So theres some bottom margin on the form – which can be removed with this CSS:
.mailster-form {
margin-bottom: 0 !important;
}
On real small screens you could add this to make the field/button stack:
@media (max-width: 600px) {
.mailster-form-fields {
flex-wrap: wrap;
}
.mailster-form .mailster-wrapper.mailster-email-wrapper,
.mailster-form .mailster-wrapper {
flex: 1 0 100%;
margin-bottom: 10px;
}
.mailster-form input {
width: 100%;
}
}
Then it just looks like you need to give the Grid Container blocks padding to put some space around the field on mobile.