/* ========================================
   G検定 勉強ノート — 共通スタイルシート
   ======================================== */

/* --- CSS変数（ダークテーマ） --- */
:root {
  --bg: #0f1923;
  --card: #19273a;
  --card-alt: #1e2f45;
  --accent: #00d4aa;
  --accent2: #6c63ff;
  --accent3: #ff6b8a;
  --yellow: #ffc857;
  --text: #e0e8f0;
  --text-dim: #8a9bb5;
  --border: #2a3f58;
  /* ページごとにオーバーライドできるヘッダーグラデーション */
  --header-from: var(--accent2);
  --header-to: var(--accent);
}

/* --- リセット＆ベース --- */
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  font-family: 'Noto Sans JP', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.8;
  min-height: 100vh;
}

/* --- コンテナ --- */
.container {
  max-width: 920px;
  margin: 0 auto;
  padding: 40px 24px 80px;
}

/* --- パンくずナビ --- */
.breadcrumb {
  font-size: 0.82rem;
  color: var(--text-dim);
  margin-bottom: 24px;
}
.breadcrumb a {
  color: var(--accent);
  text-decoration: none;
}
.breadcrumb a:hover {
  text-decoration: underline;
}
.breadcrumb .sep {
  margin: 0 6px;
  color: var(--border);
}

/* --- ヘッダー --- */
.header {
  text-align: center;
  margin-bottom: 48px;
}
.header::after {
  content: '';
  display: block;
  width: 80px;
  height: 3px;
  background: linear-gradient(90deg, var(--header-from), var(--header-to));
  margin: 20px auto 0;
  border-radius: 2px;
}
.header h1 {
  font-family: 'M PLUS Rounded 1c', sans-serif;
  font-size: 2rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--header-from), var(--header-to));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 8px;
}
.header .subtitle {
  font-size: 0.95rem;
  color: var(--text-dim);
  letter-spacing: 2px;
}

/* --- 会話バブル --- */
.bubble {
  padding: 18px 22px;
  border-radius: 16px;
  margin-bottom: 14px;
}
.beginner {
  background: var(--card);
  border-left: 4px solid var(--accent3);
  margin-right: 40px;
}
.expert {
  background: var(--card-alt);
  border-left: 4px solid var(--accent);
}
.speaker {
  font-size: 0.82rem;
  font-weight: 700;
  margin-bottom: 6px;
  letter-spacing: 1px;
}
.beginner .speaker { color: var(--accent3); }
.expert .speaker { color: var(--accent); }
.bubble p { font-size: 0.95rem; }
.bubble strong { color: #fff; }

/* --- セクションタイトル --- */
.section-title {
  font-family: 'M PLUS Rounded 1c', sans-serif;
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--accent);
  margin: 48px 0 20px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 10px;
}
.section-title .icon { font-size: 1.4rem; }

/* --- 図解ラッパー --- */
.diagram-wrapper {
  background: var(--card);
  border-radius: 20px;
  padding: 28px 20px;
  margin: 24px 0 32px;
  border: 1px solid var(--border);
  overflow-x: auto;
}
.diagram-label {
  text-align: center;
  font-size: 0.82rem;
  color: var(--text-dim);
  margin-top: 12px;
  font-style: italic;
}
svg text {
  font-family: 'Noto Sans JP', sans-serif;
}

/* --- ハイライトボックス --- */
.highlight-box {
  background: rgba(255,200,87,0.08);
  border: 1px solid var(--yellow);
  border-radius: 14px;
  padding: 20px 24px;
  margin: 20px 0;
}
.highlight-box .title {
  color: var(--yellow);
  font-weight: 700;
  font-size: 0.95rem;
  margin-bottom: 8px;
}
.highlight-box p {
  font-size: 0.9rem;
}
.highlight-box.pink {
  background: rgba(255,107,138,0.08);
  border-color: var(--accent3);
}
.highlight-box.pink .title {
  color: var(--accent3);
}
.highlight-box.green {
  background: rgba(0,212,170,0.08);
  border-color: var(--accent);
}
.highlight-box.green .title {
  color: var(--accent);
}
.highlight-box.purple {
  background: rgba(108,99,255,0.08);
  border-color: var(--accent2);
}
.highlight-box.purple .title {
  color: var(--accent2);
}

