/* ==========================================================================
   Skill Drills (Luyện Thi Theo Chuyên Đề & Dạng Bài) Styles
   ========================================================================== */

.drill-modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.72);
  backdrop-filter: blur(5px);
  z-index: 10000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
  animation: drillFadeIn 0.2s ease;
}

@keyframes drillFadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

.drill-modal-card {
  background: #ffffff;
  border-radius: 24px;
  width: min(720px, 100%);
  max-height: 92vh;
  overflow-y: auto;
  box-shadow: 0 25px 60px rgba(0, 0, 0, 0.28);
  position: relative;
  display: flex;
  flex-direction: column;
}

.drill-modal-header {
  padding: 20px 28px;
  border-bottom: 1px solid #f1f5f9;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.drill-modal-header h2 {
  margin: 0;
  font-size: 20px;
  font-weight: 800;
  color: #0f172a;
  display: flex;
  align-items: center;
  gap: 8px;
}

/* Category Grid */
.drill-category-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
  padding: 24px 28px;
}

@media (max-width: 560px) {
  .drill-category-grid {
    grid-template-columns: 1fr;
  }
}

.drill-cat-card {
  border: 1px solid #e2e8f0;
  border-radius: 16px;
  padding: 20px;
  cursor: pointer;
  background: #ffffff;
  transition: all 0.2s ease;
  text-align: left;
}

.drill-cat-card:hover {
  transform: translateY(-2px);
  border-color: #6657d9;
  box-shadow: 0 8px 24px rgba(102, 87, 217, 0.1);
}

.drill-cat-icon {
  font-size: 32px;
  margin-bottom: 10px;
}

.drill-cat-card strong {
  display: block;
  font-size: 16px;
  color: #0f172a;
  margin-bottom: 4px;
}

.drill-cat-card p {
  margin: 0;
  font-size: 13px;
  color: #64748b;
  line-height: 1.5;
}

/* Question Area */
.drill-question-container {
  padding: 20px 28px 28px;
}

.drill-progress-bar-wrap {
  height: 6px;
  background: #f1f5f9;
  border-radius: 999px;
  overflow: hidden;
  margin-bottom: 20px;
}

.drill-progress-bar-fill {
  height: 100%;
  background: #6657d9;
  border-radius: 999px;
  transition: width 0.3s ease;
}

.drill-q-card {
  background: #f8fafc;
  border: 1px solid #e2e8f0;
  border-radius: 18px;
  padding: 24px;
  margin-bottom: 20px;
}

.drill-q-prompt {
  font-size: 17px;
  font-weight: 700;
  color: #1e293b;
  margin-bottom: 16px;
  line-height: 1.6;
}

.drill-q-prompt b {
  color: #6657d9;
  font-family: STKaiti, KaiTi, serif;
  font-size: 22px;
}

.drill-options-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.drill-opt-btn {
  background: #ffffff;
  border: 1px solid #cbd5e1;
  border-radius: 12px;
  padding: 12px 18px;
  font-size: 15px;
  font-weight: 600;
  color: #1e293b;
  cursor: pointer;
  text-align: left;
  transition: all 0.15s;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.drill-opt-btn:hover:not(:disabled) {
  border-color: #6657d9;
  background: #faf5ff;
}

.drill-opt-btn.correct {
  background: #dcfce7 !important;
  border-color: #22c55e !important;
  color: #15803d !important;
  font-weight: 800;
}

.drill-opt-btn.wrong {
  background: #fee2e2 !important;
  border-color: #ef4444 !important;
  color: #b91c1c !important;
  text-decoration: line-through;
}

.drill-explanation-box {
  background: #eff6ff;
  border: 1px solid #bfdbfe;
  border-radius: 12px;
  padding: 14px 18px;
  margin-top: 16px;
  font-size: 13.5px;
  line-height: 1.6;
  color: #1e3a8a;
}

.drill-explanation-box b {
  color: #1d4ed8;
}