Restyle bio link as action button with dark mode support

src/scss/theme.scss

@@ -1343,9 +1343,15 @@ $diagram-f-stroke-dark: $nord15;
 .bio-facts { border-top-color: var(--color-border); }
 .bio-fact-label { color: var(--color-text-secondary); }
 .bio-fact-value { color: var(--color-text-tertiary); }
-.bio-link {
+.bio-action-btn,
-  color: var(--color-link);
+.bio-action-btn:visited {
-  border-top-color: var(--color-border);
+  background: var(--color-bg-tertiary);
+  color: var(--color-text-secondary);
+
+  &:hover {
+    background: var(--color-primary);
+    color: #fff;
+  }
 }
 
 // Zoom controls
@@ -2084,6 +2090,17 @@ div[id^=caldiv] {
   .bio-fact-label { color: var(--color-text-secondary) !important; }
   .bio-fact-value { color: var(--color-text-tertiary) !important; }
 
+  .bio-action-btn,
+  .bio-action-btn:visited {
+    background: var(--color-bg-tertiary) !important;
+    color: var(--color-text-secondary) !important;
+
+    &:hover {
+      background: var(--color-primary) !important;
+      color: var(--color-bg-primary) !important;
+    }
+  }
+
   .zoom-controls button {
     background: var(--color-bg-elevated) !important;
     border-color: var(--color-border) !important;