/* ================================================================
   考題練習系統 v2 - 網頁版樣式
   設計：深色主題，桌面優先，舒適閱讀
================================================================ */

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg-body:    #12151f;
  --bg-sidebar: #1a1f2e;
  --bg-main:    #1e2333;
  --bg-card:    #252b3b;
  --bg-card-hover: #2d3347;
  --bg-input:   #1a1f2e;

  --accent:     #4a90d9;
  --accent-hover: #3a7bc8;
  --green:      #4caf50;
  --red:        #e53935;
  --yellow:     #f5a623;

  --text-1: #e8eaf0;
  --text-2: #9aa0b4;
  --text-3: #6b7280;
  --border: #2e3450;

  --opt-correct-bg:     #162a1e;
  --opt-correct-border: #4caf50;
  --opt-wrong-bg:       #2a1616;
  --opt-wrong-border:   #e53935;
  --opt-selected-bg:    #1a2640;
  --opt-selected-border:#4a90d9;

  --sidebar-w: 260px;
  --header-h:  56px;
  --radius:    10px;
  --shadow:    0 2px 12px rgba(0,0,0,0.35);
}

html { font-size: 16px; }
body {
  background: var(--bg-body);
  color: var(--text-1);
  font-family: 'Noto Sans TC', 'Microsoft JhengHei', sans-serif;
  min-height: 100vh;
  line-height: 1.6;
}

/* ================================================================
   頁面切換
================================================================ */
.page { display: none; }
.page.active { display: block; }

/* ================================================================
   通用：頂部導航列（所有頁面共用）
================================================================ */
#top-nav {
  position: sticky; top: 0; z-index: 100;
  background: var(--bg-sidebar);
  border-bottom: 1px solid var(--border);
  height: var(--header-h);
  display: flex; align-items: center;
  padding: 0 24px; gap: 16px;
}
#top-nav .nav-brand {
  font-size: 18px; font-weight: 700; color: var(--text-1);
  display: flex; align-items: center; gap: 8px;
  text-decoration: none; white-space: nowrap;
}
#top-nav .nav-brand i { color: var(--accent); }
#top-nav .nav-links {
  display: flex; align-items: center; gap: 4px; flex: 1;
}
#top-nav .nav-link {
  padding: 7px 14px; border-radius: 8px;
  background: none; border: none; cursor: pointer;
  color: var(--text-2); font-size: 14px; font-weight: 500;
  transition: background 0.15s, color 0.15s;
  display: flex; align-items: center; gap: 6px;
}
#top-nav .nav-link:hover { background: var(--bg-card); color: var(--text-1); }
#top-nav .nav-link.active { background: var(--bg-card); color: var(--accent); }
#top-nav .nav-right { margin-left: auto; display: flex; gap: 8px; }

/* ================================================================
   頁面容器
================================================================ */
.page-wrap {
  max-width: 1200px;
  margin: 0 auto;
  padding: 32px 24px 60px;
}
.page-wrap-narrow {
  max-width: 860px;
  margin: 0 auto;
  padding: 32px 24px 60px;
}

/* ================================================================
   首頁：科目列表（兩欄 Grid）
================================================================ */
.subjects-header {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 24px;
}
.subjects-header h2 {
  font-size: 22px; font-weight: 700; color: var(--text-1);
}
.subjects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 16px;
}
.subject-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 22px;
  cursor: pointer;
  transition: border-color 0.15s, box-shadow 0.15s, transform 0.1s;
}
.subject-card:hover {
  border-color: var(--accent);
  box-shadow: 0 0 0 1px var(--accent), var(--shadow);
  transform: translateY(-1px);
}
.subject-card-name {
  font-size: 17px; font-weight: 600; color: var(--text-1);
  margin-bottom: 12px;
}
.subject-card-meta {
  font-size: 13px; color: var(--text-3); margin-bottom: 10px;
  display: flex; gap: 12px;
}
.progress-bar-bg {
  height: 5px; background: var(--border); border-radius: 3px; overflow: hidden;
}
.progress-bar-fill {
  height: 100%; background: var(--accent); border-radius: 3px;
  transition: width 0.4s ease;
}
.progress-pct {
  font-size: 12px; color: var(--text-3); text-align: right; margin-top: 4px;
}

