Remove all dark mode CSS filters for Plotly charts

The filter-based inversion approach was causing logo visibility issues
(e.g., kimi-k2-thinking logo not visible). Removing the filters entirely
for a simpler, more reliable solution.

content.py

@@ -1013,22 +1013,4 @@ h3 .header-link-icon {
     }
 }
 
-/* ====== Dark Mode Plotly Charts ====== */
-/* Use filter-based inversion for reliable dark mode support */
-/* This inverts the entire chart and then re-inverts specific elements */
-
-.dark .js-plotly-plot {
-    filter: invert(0.88) hue-rotate(180deg);
-}
-
-/* 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);
-}
-
-/* Modebar icons need re-inversion */
-.dark .js-plotly-plot .modebar {
-    filter: invert(1) hue-rotate(180deg);
-}
 """