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/ui/alert.tsx

@@ -0,0 +1,59 @@
+import * as React from "react";
+import { cva, type VariantProps } from "class-variance-authority";
+
+import { cn } from "@/lib/utils";
+
+const alertVariants = cva(
+  "relative w-full rounded-lg border px-4 py-3 text-sm [&>svg+div]:translate-y-[-3px] [&>svg]:absolute [&>svg]:left-4 [&>svg]:top-4 [&>svg]:text-foreground [&>svg~*]:pl-7",
+  {
+    variants: {
+      variant: {
+        default: "bg-background text-foreground",
+        destructive:
+          "border-destructive/50 text-destructive dark:border-destructive [&>svg]:text-destructive",
+      },
+    },
+    defaultVariants: {
+      variant: "default",
+    },
+  }
+);
+
+const Alert = React.forwardRef<
+  HTMLDivElement,
+  React.HTMLAttributes<HTMLDivElement> & VariantProps<typeof alertVariants>
+>(({ className, variant, ...props }, ref) => (
+  <div
+    ref={ref}
+    role="alert"
+    className={cn(alertVariants({ variant }), className)}
+    {...props}
+  />
+));
+Alert.displayName = "Alert";
+
+const AlertTitle = React.forwardRef<
+  HTMLParagraphElement,
+  React.HTMLAttributes<HTMLHeadingElement>
+>(({ className, ...props }, ref) => (
+  <h5
+    ref={ref}
+    className={cn("mb-1 font-medium leading-none tracking-tight", className)}
+    {...props}
+  />
+));
+AlertTitle.displayName = "AlertTitle";
+
+const AlertDescription = React.forwardRef<
+  HTMLParagraphElement,
+  React.HTMLAttributes<HTMLParagraphElement>
+>(({ className, ...props }, ref) => (
+  <div
+    ref={ref}
+    className={cn("text-sm [&_p]:leading-relaxed", className)}
+    {...props}
+  />
+));
+AlertDescription.displayName = "AlertDescription";
+
+export { Alert, AlertTitle, AlertDescription };

components/ui/input.tsx

@@ -0,0 +1,24 @@
+import * as React from "react";
+
+import { cn } from "@/lib/utils";
+
+export type InputProps = React.InputHTMLAttributes<HTMLInputElement>
+
+const Input = React.forwardRef<HTMLInputElement, InputProps>(
+  ({ className, type, ...props }, ref) => {
+    return (
+      <input
+        type={type}
+        className={cn(
+          "flex h-10 w-full rounded-md border border-input bg-background px-3 py-2 text-sm ring-offset-background file:border-0 file:bg-transparent file:text-sm file:font-medium file:text-foreground placeholder:text-muted-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 disabled:cursor-not-allowed disabled:opacity-50",
+          className
+        )}
+        ref={ref}
+        {...props}
+      />
+    );
+  }
+);
+Input.displayName = "Input";
+
+export { Input };

components/ui/label.tsx

@@ -0,0 +1,26 @@
+"use client";
+
+import * as React from "react";
+import * as LabelPrimitive from "@radix-ui/react-label";
+import { cva, type VariantProps } from "class-variance-authority";
+
+import { cn } from "@/lib/utils";
+
+const labelVariants = cva(
+  "text-sm font-medium leading-none peer-disabled:cursor-not-allowed peer-disabled:opacity-70"
+);
+
+const Label = React.forwardRef<
+  React.ElementRef<typeof LabelPrimitive.Root>,
+  React.ComponentPropsWithoutRef<typeof LabelPrimitive.Root> &
+    VariantProps<typeof labelVariants>
+>(({ className, ...props }, ref) => (
+  <LabelPrimitive.Root
+    ref={ref}
+    className={cn(labelVariants(), className)}
+    {...props}
+  />
+));
+Label.displayName = LabelPrimitive.Root.displayName;
+
+export { Label };

