Optimize and rewrite backdrop rendering

res/css/structures/_BackdropPanel.scss

@@ -21,16 +21,6 @@ limitations under the License.
     height: 100vh;
     width: 100%;
     overflow: hidden;
-
-    &::before {
-        content: " ";
-        position: absolute;
-        left: 0;
-        top: 0;
-        height: 100vh;
-        width: 100%;
-        background-color: var(--lp-background-overlay);
-    }
 }
 
 .mx_BackdropPanel--canvas {

res/css/structures/_LeftPanel.scss

@@ -27,8 +27,37 @@ $roomListCollapsedWidth: 68px;
 .mx_LeftPanel_wrapper {
     display: flex;
     max-width: 50%;
+
+    .mx_LeftPanel_background {
+
+        &::before {
+            content: " ";
+            position: absolute;
+            left: 0;
+            top: 0;
+            height: 100vh;
+            width: 100%;
+            background-color: var(--lp-background-overlay);
+        }
+
+        position: absolute;
+        left: 0;
+        top: 0;
+        width: 100%;
+        height: 100%;
+        background-color: $roomlist-bg-color;
+        opacity: 0.5;
+    }
+
+    .mx_LeftPanel_wrapper--user {
+        display: flex;
+        overflow: hidden;
+        position: relative;
+    }
 }
 
+
+
 .mx_LeftPanel {
     background-color: $roomlist-bg-color;
     // TODO decrease this once Spaces launches as it'll no longer need to include the 56px Community Panel

res/themes/dark/css/_dark.scss

@@ -240,7 +240,6 @@ $appearance-tab-border-color: $room-highlight-color;
 
 // blur amounts for left left panel (only for element theme)
 :root {
-    --llp-background-blur: 160px;
     --lp-background-blur: 90px;
     --lp-background-overlay: rgba(255, 255, 255, 0.055);
 }

res/themes/light/css/_light.scss

@@ -363,7 +363,6 @@ $appearance-tab-border-color: $input-darker-bg-color;
 
 // blur amounts for left left panel (only for element theme)
 :root {
-    --llp-background-blur: 120px;
     --lp-background-blur: 60px;
     --lp-background-overlay: rgba(0, 0, 0, 0.055);
 }