To decrease or increase a section height on Mobile Squarespace, you can follow these.
First, you need to find the Section ID, using the Squarespace ID Finder tool.
In my example, we will have ID:
section[data-section-id="6673f2e18432c25013aee9a2"]
Next, use this code to Custom CSS box
Replace 30 with the number that you want. You can also use vh or px.
@media screen and (max-width:767px) {
section[data-section-id="6673f2e18432c25013aee9a2"] {
min-height: unset !important;
height: 30vh !important;
}
}