[Improvement] Steam logo doesn't really match the theme

[qvieth]

The current steam logo look doesn't fit with the theme. The look is just quite not match for me.

So for the replacement, I think something like these would be a better fit.

This issue is quite my personal feeling and quite a small detail. Also, so if you think the issue is not relevant or unnecessary, please just close it.

And thank you for creating this awesome HUGO theme.