/* ================================================================
   章節列表頁（兩欄：左側章節，右側設定）
================================================================ */
.chapter-layout {
  display: grid;
  grid-template-columns: 1fr 340px;
  gap: 24px;
  align-items: start;
}
@media (max-width: 900px) {
  .chapter-layout { grid-template-columns: 1fr; }
}
.chapter-list-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}
.chapter-list-header {
  padding: 16px 20px;
  border-bottom: 1px solid var(--border);
  display: flex; align-items: center; justify-content: space-between;
}
.chapter-list-title {
  font-size: 16px; font-weight: 600; color: var(--text-1);
}
.chapter-item {
  display: flex; align-items: center; justify-content: space-between;
  padding: 14px 20px;
  border-bottom: 1px solid var(--border);
  cursor: pointer;
  transition: background 0.15s;
}
.chapter-item:last-child { border-bottom: none; }
.chapter-item:hover { background: var(--bg-card-hover); }
.chapter-item.selected { background: var(--opt-selected-bg); border-left: 3px solid var(--accent); }
.chapter-name { font-size: 15px; color: var(--text-1); }
.chapter-pct {
  font-size: 13px; color: var(--yellow);
  display: flex; align-items: center; gap: 4px;
}

/* 右側設定卡 */
.setup-panel {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  position: sticky; top: calc(var(--header-h) + 16px);
}
.setup-panel-header {
  padding: 16px 20px;
  border-bottom: 1px solid var(--border);
  font-size: 15px; font-weight: 600; color: var(--text-1);
}
.setup-row {
  display: flex; align-items: center; justify-content: space-between;
  padding: 13px 20px;
  border-bottom: 1px solid var(--border);
  gap: 12px;
}
.setup-row:last-of-type { border-bottom: none; }
.setup-label { font-size: 14px; color: var(--text-2); white-space: nowrap; }
.setup-select {
  background: var(--bg-input); color: var(--text-1);
  border: 1px solid var(--border); border-radius: 7px;
  padding: 6px 10px; font-size: 13px;
  outline: none; cursor: pointer; min-width: 130px;
  transition: border-color 0.15s;
}
.setup-select:focus { border-color: var(--accent); }
.btn-start {
  display: block; width: calc(100% - 40px);
  margin: 16px 20px;
  padding: 13px;
  background: var(--accent); color: white;
  border: none; border-radius: 8px;
  font-size: 15px; font-weight: 600; cursor: pointer;
  transition: background 0.15s;
}
.btn-start:hover { background: var(--accent-hover); }

/* ================================================================
   答題頁面（三欄：左側資訊 + 中間題目 + 右側工具）
================================================================ */
#page-quiz { display: none; }
#page-quiz.active { display: block; }

.quiz-layout {
  max-width: 1100px;
  margin: 0 auto;
  padding: 24px 24px 40px;
  display: grid;
  grid-template-columns: 220px 1fr 200px;
  gap: 24px;
  align-items: start;
}
@media (max-width: 1000px) {
  .quiz-layout { grid-template-columns: 1fr; }
  .quiz-sidebar-left, .quiz-sidebar-right { display: none; }
}

/* 左側：進度資訊 */
.quiz-sidebar-left {
  position: sticky; top: calc(var(--header-h) + 16px);
}
.quiz-info-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
}
.quiz-info-title {
  font-size: 14px; font-weight: 600; color: var(--text-1);
  margin-bottom: 14px; line-height: 1.4;
}
.quiz-progress-ring-wrap {
  display: flex; justify-content: center; margin-bottom: 16px;
}
.quiz-progress-ring {
  width: 80px; height: 80px;
  border-radius: 50%;
  background: conic-gradient(var(--accent) 0%, var(--border) 0%);
  display: flex; align-items: center; justify-content: center;
  position: relative;
}
.quiz-progress-ring::before {
  content: ''; position: absolute;
  width: 60px; height: 60px;
  background: var(--bg-card); border-radius: 50%;
}
.quiz-progress-text {
  position: relative; z-index: 1;
  font-size: 15px; font-weight: 700; color: var(--text-1);
}
.quiz-stat-row {
  display: flex; justify-content: space-between;
  font-size: 13px; padding: 5px 0;
  border-bottom: 1px solid var(--border);
}
.quiz-stat-row:last-child { border-bottom: none; }
.quiz-stat-label { color: var(--text-3); }
.quiz-stat-val { color: var(--text-1); font-weight: 500; }
.quiz-stat-val.green { color: var(--green); }
.quiz-stat-val.red { color: var(--red); }

