/* ========================================
   知识点复习模块 · 专属样式
   ======================================== */

/* ----- 页面布局 ----- */
.kr-app {
  position: relative; z-index: 1;
  max-width: 960px; margin: 0 auto; padding: 28px 20px 60px;
  perspective: 1200px;
}

.kr-header {
  text-align: center; padding: 20px 0 32px;
}
.kr-header h1 {
  font-size: 24px; font-weight: 500; letter-spacing: -0.5px;
  background: linear-gradient(135deg, #CECBF6, #AFA9EC, #7F77DD);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.kr-header .kr-subtitle {
  margin-top: 6px; font-size: 13px; color: var(--text-muted);
}

/* ----- 模式切换栏 ----- */
.kr-toolbar {
  display: flex; align-items: center; gap: 8px;
  margin-bottom: 28px; flex-wrap: wrap;
  justify-content: center;
  padding: 6px;
  background: var(--bg-card); border-radius: var(--radius-lg);
  border: 1px solid var(--border);
}
.kr-toolbar .mode-btn {
  padding: 7px 18px; border-radius: var(--radius-md);
  font-size: 13px; font-weight: 500; cursor: pointer; border: none;
  background: transparent; color: var(--text-muted);
  transition: all var(--transition-fast); font-family: var(--font-sans);
}
.kr-toolbar .mode-btn:hover { color: var(--text-primary); background: var(--bg-surface); }
.kr-toolbar .mode-btn.active {
  background: var(--accent); color: #fff;
  box-shadow: 0 0 16px var(--accent-glow);
}

/* ----- 章节卡片网格 ----- */
.kr-chapters {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-bottom: 24px;
}

.chapter-card {
  position: relative;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 20px;
  cursor: pointer;
  transition: all var(--transition);
  overflow: hidden;
  user-select: none;
}
.chapter-card::before {
  content: "";
  position: absolute; inset: 0;
  background: radial-gradient(ellipse 100% 100% at 0% 0%, rgba(83,74,183,0.04), transparent);
  opacity: 0; transition: opacity var(--transition);
}
.chapter-card:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
  box-shadow: 0 8px 30px var(--accent-glow);
}
.chapter-card:hover::before { opacity: 1; }
.chapter-card:active { transform: translateY(-1px); }

.chapter-card .chap-num {
  font-size: 11px; color: var(--text-muted);
  text-transform: uppercase; letter-spacing: 1px;
  margin-bottom: 4px;
}
.chapter-card .chap-name {
  font-size: 16px; font-weight: 500; color: var(--text-primary);
  margin-bottom: 4px;
}
.chapter-card .chap-desc {
  font-size: 12px; color: var(--text-secondary);
  margin-bottom: 12px;
}
.chapter-card .chap-stats {
  display: flex; gap: 6px; flex-wrap: wrap;
}
.chapter-card .chap-stats .stat-dot {
  display: inline-flex; align-items: center; gap: 3px;
  font-size: 11px; padding: 2px 8px; border-radius: 4px;
}
.chapter-card .chap-core {
  margin-top: 12px; font-size: 11px; color: var(--text-muted);
  padding-top: 10px; border-top: 1px solid var(--border);
}

/* ----- 章节详情页 ----- */
.kr-detail-header {
  display: flex; align-items: center; gap: 12px;
  margin-bottom: 20px;
}
.kr-detail-header .back-btn {
  display: flex; align-items: center; gap: 4px;
  padding: 6px 14px; border-radius: var(--radius-md);
  font-size: 13px; cursor: pointer; border: 1px solid var(--border);
  background: var(--bg-card); color: var(--text-secondary);
  transition: all var(--transition-fast); font-family: var(--font-sans);
}
.kr-detail-header .back-btn:hover { border-color: var(--accent); color: var(--text-primary); }
.kr-detail-header h2 { flex: 1; }

