You can find web-based Citra themes and skins here that change background colors and schemes.
Finding a direct "download and install" link for a theme is different from standard Android apps. Themes are usually shared as ZIP files within enthusiast communities:
Download your preferred theme ZIP file.
To make games look high-definition, search for specific game packs (e.g., "Mario 3D Land HD textures"). In Citra, enable "Use Custom Textures" in graphics settings. This creates a load/textures folder where you can place extracted texture folders matching the game's unique Title ID.
Copy the theme files (often a .zip or a folder containing .png assets) into the theme subfolder within Citra EMU . citra android themes link
Modern versions like Citra Enhanced include built-in support for system-wide dark modes and Material U coloring, which adapts the emulator's UI colors to match your Android wallpaper. System Requirements for Heavy Themes
Beyond just "themes," you can fundamentally change how the game looks through layout modifications and HD texture packs. You can find web-based Citra themes and skins
Open your file explorer and navigate to your internal storage. Look for a folder named Citra EMU .