/* --- テーブル --- */
.table-wrapper {
  background: var(--card);
  border-radius: 16px;
  padding: 24px;
  margin: 24px 0;
  border: 1px solid var(--border);
  overflow-x: auto;
}
table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}
thead th {
  background: var(--accent2);
  color: #fff;
  padding: 12px 14px;
  text-align: center;
  font-weight: 700;
  font-size: 0.85rem;
}
thead th:first-child { border-radius: 10px 0 0 0; }
thead th:last-child { border-radius: 0 10px 0 0; }
thead th.pink { background: var(--accent3); }
tbody td {
  padding: 12px 14px;
  border-bottom: 1px solid var(--border);
  text-align: center;
  vertical-align: middle;
}
tbody tr:last-child td { border-bottom: none; }
tbody tr:hover { background: rgba(108, 99, 255, 0.06); }
td strong { color: var(--accent); }
td.left { text-align: left; }

/* --- キーポイント --- */
.keypoints {
  background: linear-gradient(135deg, rgba(0,212,170,0.08), rgba(108,99,255,0.08));
  border: 1px solid var(--accent);
  border-radius: 16px;
  padding: 28px;
  margin: 32px 0;
}
.keypoints h3 {
  font-family: 'M PLUS Rounded 1c', sans-serif;
  color: var(--accent);
  font-size: 1.1rem;
  margin-bottom: 14px;
}
.keypoints ul {
  list-style: none;
  padding: 0;
}
.keypoints li {
  padding: 6px 0 6px 24px;
  position: relative;
  font-size: 0.93rem;
}
.keypoints li::before {
  content: '\2713';
  position: absolute;
  left: 0;
  color: var(--accent);
  font-weight: 700;
}

/* --- チェーン矢印（進化フロー用） --- */
.chain-arrow {
  text-align: center;
  color: var(--accent2);
  font-size: 1.4rem;
  line-height: 1;
  margin: -2px 0;
  opacity: 0.6;
}

/* --- 比較ボックス（2列） --- */
.comparison-box {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin: 24px 0;
}
@media (max-width: 650px) {
  .comparison-box { grid-template-columns: 1fr; }
}
.compare-card {
  background: var(--card);
  border-radius: 16px;
  padding: 24px;
  border: 2px solid var(--border);
}
.compare-card h4 {
  font-family: 'M PLUS Rounded 1c', sans-serif;
  font-size: 1rem;
  margin-bottom: 14px;
  text-align: center;
}
.compare-card p {
  font-size: 0.9rem;
  text-align: center;
}
.compare-card.bad { border-color: var(--accent3); }
.compare-card.bad h4 { color: var(--accent3); }
.compare-card.good { border-color: var(--accent); }
.compare-card.good h4 { color: var(--accent); }
.compare-card.supervised { border-color: var(--accent2); }
.compare-card.supervised h4 { color: var(--accent2); }
.compare-card.unsupervised { border-color: var(--accent); }
.compare-card.unsupervised h4 { color: var(--accent); }
.compare-card.reinforcement { border-color: var(--yellow); }
.compare-card.reinforcement h4 { color: var(--yellow); }

/* --- 比較ボックス（3列） --- */
.comparison-box-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin: 24px 0;
}
@media (max-width: 750px) {
  .comparison-box-3 { grid-template-columns: 1fr; }
}
.comparison-box-3 .compare-card {
  padding: 20px;
}
.comparison-box-3 .compare-card h4 {
  font-size: 0.95rem;
  margin-bottom: 12px;
}
.comparison-box-3 .compare-card p {
  font-size: 0.85rem;
  color: var(--text-dim);
}

/* --- 用語ボックス --- */
.term-box {
  background: var(--card-alt);
  border-radius: 12px;
  padding: 16px 20px;
  margin: 16px 0;
}
.term-box .term {
  color: var(--yellow);
  font-weight: 700;
  font-size: 0.95rem;
  margin-bottom: 6px;
}
.term-box .desc {
  font-size: 0.9rem;
  color: var(--text);
}

