fix(ui): change ui theme color

feat(calc): add geogebra based graph calculator for tests

src/pages/student/targeted-practice/page.tsx

@@ -126,7 +126,7 @@ export const TargetedPractice = () => {
                     <div>
                       <Loader2
                         size={30}
-                        color="purple"
+                        color="indigo"
                         className="animate-spin"
                       />
                     </div>
@@ -162,7 +162,7 @@ export const TargetedPractice = () => {
     ${
       selectedTopics.length === 0
         ? "bg-gray-300 text-gray-500 cursor-not-allowed"
-        : "bg-linear-to-br from-purple-500 to-purple-600 text-white"
+        : "bg-linear-to-br from-indigo-500 to-indigo-600 text-white"
     }`}
               >
                 Next
@@ -249,7 +249,7 @@ export const TargetedPractice = () => {
     ${
       step !== "review"
         ? "opacity-0 pointer-events-none"
-        : "bg-linear-to-br from-purple-500 to-purple-600 text-white"
+        : "bg-linear-to-br from-indigo-500 to-indigo-600 text-white"
     }`}
         onClick={() => {
           handleStartTargetedPractice();