/* 中間：題目主體 */
.quiz-main-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}
.quiz-card-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 14px 20px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-sidebar);
}
.quiz-card-title {
  font-size: 14px; color: var(--text-2); font-weight: 500;
}
.quiz-card-badge {
  font-size: 13px; color: var(--text-3);
  background: var(--bg-input); padding: 3px 10px; border-radius: 12px;
}
.quiz-toolbar {
  display: flex; align-items: center; gap: 4px;
  padding: 8px 16px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-sidebar);
  flex-wrap: wrap;
}
.toolbar-btn {
  width: 34px; height: 34px;
  display: flex; align-items: center; justify-content: center;
  background: none; border: none; cursor: pointer;
  color: var(--text-2); font-size: 15px;
  border-radius: 7px;
  transition: background 0.15s, color 0.15s;
}
.toolbar-btn:hover { background: var(--bg-card-hover); color: var(--text-1); }
.toolbar-btn.active { color: var(--yellow); }
.toolbar-btn.active-heart { color: var(--red); }
.toolbar-sep { width: 1px; height: 20px; background: var(--border); margin: 0 4px; }

/* 題目文字 */
.quiz-question-wrap { padding: 28px 28px 20px; }
.question-text {
  font-size: 18px; line-height: 1.8;
  color: var(--text-1); font-weight: 400;
  margin-bottom: 8px;
}
.question-text.font-lg { font-size: 21px; }
.question-text.font-sm { font-size: 15px; }
.multi-hint {
  font-size: 13px; color: var(--accent);
  margin-bottom: 16px;
  display: flex; align-items: center; gap: 5px;
}

/* 選項 */
.options-list { padding: 0 20px 20px; display: flex; flex-direction: column; gap: 10px; }
.option-item {
  display: flex; align-items: center; gap: 14px;
  padding: 14px 18px;
  border: 1px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
  background: var(--bg-input);
}
.option-item:hover { border-color: var(--accent); background: var(--opt-selected-bg); }
.option-label {
  font-size: 15px; color: var(--text-3);
  min-width: 40px; font-weight: 600;
  background: var(--bg-card); border-radius: 5px;
  padding: 2px 8px; text-align: center;
  flex-shrink: 0;
}
.option-text { font-size: 16px; color: var(--text-1); flex: 1; line-height: 1.5; }
.option-icon { font-size: 18px; flex-shrink: 0; }

/* 選項狀態 */
.option-item.correct {
  background: var(--opt-correct-bg);
  border-color: var(--opt-correct-border);
}
.option-item.correct .option-label { background: var(--opt-correct-border); color: white; }
.option-item.correct .option-text { color: var(--green); }
.option-item.wrong {
  background: var(--opt-wrong-bg);
  border-color: var(--opt-wrong-border);
}
.option-item.wrong .option-label { background: var(--opt-wrong-border); color: white; }
.option-item.wrong .option-text { color: var(--red); }
.option-item.selected {
  background: var(--opt-selected-bg);
  border-color: var(--opt-selected-border);
}
.option-item.selected .option-label { background: var(--accent); color: white; }

/* 是非題特殊樣式：○/✕ 標籤更大 */
.option-item .option-label.tf-label {
  font-size: 20px; min-width: 44px;
  background: none; padding: 0;
}

/* 解釋說明 */
.explanation-box {
  margin: 0 20px 20px;
  background: #162030;
  border-left: 3px solid var(--accent);
  border-radius: 8px;
  padding: 14px 16px;
  font-size: 14px; color: var(--text-2); line-height: 1.7;
}
.explanation-title {
  color: var(--accent); font-weight: 600; margin-bottom: 6px;
  font-size: 13px; display: flex; align-items: center; gap: 5px;
}

