:root {
      --primary: #4361ee;
      --primary-dark: #3a0ca3;
      --secondary: #7209b7;
      --accent: #f72585;
      --light: #f8f9fa;
      --dark: #212529;
      --success: #4cc9f0;
      --warning: #fca311;
      --danger: #e63946;
      --card-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
      --transition: all 0.3s ease;
    }

    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }

    body {
      font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
      background: linear-gradient(135deg, #1a2a6c, #b21f1f, #1a2a6c);
      background-size: 400% 400%;
      animation: gradientBG 15s ease infinite;
      color: var(--light);
      min-height: 100vh;
      padding: 20px;
      display: flex;
      justify-content: center;
      align-items: center;
    }

    @keyframes gradientBG {
      0% { background-position: 0% 50%; }
      50% { background-position: 100% 50%; }
      100% { background-position: 0% 50%; }
    }

    .quiz-container {
      width: 100%;
      max-width: 800px;
      background: rgba(255, 255, 255, 0.1);
      backdrop-filter: blur(10px);
      border-radius: 20px;
      padding: 30px;
      box-shadow: var(--card-shadow);
      border: 1px solid rgba(255, 255, 255, 0.2);
      position: relative;
      overflow: hidden;
    }

    .quiz-container::before {
      content: '';
      position: absolute;
      top: -50%;
      left: -50%;
      width: 200%;
      height: 200%;
      background: radial-gradient(circle, rgba(255,255,255,0.1) 0%, rgba(255,255,255,0) 70%);
      z-index: -1;
    }

    .quiz-header {
      display: flex;
      justify-content: space-between;
      align-items: center;
      margin-bottom: 30px;
      padding-bottom: 15px;
      border-bottom: 1px solid rgba(255, 255, 255, 0.2);
    }

    h1 {
      font-size: 2.5rem;
      text-align: center;
      background: linear-gradient(to right, var(--success), var(--accent));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      margin-bottom: 10px;
      font-weight: 700;
      letter-spacing: 1px;
    }

    .timer-container {
      display: flex;
      align-items: center;
      background: rgba(0, 0, 0, 0.3);
      padding: 10px 20px;
      border-radius: 50px;
      font-weight: 600;
    }

    .timer-container i {
      margin-right: 10px;
      color: var(--warning);
    }

    #timer {
      font-size: 1.5rem;
      font-weight: 700;
      color: var(--warning);
    }

    .question-container {
      background: rgba(255, 255, 255, 0.05);
      border-radius: 15px;
      padding: 25px;
      margin-bottom: 30px;
      position: relative;
      overflow: hidden;
      transition: var(--transition);
    }

    .question-container::after {
      content: '';
      position: absolute;
      top: 0;
      left: 0;
      width: 5px;
      height: 100%;
      background: linear-gradient(to bottom, var(--accent), var(--primary));
    }

    #ques {
      font-size: 1.4rem;
      line-height: 1.6;
      margin-bottom: 0;
      color: var(--light);
      font-weight: 500;
    }

    .options-container {
      display: flex;
      flex-direction: column;
      gap: 15px;
      margin-bottom: 30px;
    }

    label {
      display: flex;
      align-items: center;
      padding: 18px 20px;
      background: rgba(255, 255, 255, 0.07);
      border-radius: 12px;
      cursor: pointer;
      transition: var(--transition);
      border: 2px solid transparent;
      position: relative;
      overflow: hidden;
    }

    label:hover {
      background: rgba(67, 97, 238, 0.2);
      transform: translateY(-3px);
      border-color: rgba(67, 97, 238, 0.5);
    }

    label::before {
      content: '';
      position: absolute;
      top: 0;
      left: 0;
      width: 5px;
      height: 100%;
      background: var(--primary);
      opacity: 0;
      transition: var(--transition);
    }

    label:hover::before {
      opacity: 1;
    }

    input[type="radio"] {
      width: 22px;
      height: 22px;
      margin-right: 15px;
      accent-color: var(--primary);
      cursor: pointer;
    }

    .option-text {
      font-size: 1.1rem;
      color: var(--light);
      flex: 1;
    }

    .btn-container {
      display: flex;
      justify-content: center;
    }

    #btn {
      background: linear-gradient(to right, var(--primary), var(--secondary));
      color: white;
      border: none;
      padding: 15px 40px;
      font-size: 1.1rem;
      border-radius: 50px;
      cursor: pointer;
      transition: var(--transition);
      font-weight: 600;
      letter-spacing: 1px;
      box-shadow: 0 5px 15px rgba(67, 97, 238, 0.4);
      display: flex;
      align-items: center;
      gap: 10px;
    }

    #btn:hover {
      transform: translateY(-3px);
      box-shadow: 0 8px 20px rgba(67, 97, 238, 0.6);
    }

    #btn:disabled {
      background: rgba(255, 255, 255, 0.1);
      color: rgba(255, 255, 255, 0.4);
      cursor: not-allowed;
      transform: none;
      box-shadow: none;
    }

    .progress-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      margin-bottom: 20px;
    }

    .progress-bar {
      height: 10px;
      flex: 1;
      background: rgba(255, 255, 255, 0.1);
      border-radius: 5px;
      overflow: hidden;
      margin: 0 15px;
    }

    .progress-fill {
      height: 100%;
      background: linear-gradient(to right, var(--accent), var(--success));
      border-radius: 5px;
      width: 0%;
      transition: width 0.5s ease;
    }

    .progress-text {
      font-weight: 600;
      font-size: 1rem;
      min-width: 70px;
      text-align: right;
      color: var(--success);
    }

    .quiz-footer {
      display: flex;
      justify-content: space-between;
      align-items: center;
      margin-top: 20px;
      padding-top: 20px;
      border-top: 1px solid rgba(255, 255, 255, 0.1);
      font-size: 0.9rem;
      color: rgba(255, 255, 255, 0.7);
    }

    .difficulty {
      display: flex;
      align-items: center;
      gap: 8px;
    }

    .difficulty i {
      color: var(--warning);
    }

    /* Responsive design */
    @media (max-width: 768px) {
      .quiz-container {
        padding: 20px;
      }
      
      h1 {
        font-size: 2rem;
      }
      
      #ques {
        font-size: 1.2rem;
      }
      
      label {
        padding: 15px;
      }
      
      .option-text {
        font-size: 1rem;
      }
      
      #btn {
        padding: 12px 30px;
      }
    }

    @media (max-width: 480px) {
      body {
        padding: 10px;
      }
      
      .quiz-header {
        flex-direction: column;
        gap: 15px;
      }
      
      .timer-container {
        width: 100%;
        justify-content: center;
      }
      
      .progress-container {
        flex-direction: column;
        gap: 10px;
      }
      
      .progress-bar {
        width: 100%;
        margin: 5px 0;
      }
      
      .quiz-footer {
        flex-direction: column;
        gap: 10px;
        text-align: center;
      }
    }

    /* Animation for options */
    @keyframes fadeIn {
      from { opacity: 0; transform: translateY(10px); }
      to { opacity: 1; transform: translateY(0); }
    }

    label {
      animation: fadeIn 0.5s ease-out;
    }

    label:nth-child(1) { animation-delay: 0.1s; }
    label:nth-child(2) { animation-delay: 0.2s; }
    label:nth-child(3) { animation-delay: 0.3s; }