/* --- テクニカルカード --- */
.tech-card {
  background: var(--card);
  border-radius: 16px;
  padding: 24px;
  margin: 20px 0;
  border: 1px solid var(--border);
}
.tech-card h4 {
  font-family: 'M PLUS Rounded 1c', sans-serif;
  font-size: 1.05rem;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.tech-card h4.yellow { color: var(--yellow); }
.tech-card h4.green { color: var(--accent); }
.tech-card h4.purple { color: var(--accent2); }
.tech-card h4.pink { color: var(--accent3); }
.tech-card .desc {
  font-size: 0.9rem;
  margin-bottom: 12px;
}
.tech-card .detail {
  background: var(--card-alt);
  border-radius: 10px;
  padding: 14px 18px;
  font-size: 0.85rem;
  color: var(--text-dim);
}

/* --- 3列グリッドカード --- */
.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin: 24px 0;
}
@media (max-width: 750px) {
  .grid-3 { grid-template-columns: 1fr; }
}
.grid-3 .card {
  background: var(--card);
  border-radius: 16px;
  padding: 20px;
  border: 2px solid var(--border);
  text-align: center;
}
.grid-3 .card h4 {
  font-family: 'M PLUS Rounded 1c', sans-serif;
  font-size: 0.95rem;
  margin-bottom: 10px;
}
.grid-3 .card p {
  font-size: 0.85rem;
  color: var(--text-dim);
}
.grid-3 .card.c-yellow { border-color: var(--yellow); }
.grid-3 .card.c-yellow h4 { color: var(--yellow); }
.grid-3 .card.c-green { border-color: var(--accent); }
.grid-3 .card.c-green h4 { color: var(--accent); }
.grid-3 .card.c-pink { border-color: var(--accent3); }
.grid-3 .card.c-pink h4 { color: var(--accent3); }
.grid-3 .card.c-purple { border-color: var(--accent2); }
.grid-3 .card.c-purple h4 { color: var(--accent2); }

/* ========================================
   ナビゲーションページ用（index, 一覧ページ）
   ======================================== */

/* --- セクションラベル（一覧ページ用） --- */
.section-label {
  font-family: 'M PLUS Rounded 1c', sans-serif;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--accent);
  margin: 36px 0 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}

/* --- リンクリスト（一覧ページ用） --- */
.link-list {
  list-style: none;
  padding: 0;
}
.link-list li {
  margin-bottom: 12px;
}
.link-list a {
  display: block;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px 20px;
  color: var(--text);
  text-decoration: none;
  transition: border-color 0.2s, background 0.2s;
}
.link-list a:hover {
  border-color: var(--accent);
  box-shadow: 0 0 0 1px var(--accent);
}
.link-list .title {
  font-weight: 700;
  font-size: 1rem;
  margin-bottom: 4px;
}
.link-list .desc {
  font-size: 0.82rem;
  color: var(--text-dim);
}

/* --- タグ --- */
.tag {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: 4px;
  margin-right: 6px;
  vertical-align: middle;
}
.tag.visual { background: rgba(0,212,170,0.15); color: var(--accent); }
.tag.glossary { background: rgba(108,99,255,0.15); color: var(--accent2); }

/* --- ハブカード（トップページ用） --- */
.hub-cards {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  margin: 40px 0;
}
@media (max-width: 600px) {
  .hub-cards { grid-template-columns: 1fr; }
}
.hub-card {
  display: block;
  background: var(--card);
  border: 2px solid var(--border);
  border-radius: 20px;
  padding: 32px 24px;
  text-decoration: none;
  color: var(--text);
  text-align: center;
  transition: border-color 0.2s, transform 0.2s;
}
.hub-card:hover {
  transform: translateY(-2px);
  border-color: var(--accent);
  box-shadow: 0 4px 20px rgba(0,212,170,0.1);
}
.hub-card .hub-icon {
  font-size: 2.5rem;
  margin-bottom: 12px;
}
.hub-card .hub-title {
  font-family: 'M PLUS Rounded 1c', sans-serif;
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 8px;
}
.hub-card .hub-desc {
  font-size: 0.85rem;
  color: var(--text-dim);
}
.hub-card.visual-card { border-color: rgba(0,212,170,0.3); }
.hub-card.visual-card .hub-title { color: var(--accent); }
.hub-card.glossary-card { border-color: rgba(108,99,255,0.3); }
.hub-card.glossary-card .hub-title { color: var(--accent2); }

