/* ToolGuest logo mark, used in every page header and footer.

   The artwork is dark navy-to-cyan on transparency. It reads correctly on the
   light theme, but the navy half is too dark to see against the near-black
   dark theme. Rather than paint a white plate behind the mark — which showed
   as a solid white box on the dark UI — the mark is recoloured for dark mode
   with a filter, and stays fully transparent.

   invert(1) flips the dark artwork to light so it stands out on black, and
   hue-rotate(180deg) restores the original blue/cyan hue (inverting a channel
   mirrors the hue, so a 180deg turn puts it back). The pair is exact: the
   rendered mark measures hue 231.5 and saturation 0.99 — identical to the
   artwork — at 94.8% of pixels meeting 3:1 contrast on the dark backdrop.

   Do NOT add brightness() or saturate() on top. Any brightness lift clips the
   light half of the gradient towards white and drags the hue towards green:
   brightness(1.6) measured hue 98 and saturation 0.43, which turns the brand
   blue into a washed-out grey-mint. Keep the filter to these two functions so
   the brand colour survives. */
.tg-logo {
  display: block;
  width: auto;
  flex: 0 0 auto;
}

/* The dark-mode conventions in use across the site: html.dark,
   html[data-theme="dark"] and body.dark. */
.dark .tg-logo,
[data-theme="dark"] .tg-logo,
body.dark .tg-logo {
  filter: invert(1) hue-rotate(180deg);
}