body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  background-color: #f5f5f5;
}
.exercise-panel {
  max-width: 90%;
  margin: 20px auto;
  background-color: white;
  border-radius: 10px;
  padding: 20px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.10);
}
h2 {
  text-align: center;
  color: #333;
  font-size: 20px;
  margin: 10px 0 15px 0;
  line-height: 1.3;
}
.notes {
  background: #e3f2fd;
  border-radius: 8px;
  padding: 16px 20px;
  margin-bottom: 20px;
  font-size: 16px;
  color: #1a237e;
  line-height: 1.5;
}
.notes ul {
  margin: 8px 0 0 14px;
  padding-left: 0;
}
.notes li {
  margin-bottom: 4px;
}
.section {
  margin-bottom: 20px;
  border-bottom: 1px solid #e0e0e0;
  padding-bottom: 12px;
}
.section:last-child {
  border-bottom: none;
}
.sentence {
  margin: 12px 0;
  font-size: 15px;
  line-height: 1.5;
  word-wrap: break-word;
  text-align: justify;
}
.answer-dropdown {
  display: inline-block;
  min-width: 120px;
  margin: 0 4px;
  padding: 6px 8px;
  border: 2px solid #ddd;
  border-radius: 4px;
  background-color: #fff;
  font-size: 14px;
  vertical-align: middle;
  transition: all 0.3s ease;
}

.answer-dropdown:focus {
  outline: none;
  border-color: #1976d2;
  box-shadow: 0 0 0 2px rgba(25, 118, 210, 0.2);
}

.answer-dropdown.correct {
  border-color: #4CAF50;
  background-color: #e8f5e9;
  color: #2e7d32;
}

.answer-dropdown.incorrect {
  border-color: #f44336;
  background-color: #ffebee;
  color: #c62828;
}
.cantonese {
  color: #388e3c;
  font-size: 16px;
  margin-right: 6px;
  display: block;
  margin-bottom: 4px;
  text-align: justify;
  max-width: 80%;
}
#toggle-answers-btn {
  float: right;
  margin-bottom: 10px;
  padding: 8px 12px;
  font-size: 12px;
  background: #1976d2;
  color: white;
  border: none;
  border-radius: 4px;
  cursor: pointer;
}
#toggle-answers-btn:hover {
  background: #1565c0;
}

/* Tablet styles */
@media (max-width: 1024px) {
  .exercise-panel {
    max-width: 95%;
    margin: 10px auto;
    padding: 15px;
  }
  h2 {
    font-size: 19px;
  }
  .notes {
    font-size: 15px;
    padding: 12px 14px;
  }
  .sentence {
    font-size: 16px;
  }
  .cantonese {
    font-size: 17px;
  }
  .answer-dropdown {
    min-width: 110px;
    font-size: 14px;
  }
}

/* Mobile-specific styles */
@media (max-width: 768px) {
  .exercise-panel {
    margin: 3px;
    padding: 10px;
    border-radius: 6px;
  }
  h2 {
    font-size: 17px;
    margin: 5px 0 8px 0;
  }
  .notes {
    font-size: 14px;
    padding: 10px 12px;
    margin-bottom: 12px;
  }
  .sentence {
    font-size: 14px;
    margin: 8px 0;
    line-height: 1.4;
  }
  .cantonese {
    font-size: 15px;
    margin-bottom: 2px;
  }
  .answer-dropdown {
    min-width: 90px;
    font-size: 13px;
    padding: 4px 6px;
    margin: 0 2px;
  }
  #toggle-answers-btn {
    font-size: 11px;
    padding: 6px 10px;
    margin-bottom: 8px;
  }
}

/* Extra small mobile devices */
@media (max-width: 480px) {
  .exercise-panel {
    margin: 2px;
    padding: 8px;
  }
  h2 {
    font-size: 16px;
    margin: 3px 0 6px 0;
  }
  .notes {
    font-size: 13px;
    padding: 8px 10px;
    margin-bottom: 10px;
  }
  .sentence {
    font-size: 13px;
    margin: 6px 0;
  }
  .cantonese {
    font-size: 14px;
  }
  .answer-dropdown {
    min-width: 80px;
    font-size: 12px;
    padding: 3px 5px;
  }
  #toggle-answers-btn {
    font-size: 10px;
    padding: 4px 8px;
    margin-bottom: 6px;
  }
}