.kr-detail-filter {
  display: flex; gap: 8px; margin-bottom: 20px; flex-wrap: wrap;
}
.kr-detail-filter .filter-btn {
  font-size: 12px; padding: 5px 14px; border-radius: var(--radius-md);
  cursor: pointer; border: 1px solid var(--border);
  background: transparent; color: var(--text-secondary);
  transition: all var(--transition-fast); font-family: var(--font-sans);
}
.kr-detail-filter .filter-btn:hover { color: var(--text-primary); border-color: var(--accent); }
.kr-detail-filter .filter-btn.active { background: var(--accent); border-color: var(--accent); color: #fff; }

/* ----- 知识点卡片 ----- */
.kr-section {
  margin-bottom: 20px;
}
.kr-section-title {
  font-size: 14px; font-weight: 500; color: var(--accent-light);
  padding-bottom: 8px; margin-bottom: 12px;
  border-bottom: 1px solid var(--border);
}

.kr-knowledge-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
}

.knowledge-card {
  min-height: 110px;
  cursor: pointer;
}

.knowledge-card .card-inner {
  display: grid;
  position: relative; width: 100%;
  min-height: inherit;
  transition: transform 0.45s cubic-bezier(0.25, 0.1, 0.25, 1);
  transform-style: preserve-3d;
  transform-origin: center center;
  will-change: transform;
}
.knowledge-card.flipped .card-inner { transform: rotateX(180deg); }

.k-card-face {
  grid-area: 1 / 1;
  backface-visibility: hidden;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
  padding: 14px;
  display: flex; flex-direction: column;
}
.k-card-front {
  background: var(--bg-card);
}
.k-card-front:hover {
  border-color: var(--accent);
  box-shadow: 0 0 20px var(--accent-glow);
}
.k-card-back {
  background: var(--bg-card);
  transform: rotateX(180deg);
  border-color: rgba(216,90,48,0.25);
}

/* ----- 正面：名称行 ----- */
.k-card-front .k-name-row {
  display: flex; justify-content: space-between; align-items: center;
  margin-bottom: 10px;
}
.k-card-front .k-name-row .k-name {
  font-size: 14px; font-weight: 500; color: var(--text-primary);
}

/* ----- 正面：操作行（📖 问题 + 💡 提示 并排） ----- */
.k-card-front .k-actions-row {
  display: flex; gap: 8px; margin-bottom: 6px;
}
.k-card-front .k-question-area,
.k-card-front .k-hint-area {
  flex: 1;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  gap: 4px; padding: 14px 8px;
  background: rgba(83,74,183,0.05); border-radius: var(--radius-md);
  border: 1px dashed rgba(83,74,183,0.18);
  cursor: pointer; transition: all var(--transition-fast);
  user-select: none; text-align: center;
}
.k-card-front .k-hint-area {
  background: rgba(186,117,23,0.05); border-color: rgba(186,117,23,0.15);
}
.k-card-front .k-question-area:hover {
  background: rgba(83,74,183,0.12); border-color: var(--accent);
}
.k-card-front .k-hint-area:hover {
  background: rgba(186,117,23,0.12); border-color: #BA7517;
}
.k-card-front .k-q-icon { font-size: 18px; }
.k-card-front .k-q-text {
  font-size: 11px; color: rgba(152,152,176,0.8);
}

/* ----- 正面：提示展开内容 ----- */
.k-card-front .k-hint-content {
  max-height: 0; overflow: hidden; opacity: 0;
  transition: max-height 0.3s ease, opacity 0.3s ease, margin 0.3s ease;
  text-align: center; font-family: var(--font-mono);
  font-size: 14px; color: var(--accent-light);
  background: rgba(83,74,183,0.06); border-radius: var(--radius-md);
  padding: 0 12px; margin: 0;
}
.knowledge-card.hint-shown .k-hint-content {
  max-height: 60px; opacity: 1; padding: 10px 12px; margin: 6px 0 4px;
}

