[THEME] Use better color for labels/counters

- improves contrast
- looks good
- improves consistency with other label-y elements

(cherry picked from commit a245fb5c83bfb19bd7edbcb1dae46262a0e768e0)

web_src/css/base.css

@@ -1222,6 +1222,10 @@ overflow-menu .ui.label {
   color: var(--color-label-text);
 }
 
+.ui.menu .active.item > .label {
+  background: var(--color-label-bg-alt, var(--color-label-bg));
+}
+
 .lines-blame-btn {
   padding: 0 0 0 5px;
   display: flex;

web_src/css/themes/theme-forgejo-dark.css

@@ -225,9 +225,10 @@
   --color-nav-bg: var(--steel-900);
   --color-nav-hover-bg: var(--steel-600);
   --color-label-text: #fff;
-  --color-label-bg: #cacaca5b;
+  --color-label-bg: var(--steel-600);
-  --color-label-hover-bg: #cacacaa0;
+  --color-label-hover-bg: var(--steel-550);
-  --color-label-active-bg: #cacacaff;
+  --color-label-active-bg: var(--steel-500);
+  --color-label-bg-alt: var(--steel-550);
   --color-accent: var(--color-primary-light-1);
   --color-small-accent: var(--color-primary-light-5);
   --color-highlight-fg: var(--color-primary-light-4);

web_src/css/themes/theme-forgejo-light.css

@@ -245,6 +245,7 @@
   --color-label-bg: #cacaca5b;
   --color-label-hover-bg: #cacacaa0;
   --color-label-active-bg: #cacacaff;
+  --color-label-bg-alt: #cacacaff;
   --color-accent: var(--color-primary-light-1);
   --color-small-accent: var(--color-primary-light-5);
   --color-highlight-fg: var(--color-primary-light-4);