masthead resizing not working on my premium vantage theme

Hey Y’all

I am trying to shrink down my masthead to essentially the same size of the wordpress administrative size.

I have tried changing the header size from the default 45 to 10 and have also tried using the custom css

/* Header Padding */

header#masthead .hgroup {
padding-bottom: 10px !important;
padding-top: 10px !important;
}

I do not have a logo in my header forcing the size to grow.

Any help would be appreciated.

best,
Greg