.form-floating-box {
    position: sticky;
    top: 100px;
    z-index: 10;
}

.contact-form {
    background: #fff;
    padding: 20px;
    border-radius: 16px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.15);
    border: 1px solid #eee;
}

/* CLAVE REAL: evita que el sticky “invada” el footer visualmente */
#formulario {
    padding-bottom: 120px;
}