Refactor: CSS handling (#2344)

* refactor(css): only load base styles, add css task, cleanup exports
* style(base): add edge label bg
* refactor(css): use css-utils
* feat(core): add Panel component
* refactor(background): cleanup
* refactor(css-handling): cleanup

packages/core/src/utils/index.ts

@@ -36,7 +36,7 @@ export const boxToRect = ({ x, y, x2, y2 }: Box): Rect => ({
   height: y2 - y,
 });
 
-export const getBoundsofRects = (rect1: Rect, rect2: Rect): Rect =>
+export const getBoundsOfRects = (rect1: Rect, rect2: Rect): Rect =>
   boxToRect(getBoundsOfBoxes(rectToBox(rect1), rectToBox(rect2)));
 
 export const isNumeric = (n: any): n is number => !isNaN(n) && isFinite(n);