/* 底部導航 */
.quiz-nav-bar {
  display: flex; align-items: center; justify-content: space-between;
  padding: 14px 20px;
  border-top: 1px solid var(--border);
  background: var(--bg-sidebar);
  gap: 10px;
}
.quiz-nav-btn {
  padding: 9px 24px;
  border: 1px solid var(--border); border-radius: 8px;
  background: var(--bg-input); color: var(--text-2);
  font-size: 14px; font-weight: 500; cursor: pointer;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
  display: flex; align-items: center; gap: 6px;
}
.quiz-nav-btn:hover { background: var(--bg-card-hover); color: var(--text-1); }
.quiz-nav-btn:disabled { opacity: 0.35; cursor: not-allowed; }
.quiz-nav-btn.primary {
  background: var(--accent); color: white; border-color: var(--accent);
}
.quiz-nav-btn.primary:hover { background: var(--accent-hover); }
.quiz-nav-btn.danger {
  border-color: var(--red); color: var(--red);
}
.quiz-nav-btn.danger:hover { background: var(--opt-wrong-bg); }
.quiz-nav-center { display: flex; align-items: center; gap: 8px; }
.quiz-footer-id { font-size: 12px; color: var(--text-3); }

/* 右側：快速跳題 */
.quiz-sidebar-right {
  position: sticky; top: calc(var(--header-h) + 16px);
}
.quiz-jump-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px;
}
.quiz-jump-title {
  font-size: 13px; color: var(--text-3); margin-bottom: 10px; font-weight: 600;
}
.quiz-jump-grid {
  display: grid; grid-template-columns: repeat(5, 1fr); gap: 5px;
}
.jump-btn {
  aspect-ratio: 1; border: 1px solid var(--border);
  border-radius: 5px; background: var(--bg-input);
  color: var(--text-2); font-size: 12px; cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: background 0.1s, color 0.1s;
}
.jump-btn:hover { background: var(--accent); color: white; border-color: var(--accent); }
.jump-btn.current { background: var(--accent); color: white; border-color: var(--accent); }
.jump-btn.answered-correct { background: var(--opt-correct-bg); border-color: var(--opt-correct-border); color: var(--green); }
.jump-btn.answered-wrong { background: var(--opt-wrong-bg); border-color: var(--opt-wrong-border); color: var(--red); }

/* ================================================================
   結果頁面
================================================================ */
.result-layout {
  max-width: 700px; margin: 0 auto;
  padding: 40px 24px 60px;
}
.result-header-title {
  text-align: center; font-size: 20px; font-weight: 700;
  color: var(--text-1); margin-bottom: 32px;
}
.result-top {
  display: flex; align-items: center; justify-content: center;
  gap: 40px; margin-bottom: 32px; flex-wrap: wrap;
}
.result-circle {
  width: 160px; height: 160px; border-radius: 50%;
  background: var(--bg-card); border: 5px solid var(--bg-card-hover, #353b52);
  display: flex; flex-direction: column;
  align-items: center; justify-content: center; gap: 2px;
  flex-shrink: 0;
}
.result-circle-label { font-size: 13px; color: var(--text-3); }
.result-circle-value { font-size: 56px; font-weight: 800; color: var(--text-1); line-height: 1; }
.result-circle-unit { font-size: 18px; color: var(--text-2); }
.result-meta { display: flex; flex-direction: column; gap: 10px; }
.result-meta-row {
  display: flex; align-items: center; gap: 10px;
  font-size: 15px; color: var(--text-2);
}
.result-meta-row i { width: 20px; text-align: center; }
.result-message {
  text-align: center; font-size: 20px; font-weight: 600;
  color: var(--text-1); margin-bottom: 24px;
}
.result-stats-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 20px 24px;
  display: flex; flex-direction: column; gap: 16px;
  margin-bottom: 32px;
}
.result-stat-row { display: flex; align-items: center; gap: 14px; }
.stat-icon { font-size: 18px; min-width: 24px; text-align: center; }
.stat-correct { color: var(--accent); }
.stat-wrong { color: var(--red); }
.stat-star { color: var(--yellow); }
.stat-bar-wrap {
  flex: 1; height: 8px; background: var(--border);
  border-radius: 4px; overflow: hidden;
}
.stat-bar { height: 100%; border-radius: 4px; transition: width 0.6s ease; }
.stat-bar-correct { background: var(--accent); }
.stat-bar-wrong { background: var(--red); }
.stat-bar-star { background: var(--yellow); }
.stat-count {
  font-size: 15px; color: var(--text-2);
  min-width: 70px; text-align: right;
  display: flex; align-items: center; gap: 5px; justify-content: flex-end;
}
.stat-delta { color: var(--yellow); font-size: 13px; }
.result-actions {
  display: flex; gap: 12px; justify-content: center; flex-wrap: wrap;
}
.result-btn {
  padding: 11px 28px; border-radius: 8px;
  border: 1px solid var(--border); background: var(--bg-card);
  color: var(--text-1); font-size: 15px; font-weight: 500; cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
  min-width: 120px;
}
.result-btn:hover { background: var(--bg-card-hover); }
.result-btn.primary { background: var(--accent); border-color: var(--accent); color: white; }
.result-btn.primary:hover { background: var(--accent-hover); }
.result-btn:disabled { opacity: 0.4; cursor: not-allowed; }

