fix contrast

apps/client/src/components/ui/custom-avatar.tsx

@@ -1,5 +1,5 @@
 import React from "react";
-import { Avatar } from "@mantine/core";
+import { Avatar, MantineColor } from "@mantine/core";
 import { getAvatarUrl } from "@/lib/config.ts";
 import { AvatarIconType } from "@/features/attachments/types/attachment.types.ts";
 
@@ -16,11 +16,39 @@ interface CustomAvatarProps {
   mt?: string | number;
 }
 
+// `color.shade` pairs whose filled background meets WCAG AA (4.5:1) against
+// white text. Avoids lime/yellow/green/orange — even their dark shades have
+// weak white-text contrast.
+const SAFE_INITIALS_COLORS: MantineColor[] = [
+  "blue.8",
+  "cyan.9",
+  "grape.7",
+  "indigo.7",
+  "pink.8",
+  "red.8",
+  "violet.7",
+];
+
+function hashName(input: string) {
+  let hash = 0;
+  for (let i = 0; i < input.length; i += 1) {
+    hash = (hash << 5) - hash + input.charCodeAt(i);
+    hash |= 0;
+  }
+  return Math.abs(hash);
+}
+
+function pickInitialsColor(name: string) {
+  return SAFE_INITIALS_COLORS[hashName(name) % SAFE_INITIALS_COLORS.length];
+}
+
 export const CustomAvatar = React.forwardRef<
   HTMLInputElement,
   CustomAvatarProps
->(({ avatarUrl, name, type, ...props }: CustomAvatarProps, ref) => {
+>(({ avatarUrl, name, type, color, ...props }: CustomAvatarProps, ref) => {
   const avatarLink = getAvatarUrl(avatarUrl, type);
+  const resolvedColor =
+    !color || color === "initials" ? pickInitialsColor(name ?? "") : color;
 
   return (
     <Avatar
@@ -28,7 +56,7 @@ export const CustomAvatar = React.forwardRef<
       src={avatarLink}
       name={name}
       alt={name}
-      color="initials"
+      color={resolvedColor}
       {...props}
     />
   );