Custom header grey area both sides

Hi, I changed the backgroundcoulour of the custom header in extra css. Now there is a grey area left on both sides. How can I change the grey sides to the blue background colour? https://webcats.nl/kosten-vergoedingen/ .custom-header .custom-header-content { padding-bottom: 15px; padding-top: 37px; background-color: #68aaaa; } Thank you very much!