/* css/index.css */

/* 基本スタイル */
body {
  padding: 20px;
  background: var(--col-bg);
  min-height: 100vh;
}
.container {
  max-width: 1200px;
  margin: 0 auto;
}

/* ヘッダー */
.main-header {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  margin-bottom: 40px;
  animation: pageEnter 0.5s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

h1 {
  text-align: center;
  font-size: 2.2rem;
  margin: 0;
  background: var(--gradient-hero);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: 0.1em;
}

/* タブエリア */
.material-tabs {
  display: flex;
  justify-content: center;
  gap: 12px;
  margin-bottom: 40px;
  flex-wrap: wrap;
  animation: staggerFadeIn 0.5s 0.1s cubic-bezier(0.4, 0, 0.2, 1) forwards;
  opacity: 0;
}
.tab-btn {
  padding: 12px 24px;
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--col-text-sub);
  background: var(--card-bg);
  border: 2px solid var(--card-border);
  border-radius: 50px;
  cursor: pointer;
  transition: all var(--transition-normal);
  min-width: 140px;
  position: relative;
  overflow: hidden;
}
.tab-btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--gradient-card-hover);
  opacity: 0;
  transition: opacity var(--transition-fast);
}
.tab-btn:hover::before {
  opacity: 1;
}
.tab-btn:hover {
  border-color: var(--col-primary);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(59, 130, 246, 0.15);
}
.tab-btn.active {
  background: var(--gradient-primary);
  color: #fff;
  border-color: transparent;
  box-shadow: 0 4px 16px rgba(59, 130, 246, 0.4);
  transform: translateY(-2px);
}
.tab-btn.active::before {
  display: none;
}

/* 検索・ブックマーク */
.search-and-bookmarks {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 24px;
  flex-wrap: wrap;
  animation: staggerFadeIn 0.5s 0.2s cubic-bezier(0.4, 0, 0.2, 1) forwards;
  opacity: 0;
}
.search-container {
  display: flex;
  align-items: center;
  gap: 8px;
  flex: 1;
  min-width: 200px;
  max-width: 460px;
  position: relative;
}
.search-input {
  flex: 1;
  padding: 12px 16px 12px 42px;
  border: 2px solid var(--card-border);
  border-radius: 24px;
  font-size: 1rem;
  font-family: var(--font-base);
  transition: all var(--transition-normal);
  background: var(--card-bg);
  color: var(--col-text);
}
.search-input:focus {
  border-color: var(--col-primary);
  outline: none;
  box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.1);
}
.search-icon {
  position: absolute;
  left: 14px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--col-text-sub);
  font-size: 1rem;
  pointer-events: none;
}
.btn-clear-search {
  width: 40px;
  height: 40px;
  min-width: 44px;
  min-height: 44px;
  border: none;
  background: var(--col-primary-light);
  border-radius: 50%;
  cursor: pointer;
  font-size: 1rem;
  color: var(--col-text-sub);
  transition: all var(--transition-fast);
}
.btn-clear-search:hover {
  background: var(--col-primary);
  color: #fff;
}
.btn-bookmarks-link {
  padding: 10px 18px;
  background: var(--col-primary-light);
  color: var(--col-primary);
  border-radius: 24px;
  font-weight: 700;
  transition: all var(--transition-normal);
  white-space: nowrap;
  border: 1px solid transparent;
}
.btn-bookmarks-link:hover {
  background: var(--col-primary);
  color: #fff;
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}
.search-result-count {
  font-size: 0.9rem;
  color: var(--col-text-sub);
  margin-left: 4px;
}
.btn-retry {
  display: block;
  margin: 16px auto 0;
  padding: 10px 24px;
  font-size: 1rem;
  font-weight: 700;
  color: #fff;
  background: var(--col-primary);
  border: none;
  border-radius: 24px;
  cursor: pointer;
  transition: background 0.2s, transform 0.1s;
}
.btn-retry:hover {
  background: var(--col-primary-dark, #1d4ed8);
}
.btn-retry:focus-visible {
  outline: 2px solid var(--col-primary);
  outline-offset: 4px;
}
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}
.bookmarks-section {
  margin-top: 40px;
  padding: 24px;
  border: 1px solid var(--card-border);
  border-radius: 20px;
  background: var(--card-bg);
  box-shadow: var(--card-shadow);
}
.bookmarks-section h2 {
  font-size: 1.3rem;
  color: var(--col-text);
  margin-bottom: 16px;
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.bookmarks-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.bookmarks-list .prob-link {
  max-width: 100%;
}

