Default UI redesign (#7429)

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* Update default.sidebar.vue

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* Update sticky-sidebar.ts

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* Update messaging-room.form.vue

* Update timeline.vue

src/client/pages/explore.vue

@@ -1,5 +1,5 @@
 <template>
-<div class="lznhrdub">
+<div class="lznhrdub _root">
 	<div class="_section">
 		<MkInput v-model:value="query" :debounce="true" type="search"><template #icon><Fa :icon="faSearch"/></template><span>{{ $ts.searchUser }}</span></MkInput>