/* ================================================================
   題庫管理頁
================================================================ */
.manage-toolbar {
  display: flex; align-items: center; gap: 10px;
  margin-bottom: 16px; flex-wrap: wrap;
}
.search-bar {
  display: flex; align-items: center;
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: 8px; padding: 0 12px; flex: 1; min-width: 200px;
}
.search-icon { color: var(--text-3); font-size: 14px; margin-right: 8px; }
.search-input {
  flex: 1; background: none; border: none; outline: none;
  color: var(--text-1); font-size: 14px; padding: 10px 0;
}
.filter-select {
  background: var(--bg-card); color: var(--text-1);
  border: 1px solid var(--border); border-radius: 8px;
  padding: 9px 12px; font-size: 13px; outline: none; cursor: pointer;
}
.manage-list { display: flex; flex-direction: column; gap: 8px; }
.manage-item {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: 8px; padding: 14px 16px;
  transition: border-color 0.15s;
}
.manage-item:hover { border-color: var(--accent); }
.manage-item-header {
  display: flex; align-items: flex-start; justify-content: space-between; gap: 10px;
}
.manage-item-q {
  font-size: 14px; color: var(--text-1); flex: 1; line-height: 1.5;
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden;
}
.manage-item-actions { display: flex; gap: 6px; flex-shrink: 0; }
.manage-item-btn {
  width: 30px; height: 30px; background: var(--bg-input);
  border: 1px solid var(--border); border-radius: 6px;
  color: var(--text-3); font-size: 13px; cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: color 0.15s, border-color 0.15s;
}
.manage-item-btn:hover { color: var(--text-1); border-color: var(--text-2); }
.manage-item-btn.delete:hover { color: var(--red); border-color: var(--red); }
.manage-item-tags { display: flex; gap: 6px; margin-top: 8px; flex-wrap: wrap; }
.tag {
  font-size: 11px; padding: 2px 8px; border-radius: 10px;
  background: var(--bg-input); color: var(--text-3);
}
.tag-subject { background: #162030; color: var(--accent); }
.tag-type { background: #162016; color: var(--green); }
.pagination {
  display: flex; justify-content: center; gap: 6px; margin-top: 20px; flex-wrap: wrap;
}
.page-btn {
  min-width: 34px; height: 34px; padding: 0 8px;
  background: var(--bg-card); color: var(--text-2);
  border: 1px solid var(--border); border-radius: 6px;
  font-size: 13px; cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: background 0.15s;
}
.page-btn.active { background: var(--accent); color: white; border-color: var(--accent); }
.page-btn:hover:not(.active) { background: var(--bg-card-hover); }

