You inserted the rules at the wrong place I suppose as your CSS shows
.search-field,#header-search .search-field:focus #branding {position:inherit;}
#header-search {position:absolute;top:0px;right:0px;}
instead of
#branding {position:inherit;}
#header-search {position:absolute;top:0px;right:0px;}
The rules I gave you were to insert in Main Options > Fonts & custom > Custom CSS rule box