Uikit -Thema
// default value
@button-height: 30px;
The Gem Dev
// default value
@button-height: 30px;// CSS rule
.uk-panel {
background: @background;
// mixin to add new declaration
.hook-panel;
}// new value
@button-height: 35px;// mixin to add new declaration
.hook-panel() { color: #fff; }