Apply company branding to ATS Web Page

The ATS page styling looks terrible and does not fit in with any other page we have on our website - how do we remove the company name and apply styling to fit in with our company website. I can remove the logo but this removes it completely from PeopleHR. If i change the company branding colour this changes the top banner to white and doing this makes the navigation in HR Admin unusable.

Can this be controled by a css that we upload to people HR ?

i frames don't work with cms manged websites so this is not an option