This issue is very similar to #299. Everything there holds true for this one, just that this one is for api.coala.io instead of docs.coala.io.
This would make a nice newcomer issue. Once one of them is solved, the person can follow the same process to solve the other one.
Overview Description
The coala header in https://api.coala.io/en/latest/ gets scaled only horizontally when viewed using mobile browsers leading to a distortion of the logo. It would be better if the consistency of the logo is maintained.
Steps to Reproduce
Open https://api.coala.io/en/latest/ in any mobile web browser (portrait mode)
Actual Results

Expected Results
If the image scales while preserving aspect ratio and is aligned to the center or to the left, the logo would remain round.