fix: Admin students Bulk CSV button hover UI

src/app/admin/students/page.tsx

@@ -111,7 +111,7 @@ export default function StudentsPage() {
         </div>
         <div className="flex gap-2">
           <input type="file" accept=".csv" className="hidden" ref={fileInputRef} onChange={handleBulkUpload} />
-          <Button variant="outline" className="border-border hover:bg-secondary text-[var(--cyan-ai)]" onClick={() => fileInputRef.current?.click()}>
+          <Button variant="outline" className="border-border hover:bg-secondary" onClick={() => fileInputRef.current?.click()}>
             <Upload size={16} className="mr-2" /> Bulk Register CSV
           </Button>
           <Button variant="outline" className="border-border hover:bg-secondary" onClick={downloadTemplate}>