diff --git a/src/app/components/upload-card/UploadCardRenderer.tsx b/src/app/components/upload-card/UploadCardRenderer.tsx
index 4628e2b26..fe616c746 100644
--- a/src/app/components/upload-card/UploadCardRenderer.tsx
+++ b/src/app/components/upload-card/UploadCardRenderer.tsx
@@ -13,6 +13,7 @@ import {
 import { useObjectURL } from '../../hooks/useObjectURL';
 import { useMediaConfig } from '../../hooks/useMediaConfig';
 import { compressImage, formatFileSize, isCompressible } from '../../utils/imageCompression';
+import { tryDeleteMxcContent } from '../../utils/matrix';
 
 type PreviewImageProps = {
   fileItem: TUploadItem;
@@ -274,6 +275,10 @@ export function UploadCardRenderer({
   };
 
   const removeUpload = () => {
+    if (upload.status === UploadStatus.Success) {
+      // Upload already completed — delete the orphaned MXC from the server.
+      tryDeleteMxcContent(mx, upload.mxc);
+    }
     cancelUpload();
     onRemove(file);
   };
diff --git a/src/app/features/room/RoomInput.tsx b/src/app/features/room/RoomInput.tsx
index 6c54104a1..0444365f2 100644
--- a/src/app/features/room/RoomInput.tsx
+++ b/src/app/features/room/RoomInput.tsx
@@ -65,6 +65,7 @@ import {
   getImageInfo,
   getMxIdLocalPart,
   mxcUrlToHttp,
+  tryDeleteMxcContent,
 } from '../../utils/matrix';
 import { compressImage } from '../../utils/imageCompression';
 import { useTypingStatusUpdater } from '../../hooks/useTypingStatusUpdater';
@@ -434,6 +435,8 @@ export const RoomInput = forwardRef<HTMLDivElement, RoomInputProps>(
             });
             const compressedMxc = (uploadRes as { content_uri: string }).content_uri;
             if (compressedMxc) {
+              // Delete the pre-uploaded original so only one copy lives on the server.
+              tryDeleteMxcContent(mx, upload.mxc);
               mxc = compressedMxc;
               // Build a synthetic fileItem that refers to the compressed file so
               // getImageMsgContent picks up the correct dimensions and type.
diff --git a/src/app/pages/client/SidebarNav.tsx b/src/app/pages/client/SidebarNav.tsx
index 8f0ec1ead..9a5910eae 100644
--- a/src/app/pages/client/SidebarNav.tsx
+++ b/src/app/pages/client/SidebarNav.tsx
@@ -1,4 +1,4 @@
-import React, { useRef } from 'react';
+import React, { useEffect, useRef } from 'react';
 import { Scroll } from 'folds';
 import classNames from 'classnames';
 
@@ -23,10 +23,42 @@ import {
 import { CreateTab } from './sidebar/CreateTab';
 import { useSetting } from '../../state/hooks/settings';
 import { settingsAtom } from '../../state/settings';
+import { useTheme, ThemeKind } from '../../hooks/useTheme';
+import { getChatBg } from '../../features/lotus/chatBackground';
 
 export function SidebarNav() {
   const scrollRef = useRef<HTMLDivElement>(null) as React.RefObject<HTMLDivElement>;
   const [glassmorphismSidebar] = useSetting(settingsAtom, 'glassmorphismSidebar');
+  const [chatBackground] = useSetting(settingsAtom, 'chatBackground');
+  const [lotusTerminal] = useSetting(settingsAtom, 'lotusTerminal');
+  const theme = useTheme();
+  const isDark = theme.kind === ThemeKind.Dark;
+
+  // backdrop-filter only blurs content directly behind the element in the z-axis.
+  // The sidebar is a flex sibling of the room view, so nothing sits behind it by default.
+  // Fix: mirror the active chat background onto document.body so the sidebar blurs through it.
+  useEffect(() => {
+    const { style } = document.body;
+    if (!glassmorphismSidebar) {
+      style.removeProperty('background-image');
+      style.removeProperty('background-color');
+      style.removeProperty('background-size');
+      style.removeProperty('background-position');
+      return;
+    }
+    const effectiveBg = lotusTerminal && chatBackground === 'none' ? 'tactical' : chatBackground;
+    const bgStyle = getChatBg(effectiveBg, isDark);
+    style.backgroundImage = (bgStyle.backgroundImage as string | undefined) ?? '';
+    style.backgroundColor = (bgStyle.backgroundColor as string | undefined) ?? '';
+    style.backgroundSize = (bgStyle.backgroundSize as string | undefined) ?? '';
+    style.backgroundPosition = (bgStyle.backgroundPosition as string | undefined) ?? '';
+    return () => {
+      style.removeProperty('background-image');
+      style.removeProperty('background-color');
+      style.removeProperty('background-size');
+      style.removeProperty('background-position');
+    };
+  }, [glassmorphismSidebar, chatBackground, lotusTerminal, isDark]);
 
   return (
     <Sidebar className={classNames(glassmorphismSidebar && SidebarGlass)}>
diff --git a/src/app/utils/matrix.ts b/src/app/utils/matrix.ts
index 21ddaca8b..cc83cee3c 100644
--- a/src/app/utils/matrix.ts
+++ b/src/app/utils/matrix.ts
@@ -401,3 +401,20 @@ export const creatorsSupported = (version: string): boolean => {
   const unsupportedVersion = ['1', '2', '3', '4', '5', '6', '7', '8', '9', '10', '11'];
   return !unsupportedVersion.includes(version);
 };
+
+// Best-effort deletion of a user-owned MXC URI from the homeserver.
+// Synapse 1.97+ supports DELETE /_matrix/client/v1/media/{server}/{mediaId} for media owners.
+// Failures are silently ignored — this is cleanup only, not critical path.
+export const tryDeleteMxcContent = async (mx: MatrixClient, mxcUrl: string): Promise<void> => {
+  try {
+    const path = mxcUrl.replace('mxc://', '');
+    const token = mx.getAccessToken();
+    if (!token || !path.includes('/')) return;
+    await fetch(`${mx.getHomeserverUrl()}/_matrix/client/v1/media/${path}`, {
+      method: 'DELETE',
+      headers: { Authorization: `Bearer ${token}` },
+    });
+  } catch {
+    // Intentionally swallowed
+  }
+};