fix(client): close #37, use scoped style

BREAKING CHANGE: This plugin's components will use scoped style,
see https://vue-loader.vuejs.org/guide/scoped-css.html#scoped-css

Author: BuptStEve

src/client/DemoAndCode.vue

@@ -153,11 +153,12 @@ export default {
 </script>
 
 <style lang="stylus">
-
 html {
   scroll-behavior: smooth;
 }
+</style>
 
+<style lang="stylus" scoped>
 .demo-and-code-wrapper {
   padding: 20px 0;
 

src/client/OnlineEdit.vue

@@ -110,7 +110,7 @@ export default {
 }
 </script>
 
-<style lang="stylus">
+<style lang="stylus" scoped>
 .demo-and-code-online-edit-wrapper {
   display: inline-block;