Add the code below to the Custom CSS field on your Form widget’s Appearance tab:
@media (max-width: 600px) {
[class*="HorizontalLayout__Grid-sc"] {
display: flex;
flex-direction: column;
gap: 10px;
}
[class*="HorizontalLayout__HorizontalSubmitButton-sc"] {
margin: 0;
}
.es-field-layout-container {
padding: 0;
}
}