/* Reset y configuración base */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: #333;
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

/* Header */
header {
    text-align: center;
    margin-bottom: 30px;
    background: rgba(255, 255, 255, 0.95);
    padding: 30px;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    backdrop-filter: blur(10px);
}

header h1 {
    font-size: 2.5rem;
    color: #4a5568;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.1);
}

header p {
    font-size: 1.2rem;
    color: #718096;
    font-weight: 500;
}

/* Controles */
.controls {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 20px;
    margin-bottom: 30px;
    flex-wrap: wrap;
}

.btn {
    padding: 15px 30px;
    border: none;
    border-radius: 50px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 1px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

.btn-primary {
    background: linear-gradient(45deg, #48bb78, #38a169);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(72, 187, 120, 0.4);
}

.btn-secondary {
    background: linear-gradient(45deg, #ed8936, #dd6b20);
    color: white;
}

.btn-secondary:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(237, 137, 54, 0.4);
}

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

.score {
    background: rgba(255, 255, 255, 0.9);
    padding: 15px 25px;
    border-radius: 25px;
    font-weight: 600;
    font-size: 1.1rem;
    color: #4a5568;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

/* Grid de multiplicaciones */
.multiplications-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.multiplication-item {
    background: rgba(255, 255, 255, 0.95);
    padding: 25px;
    border-radius: 15px;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
}

.multiplication-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.2);
}

.multiplication-text {
    font-size: 1.4rem;
    font-weight: 600;
    color: #2d3748;
    margin-bottom: 15px;
    text-align: center;
}

.multiplication-input {
    width: 100%;
    padding: 15px;
    border: 3px solid #e2e8f0;
    border-radius: 10px;
    font-size: 1.2rem;
    text-align: center;
    transition: all 0.3s ease;
    background: #f7fafc;
}

.multiplication-input:focus {
    outline: none;
    border-color: #667eea;
    background: white;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.multiplication-input.correct {
    border-color: #48bb78;
    background: #f0fff4;
}

.multiplication-input.incorrect {
    border-color: #f56565;
    background: #fff5f5;
}

.multiplication-input.disabled {
    background: #edf2f7;
    cursor: not-allowed;
}

/* Resultados */
.results {
    background: rgba(255, 255, 255, 0.95);
    padding: 40px;
    border-radius: 20px;
    text-align: center;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    backdrop-filter: blur(10px);
}

.results h2 {
    font-size: 2rem;
    color: #4a5568;
    margin-bottom: 20px;
}

.score-display {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 20px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.score-display span {
    font-size: 2.5rem;
    font-weight: 700;
    padding: 20px 30px;
    border-radius: 15px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

#finalScore {
    background: linear-gradient(45deg, #667eea, #764ba2);
    color: white;
}

#percentage {
    background: linear-gradient(45deg, #48bb78, #38a169);
    color: white;
}

.message {
    font-size: 1.3rem;
    font-weight: 600;
    padding: 20px;
    border-radius: 10px;
    margin-top: 20px;
}

.message.excellent {
    background: linear-gradient(45deg, #48bb78, #38a169);
    color: white;
}

.message.good {
    background: linear-gradient(45deg, #ed8936, #dd6b20);
    color: white;
}

.message.needs-improvement {
    background: linear-gradient(45deg, #f56565, #e53e3e);
    color: white;
}

/* Responsive */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    header h1 {
        font-size: 2rem;
    }
    
    header p {
        font-size: 1rem;
    }
    
    .controls {
        flex-direction: column;
        gap: 15px;
    }
    
    .btn {
        width: 100%;
        max-width: 300px;
    }
    
    .multiplications-grid {
        grid-template-columns: 1fr;
        gap: 15px;
    }
    
    .multiplication-item {
        padding: 20px;
    }
    
    .multiplication-text {
        font-size: 1.2rem;
    }
    
    .multiplication-input {
        font-size: 1.1rem;
        padding: 12px;
    }
    
    .score-display {
        flex-direction: column;
        gap: 15px;
    }
    
    .score-display span {
        font-size: 2rem;
        padding: 15px 25px;
    }
}

@media (max-width: 480px) {
    header h1 {
        font-size: 1.8rem;
    }
    
    .multiplication-text {
        font-size: 1.1rem;
    }
    
    .multiplication-input {
        font-size: 1rem;
        padding: 10px;
    }
    
    .score-display span {
        font-size: 1.8rem;
        padding: 12px 20px;
    }
}

/* Animaciones */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.multiplication-item {
    animation: fadeIn 0.5s ease-out;
}

.multiplication-item:nth-child(odd) {
    animation-delay: 0.1s;
}

.multiplication-item:nth-child(even) {
    animation-delay: 0.2s;
}

/* Efectos de hover mejorados */
.multiplication-item:hover .multiplication-input {
    border-color: #667eea;
    transform: scale(1.02);
}

/* Estados de validación */
.multiplication-item.validated .multiplication-input {
    pointer-events: none;
}

.multiplication-item.validated.correct {
    background: linear-gradient(135deg, #f0fff4, #c6f6d5);
}

.multiplication-item.validated.incorrect {
    background: linear-gradient(135deg, #fff5f5, #fed7d7);
}