/* ============================================
   在线题库频道样式 — 专业学习门户
   ============================================ */

/* --- Hero --- */
.qb-hero{
  background: linear-gradient(135deg, #0B4A54 0%, #1C7C8C 48%, #2FA0A8 100%);
  color: #fff;
  padding: 42px 0 48px;
  position: relative;
  overflow: hidden;
}
.qb-hero::before{
  content: '';
  position: absolute;
  right: -80px; top: -80px;
  width: 320px; height: 320px;
  background: rgba(255,255,255,0.08);
  border-radius: 50%;
}
.qb-hero::after{
  content: '';
  position: absolute;
  left: -60px; bottom: -60px;
  width: 240px; height: 240px;
  background: rgba(255,255,255,0.05);
  border-radius: 50%;
}
.qb-hero__inner{
  position: relative; z-index: 1;
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 40px;
  align-items: center;
}
.qb-hero__tag{
  display: inline-flex; align-items: center; gap: 6px;
  background: rgba(255,255,255,0.12);
  border: 1px solid rgba(255,255,255,0.25);
  border-radius: 999px;
  padding: 5px 14px;
  font-size: 13px; font-weight: 500;
  margin-bottom: 14px;
}
.qb-hero__main h1{
  font-size: 34px; font-weight: 800; line-height: 1.2;
  margin: 0 0 12px;
}
.qb-hero__main p{
  font-size: 15px; line-height: 1.8;
  color: rgba(255,255,255,0.82);
  max-width: 560px;
  margin: 0 0 22px;
}
.qb-hero__actions{
  display: flex; gap: 12px; flex-wrap: wrap;
}
.qb-hero__btn{
  display: inline-flex; align-items: center; gap: 6px;
  padding: 11px 22px; border-radius: 999px;
  font-size: 14px; font-weight: 600; text-decoration: none;
  transition: var(--transition);
}
.qb-hero__btn--primary{
  background: #fff; color: #1C7C8C;
  box-shadow: 0 6px 18px rgba(0,0,0,0.12);
}
.qb-hero__btn--primary:hover{
  transform: translateY(-2px);
  box-shadow: 0 10px 24px rgba(0,0,0,0.18);
}
.qb-hero__btn--ghost{
  background: rgba(255,255,255,0.12); color: #fff;
  border: 1px solid rgba(255,255,255,0.35);
}
.qb-hero__btn--ghost:hover{
  background: rgba(255,255,255,0.22);
}
.qb-hero__stats{
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
}
.qb-hero__stat{
  background: rgba(255,255,255,0.10);
  border: 1px solid rgba(255,255,255,0.18);
  border-radius: 16px;
  padding: 18px 20px;
  text-align: center;
  backdrop-filter: blur(4px);
}
.qb-hero__stat b{
  display: block;
  font-size: 30px; font-weight: 800; line-height: 1;
  margin-bottom: 6px;
}
.qb-hero__stat span{
  font-size: 13px; color: rgba(255,255,255,0.78);
}
.qb-hero__stat--accent{
  background: rgba(224,145,59,0.22);
  border-color: rgba(224,145,59,0.35);
}

/* --- 能量规则条 --- */
.qb-points-bar{
  display: flex; align-items: center; flex-wrap: wrap; gap: 10px 18px;
  background: #fff;
  border: 1px solid var(--border); border-radius: var(--radius-lg);
  padding: 14px 20px; margin: 18px 0;
  box-shadow: 0 2px 10px rgba(0,0,0,0.03);
}
.qb-points-bar__item{
  display: flex; align-items: center; gap: 8px;
}
.qb-points-bar__label{
  font-size: 12px; color: var(--text-3);
}
.qb-points-bar__num{
  font-size: 18px; font-weight: 800; color: var(--primary-dark);
}
.qb-points-bar__tag{
  font-size: 12px; font-weight: 600;
  background: var(--primary-bg); color: var(--primary-dark);
  padding: 3px 10px; border-radius: 999px;
}
.qb-points-bar__divider{
  width: 1px; height: 20px; background: var(--border-light);
}
.qb-points-bar__cta{
  margin-left: auto;
  font-size: 13px; font-weight: 600; color: var(--primary);
  text-decoration: none;
  padding: 6px 14px; border-radius: 999px;
  background: var(--primary-bg);
  transition: var(--transition);
}
.qb-points-bar__cta:hover{
  background: var(--primary); color: #fff;
}

