chore: update color variables in default-dark theme for improved contrast

web/src/themes/default-dark.css

 :root {
-  --background: oklch(0.25 0.003 270);
-  --foreground: oklch(0.75 0.003 270);
-  --card: oklch(0.28 0.003 270);
-  --card-foreground: oklch(0.75 0.003 270);
-  --popover: oklch(0.28 0.003 270);
-  --popover-foreground: oklch(0.72 0.003 270);
+  --background: oklch(0.20 0.003 270);
+  --foreground: oklch(0.80 0.003 270);
+  --card: oklch(0.23 0.003 270);
+  --card-foreground: oklch(0.80 0.003 270);
+  --popover: oklch(0.23 0.003 270);
+  --popover-foreground: oklch(0.77 0.003 270);
   --primary: oklch(0.6 0.08 250);
-  --primary-foreground: oklch(0.25 0.003 270);
-  --secondary: oklch(0.32 0.005 270);
-  --secondary-foreground: oklch(0.7 0.003 270);
-  --muted: oklch(0.3 0.005 270);
-  --muted-foreground: oklch(0.55 0.003 270);
-  --accent: oklch(0.35 0.008 270);
-  --accent-foreground: oklch(0.75 0.003 270);
+  --primary-foreground: oklch(0.20 0.003 270);
+  --secondary: oklch(0.27 0.005 270);
+  --secondary-foreground: oklch(0.75 0.003 270);
+  --muted: oklch(0.25 0.005 270);
+  --muted-foreground: oklch(0.58 0.003 270);
+  --accent: oklch(0.30 0.008 270);
+  --accent-foreground: oklch(0.80 0.003 270);
   --destructive: oklch(0.55 0.1 25);
-  --destructive-foreground: oklch(0.9 0.005 270);
-  --border: oklch(0.38 0.005 270);
-  --input: oklch(0.42 0.008 270);
+  --destructive-foreground: oklch(0.92 0.005 270);
+  --border: oklch(0.33 0.005 270);
+  --input: oklch(0.37 0.008 270);
   --ring: oklch(0.6 0.08 250);
   --chart-1: oklch(0.65 0.12 30);
   --chart-2: oklch(0.65 0.12 260);
   --chart-3: oklch(0.58 0.1 120);
   --chart-4: oklch(0.62 0.12 300);
   --chart-5: oklch(0.7 0.15 60);
-  --sidebar: oklch(0.22 0.002 270);
-  --sidebar-foreground: oklch(0.75 0.003 270);
+  --sidebar: oklch(0.17 0.002 270);
+  --sidebar-foreground: oklch(0.80 0.003 270);
   --sidebar-primary: oklch(0.6 0.08 250);
-  --sidebar-primary-foreground: oklch(0.25 0.003 270);
-  --sidebar-accent: oklch(0.35 0.008 270);
-  --sidebar-accent-foreground: oklch(0.75 0.003 270);
-  --sidebar-border: oklch(0.38 0.005 270);
+  --sidebar-primary-foreground: oklch(0.20 0.003 270);
+  --sidebar-accent: oklch(0.30 0.008 270);
+  --sidebar-accent-foreground: oklch(0.80 0.003 270);
+  --sidebar-border: oklch(0.33 0.005 270);
   --sidebar-ring: oklch(0.6 0.08 250);
   --font-sans:
     ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif,