
.term-icon { font-size: 18px; }

/* ---------- STEP2 ○×ゲーム ---------- */
.mb-box { border: 2px solid var(--line); border-radius: 14px; background: #fff; padding: 26px 28px; }
.mb-progress { display: flex; justify-content: space-between; align-items: center; font-family: 'Inter', sans-serif; font-weight: 600; font-size: 13px; color: var(--gray); margin-bottom: 12px; }
.mb-q { font-size: 16.5px; font-weight: 900; color: var(--navy); margin-bottom: 18px; line-height: 1.7; }
.mb-q .q-icon { font-size: 22px; margin-right: 6px; }
.mb-btns { display: flex; gap: 12px; }
.mb-btn { flex: 1; font-family: inherit; font-size: 22px; font-weight: 900; cursor: pointer; border: 2px solid var(--line); background: var(--bg); border-radius: 12px; padding: 16px 0; transition: .12s; }
.mb-btn.maru { color: var(--green); }
.mb-btn.batsu { color: var(--red); }
.mb-btn:hover { border-color: var(--blue); background: var(--blue-soft); }
.mb-btn:disabled { cursor: default; opacity: .5; }
.mb-btn.chosen-correct { border-color: var(--green); background: #f2fbf6; opacity: 1; }
.mb-btn.chosen-wrong { border-color: var(--red); background: #fdf0ef; opacity: 1; }
.mb-note { margin-top: 16px; background: var(--blue-soft); border-radius: 10px; padding: 12px 16px; font-size: 13.5px; color: var(--navy); font-weight: 500; line-height: 1.7; }
.mb-note[hidden] { display: none; }
.mb-note .mb-verdict { font-weight: 900; }
.mb-next { margin-top: 14px; }
.mb-final { text-align: center; padding: 10px 0; }
.mb-final .mbf-score { font-family: 'Inter', sans-serif; font-weight: 800; font-size: 50px; color: var(--navy); }
.mb-final .mbf-score small { font-size: 18px; }
.mb-final p { margin: 6px 0 14px; font-weight: 900; color: var(--navy); }

/* ---------- STEP3 フォントチェッカー ---------- */
.font-checker { display: flex; flex-direction: column; gap: 16px; }
.fc-group { display: flex; flex-direction: column; gap: 8px; }
.fc-label { font-size: 12.5px; font-weight: 800; color: var(--navy); }
.fc-btns { display: flex; gap: 8px; flex-wrap: wrap; }
.fc-btn { font-family: inherit; font-size: 12.5px; font-weight: 700; cursor: pointer; border: 1.5px solid var(--line); background: #fff; color: var(--gray); border-radius: 999px; padding: 8px 16px; transition: .12s; }
.fc-btn.on { border-color: var(--navy); background: var(--navy); color: #fff; }
.fc-result { border-radius: 12px; padding: 18px 20px; font-size: 14px; line-height: 1.7; display: flex; gap: 14px; align-items: flex-start; }
.fc-result .fc-mark { font-size: 30px; font-weight: 900; flex-shrink: 0; line-height: 1.2; }
.fc-result.good { background: #f2fbf6; border: 1.5px solid var(--green); }
.fc-result.good .fc-mark { color: var(--green); }
.fc-result.mid { background: #fff8ec; border: 1.5px solid #f0c069; }
.fc-result.mid .fc-mark { color: #d98a1f; }
.fc-result.bad { background: #fdf0ef; border: 1.5px solid var(--red); }
.fc-result.bad .fc-mark { color: var(--red); }
.fc-result .fc-text strong { color: var(--navy); }

