/* ===== 共通スタイル ===== */
body {
  font-family: 'Hiragino Kaku Gothic ProN', 'Hiragino Sans', 'Meiryo', sans-serif;
  background: #ffffff;
  margin: 0;
  padding: 0;
  font-size: 18px;
  line-height: 1.9;
  color: #333;
}

/* ===== ヘッダー ===== */
.page-header {
  padding: 14px 20px;
  color: white;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
}
.bronze .page-header { background: #E8821A; }
.silver .page-header { background: #4169E1; }

.chapter-label {
  font-size: 13px;
  opacity: 0.85;
  margin-bottom: 2px;
}
.page-header h1 {
  font-size: 22px;
  margin: 0;
}

/* ===== Scratchボタン ===== */
.scratch-btn {
  display: inline-block;
  background: #ffffff;
  padding: 10px 18px;
  border-radius: 20px;
  text-decoration: none;
  font-size: 15px;
  font-weight: bold;
  white-space: nowrap;
}
.bronze .scratch-btn { color: #E8821A; }
.silver .scratch-btn { color: #4169E1; }

/* ===== 本文エリア ===== */
.content {
  padding: 20px 24px 40px;
}

/* ===== ふりがな ===== */
ruby { ruby-position: over; }
rt { font-size: 0.55em; }

/* ===== 画像 ===== */
figure {
  margin: 12px 0;
  text-align: center;
}
figure img {
  max-width: 100%;
  border-radius: 8px;
  border: 2px solid #eee;
}
figcaption {
  font-size: 14px;
  color: #666;
  margin-top: 4px;
}

/* ===== プレースホルダー（未撮影スクリーンショット）===== */
.placeholder {
  background: #f5f5f5;
  border: 2px dashed #ccc;
  border-radius: 8px;
  padding: 24px;
  text-align: center;
  color: #999;
  margin: 12px 0;
  font-size: 14px;
}

/* ===== ヒントボックス ===== */
.tip {
  background: #FFF9C4;
  border-left: 4px solid #FFC107;
  padding: 12px 16px;
  border-radius: 0 8px 8px 0;
  margin: 16px 0;
}
.tip-title {
  font-weight: bold;
  margin-bottom: 4px;
}

/* ===== 発展ボックス ===== */
.challenge {
  background: #E8F5E9;
  border-left: 4px solid #4CAF50;
  padding: 12px 16px;
  border-radius: 0 8px 8px 0;
  margin: 16px 0;
}

/* ===== まとめボックス ===== */
.summary {
  background: #E3F2FD;
  border: 2px solid #90CAF9;
  border-radius: 8px;
  padding: 16px 20px;
  margin: 20px 0;
}
.summary h2 {
  font-size: 18px;
  margin: 0 0 8px;
  color: #1565C0;
}

/* ===== ステップ番号 ===== */
.step-list {
  list-style: none;
  padding: 0;
  margin: 0;
}
.step-list li {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  margin-bottom: 12px;
}
.step-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 28px;
  height: 28px;
  border-radius: 50%;
  color: white;
  font-weight: bold;
  font-size: 14px;
  margin-top: 2px;
}
.bronze .step-num { background: #E8821A; }
.silver .step-num { background: #4169E1; }

/* ===== 次のチャプターボタン ===== */
.next-btn {
  display: block;
  width: fit-content;
  margin: 36px auto 16px;
  padding: 14px 36px;
  font-size: 18px;
  border: none;
  border-radius: 30px;
  color: white;
  cursor: pointer;
  font-family: inherit;
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}
.bronze .next-btn { background: #E8821A; }
.silver .next-btn { background: #4169E1; }
.next-btn:active { transform: scale(0.97); }