@import url('https://fonts.googleapis.com/css2?family=Roboto:wght@300;400;500;700;900&display=swap');

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

        body {
            font-family: 'Roboto', sans-serif;
            background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
            min-height: 100vh;
            display: flex;
            justify-content: center;
            align-items: center;
            padding: 20px;
            position: relative;
            overflow-x: hidden;
        }

        body::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: 
                radial-gradient(circle at 20% 20%, rgba(255, 69, 0, 0.08) 0%, transparent 50%),
                radial-gradient(circle at 80% 80%, rgba(0, 123, 255, 0.08) 0%, transparent 50%);
            pointer-events: none;
        }

        .quiz-container {
            background: linear-gradient(145deg, #ffffff, #f8f9fa);
            border-radius: 25px;
            box-shadow: 0 25px 50px rgba(0, 0, 0, 0.2);
            max-width: 650px;
            width: 100%;
            overflow: hidden;
            position: relative;
            animation: slideIn 0.8s ease-out;
        }

        @keyframes slideIn {
            from {
                opacity: 0;
                transform: translateY(50px) scale(0.95);
            }
            to {
                opacity: 1;
                transform: translateY(0) scale(1);
            }
        }

        .header {
            background: linear-gradient(135deg, #ff4500, #ff6500);
            padding: 25px;
            text-align: center;
            position: relative;
            overflow: hidden;
        }

        .header::before {
            content: '🏙️';
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            font-size: 120px;
            opacity: 0.1;
            animation: rotate 20s linear infinite;
        }

        @keyframes rotate {
            0% { transform: translate(-50%, -50%) rotate(0deg); }
            100% { transform: translate(-50%, -50%) rotate(360deg); }
        }

        .logo {
            color: white;
            font-size: 28px;
            font-weight: 900;
            text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
            margin-bottom: 8px;
            position: relative;
            z-index: 2;
        }

        .subtitle {
            color: rgba(255, 255, 255, 0.95);
            font-size: 18px;
            font-weight: 600;
            margin-bottom: 5px;
            position: relative;
            z-index: 2;
        }

        .tagline {
            color: rgba(255, 255, 255, 0.8);
            font-size: 13px;
            font-weight: 400;
            position: relative;
            z-index: 2;
        }

        .quiz-content {
            padding: 30px;
        }

        .start-screen {
            text-align: center;
        }

        .start-screen h2 {
            color: #333;
            font-size: 26px;
            font-weight: 700;
            margin-bottom: 15px;
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 10px;
        }

        .start-screen p {
            color: #666;
            font-size: 16px;
            line-height: 1.6;
            margin-bottom: 25px;
        }

        .difficulty-selector {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
            gap: 15px;
            margin-bottom: 25px;
        }

        .difficulty-btn {
            background: linear-gradient(145deg, #ffffff, #f8f9fa);
            border: 2px solid #e9ecef;
            border-radius: 12px;
            padding: 15px;
            cursor: pointer;
            transition: all 0.3s ease;
            text-align: center;
        }

        .difficulty-btn:hover {
            border-color: #ff4500;
            transform: translateY(-2px);
            box-shadow: 0 8px 20px rgba(255, 69, 0, 0.15);
        }

        .difficulty-btn.selected {
            background: linear-gradient(145deg, #ff4500, #ff6500);
            border-color: #cc3700;
            color: white;
        }

        .difficulty-title {
            font-weight: 600;
            font-size: 16px;
            margin-bottom: 5px;
        }

        .difficulty-desc {
            font-size: 12px;
            opacity: 0.8;
        }

        .quiz-screen {
            display: none;
        }

        .progress-section {
            margin-bottom: 25px;
        }

        .progress-bar {
            background: #e9ecef;
            border-radius: 10px;
            height: 8px;
            margin-bottom: 15px;
            overflow: hidden;
        }

        .progress-fill {
            background: linear-gradient(90deg, #ff4500, #ff6500);
            height: 100%;
            border-radius: 10px;
            transition: width 0.3s ease;
            width: 0%;
        }

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

        .question-counter {
            color: #666;
            font-size: 14px;
            font-weight: 500;
        }

        .timer {
            background: linear-gradient(145deg, #1a1a2e, #16213e);
            color: white;
            padding: 8px 16px;
            border-radius: 20px;
            font-size: 14px;
            font-weight: 600;
            box-shadow: 0 3px 8px rgba(0, 0, 0, 0.2);
        }

        .question {
            background: linear-gradient(145deg, #f8f9fa, #ffffff);
            border: 2px solid #e9ecef;
            border-radius: 15px;
            padding: 25px;
            margin-bottom: 25px;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
            position: relative;
        }

        .question-category {
            position: absolute;
            top: -10px;
            left: 20px;
            background: linear-gradient(145deg, #0f3460, #16213e);
            color: white;
            padding: 5px 12px;
            border-radius: 12px;
            font-size: 11px;
            font-weight: 600;
            text-transform: uppercase;
            letter-spacing: 1px;
        }

        .question h3 {
            color: #333;
            font-size: 20px;
            font-weight: 600;
            line-height: 1.4;
            margin-bottom: 20px;
            margin-top: 10px;
        }

