So the UI appears mostly white with the files/transfers tabs having black backgrounds. I want the entire border to be black. Here's an image of what I mean.
(Pic removed by Mod)

I won't be using Windows 10 for a few years (or at all, depending on what comes after it) so I can't give you step-by-step instructions, but have you at all tried reading the inline help that comes with your Windows OS, hmm, I dunno, press F1 or click on "Help" or something ?

I would presume that something as simple as what you request would be somewhat trivial, hmm, I dunno, right-click on the desktop or go to the control panel and select any option that speaks about "personalize", "themes", or something ?...

Requires you to change your system scheme unfortunately.

upgrade to windows 7.
since 8 all color schemes suck

I hope Tixati developer fixes the UI, have you seen how Perfect Tube? or VLC look like? they look nice, and they only have the Title bar with the same color of the app.
I don't dislike white title bars on Windows 10, but next update will let you color your title bars, that's what you can do on the insiders preview. I don't like it, I would rather developers to bring a modern and nice interface by just make the title bar mixed with the color of the UI. or add a black titlebar.

anyway you could do it by downloading a hacked theme and get the patch to use unofficial themes on Windows 10 like you cold do on previous versions.

Windows 10 is nice, but I wish developers would work on the UI and make it modern like some new Windows 10 store apps like perfect tube or vlc, or just other apps that have colores titlebars and it looks like it fits on the UI like twitter windows 10 app.

I agree, the window is starting to be dated.

Shouldn't dark theme in window make app gui also back?
cuz I have contrast win10 theme and app ui follows it perfectly