Windows 10 windows background color

You can choose a picture for your desktop background or change the accent color for Start, the taskbar, and other items.

Select Start  > Settings  > Personalization. The preview window gives you a sneak peek of your changes as you make them.

• In Background, you can select a picture or solid color, or create a slideshow of pictures.

• In Colors, you can let Windows pull an accent color from your background, or choose your own color adventure. After you’ve selected an accent color, scroll down to indicate where you want to see the color show up. Or scroll up to Choose your mode and you can see whether your accent color looks better in a Dark or Light mode.

You can choose a picture worthy of gracing your desktop background, or you can change the accent color for Start, the taskbar, and other items.

Select Start > Settings > Personalization . The preview window gives you a sneak peek of your changes as you make them.

• In Background, you can select a picture or solid color, or create a slideshow of pictures.
  

• In Colors, you can let Windows pull an accent color from your background, or choose your own color adventure.
  
  After you’ve selected an accent color, scroll down to decide where you want to see the color show up, and whether it looks better in a dark or light setting.
  
  The above screen shows the Dark setting.

Apologies for the late answer. It had completely skipped my mind.

I haven’t tested this solution thoroughly but it seems to do the job. You’ll need to switch to a High Contrast theme for this to work. After you apply the theme, Windows should look like this:

Context Menus and Metro UI apps are also affected:

If you use Google Chrome for web browsing, it’ll prompt you to install the High Contrast extension after you apply the High Contrast theme so you can also browse the web in high contrast. You can also use the extension without enabling High Contrast mode.

As @Unsigned mentioned earlier, enabling High Contrast may change the look of several UI elements.

If you still want to enable High Contrast mode, you can copy the following into Notepad and save it as a .theme file and double-click on it to apply it.

[Theme]
DisplayName=High Contrast Black

[Control Panel\Colors]
Background=0 0 0
Window=0 0 0
Menu=0 0 0
InfoWindow=0 0 0
WindowFrame=0 0 0
AppWorkspace=0 0 0
ButtonFace=0 0 0
ButtonHilight=0 0 0
ButtonLight=0 0 0
HilightText=255 255 255
Titletext=255 255 255
WindowText=255 255 255
ButtonText=255 255 255

[Control Panel\Desktop]
TileWallpaper=0
WallpaperStyle=10

[VisualStyles]
Path=%SystemRoot%\resources\themes\Aero\AeroLite.msstyles
ColorStyle=NormalColor
Size=NormalSize
HighContrast=1

[MasterThemeSelector]
MTSM=DABJDKT

I’m not sure if every one of those entries is necessary, so feel free to experiment. I found some information on the color section here, if it helps (link broken; WaybackMachine mirror).

EDIT:
If you do not want to enable High Contrast mode and only need to change the background window color from white to something else, you can use this theme instead:

[Theme]
DisplayName=Beige

[Control Panel\Colors]
Window=227 221 191

[Control Panel\Desktop]
TileWallpaper=0
WallpaperStyle=10

[VisualStyles]
Path=%SystemRoot%\resources\themes\Aero\AeroLite.msstyles
ColorStyle=NormalColor
Size=NormalSize

[MasterThemeSelector]
MTSM=DABJDKT

Just copy that to into Notepad and save it as beige.theme and double click on the file to apply the theme. Windows should look like this after you apply it:

You do not have to enable High Contrast mode or save the theme file to a particular location for it to work. Make sure that %SystemRoot%\resources\themes\Aero\ contains a file named AeroLite.msstyles.