.quiz-layout { display: flex; gap: 20px; margin-top: 20px; }
.quiz-sidebar { width: 200px; border-right: 1px solid #ddd; padding-right: 0px; }
.question-grid { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 4px; font-size: 12px; }
.q-nav-btn { padding: 0px; color: #333; border: 1px solid #ccc; background: #eee; cursor: pointer; border-radius: 50%; width: 35px; height: 35px; margin-bottom: 0px; margin-right: 0px; }
.q-nav-btn.answered { color: #fff; background: #2ecc71;}
.q-nav-btn.active { background: #2ecc71; border: 0px solid #3498db; line-height: 0px; color: #fff; }
.q-nav-btn.wrong { background: #e74c3c; color: #fff; }

.quiz-main { flex: 1; padding: 0px; background: #f9f9f9; border-radius: 8px; margin-bottom: 0px;}
.answer-label { display: flex; align-items: center; padding: 0px; background: #fff; border: 1px solid #ddd; cursor: pointer; margin-bottom: 10px; }
.answer-label input { margin-bottom: 0px; margin-right: 0px; margin-top: 0px; }
.answer-label:hover { background: #f0f0f0; }

.quiz-header { display: flex; justify-content: space-between; align-items: center; border-bottom: 2px solid #333; line-height: 1.125; }
#timer-display { font-size: 24px; font-weight: bold; color: #c0392b; }

.quiz-controls button {
    all: unset;        /* reset sạch */
    display: inline-flex;
    align-items: center;
    justify-content: center;

    border: 1px solid #ccc;
    border-radius: 4px;
    padding: 1px 10px;
    background-color: #fff;
    color: #333;
    font-size: 14px;
    font-weight: 500;
}

#quiz-form { margin-bottom: 8px; }

@media (max-width: 768px) {
   .quiz-layout{
      flex-direction: column;
   }

   .question-grid{
      width: 100%;
      display: grid;
      grid-template-columns: repeat(15, minmax(0, 1fr));
   }
   .quiz-sidebar{
      width: 100%;
   }
   .quiz-header h2{
      font-size: 20px;
   }

   #quiz-timer{
      font-size: 16px;
   }
}

@media (max-width: 480px) {

    .question-grid{
      width: 100%;
      display: grid;
      grid-template-columns: repeat(8, minmax(0, 1fr));
   }

   #quiz-intro-screen{
      font-size: 14px;
   }
}