.qb-alert{
  background: #fff4e6; border: 1px solid #ffd8a8; color: #b54708;
  border-radius: var(--radius); padding: 14px 18px; margin: 14px 0; font-size: 14px;
}

/* --- 区块标题 --- */
.qb-sec-head{
  display: flex; align-items: flex-end; justify-content: space-between;
  margin: 36px 0 18px;
}
.qb-sec-title{
  font-size: 22px; font-weight: 700; color: var(--text-1);
  margin: 0 0 4px;
}
.qb-sec-title::before{
  content: '';
  display: inline-block; width: 5px; height: 20px;
  background: var(--primary);
  border-radius: 3px; margin-right: 10px; vertical-align: -2px;
}
.qb-sec-sub{
  font-size: 13px; color: var(--text-3); margin: 0;
}

/* --- 学科卡片 --- */
.qb-subject-grid{
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px;
}
.qb-subject-card{
  border-radius: var(--radius-lg); border: 1px solid rgba(0,0,0,0.05);
  padding: 22px;
  transition: var(--transition);
  position: relative; overflow: hidden;
}
.qb-subject-card:hover{
  transform: translateY(-4px);
  box-shadow: 0 14px 36px rgba(28,124,140,0.12);
}
.qb-subject-card__head{
  display: flex; align-items: center; gap: 12px; margin-bottom: 10px;
}
.qb-subject-card__icon{
  width: 52px; height: 52px; border-radius: 14px;
  display: flex; align-items: center; justify-content: center;
  font-size: 26px; flex-shrink: 0;
  box-shadow: 0 6px 16px rgba(0,0,0,0.10);
}
.qb-subject-card__info h3{
  font-size: 20px; font-weight: 700; color: var(--text-1); margin: 0 0 2px;
}
.qb-subject-card__info span{
  font-size: 12px; color: var(--text-3);
}
.qb-subject-card__desc{
  font-size: 13px; color: var(--text-2); line-height: 1.6;
  margin: 0 0 16px; min-height: 42px;
}
.qb-grade-grid{
  display: grid; grid-template-columns: repeat(5, 1fr); gap: 8px;
}
.qb-grade-chip{
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  background: #fff; border: 1px solid var(--border-light); border-radius: 10px;
  padding: 8px 4px; text-decoration: none; color: var(--text-1);
  transition: var(--transition);
}
.qb-grade-chip:hover{
  background: var(--primary); border-color: var(--primary); color: #fff;
  transform: translateY(-2px);
}
.qb-grade-chip__num{
  font-size: 16px; font-weight: 700; line-height: 1;
}
.qb-grade-chip__label{
  font-size: 11px; margin-top: 2px;
}
.qb-subject-card__foot{
  margin-top: 16px;
}
.qb-subject-card__primary{
  display: block; text-align: center;
  background: var(--subject-color, var(--primary)); color: #fff;
  border-radius: 10px; padding: 10px 16px;
  font-size: 14px; font-weight: 600; text-decoration: none;
  transition: var(--transition);
}
.qb-subject-card__primary:hover{
  opacity: 0.92; transform: translateY(-1px);
}