/* コンテンツエリア */
.group-section {
  margin-bottom: 60px;
}
.group-title {
  font-size: 1.5rem;
  font-weight: bold;
  color: var(--col-text);
  margin-bottom: 20px;
  padding-left: 15px;
  border-left: 6px solid var(--col-primary);
  border-image: var(--gradient-primary) 1;
}

.subject-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: 30px;
}
.subject-card {
  background: var(--card-bg);
  border-radius: 24px;
  padding: 30px;
  box-shadow: var(--card-shadow);
  border: 1px solid var(--card-border);
  transition: all var(--transition-normal);
  animation: staggerFadeIn 0.5s cubic-bezier(0.4, 0, 0.2, 1) forwards;
  opacity: 0;
}
.subject-card:hover {
  box-shadow: 0 20px 40px -10px rgba(0, 0, 0, 0.1);
  transform: translateY(-2px);
}
.subject-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
  padding-bottom: 12px;
  margin-bottom: 20px;
  border-bottom: 2px solid var(--card-border);
}
.subject-name {
  font-size: 1.4rem;
  font-weight: 700;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin: 0;
}
.index-legend {
  font-size: 0.8rem;
  color: #64748b;
  flex-shrink: 0;
  white-space: nowrap;
}
.part-name {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--col-text-sub);
  margin: 20px 0 10px;
  padding-left: 10px;
  border-left: 4px solid var(--col-primary-light);
}

/* Part (編) Grouping */
.part-group {
  margin-bottom: 25px;
}
.part-title {
  font-size: 1.1rem;
  font-weight: bold;
  color: #475569;
  margin-bottom: 10px;
  padding: 6px 10px;
  background: #f1f5f9;
  border-radius: 8px;
}

/* --- 新レイアウト: 編グループヘッダー + 章カードグリッド --- */
.part-section {
  margin-bottom: 36px;
}
.part-section-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 18px;
  padding: 10px 16px;
  background: linear-gradient(135deg, var(--col-primary-light), #e0f2fe);
  border-radius: 14px;
  border-left: 5px solid var(--col-primary);
}
.part-section-title {
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--col-text);
  margin: 0;
  flex: 1;
}
.part-section-stats {
  font-size: 0.82rem;
  color: var(--col-text-sub);
  font-weight: 600;
  white-space: nowrap;
}
.part-section-progress {
  width: 64px;
  height: 5px;
  background: #e2e8f0;
  border-radius: 3px;
  overflow: hidden;
  flex-shrink: 0;
}
.part-section-progress-fill {
  height: 100%;
  background: var(--gradient-primary);
  border-radius: 3px;
}
.chapter-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 16px;
}
.chapter-card {
  background: var(--card-bg);
  border-radius: 16px;
  border: 1px solid var(--card-border);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
  overflow: hidden;
  transition: all var(--transition-normal);
  animation: staggerFadeIn 0.4s cubic-bezier(0.4, 0, 0.2, 1) forwards;
  opacity: 0;
}
.chapter-card:hover {
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
  transform: translateY(-2px);
  border-color: var(--col-primary);
}
.chapter-card-header {
  padding: 14px 16px;
  display: flex;
  align-items: center;
  gap: 10px;
  border-bottom: 1px solid var(--card-border);
  background: var(--col-bg);
  cursor: pointer;
  user-select: none;
}
.chapter-card-header::before {
  content: "▶";
  font-size: 0.65rem;
  color: var(--col-text-sub);
  transition: transform 0.2s;
  flex-shrink: 0;
}
.chapter-card.is-open .chapter-card-header::before {
  transform: rotate(90deg);
}
.chapter-card-name {
  flex: 1;
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--col-text);
  margin: 0;
  line-height: 1.3;
}
.chapter-card-meta {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
}
.chapter-card-progress {
  width: 48px;
  height: 4px;
  background: #e2e8f0;
  border-radius: 2px;
  overflow: hidden;
}
.chapter-card-progress-fill {
  height: 100%;
  background: var(--gradient-primary);
  border-radius: 2px;
}
.chapter-card-count {
  font-size: 0.78rem;
  color: #94a3b8;
  font-weight: 600;
  white-space: nowrap;
}
.chapter-card-body {
  padding: 12px 14px 14px;
  display: none;
}
.chapter-card.is-open .chapter-card-body {
  display: block;
}

