MediaWiki:Common.css

Note: After saving, you may have to bypass your browser's cache to see the changes.

• Firefox / Safari: Hold Shift while clicking Reload, or press either Ctrl-F5 or Ctrl-R (⌘-R on a Mac)
• Google Chrome: Press Ctrl-Shift-R (⌘-Shift-R on a Mac)
• Internet Explorer / Edge: Hold Ctrl while clicking Refresh, or press Ctrl-F5
• Opera: Go to Menu → Settings (Opera → Preferences on a Mac) and then to Privacy & security → Clear browsing data → Cached images and files.

/* Top-left banner (final) */
#mw-head,                /* Vector (legacy) */
.vector-header-container,/* Vector 2022 */
#p-logo,                 /* Monobook/Modern */
.ts-header {             /* Timeless */
  background-image: url("/Special:FilePath/BannerImage.png");
  background-repeat: no-repeat;
  background-position: left top;
  background-size: 420px 140px;  /* adjust to your image */
  min-height: 140px;
}

/* Remove base header strips some skins add */
#mw-page-base, #mw-head-base { background: transparent !important; }