Fix dark mode logo visibility by simplifying CSS filters

Removed the complex exclusion rules for OpenHands logos and simplified
the CSS to apply the same re-inversion filter to all images in charts.
This fixes logos like Moonshot/Kimi that weren't displaying correctly
in dark mode due to color inversion issues.

content.py

@@ -1021,21 +1021,12 @@ h3 .header-link-icon {
     filter: invert(0.88) hue-rotate(180deg);
 }
 
-/* Re-invert all images so they display correctly (no glow) */
-/* Exclude OpenHands logos which are handled by JavaScript */
-.dark .js-plotly-plot .layer-above image:not([href*="openhands="]):not([xlink\\:href*="openhands="]),
-.dark .js-plotly-plot .imagelayer image:not([href*="openhands="]):not([xlink\\:href*="openhands="]) {
+/* Re-invert all images so they display correctly (no filters/effects) */
+.dark .js-plotly-plot .layer-above image,
+.dark .js-plotly-plot .imagelayer image {
     filter: invert(1) hue-rotate(180deg);
 }
 
-/* OpenHands logos: JavaScript handles visibility, CSS just removes any filters */
-.dark .js-plotly-plot .layer-above image[href*="openhands="],
-.dark .js-plotly-plot .layer-above image[xlink\\:href*="openhands="],
-.dark .js-plotly-plot .imagelayer image[href*="openhands="],
-.dark .js-plotly-plot .imagelayer image[xlink\\:href*="openhands="] {
-    filter: none !important;
-}
-
 /* Modebar icons need re-inversion */
 .dark .js-plotly-plot .modebar {
     filter: invert(1) hue-rotate(180deg);