Div moves when a browser window is rezised

I looked at some other answered questions about this but just none helped.

Here is how I want it too look and when I am in full screen / https://gyazo.com/64ba88bd3b777eb9ac248cba58ad4959

Here is when I minimize/maximize the window - https://gyazo.com/364a876f9ea914ec0601f8df1a1e478a

My index/HTML file - https://www.mediafire.com/?md59u10c20emy21

My CSS file - https://www.mediafire.com/?nhcbp14447sfll9

The files is in another format which is .hbs don't worry about that. Game.hbs is the index layout.hbs is the CSS. The ytpromo CSS is the yt promotion box, you can experiment with that.