You’re trying to see the cute dog pictures on ctf.rc3.club. But every time you click on one of them, it brings you to a bad gateway. https://ctf.rc3.club:3000/ -- Your friendly neighborhood webadmin
Quickly scrolling through the page, I noticed that one image was broken. Inspecting that image gives us this:
<img class="philarydufflebag" src="http://admissions.vanderbilt.edu/insidedores/doge/this-aint-the-RC3-flag-we're-getting-there-though.jpg">
Not the flag, but we’re close. Looking through the rest of the contents of the page there wasn’t much. Let’s check out the only other thing we seem to be given,
Sure enough, scroll to the bottom of
doge.css and you can find the flag.