/* ----- 正面：翻转引导 ----- */
.k-card-front .k-flip-hint {
  font-size: 10px; color: var(--text-muted); text-align: center; margin-top: 6px;
  cursor: pointer; transition: color var(--transition-fast);
}
.k-card-front .k-flip-hint:hover { color: var(--accent-light); }

/* ----- 背面 ----- */
.k-card-back .k-label {
  font-size: 11px; color: var(--text-muted); margin-bottom: 2px;
  text-transform: uppercase; letter-spacing: 0.5px;
}
.k-card-back .k-name-back {
  font-size: 16px; font-weight: 500; color: var(--accent-light); margin-bottom: 6px;
}
.k-card-back .k-formula-back {
  font-family: var(--font-mono); font-size: 22px; font-weight: 500;
  color: #F0997B; margin-bottom: 8px;
  line-height: 1.4;
}
.k-card-back .k-mistake {
  font-size: 13px; color: var(--text-secondary); line-height: 1.6;
}
.k-card-back .k-tap-hint {
  font-size: 11px; color: var(--text-muted); margin-top: auto; text-align: right;
  cursor: pointer; transition: color var(--transition-fast);
}
.k-card-back .k-tap-hint:hover { color: #F0997B; }

/* ----- 自测模式 ----- */
.kr-quiz-panel {
  background: var(--bg-card); border-radius: var(--radius-xl);
  border: 1px solid var(--border); padding: 32px;
  text-align: center; max-width: 600px; margin: 0 auto;
}

.kr-quiz-panel .quiz-step { font-size: 13px; color: var(--text-muted); margin-bottom: 6px; }
.kr-quiz-panel .quiz-total { font-size: 12px; color: var(--text-muted); margin-bottom: 16px; }

.kr-quiz-panel .quiz-card {
  background: var(--bg-surface); border-radius: var(--radius-lg);
  border: 1px solid var(--border); padding: 24px;
  margin-bottom: 20px; min-height: 160px;
  display: flex; flex-direction: column;
  align-items: center; justify-content: center;
  transition: all var(--transition);
}
.kr-quiz-panel .quiz-card.revealed { border-color: rgba(216,90,48,0.3); }

.kr-quiz-panel .quiz-card .q-name {
  font-size: 18px; font-weight: 500; margin-bottom: 16px;
}
.kr-quiz-panel .quiz-card .q-hint {
  font-size: 12px; color: var(--text-muted); margin-bottom: 12px;
}

/* 自测信息行（标签 + 💡 提示按钮，同一行） */
.kr-quiz-panel .quiz-card .q-info-row {
  display: flex; align-items: center; justify-content: center; gap: 10px;
  margin-bottom: 12px;
}
.kr-quiz-panel .quiz-card .q-hint-trigger {
  font-size: 14px; cursor: pointer;
  padding: 2px 6px; border-radius: 4px;
  transition: all var(--transition-fast);
  user-select: none;
  color: rgba(186,117,23,0.55);
}
.kr-quiz-panel .quiz-card .q-hint-trigger:hover {
  color: #FAC775; background: rgba(186,117,23,0.08);
}

/* 模糊区切换为提示文字 */
.kr-quiz-panel .quiz-card .q-blurred.q-hint-shown {
  filter: blur(0) !important;
  color: var(--accent-light);
  user-select: text;
}
.kr-quiz-panel .quiz-card .q-blurred {
  font-family: var(--font-mono); font-size: 20px; padding: 14px 28px;
  background: rgba(83,74,183,0.06); border-radius: var(--radius-md);
  filter: blur(8px); user-select: none;
  transition: filter 0.4s ease;
}
.kr-quiz-panel .quiz-card .q-cleared { filter: blur(0); }
.kr-quiz-panel .quiz-card .q-formula-full {
  font-family: var(--font-mono); font-size: 20px;
  padding: 14px 28px; margin-bottom: 10px;
  background: rgba(83,74,183,0.06); border-radius: var(--radius-md);
  color: var(--accent-light);
  animation: fadeIn 0.3s ease both;
}
.kr-quiz-panel .quiz-card .q-mistake-full {
  font-size: 13px; color: #F0997B; line-height: 1.6;
  animation: fadeIn 0.4s ease both;
}

