You should modify the unity.css
file of the theme. Here is an example from a theme I modified.
UnityDecoration {
-UnityDecoration-extents: 28px 0 0 0;
-UnityDecoration-input-extents: 10px;
-UnityDecoration-shadow-offset-x: 0px;
-UnityDecoration-shadow-offset-y: 3px;
-UnityDecoration-active-shadow-color: rgba(0, 0, 0, 0.3);
-UnityDecoration-active-shadow-radius: 10px;
-UnityDecoration-inactive-shadow-color: rgba(0, 0, 0, 0.1);
-UnityDecoration-inactive-shadow-radius: 5px;
-UnityDecoration-glow-size: 10px;
-UnityDecoration-glow-color: rgb(221, 72, 20);
-UnityDecoration-title-indent: 10px;
-UnityDecoration-title-fade: 35px;
-UnityDecoration-title-alignment: 0.0;
}
There you see the shaddow
properties which are pretty human readable, at least developer readable. Everybody should know CSS. :-)