refactor(frontend): prefix css variables (UI) (#14739)

* refactor(frontend): prefix css variables

* `MI_UI` -> `MI`

* fix

* `stickyBottom`

* stickyTop

packages/frontend/src/pages/settings/avatar-decoration.dialog.vue

@@ -151,7 +151,7 @@ async function detach() {
 	left: 0;
 	padding: 12px;
 	border-top: solid 0.5px var(--MI_THEME-divider);
-	-webkit-backdrop-filter: var(--blur, blur(15px));
-	backdrop-filter: var(--blur, blur(15px));
+	-webkit-backdrop-filter: var(--MI-blur, blur(15px));
+	backdrop-filter: var(--MI-blur, blur(15px));
 }
 </style>

packages/frontend/src/pages/settings/avatar-decoration.vue

@@ -145,7 +145,7 @@ definePageMetadata(() => ({
 
 .current {
 	padding: 16px;
-	border-radius: var(--radius);
+	border-radius: var(--MI-radius);
 }
 
 .decorations {

packages/frontend/src/pages/settings/emoji-picker.vue

@@ -248,8 +248,8 @@ definePageMetadata(() => ({
 
 <style lang="scss" module>
 .tab {
-	margin: calc(var(--margin) / 2) 0;
-	padding: calc(var(--margin) / 2) 0;
+	margin: calc(var(--MI-margin) / 2) 0;
+	padding: calc(var(--MI-margin) / 2) 0;
 	background: var(--MI_THEME-bg);
 }
 

packages/frontend/src/pages/settings/preferences-backups.vue

@@ -445,7 +445,7 @@ definePageMetadata(() => ({
 <style lang="scss" module>
 .buttons {
 	display: flex;
-	gap: var(--margin);
+	gap: var(--MI-margin);
 	flex-wrap: wrap;
 }
 

packages/frontend/src/pages/settings/theme.vue

@@ -412,7 +412,7 @@ definePageMetadata(() => ({
 .rsljpzjq {
 	> .selects {
 		display: flex;
-		gap: 1.5em var(--margin);
+		gap: 1.5em var(--MI-margin);
 		flex-wrap: wrap;
 
 		> .select {