Module:Infobox/styles.css

/* === Force infobox background to white with standard borders/text === */

/* Light/default and general base styles */
.infobox,
.infobox-subbox,
.infobox-table {
  background-color: #fff !important;
  color: #202122 !important; /* Standard MediaWiki text color */
  border: 1px solid #202122 !important; /* Box line color */
}

/* Night mode override: ensure background stays white and text/borders stay dark */
@media screen {
  html.skin-theme-clientpref-night .infobox,
  html.skin-theme-clientpref-night .infobox-full-data:not(.notheme) > div:not(.notheme)[style] {
    background: #fff !important;
    color: #202122 !important;
    border: 1px solid #202122 !important;
  }
}

/* OS-driven dark mode override */
@media screen and (prefers-color-scheme: dark) {
  html.skin-theme-clientpref-os .infobox,
  html.skin-theme-clientpref-os .infobox-full-data:not(.notheme) > div:not(.notheme)[style] {
    background: #fff !important;
    color: #202122 !important;
    border: 1px solid #202122 !important;
  }
}

/* Remove the forced border specifically for the navigation menu infobox */
.infobox.navigation-menu {
    border: none !important;
    background-color: transparent !important;
}

/* If the internal cells still show lines, use this: */
.infobox.navigation-menu th, 
.infobox.navigation-menu td {
    border: none !important;
}