fix(core): update

ts/domtools.elementbasic.ts

@@ -10,6 +10,7 @@ import { html, LitElement } from 'lit-element';
 export const styles = html`
   <style>
     * {
+      transition: background 0.2s, color 0.1s;
       font-family: 'Roboto', sans-serif;
       box-sizing: border-box;
     }