/* ---------- STEP4 クレジット ---------- */
.credit-area { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.credit-toggles { display: flex; flex-direction: column; gap: 10px; }
.credit-tg { display: flex; align-items: flex-start; gap: 10px; cursor: pointer; background: var(--bg); border: 1.5px solid var(--line); border-radius: 10px; padding: 12px 14px; transition: .12s; }
.credit-tg:hover { border-color: var(--blue); }
.credit-tg.on { border-color: var(--green); background: #f2fbf6; }
.credit-tg input { width: 18px; height: 18px; margin-top: 2px; accent-color: var(--green); flex-shrink: 0; }
.credit-tg .ct-label { font-size: 13.5px; font-weight: 700; color: var(--ink); }
.credit-tg .ct-label small { display: block; font-size: 11.5px; font-weight: 500; color: var(--gray); }
.credit-preview-wrap { background: #fff; border: 1px solid var(--line); border-radius: 12px; overflow: hidden; align-self: start; }
.credit-preview-head { background: var(--bg); padding: 10px 16px; font-size: 12.5px; font-weight: 700; color: var(--navy); border-bottom: 1px solid var(--line); }
.credit-preview { padding: 18px; font-size: 14px; color: var(--ink); min-height: 60px; line-height: 1.8; word-break: break-word; }
.credit-preview .cp-empty { color: #b5c2cc; font-size: 13px; }
#credit-check { margin: 0 18px 16px; }
.credit-feedback { margin: 0 18px 16px; border-radius: 10px; padding: 12px 16px; font-size: 13px; font-weight: 700; line-height: 1.7; }
.credit-feedback[hidden] { display: none; }
.credit-feedback.ok { background: #f2fbf6; color: #1d7a4d; border: 1px solid #bfe8d2; }
.credit-feedback.ng { background: #fff4ec; color: #8a4a22; border: 1px solid #ffd9bd; }

/* ---------- btn / toast / table / note ---------- */
.btn { font-family: inherit; font-size: 13.5px; font-weight: 700; padding: 9px 18px; border-radius: 999px; cursor: pointer; border: 1.5px solid var(--line); background: #fff; color: var(--navy); transition: .15s; }
.btn:hover { border-color: var(--blue); color: var(--blue); }
.btn-primary { background: var(--navy); border-color: var(--navy); color: #fff; }
.btn-primary:hover { background: var(--navy-dark); color: #fff; }

.shortcut-table { width: 100%; border-collapse: collapse; font-size: 13.5px; }
.shortcut-table th, .shortcut-table td { text-align: left; padding: 10px 14px; border-bottom: 1px solid var(--line); }
.shortcut-table th { background: var(--bg); color: var(--navy); font-size: 12.5px; }
.note { margin-top: 18px; background: #fff8f0; border: 1px solid #ffd9bd; border-radius: 10px; padding: 16px 20px; font-size: 13.5px; color: #6b4a2f; }
.note strong { color: #b34a14; }
.toast { position: fixed; left: 50%; bottom: 28px; transform: translateX(-50%); background: var(--navy); color: #fff; font-size: 13.5px; font-weight: 700; padding: 10px 22px; border-radius: 999px; box-shadow: 0 6px 20px rgba(0,0,0,.25); z-index: 1000; transition: opacity .3s; max-width: 90vw; text-align: center; }
.toast[hidden] { display: none; }
.site-footer { background: var(--navy); color: #9fc0dd; text-align: center; padding: 24px 20px; font-size: 12.5px; margin-top: 48px; }
.site-footer p { margin: 0; }

/* ---------- ページ送りナビ ---------- */
.page-nav { display: flex; gap: 12px; align-items: stretch; margin: 44px auto 0; }
.pgnav { flex: 1; display: flex; flex-direction: column; justify-content: center; gap: 3px; text-decoration: none; background: #fff; border: 1.5px solid #dde5ec; border-radius: 12px; padding: 14px 18px; transition: .15s; box-shadow: 0 2px 12px rgba(0,42,84,.08); }
.pgnav:hover { border-color: #009fe6; transform: translateY(-2px); }
.pgnav.prev { text-align: left; }
.pgnav.next { text-align: right; }
.pgnav.top { flex: 0 0 130px; text-align: center; background: #003a73; border-color: #003a73; }
.pgnav.top .pgnav-dir, .pgnav.top .pgnav-name { color: #fff; }
.pgnav.top:hover { background: #002a54; border-color: #002a54; }
.pgnav-dir { font-size: 12px; font-weight: 700; color: #ff7a45; }
.pgnav-name { font-size: 14px; font-weight: 900; color: #003a73; }
.pgnav.is-disabled { visibility: hidden; }
@media (max-width: 560px) { .page-nav { flex-wrap: wrap; } .pgnav.top { order: -1; flex-basis: 100%; } }

@media (max-width: 700px) {
  .hero h1 { font-size: 26px; }
  .lesson { padding: 24px 18px; }
  .header-inner { flex-direction: column; height: auto; padding: 10px 20px; gap: 4px; }
  .credit-area { grid-template-columns: 1fr; }
}