fix: improve dark mode compatibility and chart visibility

- Fix TopQuestionsChart with proper dark mode colors using CSS variables and shadcn/ui components
- Enhance ResponseTimeDistribution with thicker bars (maxBarSize: 60)
- Replace GeographicMap with dark/light mode compatible CartoDB tiles
- Add custom text selection background color with primary theme color
- Update all loading states to use proper CSS variables instead of hardcoded colors
- Fix dashboard layout background to use bg-background instead of bg-gray-100

components/magicui/aurora-text.tsx

@@ -0,0 +1,43 @@
+"use client";
+
+import React, { memo } from "react";
+
+interface AuroraTextProps {
+  children: React.ReactNode;
+  className?: string;
+  colors?: string[];
+  speed?: number;
+}
+
+export const AuroraText = memo(
+  ({
+    children,
+    className = "",
+    colors = ["#FF0080", "#7928CA", "#0070F3", "#38bdf8"],
+    speed = 1,
+  }: AuroraTextProps) => {
+    const gradientStyle = {
+      backgroundImage: `linear-gradient(135deg, ${colors.join(", ")}, ${
+        colors[0]
+      })`,
+      WebkitBackgroundClip: "text",
+      WebkitTextFillColor: "transparent",
+      animationDuration: `${10 / speed}s`,
+    };
+
+    return (
+      <span className={`relative inline-block ${className}`}>
+        <span className="sr-only">{children}</span>
+        <span
+          className="relative animate-aurora bg-[length:200%_auto] bg-clip-text text-transparent"
+          style={gradientStyle}
+          aria-hidden="true"
+        >
+          {children}
+        </span>
+      </span>
+    );
+  },
+);
+
+AuroraText.displayName = "AuroraText";