/* --- 準備中バッジ --- */
.wip-badge {
  display: inline-block;
  font-size: 0.7rem;
  background: rgba(255,200,87,0.15);
  color: var(--yellow);
  padding: 2px 8px;
  border-radius: 4px;
  margin-left: 8px;
}

/* --- 検索ボックス --- */
.search-box {
  position: relative;
  margin: 0 0 12px;
}
.search-input-wrapper {
  position: relative;
  display: flex;
  align-items: center;
}
.search-icon {
  position: absolute;
  left: 16px;
  font-size: 1.1rem;
  pointer-events: none;
  opacity: 0.5;
}
#search-input {
  width: 100%;
  padding: 14px 44px 14px 44px;
  background: var(--card);
  border: 2px solid var(--border);
  border-radius: 14px;
  color: var(--text);
  font-size: 0.95rem;
  font-family: 'Noto Sans JP', sans-serif;
  outline: none;
  transition: border-color 0.2s;
}
#search-input::placeholder {
  color: var(--text-dim);
  opacity: 0.7;
}
#search-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 2px rgba(0, 212, 170, 0.15);
}
.search-clear {
  position: absolute;
  right: 12px;
  background: none;
  border: none;
  color: var(--text-dim);
  font-size: 1.4rem;
  cursor: pointer;
  padding: 4px 8px;
  line-height: 1;
}
.search-clear:hover {
  color: var(--text);
}
.search-results {
  display: none;
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  right: 0;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  max-height: 400px;
  overflow-y: auto;
  z-index: 100;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
}
.search-result-item {
  display: block;
  padding: 14px 18px;
  text-decoration: none;
  color: var(--text);
  border-bottom: 1px solid var(--border);
  transition: background 0.15s;
}
.search-result-item:last-child {
  border-bottom: none;
}
.search-result-item:hover {
  background: rgba(0, 212, 170, 0.08);
}
.search-result-title {
  font-weight: 700;
  font-size: 0.95rem;
  margin-bottom: 4px;
}
.search-result-category {
  font-size: 0.75rem;
  color: var(--accent2);
  margin-bottom: 6px;
}
.search-result-terms {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}
.search-term-tag {
  display: inline-block;
  font-size: 0.72rem;
  background: rgba(0, 212, 170, 0.12);
  color: var(--accent);
  padding: 2px 8px;
  border-radius: 6px;
}
.search-no-result {
  padding: 20px 18px;
  text-align: center;
  color: var(--text-dim);
  font-size: 0.9rem;
}

/* --- ハブカード（暗記カード用） --- */
.hub-card.flashcard-card { border-color: rgba(255,107,138,0.3); }
.hub-card.flashcard-card .hub-title { color: var(--accent3); }

/* --- ハブカード（弱点項目用） --- */
.hub-card.weakpoint-card { border-color: rgba(255,179,64,0.3); }
.hub-card.weakpoint-card .hub-title { color: #ffb340; }

/* --- フラッシュカード --- */

/* フィルタ共通 */
.flashcard-filter {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 12px;
}
.flashcard-filter-label {
  font-size: 0.82rem;
  color: var(--text-dim);
  width: 100%;
  margin-bottom: 2px;
  font-weight: 700;
}
.filter-btn {
  display: inline-block;
  padding: 6px 14px;
  font-size: 0.82rem;
  font-family: 'Noto Sans JP', sans-serif;
  border: 1px solid var(--border);
  border-radius: 20px;
  background: var(--card);
  color: var(--text-dim);
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s, color 0.2s;
}
.filter-btn:hover {
  border-color: var(--accent);
  color: var(--text);
}
.filter-btn.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #0f1923;
  font-weight: 700;
}
/* 理解度フィルタ色 */
.filter-btn.ok.active { background: #22c55e; border-color: #22c55e; color: #fff; }
.filter-btn.mid.active { background: #eab308; border-color: #eab308; color: #0f1923; }
.filter-btn.ng.active { background: #ef4444; border-color: #ef4444; color: #fff; }
.filter-btn.none.active { background: var(--text-dim); border-color: var(--text-dim); color: #0f1923; }