/* ================================================================
   設定頁面
================================================================ */
.settings-layout {
  max-width: 700px; margin: 0 auto; padding: 32px 24px 60px;
}
.settings-section {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius); margin-bottom: 20px; overflow: hidden;
}
.settings-section-title {
  font-size: 12px; color: var(--text-3); text-transform: uppercase;
  letter-spacing: 0.8px; padding: 12px 18px 10px;
  border-bottom: 1px solid var(--border); font-weight: 600;
}
.settings-item {
  display: flex; align-items: center; justify-content: space-between;
  padding: 15px 18px; border-bottom: 1px solid var(--border);
}
.settings-item:last-child { border-bottom: none; }
.settings-item-info { flex: 1; }
.settings-item-name { font-size: 15px; color: var(--text-1); }
.settings-item-desc { font-size: 12px; color: var(--text-3); margin-top: 2px; }
.toggle { position: relative; display: inline-block; width: 46px; height: 26px; }
.toggle input { opacity: 0; width: 0; height: 0; }
.toggle-slider {
  position: absolute; inset: 0;
  background: var(--border); border-radius: 13px; cursor: pointer;
  transition: background 0.2s;
}
.toggle-slider::before {
  content: ''; position: absolute;
  width: 20px; height: 20px; border-radius: 50%;
  background: white; left: 3px; top: 3px;
  transition: transform 0.2s;
}
.toggle input:checked + .toggle-slider { background: var(--accent); }
.toggle input:checked + .toggle-slider::before { transform: translateX(20px); }
.settings-action-btn {
  width: 100%; padding: 14px 18px;
  background: none; border: none; border-bottom: 1px solid var(--border);
  color: var(--text-1); font-size: 14px; text-align: left; cursor: pointer;
  display: flex; align-items: center; gap: 10px;
  transition: background 0.15s;
}
.settings-action-btn:last-child { border-bottom: none; }
.settings-action-btn:hover { background: var(--bg-card-hover); }
.settings-action-btn.danger { color: var(--red); }
.settings-about { padding: 20px; text-align: center; }
.about-name { font-size: 17px; color: var(--text-1); font-weight: 700; }
.about-version { font-size: 13px; color: var(--text-3); margin-top: 4px; }

/* ================================================================
   彈窗（置中，非底部滑出）
================================================================ */
.modal-overlay {
  position: fixed; inset: 0;
  background: rgba(0,0,0,0.65);
  z-index: 500;
  display: flex; align-items: center; justify-content: center;
  padding: 20px;
}
.modal-overlay.hidden { display: none; }
.modal-box {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: 14px; padding: 28px 28px 24px;
  width: 100%; max-width: 360px;
  box-shadow: 0 8px 40px rgba(0,0,0,0.5);
}
.modal-box-title {
  font-size: 17px; font-weight: 600; color: var(--text-1);
  text-align: center; margin-bottom: 20px;
}
.modal-sheet {
  background: var(--bg-sidebar); border: 1px solid var(--border);
  border-radius: 14px;
  width: 100%; max-width: 600px; max-height: 85vh;
  display: flex; flex-direction: column;
  box-shadow: 0 8px 40px rgba(0,0,0,0.5);
}
.modal-sheet-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 16px 20px; border-bottom: 1px solid var(--border); flex-shrink: 0;
}
.modal-sheet-title { font-size: 16px; font-weight: 600; color: var(--text-1); }
.modal-close-btn {
  background: none; border: none; cursor: pointer;
  color: var(--text-3); font-size: 18px; width: 32px; height: 32px;
  display: flex; align-items: center; justify-content: center;
  border-radius: 6px; transition: background 0.15s;
}
.modal-close-btn:hover { background: var(--bg-card); color: var(--text-1); }
.modal-sheet-body { flex: 1; overflow-y: auto; padding: 18px 20px; }
.modal-sheet-footer {
  display: flex; gap: 10px; padding: 14px 20px;
  border-top: 1px solid var(--border); flex-shrink: 0;
}
.btn-modal {
  flex: 1; height: 42px; border: none; border-radius: 8px;
  font-size: 15px; font-weight: 600; cursor: pointer;
  transition: background 0.15s;
}
.btn-modal-no { background: var(--bg-input); color: var(--text-2); border: 1px solid var(--border); }
.btn-modal-no:hover { background: var(--bg-card-hover); }
.btn-modal-yes { background: var(--accent); color: white; }
.btn-modal-yes:hover { background: var(--accent-hover); }
.btn-primary {
  flex: 1; height: 42px; background: var(--accent); color: white;
  border: none; border-radius: 8px; font-size: 14px; font-weight: 600; cursor: pointer;
  transition: background 0.15s;
}
.btn-primary:hover { background: var(--accent-hover); }
.btn-secondary {
  flex: 1; height: 42px; background: var(--bg-input); color: var(--text-1);
  border: 1px solid var(--border); border-radius: 8px; font-size: 14px; cursor: pointer;
  transition: background 0.15s;
}
.btn-secondary:hover { background: var(--bg-card-hover); }
.form-group { margin-bottom: 14px; }
.form-label { font-size: 13px; color: var(--text-3); margin-bottom: 6px; display: block; }
.setup-input {
  background: var(--bg-input); color: var(--text-1);
  border: 1px solid var(--border); border-radius: 7px;
  padding: 9px 12px; font-size: 14px; width: 100%; outline: none;
  transition: border-color 0.15s;
}
.setup-input:focus { border-color: var(--accent); }
.setup-textarea {
  background: var(--bg-input); color: var(--text-1);
  border: 1px solid var(--border); border-radius: 7px;
  padding: 9px 12px; font-size: 14px; width: 100%;
  outline: none; resize: vertical; min-height: 80px;
  transition: border-color 0.15s;
}
.setup-textarea:focus { border-color: var(--accent); }
.import-textarea {
  width: 100%; min-height: 180px; resize: vertical;
  background: var(--bg-body); color: var(--text-1);
  border: 1px solid var(--border); border-radius: 8px;
  padding: 10px 12px; font-size: 13px; outline: none;
  font-family: 'Courier New', monospace; line-height: 1.6;
  transition: border-color 0.15s;
}
.import-textarea:focus { border-color: var(--accent); }
.import-preview {
  background: var(--bg-body); border: 1px solid var(--border);
  border-radius: 8px; padding: 10px 12px; margin-top: 10px;
  font-size: 13px; color: var(--text-2); max-height: 180px; overflow-y: auto;
}
.import-subject-row, .import-label { margin-bottom: 10px; }
.import-label { font-size: 13px; color: var(--text-3); display: block; margin-bottom: 5px; }
.edit-option-row { display: flex; gap: 8px; margin-bottom: 7px; align-items: center; }
.edit-option-input {
  flex: 1; background: var(--bg-input); color: var(--text-1);
  border: 1px solid var(--border); border-radius: 7px;
  padding: 8px 10px; font-size: 14px; outline: none;
}
.btn-add-option {
  background: none; border: 1px dashed var(--border); border-radius: 7px;
  color: var(--text-3); font-size: 13px; padding: 8px 12px;
  cursor: pointer; width: 100%; margin-top: 4px;
  transition: border-color 0.15s, color 0.15s;
}
.btn-add-option:hover { border-color: var(--accent); color: var(--accent); }

