Transparent header turns grey when scroll down

Hi. some days ago an automatic update of wordpress turned all my font size crazy. They change colour and delete all my CSS. The first problem i have is that they delete my header logo (now is ok) and i put it on transparent but it turns grey when I scroll down and i would like to put it transparent always. Can i? When i scroll down the logo change with the ENFOLD theme logo too. How can i delete that? THanks for all!

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