* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: #f5f7fa;
    color: #333;
    line-height: 1.6;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.container {
    max-width: 800px;
    width: 100%;
    margin: 0 auto;
    background-color: white;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    padding: 40px;
    overflow: hidden;
}

h1 {
    color: #2c3e50;
    text-align: center;
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 3px solid #3498db;
    font-size: 1.8rem;
}

h2 {
    color: #2c3e50;
    margin-bottom: 25px;
    font-size: 1.4rem;
    text-align: center;
}

.step {
    display: none;
    animation: fadeIn 0.5s ease-in-out;
}

.step.active {
    display: block;
}

.options {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    margin: 30px 0;
    justify-content: center;
}

.option-btn {
    flex: 1 1 calc(50% - 15px);
    min-width: 250px;
    padding: 18px 20px;
    background-color: #3498db;
    color: white;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    font-size: 16px;
    font-weight: 500;
    transition: all 0.3s ease;
    text-align: center;
    box-shadow: 0 4px 6px rgba(50, 50, 93, 0.11);
}

.option-btn:hover {
    background-color: #2980b9;
    transform: translateY(-3px);
    box-shadow: 0 7px 14px rgba(50, 50, 93, 0.1);
}

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

.back-btn {
    background-color: #95a5a6;
}

.back-btn:hover {
    background-color: #7f8c8d;
}

.restart-btn {
    background-color: #2ecc71;
    font-weight: 600;
}

.restart-btn:hover {
    background-color: #27ae60;
}

.result {
    background-color: #e8f4fc;
    border-left: 5px solid #3498db;
    padding: 25px;
    margin: 30px 0;
    border-radius: 8px;
    display: none;
    animation: fadeIn 0.5s ease-in-out;
}

.result.active {
    display: block;
}

.result h3 {
    color: #2c3e50;
    margin-bottom: 15px;
    font-size: 1.3rem;
}

.result p {
    margin-bottom: 10px;
    font-size: 1.1rem;
    line-height: 1.8;
    color: #2c3e50;
    background-color: white;
    padding: 15px;
    border-radius: 5px;
    border-left: 4px solid #2ecc71;
}

strong {
    color: #2c3e50;
    font-weight: 600;
}

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

@media (max-width: 768px) {
    .container {
        padding: 25px;
        margin: 10px;
    }
    
    .option-btn {
        flex: 1 1 100%;
        min-width: 100%;
    }
    
    h1 {
        font-size: 1.5rem;
    }
    
    h2 {
        font-size: 1.2rem;
    }
}

@media (max-width: 480px) {
    body {
        padding: 10px;
    }
    
    .container {
        padding: 20px;
    }
    
    .option-btn {
        padding: 16px;
        font-size: 15px;
    }
}

.option-btn:focus {
    outline: 3px solid #3498db;
    outline-offset: 2px;
}

.option-btn:disabled {
    background-color: #bdc3c7;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

/* --- Botones tipo checkbox --- */
.option-btn.checkbox-btn.selected {
    background-color: #27ae60;
    box-shadow: inset 0 0 0 3px #ffffff, 0 4px 6px rgba(50, 50, 93, 0.11);
}

.option-btn.checkbox-btn.selected::before {
    content: "✓ ";
    font-weight: 700;
}