There are several updates are released regarding the OS X Yosemite, the current news update says that Apple has introduced a Dark Mode in OS X Yosemite. This allows you the users to customize their desktop appearance and look. In the early June, the company has tested this mode and teased during its WWDC keynote. But the main thing is that, the official implementation of dark mode in OS X Yosemite was not present over the first two beta release of it.
Apple has released third beta version of OS X Yosemite this week, and officially introduces the Dark Mode in OS X Yosemite operating system. In the previous two beta versions, the developers can enable the Dark Mode via terminal. But in this release, the dark mode can be easily enabled through the system preferences settings itself.
Go to System Preferences -> General. In the general section, you will find a new option called Theme. Generally, the theme will set to Light Mode, the default appearance of OS X Yosemite. If you want to customize the look and feel of the OS X Yosemite, then change it to Dark Mode. Once you have changed the mode to the dark, then you can see the newer side of OS X Yosemite. The menu bar and Dock back ground color will change when you set the mode to the dark mode.
And one more thing is that, the third-party should change their style according to the both theme. But the thing is that, those third parties application are applicable to the light mode of the OS X Yosemite. If you set the theme to dark one, the font color and background color of the desktop remains same, which makes you to feel uncomfortable. First party Apple applications and icons look great in both modes of OS X Yosemite, provides nice preview too.