/* 進捗カウンタ */
.flashcard-progress {
  text-align: center;
  font-size: 0.9rem;
  color: var(--text-dim);
  margin: 16px 0 8px;
}
.flashcard-progress strong {
  color: var(--accent);
}

/* カード表示エリア（問題面 — 紫系背景） */
.flashcard-container {
  background: linear-gradient(135deg, rgba(108,99,255,0.10), rgba(0,212,170,0.06));
  border: 2px solid rgba(108,99,255,0.3);
  border-radius: 20px;
  padding: 40px 32px;
  margin: 20px 0;
  text-align: center;
  min-height: 280px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  position: relative;
}
.flashcard-category {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  background: rgba(108,99,255,0.15);
  color: var(--accent2);
  padding: 3px 12px;
  border-radius: 12px;
  margin-bottom: 16px;
}
.flashcard-term {
  font-family: 'M PLUS Rounded 1c', sans-serif;
  font-size: 2.2rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 8px;
  word-break: break-word;
}

/* 理解度バッジ */
.mastery-badge {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 2px 10px;
  border-radius: 10px;
  margin-bottom: 20px;
}
.mastery-badge.ok { background: rgba(34,197,94,0.15); color: #22c55e; }
.mastery-badge.mid { background: rgba(234,179,8,0.15); color: #eab308; }
.mastery-badge.ng { background: rgba(239,68,68,0.15); color: #ef4444; }
.mastery-badge.none { background: rgba(138,155,181,0.15); color: var(--text-dim); }

/* 回答エリア（緑系ボーダーで問題面と区別） */
.flashcard-answer {
  width: 100%;
  margin-top: 16px;
  padding: 24px 20px;
  background: var(--card);
  border: 2px solid rgba(0,212,170,0.3);
  border-radius: 16px;
  animation: fadeIn 0.3s ease;
}
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}
.answer-fullname {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 4px;
  padding-bottom: 0;
}
.answer-name-ja {
  font-size: 0.82rem;
  color: var(--text-dim);
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border);
}

/* 回答セクション共通 */
.answer-section {
  text-align: left;
  margin-top: 14px;
}
.answer-section-title {
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 1px;
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 6px;
}
.answer-section-title.green { color: var(--accent); }
.answer-section-title.yellow { color: var(--yellow); }
.answer-section-title.pink { color: var(--accent3); }
.answer-section-title.purple { color: var(--accent2); }
.answer-section-title.blue { color: #60a5fa; }
.answer-section-title.orange { color: #fb923c; }

/* 解説 */
.answer-explanation {
  font-size: 0.93rem;
  color: var(--text);
  line-height: 1.8;
  text-align: left;
  background: var(--card-alt);
  border-radius: 10px;
  padding: 14px 18px;
}

/* 重要ポイント */
.answer-keypoints {
  list-style: none;
  padding: 0;
}
.answer-keypoints li {
  position: relative;
  padding: 4px 0 4px 20px;
  font-size: 0.88rem;
  line-height: 1.7;
}
.answer-keypoints li::before {
  content: '\2714';
  position: absolute;
  left: 0;
  color: var(--yellow);
  font-size: 0.82rem;
}

/* 開発ストーリー */
.answer-story {
  background: rgba(96,165,250,0.08);
  border: 1px solid rgba(96,165,250,0.25);
  border-radius: 10px;
  padding: 14px 18px;
  font-size: 0.88rem;
  line-height: 1.8;
  text-align: left;
}

/* かんたん解説 */
.answer-easy {
  background: rgba(255,107,138,0.08);
  border: 1px solid rgba(255,107,138,0.25);
  border-radius: 10px;
  padding: 14px 18px;
  font-size: 0.88rem;
  line-height: 1.8;
  text-align: left;
}