/* 問題サブグループ（基本例題 / 基本問題 / 応用問題） */
.prob-subgroup {
  margin-bottom: 10px;
}
.prob-subgroup:last-child {
  margin-bottom: 0;
}
.prob-subgroup-label {
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--col-text-sub);
  margin-bottom: 5px;
  padding: 2px 8px;
  background: var(--col-bg);
  border-radius: 6px;
  display: inline-block;
}
.prob-subgroup-label--example {
  color: #7c3aed;
  background: #ede9fe;
}
.prob-subgroup-label--basic {
  color: #0369a1;
  background: #e0f2fe;
}
.prob-subgroup-label--applied {
  color: #c2410c;
  background: #fff7ed;
}
.prob-subgroup-label--exercise {
  color: #0f766e;
  background: #f0fdfa;
}

/* 地域グループヘッダー（入試） */
.region-section {
  margin-bottom: 32px;
}
.region-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
  padding: 8px 14px;
  background: linear-gradient(135deg, #fef3c7, #fde68a33);
  border-radius: 12px;
  border-left: 4px solid #f59e0b;
}
.region-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: #92400e;
  margin: 0;
}
.region-count {
  font-size: 0.8rem;
  color: #b45309;
  font-weight: 600;
}

.field-list {
  list-style: none;
  padding: 0;
  margin: 0;
}
.field-item {
  margin-bottom: 10px;
}
.field-details {
  border: 1px solid var(--card-border);
  border-radius: 12px;
  overflow: hidden;
  transition: all var(--transition-normal);
}
.field-details[open] {
  border-color: var(--col-primary);
  background: var(--gradient-card-hover);
  box-shadow: 0 2px 8px rgba(59, 130, 246, 0.08);
}
.field-summary {
  list-style: none;
  cursor: pointer;
  padding: 14px 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  font-size: 1rem;
  user-select: none;
  transition: all var(--transition-fast);
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--card-bg);
  box-shadow: 0 1px 0 0 var(--card-border);
}
.field-details[open] .field-summary {
  background: var(--col-primary-light);
}
.field-summary:hover {
  background: var(--col-primary-light);
}
.field-details[open] .field-summary:hover {
  background: var(--col-primary-light);
  filter: brightness(0.97);
}
.field-summary::-webkit-details-marker,
.field-summary::marker {
  display: none;
}
.field-summary::before {
  content: "▶";
  font-size: 0.7rem;
  color: var(--col-text-sub);
  transition: transform 0.2s;
  flex-shrink: 0;
}
.field-details[open] .field-summary::before {
  transform: rotate(90deg);
}
.field-name {
  font-weight: 700;
  color: var(--col-text);
  flex: 1;
  border-left: 4px solid #f43f5e;
  padding-left: 10px;
}
.field-count {
  font-size: 0.85rem;
  color: #94a3b8;
  font-weight: 500;
}
.field-body {
  padding: 12px 14px 14px 18px;
  border-top: 1px solid #f1f5f9;
}
.field-details[open] .field-body {
  border-top-color: #e2e8f0;
}
.field-body .prob-grid {
  margin-top: 10px;
}
.field-body .prob-empty {
  margin: 10px 0 4px 0;
}

.prob-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 5px;
}
.prob-link {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 6px 10px;
  background: var(--col-bg);
  border: 1px solid var(--card-border);
  border-radius: 10px;
  color: var(--col-text);
  font-weight: 500;
  text-decoration: none;
  transition: all var(--transition-normal);
  font-size: 0.88rem;
  position: relative;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.prob-link:hover {
  background: var(--col-primary-light);
  border-color: var(--col-primary);
  color: var(--col-primary);
  box-shadow: 0 2px 8px rgba(59, 130, 246, 0.12);
  transform: translateX(2px);
}

@keyframes recentOpenFlash {
  0% {
    background: #fff;
    box-shadow: 0 0 0 0 rgba(245, 158, 11, 0.0);
    border-color: var(--card-border);
  }
  20% {
    background: #fef3c7;
    box-shadow: 0 0 0 6px rgba(245, 158, 11, 0.22);
    border-color: #f59e0b;
  }
  100% {
    background: var(--col-bg);
    box-shadow: 0 0 0 0 rgba(245, 158, 11, 0.0);
    border-color: var(--card-border);
  }
}

