.umbraco-forms-form .my-custom-container input.text, .umbraco-forms-form .my-custom-container textarea {
    max-width: 100% !important;
    padding: 10px;
    width: 100%;
}


body .umbraco-forms-form input.text,
body .umbraco-forms-form textarea {
    max-width: 100% !important;
    padding: 10px !important;
    width: 100% !important;
}