/* 覚え方のコツ */
.answer-memory-tip {
  background: rgba(251,146,60,0.08);
  border: 1px solid rgba(251,146,60,0.25);
  border-radius: 10px;
  padding: 14px 18px;
  font-size: 0.88rem;
  line-height: 1.8;
  text-align: left;
}

/* 関連用語 */
.answer-related {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}
.answer-related-tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  background: rgba(108,99,255,0.12);
  color: var(--accent2);
  padding: 3px 10px;
  border-radius: 8px;
}

/* アクションボタン */
.flashcard-actions {
  margin-top: 24px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}
.btn {
  display: inline-block;
  padding: 12px 32px;
  font-size: 1rem;
  font-family: 'Noto Sans JP', sans-serif;
  font-weight: 700;
  border: none;
  border-radius: 12px;
  cursor: pointer;
  transition: transform 0.15s, box-shadow 0.15s;
}
.btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(0,0,0,0.3);
}
.btn:active {
  transform: translateY(0);
}
.btn-reveal {
  background: linear-gradient(135deg, var(--accent2), var(--accent));
  color: #fff;
}
.btn-next {
  background: var(--card-alt);
  border: 1px solid var(--border);
  color: var(--text);
}
.btn-next:hover {
  border-color: var(--accent);
}

/* 理解度ボタン群 */
.mastery-buttons {
  display: flex;
  gap: 12px;
  justify-content: center;
}
.mastery-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  padding: 12px 20px;
  font-size: 1.4rem;
  font-family: 'Noto Sans JP', sans-serif;
  border: 2px solid var(--border);
  border-radius: 14px;
  background: var(--card);
  color: var(--text);
  cursor: pointer;
  transition: border-color 0.2s, transform 0.15s, background 0.2s;
  min-width: 80px;
}
.mastery-btn .mastery-label {
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--text-dim);
}
.mastery-btn:hover {
  transform: translateY(-2px);
}
.mastery-btn.ok:hover, .mastery-btn.ok.selected {
  border-color: #22c55e;
  background: rgba(34,197,94,0.1);
}
.mastery-btn.ok.selected .mastery-label { color: #22c55e; }
.mastery-btn.mid:hover, .mastery-btn.mid.selected {
  border-color: #eab308;
  background: rgba(234,179,8,0.1);
}
.mastery-btn.mid.selected .mastery-label { color: #eab308; }
.mastery-btn.ng:hover, .mastery-btn.ng.selected {
  border-color: #ef4444;
  background: rgba(239,68,68,0.1);
}
.mastery-btn.ng.selected .mastery-label { color: #ef4444; }

/* リセットボタン */
.flashcard-reset {
  display: inline-block;
  margin-top: 24px;
  padding: 8px 20px;
  font-size: 0.82rem;
  font-family: 'Noto Sans JP', sans-serif;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: transparent;
  color: var(--text-dim);
  cursor: pointer;
  transition: border-color 0.2s, color 0.2s;
}
.flashcard-reset:hover {
  border-color: var(--accent3);
  color: var(--accent3);
}

/* 空状態 */
.flashcard-empty {
  color: var(--text-dim);
  font-size: 0.95rem;
  padding: 40px 0;
}

/* キーボードヒント */
.keyboard-hint {
  font-size: 0.75rem;
  color: var(--text-dim);
  margin-top: 8px;
}
.keyboard-hint kbd {
  display: inline-block;
  padding: 1px 6px;
  font-size: 0.72rem;
  font-family: 'Noto Sans JP', sans-serif;
  background: var(--card-alt);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text-dim);
}

/* --- レスポンシブ --- */
@media (max-width: 600px) {
  .header h1 { font-size: 1.5rem; }
  .container { padding: 24px 16px 60px; }
  .beginner { margin-right: 16px; }

  /* フラッシュカード */
  .flashcard-container { padding: 28px 16px; min-height: 220px; }
  .flashcard-term { font-size: 1.6rem; }
  .flashcard-answer { padding: 18px 14px; }
  .mastery-buttons { gap: 8px; }
  .mastery-btn { padding: 10px 14px; min-width: 64px; font-size: 1.2rem; }
  .btn { padding: 10px 24px; font-size: 0.9rem; }
}