/* --- 我的学习 --- */
.qb-learning-sec{
  margin-bottom: 42px;
}
.qb-learning-grid{
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px;
}
.qb-learning-card{
  display: flex; align-items: center; gap: 14px;
  background: #fff; border: 1px solid var(--border); border-radius: var(--radius-lg);
  padding: 18px; text-decoration: none; color: inherit;
  transition: var(--transition);
}
.qb-learning-card:hover{
  border-color: var(--primary); box-shadow: 0 8px 22px rgba(28,124,140,0.10);
}
.qb-learning-card__icon{
  width: 48px; height: 48px; border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  font-size: 22px; flex-shrink: 0;
}
.qb-learning-card__body{
  flex: 1; min-width: 0;
}
.qb-learning-card__body h4{
  font-size: 16px; font-weight: 700; color: var(--text-1); margin: 0 0 4px;
}
.qb-learning-card__body p{
  font-size: 13px; color: var(--text-2); margin: 0;
}
.qb-learning-card__badge{
  font-size: 12px; font-weight: 600;
  background: var(--primary-bg); color: var(--primary-dark);
  padding: 4px 12px; border-radius: 999px; white-space: nowrap;
}

/* --- 选择单元页 --- */
.qb-points {
  display: flex; align-items: center; gap: 16px; flex-wrap: wrap;
  background: linear-gradient(135deg, #EAF4FC 0%, #DCEEFB 100%);
  border: 1px solid #bfe0f5; border-radius: var(--radius); padding: 14px 20px; margin: 16px 0;
  font-size: 14px; color: #2c5d7c;
}
.qb-points b { color: #2E86C1; font-size: 18px; }
.qb-points .qb-th { background: #fff; border: 1px solid #bfe0f5; border-radius: 16px; padding: 3px 12px; font-size: 12px; }
.qb-points .qb-cta { margin-left: auto; }

.qb-section-title { font-size: 18px; color: var(--text-1); margin: 24px 0 8px; display: flex; align-items: center; gap: 8px; }

.qb-units { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 18px; margin: 18px 0; }
.qb-unit-card {
  background: #fff; border: 1px solid var(--border); border-radius: var(--radius-lg);
  padding: 20px; display: flex; flex-direction: column; gap: 12px;
}
.qb-unit-head { display: flex; align-items: center; gap: 10px; }
.qb-unit-head .ic { font-size: 22px; }
.qb-unit-head h3 { font-size: 16px; font-weight: 700; color: var(--text-1); margin: 0; flex: 1; }
.qb-unit-head .cnt { font-size: 12px; color: var(--text-3); background: var(--bg-soft); padding: 3px 10px; border-radius: 999px; }
.qb-sets { display: grid; grid-template-columns: repeat(auto-fill, minmax(120px, 1fr)); gap: 10px; }
.qb-set-card {
  background: #f8fafb; border: 1px solid var(--border-light); border-radius: var(--radius-sm);
  padding: 12px; text-align: center;
}
.qb-set-title { font-size: 14px; font-weight: 700; color: var(--text-1); }
.qb-set-meta { font-size: 12px; color: var(--text-3); margin: 4px 0 10px; }
.qb-set-actions { display: flex; gap: 6px; }
.qb-set-actions a { flex: 1; font-size: 12px; font-weight: 600; text-decoration: none; padding: 6px 2px; border-radius: 6px; text-align: center; }
.qb-practice { background: #2E86C1; color: #fff; }
.qb-print { background: #fff; color: #2E86C1; border: 1px solid #2E86C1; }

/* 练习页 */
.qb-q { background: #fff; border: 1px solid var(--border); border-radius: var(--radius-lg); padding: 20px 22px; margin: 16px 0; }
.qb-q-no { font-weight: 700; color: #2E86C1; margin-right: 6px; }
.qb-q-type { font-size: 12px; padding: 2px 10px; border-radius: 12px; background: #eaf4fc; color: #2E86C1; margin-left: 8px; }
.qb-q-stem { font-size: 16px; color: var(--text-1); line-height: 1.7; margin: 10px 0; }
.qb-opts { display: flex; flex-direction: column; gap: 10px; margin-top: 6px; }
.qb-opt { display: flex; align-items: center; gap: 10px; padding: 10px 14px; border: 1.5px solid var(--border); border-radius: var(--radius-sm); cursor: pointer; transition: var(--transition); }
.qb-opt:hover { border-color: #2E86C1; }
.qb-opt input { accent-color: #2E86C1; width: 18px; height: 18px; }
.qb-opt.text input { width: 100%; padding: 8px 12px; border: 1.5px solid var(--border); border-radius: var(--radius-sm); font-size: 15px; }
.qb-submit-bar { display: flex; gap: 12px; justify-content: center; margin: 20px 0 30px; }

