Hi there, I couldn't find a tool for making custom theme in VS 2026. If it does exist then I'm an idiot but atleast I learned something and may help other stubborn people (like me) if there isn't one around. Remember, we are not talking about code format and color, only stuff around, like solution explorer color, highlight of active window, background etc. I did some looking inside VS files and reverse engineered HEX encoding.
Step by step guide how to set it to custom colors:
Please save your settings and be carefull just in case.
Go to Program Files\Microsoft Visual Studio\18\Community\Common7\IDE\CommonExtensions\Platform.
You can see files with default themes there. I have no idea how you can "properly" add your custom theme, additionaly default themes are loaded only during "settings rebuild" from those files and later stored elsewhere, probably require new GUIDs too to be accepted. So instead just pick any file with default theme you don't like (I chose MangoParadise for example) and we are gonna edit that one.
- Open file of default theme you want to edit.
You need to edit that as admin. You will see a bunch of HEX data. Use any tool to translate that into readable text (sort of xdd), I'm using ImHex. There is a bit of data inside splitted to 2 branches. What we are interested in are areas directly after name of parameter (like "EnviromentBackground").
- Edit colors
The first value after parameter name is "01" (some sort of start mark), after that you have color value in RGBA pattern, later there is "00" (probably some stop mark). After changing RGBA value beetwen "01" and "00" marks, you do not edit anything that is directly after that. Instead you go to next parameter name and set RGBA values again to desired ones.
Like I said there are 2 branches of data. Each of them has some parameters that change different things in IDE. I highlited RGBA areas with colors corresponding to what they represent (if you see aqua highlight, that means this RGBA value sets something in VS to aqua), so you can quickly compare which parameter changes which element inside VS.
- Apply changes
Save your file. Close VS (if u had it opened), open Developer Command Prompt for VS (just type this name in search bar) as admin. Type "devenv /setup", press enter, after it finishes close your command prompt. That does "settings rebuild" I mentioned earlier. You may now open Visual Studio, Your custom theme is done.
Visual Studio on my screenshots is ugly ON PURPOUSE. As said earlier, it's meant to allow you to quickly tell which RGBA value changed which element.