:root {
    --color-principal: #2ecc71;
    --color-principal-hover: #27ae60;
    --color-texto: #333;
    --color-texto-secundario: #666;
    --color-fondo: #f4f7f6;
    --color-borde: #ddd;
    --color-error: #e74c3c;
    --color-exito: #27ae60;
}

* {
    box-sizing: border-box;
}

body {
    font-family: Arial, sans-serif;
    background-color: var(--color-fondo);
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 24px 16px;
    margin: 0;
    min-height: 100vh;
}

.contenedor {
    background: white;
    padding: 32px;
    border-radius: 16px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
    width: 100%;
    max-width: 420px;
}

h1 {
    margin-top: 0;
    margin-bottom: 10px;
    text-align: center;
    color: var(--color-texto);
    font-size: clamp(1.7rem, 4vw, 2rem);
}

.subtitulo {
    text-align: center;
    color: var(--color-texto-secundario);
    margin-bottom: 24px;
    font-size: 0.95rem;
    line-height: 1.5;
}

.formulario {
    display: flex;
    flex-direction: column;
    gap: 14px;
}

input {
    padding: 14px 16px;
    border: 1px solid var(--color-borde);
    border-radius: 10px;
    font-size: 1rem;
    width: 100%;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

input:focus {
    outline: none;
    border-color: var(--color-principal);
    box-shadow: 0 0 0 3px rgba(46, 204, 113, 0.15);
}

button {
    padding: 14px 16px;
    background-color: var(--color-principal);
    color: white;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: bold;
    transition: background-color 0.2s ease, transform 0.2s ease;
}

button:hover {
    background-color: var(--color-principal-hover);
}

button:active {
    transform: translateY(1px);
}

#mensajeError {
    min-height: 1.2rem;
    margin-top: 14px;
    text-align: center;
    font-size: 0.9rem;
    line-height: 1.4;
}

.error {
    color: var(--color-error);
}

.exito {
    color: var(--color-exito);
}

@media (max-width: 480px) {
    body {
        padding: 16px 12px;
        align-items: center;
    }

    .contenedor {
        padding: 24px 18px;
        border-radius: 14px;
    }

    .subtitulo {
        margin-bottom: 20px;
    }
}