.prob-link.recent-open-highlight {
  animation: recentOpenFlash 1.6s ease-out 1;
}
.prob-link-disabled {
  opacity: 0.5;
  cursor: not-allowed;
  pointer-events: none;
  background: #e2e8f0 !important;
  color: #94a3b8 !important;
}
.prob-link-disabled:hover {
  transform: none;
  box-shadow: none;
  background: #e2e8f0 !important;
  color: #94a3b8 !important;
}
/* 📖・📹 をまとめて右詰めで表示 */
.prob-marks-wrap {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-left: auto;
  flex-shrink: 0;
}
.prob-expl-mark,
.prob-video-mark {
  display: inline-flex;
  align-items: center;
  font-size: 0.9rem;
  flex-shrink: 0;
}
.prob-expl-mark { opacity: 0.9; }
.prob-video-mark { opacity: 0.85; }
.prob-link-video-only {
  background: #f8fafc !important;
  border: 1px solid #e2e8f0;
}
.prob-link-video-only:hover {
  background: #eff6ff !important;
  border-color: var(--col-primary-light) !important;
  color: var(--col-primary) !important;
  box-shadow: 0 2px 8px rgba(59, 130, 246, 0.08);
}

/* 生徒画面: HTML/動画がない問題はグレーアウト表示 */
.prob-item {
  display: flex;
  flex-direction: column;
  gap: 3px;
  min-width: 0;
}
.prob-item .prob-link {
  min-width: 0;
}
.prob-link-no-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 6px 10px;
  background: #e2e8f0 !important;
  border-radius: 10px;
  color: #94a3b8 !important;
  font-weight: 500;
  font-size: 0.88rem;
  cursor: default;
  opacity: 0.85;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.prob-mark-none {
  opacity: 0.4;
}
.prob-request-btns {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  align-items: center;
}
/* ボタンサイズは作成有無・リクエスト有無で変えない */
.btn-request {
  padding: 3px 7px;
  font-size: 0.72rem;
  border-radius: 6px;
  border: 1px solid #cbd5e1;
  background: #f8fafc;
  color: #475569;
  cursor: pointer;
  white-space: nowrap;
  min-width: 5.5em;
  box-sizing: border-box;
  transition: background 0.2s, color 0.2s;
}
.btn-request:hover {
  background: #e2e8f0;
  color: #1e293b;
}
.btn-request.btn-request-done {
  cursor: pointer;
  opacity: 0.95;
}
.btn-request.btn-request-created {
  cursor: default;
  pointer-events: none;
  opacity: 0.75;
  border-color: #cbd5e1 !important;
  background: #e2e8f0 !important;
  color: #64748b !important;
}
.btn-request-created.btn-request-html { border-color: #cbd5e1 !important; background: #e2e8f0 !important; color: #64748b !important; }
.btn-request-created.btn-request-video { border-color: #cbd5e1 !important; background: #e2e8f0 !important; color: #64748b !important; }
.btn-request-html { border-color: #93c5fd; background: #eff6ff; color: #1d4ed8; }
.btn-request-html:hover:not(.btn-request-created) { background: #dbeafe; }
.btn-request-video { border-color: #fcd34d; background: #fffbeb; color: #b45309; }
.btn-request-video:hover:not(.btn-request-created) { background: #fef3c7; }

.prob-empty {
  color: #94a3b8;
  font-size: 0.85rem;
  padding: 6px 10px;
  font-style: italic;
}

/* 教員画面: コンテンツ作成リクエスト一覧 */
.content-requests-section {
  margin-bottom: 24px;
  padding: 16px 20px;
  background: var(--col-bg);
  border: 1px solid var(--card-border);
  border-radius: 16px;
  transition: all var(--transition-normal);
}
.content-requests-heading {
  font-size: 1.1rem;
  margin: 0 0 12px 0;
  color: #475569;
}
.content-requests-list { font-size: 0.9rem; }
.content-requests-ul { list-style: none; padding: 0; margin: 0; }
.content-requests-li {
  padding: 8px 0;
  border-bottom: 1px solid #e2e8f0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}
.content-requests-li:last-child { border-bottom: none; }
.content-requests-type {
  padding: 2px 8px;
  border-radius: 6px;
  font-size: 0.75rem;
  font-weight: 600;
}
.content-requests-type-html { background: #dbeafe; color: #1d4ed8; }
.content-requests-type-video { background: #fef3c7; color: #b45309; }
.content-requests-title { font-weight: 500; color: var(--col-text); }
.content-requests-meta { color: #64748b; font-size: 0.85rem; }
.content-requests-time { color: #94a3b8; font-size: 0.8rem; margin-left: auto; }
.content-requests-empty { color: #94a3b8; margin: 0; }

