Copying required files to work

1. Go to your Steam installation directory
2. Copy entire styles folder, webkit.css inside resource folder

Creating custom Steam skin

1. Go to your Steam installation directory
2. Create new folder you can call it whatever you want inside skins folder
3. Create new folder called resource and paste required files from steps above

Modifying webkit.css

Add following lines:

.profile_ban_status {
  display: none;
  visibility: hidden;
}

For fancier looks:

#footer {
  background-color: rgba(111, 111, 111, 0.1) !important;
}

.footer_content {
  padding-bottom: 16px;
}

#footer_spacer {
  background-color: rgba(255, 255, 255, 0.1);
}
  
.profile_customization_header {
   color: #fff !important;
}

For the last step restart Steam client and apply created skin in settings. This only effects your Steam client so only you would not see it, server will still know that your account has vac ban.