Add dark theme support in CSS and fix neutral color variable in HTML template

static/css/main.css

@@ -36,4 +36,44 @@
   --noise: 0;
 }
 
+@plugin "daisyui/theme" {
+  name: "dark";
+  default: false;
+  prefersdark: true;
+  color-scheme: "dark";
+  --color-base-100: oklch(22% 0.014 260);
+  --color-base-200: oklch(19% 0.012 260);
+  --color-base-300: oklch(16% 0.01 260);
+  --color-base-content: oklch(95% 0.01 260);
+  --color-primary: oklch(58% 0.2 270);
+  --color-primary-content: oklch(96% 0.02 272);
+  --color-secondary: oklch(62% 0.15 250);
+  --color-secondary-content: oklch(96% 0.02 250);
+  --color-accent: oklch(72% 0.18 280);
+  --color-accent-content: oklch(20% 0.02 280);
+  --color-neutral: oklch(28% 0.02 260);
+  --color-neutral-content: oklch(92% 0.004 286.32);
+  --color-info: oklch(74% 0.16 232.661);
+  --color-info-content: oklch(29% 0.066 243.157);
+  --color-success: oklch(76% 0.177 163.223);
+  --color-success-content: oklch(37% 0.077 168.94);
+  --color-warning: oklch(82% 0.189 84.429);
+  --color-warning-content: oklch(41% 0.112 45.904);
+  --color-error: oklch(71% 0.194 13.428);
+  --color-error-content: oklch(27% 0.105 12.094);
+  --radius-selector: 0.5rem;
+  --radius-field: 0.25rem;
+  --radius-box: 0.5rem;
+  --size-selector: 0.25rem;
+  --size-field: 0.25rem;
+  --border: 1px;
+  --depth: 1;
+  --noise: 0;
+}
+
+/* Dark theme: main content area uses base-200 so navbar and cards (base-100) stand out */
+[data-theme=dark] main {
+  background-color: var(--color-base-200);
+}
+
 @source "../../templates";