.empty-msg {
  text-align: center;
  color: var(--col-text-sub);
  padding: 40px 20px;
  background: var(--col-bg);
  border-radius: 16px;
  border: 2px dashed var(--card-border);
  font-size: 1.05rem;
}

/* 検索結果件数 */
.search-result-count {
  font-size: 0.9rem;
  color: var(--col-text-sub);
  margin-left: 4px;
  font-weight: 600;
}
.search-result-count:not(:empty)::before {
  content: '';
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--col-success);
  margin-right: 6px;
  vertical-align: middle;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* --- フィールド進捗バー --- */
.field-progress-wrap {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
}
.field-progress-bar {
  width: 56px;
  height: 5px;
  background: #e2e8f0;
  border-radius: 3px;
  overflow: hidden;
  flex-shrink: 0;
}
.field-progress-fill {
  display: block;
  height: 100%;
  background: var(--gradient-primary);
  border-radius: 3px;
  transition: width 0.3s ease;
}

/* --- サブジェクト進捗バー --- */
.subject-progress {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 16px;
}
.subject-progress-bar {
  flex: 1;
  height: 7px;
  background: #e2e8f0;
  border-radius: 4px;
  overflow: hidden;
}
.subject-progress-fill {
  height: 100%;
  background: var(--gradient-primary);
  border-radius: 4px;
  transition: width 0.5s ease;
}
.subject-progress-text {
  font-size: 0.78rem;
  color: var(--col-text-sub);
  font-weight: 600;
  white-space: nowrap;
}

/* --- 折りたたみサブジェクトカード（入試系） --- */
.subject-card-collapsible {
  background: var(--card-bg);
  border-radius: 24px;
  padding: 0;
  box-shadow: var(--card-shadow);
  border: 1px solid var(--card-border);
  transition: all var(--transition-normal);
  animation: staggerFadeIn 0.5s cubic-bezier(0.4, 0, 0.2, 1) forwards;
  opacity: 0;
}
.subject-card-collapsible:hover {
  box-shadow: 0 20px 40px -10px rgba(0, 0, 0, 0.1);
}
.subject-card-summary {
  list-style: none;
  cursor: pointer;
  padding: 18px 24px;
  display: flex;
  align-items: center;
  gap: 12px;
  user-select: none;
  border-radius: 24px;
  transition: background var(--transition-fast);
}
.subject-card-summary::-webkit-details-marker,
.subject-card-summary::marker {
  display: none;
}
.subject-card-summary::before {
  content: "▶";
  font-size: 0.75rem;
  color: var(--col-text-sub);
  transition: transform 0.2s;
  flex-shrink: 0;
}
.subject-card-collapsible[open] > .subject-card-summary::before {
  transform: rotate(90deg);
}
.subject-card-summary:hover {
  background: var(--col-primary-light);
}
.subject-card-summary .subject-name {
  flex: 1;
  font-size: 1.2rem;
}
.subject-summary-meta {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
}
.subject-summary-stats {
  font-size: 0.78rem;
  color: var(--col-text-sub);
  font-weight: 600;
  background: var(--col-primary-light);
  padding: 2px 10px;
  border-radius: 12px;
  white-space: nowrap;
}
.subject-summary-progress {
  width: 48px;
  height: 5px;
  background: #e2e8f0;
  border-radius: 3px;
  overflow: hidden;
  flex-shrink: 0;
}
.subject-summary-progress-fill {
  height: 100%;
  background: var(--gradient-primary);
  border-radius: 3px;
}
.subject-card-body {
  padding: 0 24px 24px;
}

