body {
  overflow-y: auto !important;
}
.hoahoc-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 20px;
  max-width: 600px;
  margin: 0 auto;
  margin-top: 90px;
}
.hoahoc-header {
  display: flex;
  justify-content: space-between;
  width: 100%;
  font-size: 1.2rem;
  font-weight: bold;
  background: rgba(255,255,255,0.1);
  padding: 15px 20px;
  border-radius: 12px;
  margin-bottom: 20px;
  backdrop-filter: blur(10px);
}
.hoahoc-timer-container {
  width: 100%;
  height: 10px;
  background: rgba(255,255,255,0.1);
  border-radius: 5px;
  overflow: hidden;
  margin-bottom: 20px;
}
.hoahoc-timer-bar {
  height: 100%;
  width: 100%;
  background: linear-gradient(90deg, #3498db, #2ecc71);
  transition: width 0.1s linear, background-color 0.3s ease;
}
.hoahoc-timer-bar.danger {
  background: linear-gradient(90deg, #e74c3c, #c0392b);
}
.hoahoc-question-box {
  background: rgba(0,0,0,0.4);
  padding: 30px 20px;
  border-radius: 16px;
  width: 100%;
  text-align: center;
  margin-bottom: 20px;
  border: 1px solid rgba(255,255,255,0.1);
  box-shadow: 0 10px 30px rgba(0,0,0,0.3);
}
.hoahoc-question-box h2 {
  font-size: 1.4rem;
  line-height: 1.5;
  color: #fff;
}
.hoahoc-options {
  display: flex;
  flex-direction: column;
  gap: 15px;
  width: 100%;
}
.hh-option-btn {
  background: rgba(255,255,255,0.1);
  border: 2px solid rgba(255,255,255,0.2);
  color: white;
  padding: 15px 20px;
  border-radius: 12px;
  font-size: 1.1rem;
  font-weight: bold;
  cursor: pointer;
  transition: all 0.2s ease;
  text-align: left;
  font-family: inherit;
}
.hh-option-btn:hover {
  background: rgba(255,255,255,0.2);
  transform: translateY(-2px);
}
.hh-option-btn:active {
  transform: translateY(0);
}
.hh-option-btn.correct {
  background: #2ecc71;
  border-color: #27ae60;
  box-shadow: 0 0 15px rgba(46, 204, 113, 0.5);
}
.hh-option-btn.wrong {
  background: #e74c3c;
  border-color: #c0392b;
  box-shadow: 0 0 15px rgba(231, 76, 60, 0.5);
  animation: shake 0.4s;
}
@keyframes shake {
  0%, 100% { transform: translateX(0); }
  20%, 60% { transform: translateX(-5px); }
  40%, 80% { transform: translateX(5px); }
}

/* Level Selection UI */
.hh-levels-container {
  max-width: 600px;
  margin: 0 auto;
  margin-top: 90px;
  padding: 20px;
}
.hh-levels-title {
  text-align: center;
  font-size: 24px;
  color: #f1c40f;
  margin-bottom: 20px;
  font-weight: 900;
  text-transform: uppercase;
}
.hh-levels-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 10px;
}
.hh-level-card {
  background: rgba(255,255,255,0.1);
  border: 1px solid rgba(255,255,255,0.2);
  border-radius: 12px;
  padding: 10px;
  text-align: center;
  cursor: pointer;
  transition: transform 0.2s, background 0.2s;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}
.hh-level-card:hover {
  background: rgba(255,255,255,0.2);
  transform: scale(1.05);
}
.hh-level-card.locked {
  background: rgba(0,0,0,0.5);
  cursor: not-allowed;
  opacity: 0.6;
}
.hh-level-card.locked:hover {
  transform: none;
}
.hh-level-num {
  font-weight: bold;
  font-size: 16px;
  margin-bottom: 4px;
}
.hh-level-score {
  font-size: 12px;
  color: #a5b1c2;
}
.hh-level-score.passed {
  color: #2ecc71;
}

@media (max-width: 400px) {
    .hh-levels-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}