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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
    color: #333;
}

/* Contenedor principal (Tarjeta) */
.registro-container {
    background: #ffffff;
    width: 100%;
    max-width: 450px; /* Ancho máximo para PC */
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.2);
}

h2 {
    text-align: center;
    margin-bottom: 20px;
    color: #444;
    font-size: 1.8rem;
}

/* Estilos de alertas PHP */
.alerta {
    padding: 12px;
    margin-bottom: 20px;
    border-radius: 6px;
    text-align: center;
    font-weight: 500;
    font-size: 0.9rem;
}
.error { background: #fee2e2; color: #991b1b; border: 1px solid #fca5a5; }
.exito { background: #dcfce7; color: #166534; border: 1px solid #86efac; }

/* Estilos del formulario */
.form-group {
    margin-bottom: 15px;
}

label {
    display: block;
    margin-bottom: 5px;
    font-weight: 600;
    font-size: 0.9rem;
    color: #555;
}

input {
    width: 100%;
    padding: 12px;
    border: 1px solid #ddd;
    border-radius: 6px;
    font-size: 1rem;
    transition: border-color 0.3s;
    height: 48px; /* Forzamos una altura fija igual para todos */
    appearance: none; /* Quita el estilo 3D nativo de iOS/Android */
    -webkit-appearance: none; /* Para Safari/Chrome en móvil */
    background-color: #fff; /* Asegura fondo blanco */
}

input:focus {
    border-color: #764ba2;
    outline: none;
    box-shadow: 0 0 0 3px rgba(118, 75, 162, 0.1);
}

/* Botón */
button {
    width: 100%;
    padding: 14px;
    background: #28a745;
    background: linear-gradient(to right, #28a745, #218838);
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 1.1rem;
    font-weight: bold;
    cursor: pointer;
    transition: transform 0.1s, opacity 0.2s;
    margin-top: 10px;
}

button:hover {
    opacity: 0.9;
}

button:active {
    transform: scale(0.98);
}

/* Texto pequeño (login link, etc) */
.footer-text {
    text-align: center;
    margin-top: 20px;
    font-size: 0.9rem;
    color: #666;
}

.footer-text a {
    color: #764ba2;
    text-decoration: none;
    font-weight: bold;
}

/* Media Queries para Móvil */
@media (max-width: 480px) {
    .registro-container {
        padding: 20px;
    }
    h2 { font-size: 1.5rem; }
    input { padding: 10px; }
}