.kr-quiz-panel .quiz-actions { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }

.kr-quiz-panel .quiz-self-rate {
  display: flex; gap: 10px; justify-content: center; flex-wrap: wrap;
  animation: slideUp 0.35s ease both;
}
.kr-quiz-panel .rate-btn {
  display: flex; flex-direction: column; align-items: center; gap: 4px;
  padding: 12px 24px; border-radius: var(--radius-lg);
  cursor: pointer; border: 1px solid var(--border);
  background: var(--bg-surface); color: var(--text-secondary);
  transition: all var(--transition-fast); font-family: var(--font-sans);
  min-width: 110px;
}
.kr-quiz-panel .rate-btn .rate-icon { font-size: 20px; }
.kr-quiz-panel .rate-btn .rate-label { font-size: 12px; }
.kr-quiz-panel .rate-btn .rate-sub { font-size: 10px; color: var(--text-muted); }

.kr-quiz-panel .rate-btn:hover { transform: translateY(-2px); }
.kr-quiz-panel .rate-btn.master:hover {
  border-color: #1D9E75; color: #5DCAA5; background: rgba(29,158,117,0.08);
}
.kr-quiz-panel .rate-btn.unsure:hover {
  border-color: #BA7517; color: #FAC775; background: rgba(186,117,23,0.08);
}
.kr-quiz-panel .rate-btn.forgot:hover {
  border-color: #E24B4A; color: #F09595; background: rgba(226,75,74,0.08);
}

/* ----- 统计面板 ----- */
.kr-stats-bar {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  margin-top: 28px;
}
.kr-stats-bar .stat-item {
  background: var(--bg-card); border-radius: var(--radius-lg);
  border: 1px solid var(--border); padding: 16px;
  text-align: center; transition: all var(--transition);
}
.kr-stats-bar .stat-item:hover { border-color: var(--accent); }
.kr-stats-bar .stat-value { font-size: 28px; font-weight: 500; }
.kr-stats-bar .stat-label { font-size: 12px; color: var(--text-muted); margin-top: 4px; }

/* ----- 综合实践 ----- */
.kr-practices {
  margin-top: 24px;
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px;
}
.kr-practice-card {
  background: var(--bg-card); border-radius: var(--radius-lg);
  border: 1px solid var(--border); padding: 16px;
  transition: all var(--transition);
}
.kr-practice-card:hover { border-color: var(--accent); }
.kr-practice-card .p-name { font-size: 14px; font-weight: 500; margin-bottom: 4px; }
.kr-practice-card .p-sub { font-size: 11px; color: var(--text-muted); }
.kr-practice-card .p-tag { margin-top: 8px; }

/* ----- 优先级视图 ----- */
#priority-list .knowledge-card {
  min-height: 105px;
}
#priority-list .kr-knowledge-grid {
  grid-template-columns: 1fr;
}

/* ----- 空状态 ----- */
.kr-empty {
  text-align: center; padding: 48px 20px; color: var(--text-muted);
}

/* ----- 响应式 ----- */
@media (max-width: 768px) {
  .kr-chapters { grid-template-columns: repeat(2, 1fr); }
  .kr-knowledge-grid { grid-template-columns: 1fr; }
  .kr-stats-bar { grid-template-columns: repeat(2, 1fr); }
  .kr-practices { grid-template-columns: 1fr; }
  .kr-quiz-panel { padding: 20px; }
  .knowledge-card { min-height: 120px; }
}

@media (max-width: 480px) {
  .kr-chapters { grid-template-columns: 1fr; }
  .kr-stats-bar { grid-template-columns: repeat(2, 1fr); }
}