You can adjust the contrast of windows and buttons so that they're easier to see. This is not the same as user interface will change.; only parts of the
Click your name on the top bar and select System Settings.
Open Universal Access and select the Seeing tab.
Under Display select the Contrast that best suits your needs. Low will make things less vivid, for example.
You can quickly change the contrast by clicking the High Contrast.on the top bar and selecting