/* ================================================================
   通用元件
================================================================ */
.screen-overlay {
  position: fixed; inset: 0; z-index: 999;
  background: var(--bg-body);
  display: flex; align-items: center; justify-content: center;
}
.spinner {
  width: 44px; height: 44px;
  border: 3px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }
.toast {
  position: fixed; bottom: 28px; left: 50%;
  transform: translateX(-50%);
  background: var(--bg-card); color: var(--text-1);
  padding: 10px 22px; border-radius: 20px;
  font-size: 14px; z-index: 600;
  box-shadow: 0 4px 20px rgba(0,0,0,0.4);
  border: 1px solid var(--border);
  white-space: nowrap;
  animation: fadeInUp 0.2s ease;
}
.toast.hidden { display: none; }
@keyframes fadeInUp {
  from { opacity: 0; transform: translateX(-50%) translateY(8px); }
  to   { opacity: 1; transform: translateX(-50%) translateY(0); }
}
.empty-state {
  display: flex; flex-direction: column;
  align-items: center; justify-content: center;
  padding: 60px 20px; text-align: center;
  color: var(--text-3);
}
.empty-state i { font-size: 40px; margin-bottom: 14px; }
.btn-icon {
  display: flex; align-items: center; gap: 7px;
  padding: 9px 16px; border-radius: 8px;
  background: var(--accent); color: white;
  border: none; font-size: 14px; font-weight: 500; cursor: pointer;
  transition: background 0.15s;
}
.btn-icon:hover { background: var(--accent-hover); }
.btn-icon.secondary {
  background: var(--bg-card); color: var(--text-1);
  border: 1px solid var(--border);
}
.btn-icon.secondary:hover { background: var(--bg-card-hover); }

/* 滾動條 */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-3); }

/* 響應式 */
@media (max-width: 768px) {
  .page-wrap, .page-wrap-narrow { padding: 20px 16px 40px; }
  .subjects-grid { grid-template-columns: 1fr; }
  .quiz-layout { padding: 16px; }
  .quiz-question-wrap { padding: 20px 16px 14px; }
  .options-list { padding: 0 12px 16px; }
  .question-text { font-size: 16px; }
  .option-text { font-size: 15px; }
}