Themes are actually just gzipped css file that overload current css, their name must start by theme- to be recognized and have proper .gz extension if they are compressed.
You only need to put inside the properties you want to customize.
Example of small changes
.feather-icon-container svg,
span.input-group-addon,
span.form-input,
input,
select,
span.text-dark,
label.text-dark,
label.hide-low,
section,
button,
.navbar,
.modal-container,
body,
.empty,
html{
background-color:rgb(200, 200, 233)!important;
color:white!important;
}
a svg.esp3dlogo{
color:#c0c0c0!important;
}
.form-switch input:checked + .form-icon {
background-color:white!important;
}
a.active svg,
a.active label.hide-low{
color:blue!important;
}
.navbar{
border-bottom:white solid 0.5px;
}
span.navbar-section{
background-color:#0e0e6d!important;
color:white!important;
}
How to set a new theme
Upload theme
Upload gzipped (or not) theme using the flash file system panel in dashboard
Select theme
Select theme in interface settings
Once change are applied the webui will automatically restart
