Add 'Now' page and update navigation; refine styles and metadata

src/components/Nav.astro

@@ -5,6 +5,7 @@ const links = [
     { href: "/", label: "home" },
     { href: "/about", label: "about" },
     { href: "/projects", label: "projects" },
+    { href: "/now", label: "now" },
     { href: "/blog", label: "blog" },
 ];
 
@@ -39,7 +40,7 @@ function isActive(href: string, current: string): boolean {
         right: 0;
         z-index: 100;
         padding: var(--space-sm) var(--space-md);
-        background: rgba(30, 30, 46, 0.85);
+        background: var(--color-glass-nav);
         backdrop-filter: blur(8px);
         border-bottom: 1px solid var(--color-surface);
     }