:root {
    --primary-color: #4361ee;
    --secondary-color: #3f37c9;
    --accent-color: #4cc9f0;
    --success-color: #4caf50;
    --error-color: #f44336;
    --warning-color: #ff9800;
    --light-color: #f8f9fa;
    --dark-color: #212529;
    --text-color: #333;
    --border-radius: 12px;
    --box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Roboto', sans-serif;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    color: var(--text-color);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.container {
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
}

.header {
    text-align: center;
    margin-bottom: 30px;
    animation: fadeIn 0.8s ease;
}

.header h1 {
    font-family: 'Poppins', sans-serif;
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.header .subtitle {
    font-size: 1.1rem;
    color: var(--dark-color);
    opacity: 0.8;
}

.student-info {
    margin-bottom: 20px;
    animation: slideUp 0.5s ease;
}

.input-group {
    margin-bottom: 15px;
}

.input-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--dark-color);
    display: flex;
    align-items: center;
    gap: 8px;
}

.input-group input {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid #ddd;
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
}

.input-group input:focus {
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.2);
}

.exercise-card {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    overflow: hidden;
    margin-bottom: 30px;
    animation: fadeIn 0.8s ease;
    transition: var(--transition);
}

.exercise-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.15);
}

.card-header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 15px 20px;
}

.card-header h2 {
    font-size: 1.3rem;
    display: flex;
    align-items: center;
    gap: 10px;
}

.card-body {
    padding: 20px;
}

#exerciseStatement {
    margin-bottom: 20px;
    font-size: 1.1rem;
    line-height: 1.6;
    color: var(--text-color);
}

.input-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
    margin-bottom: 20px;
}

.magnitude, .numInc {
    padding: 12px;
    border-radius: 8px;
    border: none;
    font-size: 1rem;
    text-align: center;
    transition: var(--transition);
}

.magnitude {
    background-color: #e3f2fd;
    color: var(--primary-color);
    font-weight: bold;
}

.numInc {
    background-color: #e8f5e9;
    color: #2e7d32;
}

.answer-section {
    margin-top: 20px;
}

.answer-section label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 8px;
}

.answer-section input {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid #ddd;
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
}

.answer-section input:focus {
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.2);
}

.card-footer {
    padding: 15px 20px;
    background-color: #f8f9fa;
    border-top: 1px solid #eee;
}

.button-container {
    display: flex;
    gap: 15px;
    margin-bottom: 15px;
}

.btn-primary, .btn-secondary {
    flex: 1;
    padding: 12px;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background-color: var(--secondary-color);
    transform: translateY(-2px);
}

.btn-primary:disabled {
    background-color: #a0a0a0;
    cursor: not-allowed;
    transform: none;
}

.btn-secondary {
    background-color: var(--light-color);
    color: var(--dark-color);
    border: 2px solid #ddd;
}

.btn-secondary:hover {
    background-color: #e9ecef;
    border-color: #ced4da;
}

.btn-secondary:disabled {
    opacity: 0.7;
    cursor: not-allowed;
}

.feedback-message {
    padding: 10px;
    border-radius: 8px;
    font-size: 0.95rem;
    display: flex;
    align-items: center;
    gap: 8px;
}

.feedback-message i {
    font-size: 1.1rem;
}

.stats-panel {
    display: flex;
    justify-content: space-around;
    background: white;
    padding: 15px;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    margin-bottom: 20px;
    animation: slideUp 0.6s ease;
}

.stat-item {
    text-align: center;
}

.stat-label {
    display: block;
    font-size: 0.9rem;
    color: #666;
    margin-bottom: 5px;
}

.stat-value {
    font-size: 1.3rem;
    font-weight: bold;
}

.stat-value.correct {
    color: var(--success-color);
}

.stat-value.incorrect {
    color: var(--error-color);
}

.watermark {
    text-align: center;
    font-size: 0.8rem;
    color: #999;
    margin-top: 20px;
    opacity: 0.7;
}

/* Animaciones */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Responsive */
@media (max-width: 768px) {
    .header h1 {
        font-size: 2rem;
    }
    
    .input-grid {
        grid-template-columns: 1fr;
    }
    
    .button-container {
        flex-direction: column;
    }
    
    .stats-panel {
        flex-direction: column;
        gap: 15px;
    }
}