Css is now included via a custom file, not inline

Author: oli-obk

src/skill_tree.md

@@ -1,29 +1,5 @@
 # Skill tree for const eval features
 
-<style>
-      /* the lines within the edges */
-      .edge:active path,
-      .edge:hover path {
-        stroke: fuchsia;
-        stroke-width: 3;
-        stroke-opacity: 1;
-      }
-      /* arrows are typically drawn with a polygon */
-      .edge:active polygon,
-      .edge:hover polygon {
-        stroke: fuchsia;
-        stroke-width: 3;
-        fill: fuchsia;
-        stroke-opacity: 1;
-        fill-opacity: 1;
-      }
-      /* If you happen to have text and want to color that as well... */
-      .edge:active text,
-      .edge:hover text {
-        fill: fuchsia;
-      }
-</style>
-
 ```skill-tree
 [[group]]
 name = "mut_ref"