I have seen a post ref this and it refers to file style.css I have just downloaded from Hostpapa and tried to change the background and the blue header, home button. Didn't work but the file I found is named stylesheet not style and the header looks like this

AbanteCart admin main CSS stylesheet.css

Developers: Pavel Rojkov (projkov@abantecart.com)

AbanteCart brand color styles: #064770 (dark blue) #F19013 (Orange)

*/
@import url('bootstrap.min.css');
@import url('bootstrap.custom.css');
@import url('jquery-ui/ui-lightness/jquery-ui-1.10.4.custom.min.css');
@import url('../javascript/jquery/fileupload/jquery.fileupload-ui.css');
@import url('font-awesome.min.css');
@import url('abantecart.jquery.ui.css');
@import url('form.css');
@import url('chosen.bootstrap.css');
@import url('fileinput.min.css');
@import url('animate.css');

body {
   /*background: #1d2939;*/
   background: #064770;
   font-family: 'Lucida Grande', 'Lucida Sans Unicode', Helvetica, sans-serif !important;
   line-height: 21px;
   color: #636e7b;

Am I in the right place?