Fix race condition with using getComputedStyle primary color for dynamic activity grid darkening

Instead just use the color from the current theme directly. Tested works on initial load and theme changes.
Fixes https://github.com/gabehf/Koito/issues/75

client/app/components/ActivityGrid.tsx

@@ -1,28 +1,10 @@
 import { useQuery } from "@tanstack/react-query"
 import { getActivity, type getActivityArgs, type ListenActivityItem } from "api/api"
 import Popup from "./Popup"
-import { useEffect, useState } from "react"
+import { useState } from "react"
 import { useTheme } from "~/hooks/useTheme"
 import ActivityOptsSelector from "./ActivityOptsSelector"
-
-function getPrimaryColor(): string {
-    const value = getComputedStyle(document.documentElement)
-        .getPropertyValue('--color-primary')
-        .trim();
-
-    const rgbMatch = value.match(/^rgb\(\s*(\d{1,3})\s*,\s*(\d{1,3})\s*,\s*(\d{1,3})\s*\)$/);
-    if (rgbMatch) {
-        const [, r, g, b] = rgbMatch.map(Number);
-        return (
-            '#' +
-            [r, g, b]
-                .map((n) => n.toString(16).padStart(2, '0'))
-                .join('')
-        );
-    }
-
-    return value;
-}
+import { themes } from "~/styles/themes.css"
 
 interface Props {
     step?: string 
@@ -47,7 +29,6 @@ export default function ActivityGrid({
         configurable = false,
     }: Props) {
 
-    const [color, setColor] = useState(getPrimaryColor())
     const [stepState, setStep] = useState(step)
     const [rangeState, setRange] = useState(range)
         
@@ -69,14 +50,8 @@ export default function ActivityGrid({
 
 
     const { theme } = useTheme();
-    useEffect(() => {
-        const raf = requestAnimationFrame(() => {
-          const color = getPrimaryColor()
-          setColor(color);
-        });
-      
-        return () => cancelAnimationFrame(raf);
-      }, [theme]);      
+    const currentTheme = themes.find(t => t.name === theme);
+    const color = currentTheme?.primary || '#f5a97f';
 
     if (isPending) { 
         return (