/* 结果页 */
.qb-result-head { text-align: center; background: #fff; border: 1px solid var(--border); border-radius: var(--radius-lg); padding: 22px; margin: 18px 0; }
.qb-score-big { font-size: 46px; font-weight: 800; color: #2E86C1; }
.qb-result-item { background: #fff; border: 1px solid var(--border); border-left: 3px solid #2E86C1; border-radius: var(--radius); padding: 16px 18px; margin: 14px 0; }
.qb-result-item.wrong { border-left-color: #F5576C; }
.qb-result-item .tag { font-size: 12px; font-weight: 700; padding: 2px 10px; border-radius: 12px; }
.qb-result-item .tag.ok { background: #CDEFD9; color: #2f8f5b; }
.qb-result-item .tag.no { background: #ffd9d2; color: #d6453f; }
.qb-your { font-size: 13px; color: var(--text-2); }
.qb-right { font-size: 14px; color: #2f8f5b; font-weight: 600; }
.qb-analysis { font-size: 13px; color: var(--text-2); line-height: 1.7; margin-top: 6px; background: #f7f9fc; padding: 8px 12px; border-radius: var(--radius-sm); }

/* 错题页 */
.qb-wrong-item { background: #fff; border: 1px solid var(--border); border-left: 3px solid #F5576C; border-radius: var(--radius); padding: 16px 18px; margin: 12px 0; }
.qb-wrong-meta { font-size: 12px; color: var(--text-3); margin-bottom: 6px; }
.qb-wrong-meta b { color: #F5576C; }

/* 打印页 */
.qb-print-sheet { background: #fff; padding: 28px 32px; max-width: 820px; margin: 0 auto; }
.qb-print-title { text-align: center; font-size: 22px; font-weight: 800; color: #222; margin-bottom: 4px; }
.qb-print-sub { text-align: center; font-size: 13px; color: #666; margin-bottom: 18px; }
.qb-print-q { margin: 14px 0; font-size: 15px; color: #222; line-height: 1.7; page-break-inside: avoid; }
.qb-print-q .no { font-weight: 700; }
.qb-print-opts { margin: 6px 0 6px 22px; }
.qb-print-answer { margin-top: 26px; border-top: 2px dashed #999; padding-top: 14px; }
.qb-print-answer h4 { color: #222; }

/* Responsive */
@media(max-width: 1100px){
  .qb-hero__inner{ grid-template-columns: 1fr; gap: 28px; }
  .qb-hero__main p{ max-width: none; }
  .qb-hero__stats{ max-width: 420px; }
  .qb-subject-grid{ grid-template-columns: 1fr; }
}
@media(max-width: 768px){
  .qb-hero{ padding: 28px 0; }
  .qb-hero__main h1{ font-size: 26px; }
  .qb-hero__stats{ grid-template-columns: repeat(2, 1fr); }
  .qb-hero__stat b{ font-size: 24px; }
  .qb-points-bar{ flex-direction: column; align-items: flex-start; gap: 10px; }
  .qb-points-bar__cta{ margin-left: 0; width: 100%; text-align: center; }
  .qb-grade-grid{ grid-template-columns: repeat(5, 1fr); }
  .qb-learning-grid{ grid-template-columns: 1fr; }
  .qb-units{ grid-template-columns: 1fr; }
}
@media(max-width: 420px){
  .qb-grade-grid{ grid-template-columns: repeat(3, 1fr); }
  .qb-hero__actions{ flex-direction: column; }
  .qb-hero__btn{ width: 100%; justify-content: center; }
}