        .answers {
            display: grid;
            gap: 12px;
        }

        .answer-btn {
            background: linear-gradient(145deg, #ffffff, #f8f9fa);
            border: 2px solid #e9ecef;
            border-radius: 12px;
            padding: 15px 20px;
            text-align: left;
            font-size: 16px;
            font-weight: 500;
            color: #333;
            cursor: pointer;
            transition: all 0.3s ease;
            position: relative;
            overflow: hidden;
        }

        .answer-btn:hover {
            background: linear-gradient(145deg, #f8f9fa, #ffffff);
            border-color: #ff4500;
            transform: translateY(-2px);
            box-shadow: 0 8px 20px rgba(255, 69, 0, 0.15);
        }

        .answer-btn.correct {
            background: linear-gradient(145deg, #28a745, #34ce57);
            border-color: #1e7e34;
            color: white;
            transform: scale(1.02);
        }

        .answer-btn.incorrect {
            background: linear-gradient(145deg, #dc3545, #e4606d);
            border-color: #b02a37;
            color: white;
        }

        .answer-btn.disabled {
            pointer-events: none;
            opacity: 0.7;
        }

        .results-screen {
            display: none;
            text-align: center;
        }

        .score-display {
            background: linear-gradient(145deg, #ff4500, #ff6500);
            color: white;
            border-radius: 20px;
            padding: 30px;
            margin-bottom: 25px;
            position: relative;
            overflow: hidden;
        }

        .score-display::before {
            content: '🏆';
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            font-size: 100px;
            opacity: 0.1;
            animation: bounce 2s infinite;
        }

        @keyframes bounce {
            0%, 100% { transform: translate(-50%, -50%) scale(1); }
            50% { transform: translate(-50%, -50%) scale(1.1); }
        }

        .score-number {
            font-size: 48px;
            font-weight: 900;
            margin-bottom: 10px;
            position: relative;
            z-index: 2;
        }

        .score-text {
            font-size: 18px;
            font-weight: 500;
            position: relative;
            z-index: 2;
        }

        .score-message {
            color: #333;
            font-size: 22px;
            font-weight: 700;
            margin-bottom: 15px;
        }

        .score-description {
            color: #666;
            font-size: 16px;
            line-height: 1.6;
            margin-bottom: 25px;
        }

        .rotterdam-title {
            background: linear-gradient(145deg, #0f3460, #16213e);
            color: white;
            padding: 15px;
            border-radius: 12px;
            margin-bottom: 20px;
            font-weight: 600;
            position: relative;
            z-index: 2;
        }

        .btn {
            background: linear-gradient(145deg, #ff4500, #ff6500);
            border: none;
            border-radius: 12px;
            color: white;
            font-size: 18px;
            font-weight: 600;
            padding: 15px 30px;
            cursor: pointer;
            transition: all 0.3s ease;
            text-transform: uppercase;
            letter-spacing: 1px;
            box-shadow: 0 5px 15px rgba(255, 69, 0, 0.3);
        }

        .btn:hover {
            background: linear-gradient(145deg, #ff6500, #ff7500);
            transform: translateY(-3px);
            box-shadow: 0 8px 25px rgba(255, 69, 0, 0.4);
        }

        .btn:active {
            transform: translateY(-1px);
        }

        .btn-secondary {
            background: linear-gradient(145deg, #6c757d, #868e96);
            box-shadow: 0 5px 15px rgba(108, 117, 125, 0.3);
            margin-left: 15px;
        }

        .btn-secondary:hover {
            background: linear-gradient(145deg, #868e96, #adb5bd);
            box-shadow: 0 8px 25px rgba(108, 117, 125, 0.4);
        }

        .rotterdam-badge {
            position: absolute;
            top: -10px;
            right: 20px;
            background: linear-gradient(145deg, #0f3460, #16213e);
            color: white;
            padding: 6px 15px;
            border-radius: 15px;
            font-size: 11px;
            font-weight: 700;
            text-transform: uppercase;
            letter-spacing: 1px;
            box-shadow: 0 3px 8px rgba(15, 52, 96, 0.4);
        }

        .powered-by {
            text-align: center;
            margin-top: 20px;
            color: #666;
            font-size: 12px;
        }

   .powered-by a {
  color: #ff4500;
  text-decoration: none;
  font-weight: 500;
}

.logo--desktop {
  display: inline;
}

.logo--mobile {
  display: none;
}

@media (max-width: 600px) {
  .quiz-container {
    margin: 10px;
  }

  .quiz-content {
    padding: 20px;
  }

  .logo {
    font-size: 20px;
    word-break: break-word;
    white-space: normal;
    text-align: center;
    padding: 0 10px;
  }

  .logo--desktop {
    display: none;
  }

  .logo--mobile {
    display: inline;
  }

  .no-wrap {
    white-space: nowrap;
    font-size: 1.4rem;
    overflow: hidden;
    text-overflow: ellipsis;
    display: block;
    text-align: center;
  }

  .question h3 {
    font-size: 18px;
  }

  .btn {
    font-size: 16px;
    padding: 12px 25px;
  }

  .btn-secondary {
    margin-left: 0;
    margin-top: 10px;
  }

  .difficulty-selector {
    grid-template-columns: 1fr;
  }
}