@ObliviaTheChangeling  
:P

@Background Pony #1A60  
Nyx!

@ObliviaTheChangeling  

 
Yes!
 

Well, Theme. Are you gonna grow a pair of wings to match the current situation?
 
EDIT: Ah, nevermind. Just saw it. Carry on.

@zylgchs  
@ObliviaTheChangeling  
She’s totally radical and drinks Ecto Cooler XD

@zylgchs  
Having a seizure.

@Badumsquish  
What about now :D

@Heroine Addict  
Her personality changes with the site’s theme too. Right now she’s a raving communist XD

And now she’s red for the day. Looks a mite peculiar that way, doesn’t she.

@ObliviaTheChangeling  
No, she’s just sick … greenly-sick.

Theme has acquired a new color, it seems.

@Badumsquish  
That’s good enough.

@Liggliluff  
Have a really crummy tutorial then :D  

Theme will be complicated to draw due to the transparency. But this image is a great base.

@Lokizade  
Yeah the whole effect is done with transparencies and the Erase blend option (that makes any shape erase everything beneath it rather than being colored. There’s a “hole” cut through the background of the image that lets the color on the website behind it bleed through.
 
Her entire fill color is Erase (so the background color bleeds through 100%) while her outlines are a very dark black set to 50% transparency (so it tints the background color behind it). Her mane and tail I colored (as best as I could; I couldn’t get them 100%) to match the two title bar colors (Where it says “Derpibooru” and the search bar is) on both the themes.
 
The only parts of her that don’t change color at all are the eyes (Her irises are a gradient from the light theme title bar to the dark theme title bar) and the inside of her mouth :P
 
Put any color (or even patterns) behind her and you can change her color. Her mane’s color scheme is intended only for the two official Derpibooru themes of course so it won’t always match the title bars, but her body will match any theme.

@Lokizade  
Ooh, I really like that version.

Sooo, she also works with the custom themes that you can find here, that’s awesome!
 
Here’s what she looks like with the Dark Twilight theme installed…  

Theme horse is a qt ❤️

Change the colors around and this would be a perfect Nyx

Lol awesome XD  
Let’s ponify everything on the site 😂

@Background Pony #04A0  
Nox.

Nyx?

D’awww! She’s a cutie!

@Badumsquish  

 
Such things appeal not only to my sense of beauty, but also to my geekiness. Nice job. :)

@Blissey1  
I’d have put it the other way around if I could XD
 
@Zebasiz  
:P
 
@SuperSupermario24  
How could I not? :P
 
Though apologies in advance to people using the custom Applejack theme and such.
 
@SuperSupermario24  
Oh man that’s like Theme after she got an invincibility star.
 
@Damaged  
Yeah it’s all done with partial transparencies and such. Her “fill” color’s blend mode is set to “erase” so it erases every layer below it completely (including the background). Hardest part was getting a color balance for the mane so it would match both theme’s banner colors (Where the search bar is). I never got it 100% but blending both theme’s colors and cranking the saturation got it reasonably close.
 
I’m going to make a “tutorial” of sorts to show how I do it, for anyone who’s interested in such things :P
 
@Damaged  
My favorite ever was when Banjo Kazooie (Or maybe the sequel) had extra unused text in the code, located beside all the other level names, that read “Ridiculously Secret Area” (or something like that). It wasn’t dummied out or anything, but literally put in to prank game hackers.