How to Use Custom CSS in Vanilla Forums (Inspired by LowEndSpirit Style)
If you’re running a Vanilla Forums site and want to make it look more modern—similar to LowEndSpirit—you can easily do that by adding custom CSS.
This guide will show you step by step how to apply your own CSS and give your forum a fresh, professional design.
Add the custom css to the file :/themes/keystone/design/custom_default.css

This guide will show you step by step how to apply your own CSS and give your forum a fresh, professional design.
Add the custom css to the file :/themes/keystone/design/custom_default.css

.Header {
-webkit-box-shadow: none;
background-color: #60A96D;
border-bottom: 0;
box-shadow: none;
color: #fff;
}
.BoxButtons .Button.Primary, .groupToolbar .Button.Primary {
-o-transition: background .1s ease,border .1s ease;
-webkit-appearance: none;
-webkit-transition: background .1s
ease, border .1s
ease;
background: #60A96D;
border: #4aa55a;
border-radius: 6px;
color: #fff;
display: inline-block;
font-family: Open Sans, Segoe UI, Helvetica Neue, Helvetica, Raleway, Arial, sans-serif;
font-size: 14px;
font-weight: 400;
line-height: 36px;
min-height: 36px;
padding: 0 12px;
text-decoration: none;
transition: background .1s
ease, border .1s
ease;
}