update docs styling

Author: Kitenite

docs/src/app/global.css

@@ -2,11 +2,18 @@
 @import 'fumadocs-ui/css/black.css';
 @import 'fumadocs-ui/css/preset.css';
 
+:root {
+  --color-fd-background: linear-gradient(135deg, #ffffff 0%, #ffffff 60%, #ffecec 100%);
+}
+.dark {
+  --color-fd-background: linear-gradient(135deg, #1a0000 0%, #000000 60%, #1a0000 100%);
+}
+
 html,
 body {
   overscroll-behavior: none;
   font-weight: 350;
-  background: linear-gradient(135deg, #1a0000 0%, #000000 60%, #1a0000 100%);
+  background: var(--color-fd-background);
   min-height: 100vh;
 }
 
@@ -35,4 +42,4 @@ h6:hover [data-hash-link] {
 .prose h5,
 .prose h6 {
     font-weight: 500;
-}
+}