/* モバイル対応 */
@media (max-width: 768px) {
  body {
    padding: 10px;
  }

  .main-header {
    margin-bottom: 30px;
    gap: 8px;
  }

  h1 {
    font-size: 1.8rem;
    margin: 0;
  }

  .material-tabs {
    gap: 10px;
    margin-bottom: 30px;
  }

  .tab-btn {
    padding: 10px 16px;
    font-size: 0.95rem;
    min-width: 120px;
    min-height: 44px; /* タッチターゲットサイズ確保 */
  }

  .subject-grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .subject-card {
    padding: 20px;
  }

  .prob-grid {
    grid-template-columns: 1fr;
  }
  .prob-link {
    min-height: 44px; /* タッチターゲットサイズ確保 */
    padding: 10px 14px;
    font-size: 0.92rem;
  }
  .subject-card-summary {
    padding: 14px 18px;
  }
  .subject-card-body {
    padding: 0 18px 18px;
  }
  .chapter-grid {
    grid-template-columns: 1fr;
    gap: 12px;
  }
  .chapter-card-header {
    min-height: 44px;
    padding: 12px 14px;
  }
  .part-section-header {
    padding: 8px 12px;
  }
  .part-section-title {
    font-size: 1.05rem;
  }
}

/* --- QRコード (追加) --- */
.qr-trigger {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
  padding: 10px;
  min-width: 44px;
  min-height: 44px;
  border: none;
  background: var(--col-primary-light);
  border-radius: 50%;
  cursor: pointer;
  color: var(--col-text-sub);
  transition: all var(--transition-normal);
  font-size: 1.2rem;
  line-height: 1;
}
.qr-trigger:hover {
  background: var(--col-primary);
  color: #fff;
  transform: scale(1.1);
}
.qr-trigger-icon {
  font-size: 1.2rem;
}

.qr-modal {
  position: fixed;
  inset: 0;
  z-index: 10000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  pointer-events: none;
  visibility: hidden;
  opacity: 0;
  transition: visibility 0.2s, opacity 0.2s;
}
.qr-modal.is-open {
  pointer-events: auto;
  visibility: visible;
  opacity: 1;
}
.qr-modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
}
.qr-modal-content {
  position: relative;
  background: var(--card-bg);
  border-radius: 20px;
  padding: 28px 32px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.25);
  max-width: 100%;
  text-align: center;
  animation: pageEnter 0.3s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}
.qr-modal-close {
  position: absolute;
  top: 12px;
  right: 12px;
  width: 36px;
  height: 36px;
  border: none;
  background: var(--col-primary-light);
  color: var(--col-text-sub);
  font-size: 1.5rem;
  line-height: 1;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}
.qr-modal-close:hover {
  background: var(--col-primary);
  color: #fff;
}
.qr-modal-title {
  margin: 0 0 20px;
  font-size: 1rem;
  color: var(--col-text-sub);
}
.qr-modal-canvas-wrap {
  width: 220px;
  height: 220px;
  margin: 0 auto 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #fff;
  border: 1px solid #e2e8f0;
  border-radius: 12px;
  overflow: hidden;
}
.qr-modal-canvas-wrap canvas,
.qr-modal-canvas-wrap img {
  max-width: 100%;
  max-height: 100%;
  width: 200px;
  height: 200px;
  object-fit: contain;
  display: block;
}
.qr-modal-url {
  margin: 0;
  font-size: 0.75rem;
  color: var(--col-text-sub);
  word-break: break-all;
  max-width: 280px;
  margin-left: auto;
  margin-right: auto;
}

/* --- コンテンツフィルタバー --- */
.content-filter-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 0;
  margin-bottom: 16px;
  flex-wrap: wrap;
}
.content-filter-label {
  font-size: 0.85rem;
  color: var(--col-text-sub);
  font-weight: 600;
}
.content-filter-btn {
  padding: 6px 14px;
  border: 1px solid #e2e8f0;
  border-radius: 20px;
  background: #fff;
  color: var(--col-text-sub);
  font-size: 0.82rem;
  cursor: pointer;
  transition: all 0.15s ease;
  white-space: nowrap;
}
.content-filter-btn:hover {
  border-color: var(--col-primary);
  color: var(--col-primary);
}
.content-filter-btn.active {
  background: var(--col-primary);
  color: #fff;
  border-color: var(--col-primary);
}
.content-filter-count {
  font-size: 0.75rem;
  opacity: 0.7;
}