Acrylic
In Zehn, the Transparency Effects option enables the Acrylic effect on various surfaces. Most of these surfaces are internally composited using backdrop blur. However, some surfaces can blur the content behind the window if you are willing to do a little additional setup!
You need to be using the Millennium patcher for this to work. This is because we require a Millennium plugin.
First, install the DWMX plugin through Millennium's interface. This modifies Steam to use Windows' native compositor so we can have transparent windows.
Windows that support behind-window blur are limited to ones that DWMX is capable of giving a transparent background.
The easiest way to do this is through Millennium's plugin install interface. Enter b4c58634419b for DWMX.
Afterwards, make sure it is enabled. Steam will have to reload.
Now, as long as Transparency Effects is enabled in Zehn, you will have transparent window backgrounds on supported windows!
DWMX is supposed also enable background blur, but as of writing it does not seem to work. However, I do have a workaround to give your Steam that blur!
You can probably find other software floating around that can do this, but I have found using Windhawk to be an absolutely pleasure. I love this software and use many mods to customize the look of Windows 11, such as having square window corners and removing the forced grey border it puts atop certain processes. I had to move from Window 10 to 11 myself after my update-blocked setup would just bluescreen all day, so I use Windhawk and other programs to bring back some Windows 10 styling. It is a decent compromise.
First, you need to enable the steamwebhelper.exe process in Windhawk. Steam is in a default exclusion list, as they took preventative measures to stop it from running on games. You will have to head to Settings, expand Advanced Settings, and click on More Advanced Settings. Add it to the inclusion list, then save and restart.
Search for the Translucent Windows mod and install it.
Make sure the mod is enabled. Go to its Settings page and adjust the following...
Disable all options under Rendering Customization. This includes Windows Theme Custom Rendering, New System Colors, and Windows Theme Accent Colorizer. Disabling the second one is important to prevent it from breaking Win32 app backgrounds, even if they are not included/are excluded. Don't ask me why!
Select Blur (AccentBlurBehind) in the dropdown. Set the color blend to 00000000 (transparent). The other effects do not seem to work with Steam, but we apply our own Acrylic noise and color in Zehn, so we just need the blur to composite behind the window.
Also, disable Flyout Effects and Immersive Darkmode Titlebar, as these are not necessary.
Ensure Extend Effects Into Entire Window is enabled.
If you are on Windows 11, you can get back some Windows 10 styling.
Set Window Corner Type to Not Rounded for square corners. Scroll further down.
Enable the Border Color option and set both color states to 0. This gets rid of the forced border that Windows 11 applies over certain applications. Now we can see Zehn's actual borders!
You can fork this mod to apply the corners and borders changes to other processes without altering the background. There are also other mods that deal exclusively with corners and borders too, so check 'em out!
That is quite the improvement. Scroll up to the top and save!
Now, switch to the Advanced tab.
Add steamwebhelper.exe to the inclusion list. Enable Ignore Mod Inclusion/Exclusion Lists.
And that should be all!
