darken dark colorblind

web_src/css/themes/theme-gitea-dark-protanopia-deuteranopia.css

 /* red/green colorblind-friendly colors */
 /* from GitHub: --diffBlob-addition-*, --diffBlob-deletion-*, etc */
 :root {
-  --color-diff-added-linenum-bg: #388bfd4d;
-  --color-diff-added-row-bg: #388bfd26;
-  --color-diff-added-word-bg: #388bfd66;
-  --color-diff-removed-linenum-bg: #db6d284d;
-  --color-diff-removed-row-bg: #db6d2826;
-  --color-diff-removed-word-bg: #db6d2866;
+  --color-diff-added-linenum-bg: #1979fd46;
+  --color-diff-added-row-bg: #1979fd20;
+  --color-diff-added-word-bg: #1979fd66;
+  --color-diff-removed-linenum-bg: #c8622146;
+  --color-diff-removed-row-bg: #c8622120;
+  --color-diff-removed-word-bg: #c8622166;
 }