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

body {
    font-family: Arial, sans-serif;
    background: linear-gradient(135deg, #667eea, #764ba2);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.contenedor {
    background: white;
    padding: 40px;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    width: 100%;
    max-width: 400px;
}

h1 {
    text-align: center;
    color: #333;
    margin-bottom: 30px;
}

.campo {
    margin-bottom: 20px;
}

label {
    display: block;
    margin-bottom: 8px;
    color: #555;
    font-weight: bold;
}

input,
select {
    width: 100%;
    padding: 12px;
    border: 2px solid #ddd;
    border-radius: 8px;
    font-size: 16px;
}

input:focus,
select:focus {
    outline: none;
    border-color: #667eea;
}

.btn-intercambiar {
    width: 100%;
    padding: 10px;
    background: #f0f0f0;
    border: 2px solid #ddd;
    border-radius: 8px;
    cursor: pointer;
    font-size: 14px;
    margin-bottom: 20px;
}

.btn-intercambiar:hover {
    background: #e0e0e0;
}

.btn-convertir {
    width: 100%;
    padding: 15px;
    background: #667eea;
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 18px;
    font-weight: bold;
    cursor: pointer;
}

.btn-convertir:hover {
    background: #5a6fd6;
}

.resultado {
    margin-top: 20px;
    padding: 15px;
    background: #d4edda;
    border-radius: 8px;
    text-align: center;
    color: #155724;
    font-weight: bold;
    display: none;
}

.error {
    margin-top: 20px;
    padding: 15px;
    background: #f8d7da;
    border-radius: 8px;
    text-align: center;
    color: #721c24;
    display: none;
}