:root {
  --navy: #003a73;
  --navy-dark: #002a54;
  --blue: #009fe6;
  --blue-soft: #e3f4fd;
  --ink: #1c2b36;
  --gray: #5b6b78;
  --line: #dde5ec;
  --bg: #f5f8fa;
  --white: #ffffff;
  --accent: #ff7a45;
  --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 ---------- */
.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: 18px;
  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;
}
.nav { display: flex; gap: 4px; flex-wrap: wrap; }
.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 { align-items: center; }
.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 ---------- */
.hero {
  background: linear-gradient(135deg, var(--navy) 0%, #00518f 70%, #0070b8 100%);
  color: #fff; padding: 64px 0 56px;
}
.hero-eyebrow {
  font-family: 'Inter', sans-serif; font-weight: 600; font-size: 12px;
  letter-spacing: .22em; 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); }

/* ---------- lesson section ---------- */
.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; }

.canvas-wrap {
  border: 1px solid var(--line); border-radius: 10px; overflow: hidden;
  background: #fff;
}
.canvas-wrap svg { display: block; width: 100%; height: auto; }

/* ---------- term cards / tips ---------- */
.term-grid, .tips-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 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-icon { color: var(--blue); font-size: 18px; font-weight: 900; }

/* ---------- STEP2 spacing playground ---------- */
.spacing-controls {
  background: var(--bg); border: 1px solid var(--line); border-radius: 10px;
  padding: 16px 20px; margin-bottom: 16px;
  display: flex; flex-direction: column; gap: 10px;
}
.control-row { display: flex; align-items: center; gap: 14px; flex-wrap: wrap; }
.control-label {
  font-size: 13px; font-weight: 700; color: var(--navy); min-width: 150px;
}
.control-row input[type="range"] { flex: 1; min-width: 160px; accent-color: var(--blue); }
.control-val {
  font-family: 'Inter', sans-serif; font-weight: 600; font-size: 13px;
  color: var(--navy); min-width: 52px; text-align: right;
}
.radio { font-size: 13.5px; font-weight: 500; display: flex; align-items: center; gap: 5px; }
.radio input { accent-color: var(--blue); }

.spec-preview {
  border: 1px solid var(--line); border-radius: 10px; background: #fff;
  padding: 28px 32px;
}
.spec-preview p {
  margin: 0; font-size: 17px; color: var(--ink);
  transition: letter-spacing .1s, line-height .1s;
}
.spec-preview.serif p { font-family: 'Noto Serif JP', serif; }

.spacing-feedback {
  margin-top: 12px; font-size: 13.5px; font-weight: 700; color: var(--navy);
  background: var(--blue-soft); border-radius: 8px; padding: 10px 16px;
}

/* ---------- STEP3 kerning game ---------- */
.game-top {
  display: flex; align-items: center; gap: 16px; margin-bottom: 12px; flex-wrap: wrap;
}
.level-dots { display: flex; gap: 7px; }
.level-dot {
  width: 12px; height: 12px; border-radius: 50%;
  background: var(--line); transition: .2s;
}
.level-dot.is-current { background: var(--blue); transform: scale(1.25); }
.level-dot.is-done { background: var(--navy); }
.level-label { font-size: 13.5px; font-weight: 700; color: var(--navy); }

.kern-stage-wrap {
  border: 1px solid var(--line); border-radius: 10px; background: #fff;
  background-image: linear-gradient(#f3f7fa 1px, transparent 1px);
  background-size: 100% 20px;
}
.kern-stage {
  position: relative; height: 240px;
  touch-action: none; user-select: none; -webkit-user-select: none;
  overflow: hidden;
}
.kern-char, .kern-ghost {
  position: absolute; top: 50%;
  width: 1em; line-height: 1; text-align: center;
  transform: translateY(-58%);
  font-weight: 500; color: var(--navy);
  white-space: nowrap;
}
.kern-char.movable { cursor: ew-resize; }
.kern-char.movable:hover { color: #0a5aa3; }
.kern-char.is-selected {
  color: var(--accent);
  text-shadow: 0 0 0 currentColor;
}
.kern-char.fixed { color: #9fb3c4; }
.kern-ghost { color: rgba(0, 159, 230, .45); pointer-events: none; }
.fixed-pin {
  position: absolute; top: 50%; margin-top: 64px;
  transform: translateX(-50%);
  font-size: 11px; color: #9fb3c4; font-weight: 700; pointer-events: none;
}

/* ---------- toolbar / buttons ---------- */
.toolbar {
  display: flex; align-items: center; gap: 10px; flex-wrap: wrap;
  margin-top: 14px;
}
.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; }
.btn-accent { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn-accent:hover { background: #e8642f; border-color: #e8642f; color: #fff; }
.status { font-size: 13px; color: var(--gray); margin-left: auto; }

/* ---------- result ---------- */
.result[hidden] { display: none; }
.result {
  margin-top: 16px; display: flex; align-items: center; gap: 24px;
  background: var(--blue-soft); border: 1.5px solid var(--blue);
  border-radius: var(--radius); padding: 20px 28px;
}
.result.final { background: #fff4ec; border-color: var(--accent); }
.result-score {
  font-family: 'Inter', sans-serif; font-weight: 800; color: var(--navy);
  display: flex; align-items: baseline; gap: 4px; flex-shrink: 0;
}
#game-score, #final-rank { font-size: 52px; line-height: 1; }
#final-rank { color: var(--accent); }
.result-unit { font-size: 16px; font-family: 'Noto Sans JP', sans-serif; font-weight: 700; }
.result-body p { margin: 0; }
#game-msg, #final-msg { font-weight: 900; color: var(--navy); font-size: 17px; }
.result-detail { font-size: 13px; color: var(--gray); margin-top: 4px !important; }
.disclaimer { font-size: 12px; color: #94a3af; margin: 14px 0 0; }

/* ---------- table / note / kbd ---------- */
.kbd {
  display: inline-block; background: var(--navy); color: #fff;
  font-size: 11.5px; font-weight: 700; padding: 2px 9px; border-radius: 6px;
  white-space: nowrap;
}
.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; }
.shortcut-table td:first-child { width: 240px; }

.note {
  margin-top: 18px; background: #fff8f0; border: 1px solid #ffd9bd;
  border-radius: 10px; padding: 16px 20px; font-size: 13.5px; color: #6b4a2f;
}
.note .kbd { background: var(--accent); }

/* ---------- footer ---------- */
.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; }

@media (max-width: 640px) {
  .hero h1 { font-size: 28px; }
  .lesson { padding: 24px 18px; }
  .header-inner { flex-direction: column; height: auto; padding: 10px 20px; gap: 4px; }
  .status { margin-left: 0; width: 100%; }
  .result { flex-direction: column; gap: 8px; text-align: center; }
  .kern-stage { height: 180px; }
  .control-label { min-width: 100%; }
}

/* ---------- 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%; }
}