However, this changes with the new build.
To enable light theme in Windows 10, you oughta go to configs > Personalization > Colors.
Then, grab the drop-down under Choose your color and select Light.
If you grab the Light mode in the tweaks app, all system UI elements will look lighter.
When you update to this build, your system color wont automatically change to the new light system color.
This is because we want everything to be exactly as you left it before you did the update.
Were leaving the choice up to you, Microsoft added.
As part of this new Light theme, Microsoft is also adding a new default wallpaper highlighting Windows Light.
Go to parameters > Personalization > Themes and select Windows Light to apply it.
This will change your PC to be light themed.
The UI change to Light theme is not ready yet.
The other notable changes in Windows 10 19H1 update are improved Action Center, dark themed OneDrive and more.
Check out the general changes, improvements, and fixes forbuild 18282 here.
source: www.techworm.net