again: Changing font size for Table Header

Sorry to contact you but I’m new to wp. I found your great plugin to import my csv.

I have now a problem that I can’t change the font size of my header.
I also like to have it in small letters.
I tried some things but don’t work for me.

Problem is that I need to have to the table width into my size of the blog.

.tablepress thead th,
{
font-family: Tahoma;
font-size: 10px;
color: #ff0000;
}

.tablepress-id-1 th,
.tablepress-id-1 td {
padding: 4px !important;
}

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