components/ui/metric-card.tsx

@@ -102,7 +102,7 @@ export default function MetricCard({
   return (
     <Card
       className={cn(
-        "relative overflow-hidden transition-all duration-200 hover:shadow-lg hover:-translate-y-0.5",
+        "relative overflow-hidden transition-all duration-300 hover:shadow-xl hover:-translate-y-1 group",
         getVariantClasses(),
         className
       )}
@@ -124,11 +124,11 @@ export default function MetricCard({
           {icon && (
             <div
               className={cn(
-                "flex h-10 w-10 shrink-0 items-center justify-center rounded-full border transition-colors",
+                "flex h-10 w-10 shrink-0 items-center justify-center rounded-full border transition-all duration-300 group-hover:scale-110",
                 getIconClasses()
               )}
             >
-              <span className="text-lg">{icon}</span>
+              <span className="text-lg transition-transform duration-300 group-hover:scale-110">{icon}</span>
             </div>
           )}
         </div>
@@ -137,7 +137,9 @@ export default function MetricCard({
       <CardContent className="relative">
         <div className="flex items-end justify-between">
           <div className="space-y-1">
-            <p className="text-2xl font-bold tracking-tight">{value ?? "—"}</p>
+            <p className="text-3xl font-bold tracking-tight bg-clip-text text-transparent bg-linear-to-r from-foreground to-foreground/80">
+              {value ?? "—"}
+            </p>
 
             {trend && (
               <Badge

components/ui/sonner.tsx

@@ -0,0 +1,31 @@
+"use client";
+
+import { useTheme } from "next-themes";
+import { Toaster as Sonner } from "sonner";
+
+type ToasterProps = React.ComponentProps<typeof Sonner>;
+
+const Toaster = ({ ...props }: ToasterProps) => {
+  const { theme = "system" } = useTheme();
+
+  return (
+    <Sonner
+      theme={theme as ToasterProps["theme"]}
+      className="toaster group"
+      toastOptions={{
+        classNames: {
+          toast:
+            "group toast group-[.toaster]:bg-background group-[.toaster]:text-foreground group-[.toaster]:border-border group-[.toaster]:shadow-lg",
+          description: "group-[.toast]:text-muted-foreground",
+          actionButton:
+            "group-[.toast]:bg-primary group-[.toast]:text-primary-foreground",
+          cancelButton:
+            "group-[.toast]:bg-muted group-[.toast]:text-muted-foreground",
+        },
+      }}
+      {...props}
+    />
+  );
+};
+
+export { Toaster };

components/ui/theme-toggle.tsx

@@ -0,0 +1,71 @@
+"use client";
+
+import * as React from "react";
+import { Moon, Sun } from "lucide-react";
+import { useTheme } from "next-themes";
+
+import { Button } from "@/components/ui/button";
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuTrigger,
+} from "@/components/ui/dropdown-menu";
+
+export function ThemeToggle() {
+  const { setTheme } = useTheme();
+
+  return (
+    <DropdownMenu>
+      <DropdownMenuTrigger asChild>
+        <Button variant="ghost" size="sm" className="h-8 w-8 px-0">
+          <Sun className="rotate-0 scale-100 transition-all dark:-rotate-90 dark:scale-0" />
+          <Moon className="absolute rotate-90 scale-0 transition-all dark:rotate-0 dark:scale-100" />
+          <span className="sr-only">Toggle theme</span>
+        </Button>
+      </DropdownMenuTrigger>
+      <DropdownMenuContent align="end">
+        <DropdownMenuItem onClick={() => setTheme("light")}>
+          Light
+        </DropdownMenuItem>
+        <DropdownMenuItem onClick={() => setTheme("dark")}>
+          Dark
+        </DropdownMenuItem>
+        <DropdownMenuItem onClick={() => setTheme("system")}>
+          System
+        </DropdownMenuItem>
+      </DropdownMenuContent>
+    </DropdownMenu>
+  );
+}
+
+export function SimpleThemeToggle() {
+  const { theme, setTheme } = useTheme();
+  const [mounted, setMounted] = React.useState(false);
+
+  React.useEffect(() => {
+    setMounted(true);
+  }, []);
+
+  if (!mounted) {
+    return (
+      <Button variant="ghost" size="sm" className="h-8 w-8 px-0">
+        <Sun className="h-4 w-4" />
+        <span className="sr-only">Toggle theme</span>
+      </Button>
+    );
+  }
+
+  return (
+    <Button
+      variant="ghost"
+      size="sm"
+      className="h-8 w-8 px-0"
+      onClick={() => setTheme(theme === "dark" ? "light" : "dark")}
+    >
+      <Sun className="h-4 w-4 rotate-0 scale-100 transition-all dark:-rotate-90 dark:scale-0" />
+      <Moon className="absolute h-4 w-4 rotate-90 scale-0 transition-all dark:rotate-0 dark:scale-100" />
+      <span className="sr-only">Toggle theme</span>
+    </Button>
+  );
+}