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

body {
    font-family: 'Segoe UI', 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: linear-gradient(135deg, #f5f7fa 0%, #e8ecf1 100%);
    min-height: 100vh;
    padding: 20px;
    color: #333;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background: #ffffff;
    border-radius: 20px;
    box-shadow: 0 10px 40px rgba(11, 94, 215, 0.15);
    padding: 30px;
    animation: fadeIn 0.5s ease-in;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

header {
    text-align: center;
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 3px solid #0b5ed7;
}

header h1 {
    color: #0b5ed7;
    font-size: 2.2em;
    margin-bottom: 10px;
    font-weight: 700;
}

.subtitle {
    color: #666;
    font-size: 1.1em;
    font-weight: 500;
}

/* Progress Section */
.progress-section {
    margin-bottom: 25px;
}

.progress-bar-container {
    width: 100%;
    height: 12px;
    background-color: #e0e0e0;
    border-radius: 10px;
    overflow: hidden;
    margin-bottom: 10px;
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.1);
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, #0b5ed7 0%, #4dabf7 100%);
    border-radius: 10px;
    transition: width 0.4s ease;
    width: 0%;
}

.progress-text {
    text-align: center;
    color: #666;
    font-weight: 500;
    font-size: 0.95em;
}

/* Score Display */
.score-display {
    text-align: center;
    background: linear-gradient(135deg, #0b5ed7 0%, #4dabf7 100%);
    color: white;
    padding: 15px;
    border-radius: 12px;
    margin-bottom: 25px;
    font-size: 1.2em;
    font-weight: 600;
    box-shadow: 0 4px 15px rgba(11, 94, 215, 0.3);
}

/* Question Container */
.question-container {
    background: #f8f9fa;
    border: 2px solid #e0e0e0;
    border-radius: 15px;
    padding: 25px;
    margin-bottom: 20px;
    animation: slideIn 0.3s ease;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-10px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.question-text {
    font-size: 1.3em;
    font-weight: 600;
    color: #0b5ed7;
    margin-bottom: 20px;
    line-height: 1.5;
}

.options-container {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.option {
    background: white;
    border: 2px solid #d0d0d0;
    border-radius: 10px;
    padding: 15px 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 1.05em;
    display: flex;
    align-items: center;
    gap: 12px;
}

.option:hover {
    border-color: #0b5ed7;
    background: #f0f7ff;
    transform: translateX(5px);
    box-shadow: 0 4px 12px rgba(11, 94, 215, 0.15);
}

.option input[type="radio"] {
    width: 20px;
    height: 20px;
    cursor: pointer;
    accent-color: #0b5ed7;
}

.option.selected {
    border-color: #0b5ed7;
    background: #e8f4ff;
    box-shadow: 0 4px 12px rgba(11, 94, 215, 0.2);
}

.option.correct {
    border-color: #28a745;
    background: #d4edda;
    animation: correctPulse 0.5s ease;
}

.option.incorrect {
    border-color: #dc3545;
    background: #f8d7da;
    animation: shake 0.5s ease;
}

@keyframes correctPulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.02); }
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    75% { transform: translateX(5px); }
}

/* Feedback Container */
.feedback-container {
    background: #f8f9fa;
    border-radius: 15px;
    padding: 25px;
    margin-bottom: 20px;
    animation: fadeInUp 0.4s ease;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.feedback-result {
    font-size: 1.4em;
    font-weight: 700;
    margin-bottom: 15px;
    padding: 12px;
    border-radius: 10px;
    text-align: center;
}

.feedback-result.correct {
    background: #d4edda;
    color: #155724;
    border: 2px solid #28a745;
}

.feedback-result.incorrect {
    background: #f8d7da;
    color: #721c24;
    border: 2px solid #dc3545;
}

.praise-message {
    font-size: 1.1em;
    font-weight: 600;
    color: #0b5ed7;
    text-align: center;
    margin-bottom: 15px;
    padding: 10px;
    background: #e8f4ff;
    border-radius: 8px;
    border-left: 4px solid #0b5ed7;
}

.explanation {
    background: white;
    padding: 18px;
    border-radius: 10px;
    margin-bottom: 15px;
    border-left: 4px solid #0b5ed7;
}

.explanation h3 {
    color: #0b5ed7;
    margin-bottom: 10px;
    font-size: 1.1em;
}

.explanation p {
    color: #555;
    line-height: 1.6;
}

.learning-note {
    background: #fff3cd;
    padding: 18px;
    border-radius: 10px;
    border-left: 4px solid #ffc107;
}

.learning-note h3 {
    color: #856404;
    margin-bottom: 10px;
    font-size: 1.1em;
}

.learning-note p {
    color: #856404;
    line-height: 1.6;
    font-weight: 500;
}

/* Learning Report */
.learning-report {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: 20px;
    padding: 35px;
    margin-bottom: 25px;
    text-align: center;
    animation: scaleIn 0.5s ease;
    box-shadow: 0 10px 30px rgba(102, 126, 234, 0.3);
}

@keyframes scaleIn {
    from {
        opacity: 0;
        transform: scale(0.9);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

.report-header {
    font-size: 2em;
    font-weight: 700;
    margin-bottom: 20px;
}

.final-score {
    font-size: 3em;
    font-weight: 700;
    margin: 20px 0;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
}

.understanding-level {
    font-size: 1.5em;
    font-weight: 600;
    margin: 20px 0;
    padding: 15px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 10px;
}

.recommendations {
    margin-top: 25px;
    text-align: left;
    background: rgba(255, 255, 255, 0.15);
    padding: 20px;
    border-radius: 10px;
}

.recommendations h3 {
    margin-bottom: 15px;
    font-size: 1.3em;
}

.recommendations ul {
    list-style: none;
    padding-left: 0;
}

.recommendations li {
    margin: 10px 0;
    padding-left: 25px;
    position: relative;
    line-height: 1.6;
}

.recommendations li:before {
    content: "📚";
    position: absolute;
    left: 0;
}

/* Buttons */
.button-group {
    display: flex;
    gap: 15px;
    justify-content: center;
    flex-wrap: wrap;
}

.btn {
    padding: 15px 30px;
    font-size: 1.1em;
    font-weight: 600;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: inherit;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.btn-primary {
    background: linear-gradient(135deg, #0b5ed7 0%, #4dabf7 100%);
    color: white;
}

.btn-primary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(11, 94, 215, 0.4);
}

.btn-primary:active:not(:disabled) {
    transform: translateY(0);
}

.btn-primary:disabled {
    background: #ccc;
    cursor: not-allowed;
    opacity: 0.6;
}

.btn-secondary {
    background: linear-gradient(135deg, #28a745 0%, #48d467 100%);
    color: white;
}

.btn-secondary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(40, 167, 69, 0.4);
}

.btn-restart {
    background: linear-gradient(135deg, #ff6b6b 0%, #ff8787 100%);
    color: white;
}

.btn-restart:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(255, 107, 107, 0.4);
}

.hidden {
    display: none;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 20px;
        border-radius: 15px;
    }

    header h1 {
        font-size: 1.6em;
    }

    .question-text {
        font-size: 1.1em;
    }

    .option {
        padding: 12px 15px;
        font-size: 1em;
    }

    .btn {
        padding: 12px 25px;
        font-size: 1em;
        width: 100%;
    }

    .button-group {
        flex-direction: column;
    }

    .final-score {
        font-size: 2.2em;
    }

    .report-header {
        font-size: 1.6em;
    }
}