Update header and sidebar styling

Header improvements:
- Align logo with left navigation (w-72 and px-8)
- Lighten header border to gray-100
- Add spacing between nav items (mr-8 for GitHub, mr-6 for Get Started)
- Reduce Get Started button font weight to light
- Add small chevron icon to Get Started button

Sidebar improvements:
- Increase border radius for selected items (rounded-xl)
- Change selected item background to #e8e8e8
- Increase padding for selected items (px-3.5 py-2)

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: groksrc

src/components/Header.astro

@@ -4,11 +4,11 @@ import MobileMenu from './MobileMenu'
 import { navConfig } from '@/config/navigation'
 ---
 
-<header class="sticky top-0 z-50 w-full border-b border-border bg-background">
+<header class="sticky top-0 z-50 w-full border-b border-gray-100 bg-background">
   <div class="flex justify-center">
     <div class="flex h-14 w-full max-w-screen-2xl items-center">
-      <!-- Logo aligned with left sidebar (w-64) -->
-      <div class="w-64 flex items-center px-4">
+      <!-- Logo aligned with left sidebar (w-72) -->
+      <div class="w-72 flex items-center px-8">
         <a href="/" class="flex items-center space-x-2">
           <img 
             src="/logo-light.png" 
@@ -37,11 +37,11 @@ import { navConfig } from '@/config/navigation'
           </button>
         </div>
 
-        <nav class="flex items-center space-x-8 ml-8">
+        <nav class="flex items-center ml-8">
           {navConfig.topNav.map((item) => (
             <a 
               href={item.href} 
-              class="text-sm font-normal transition-colors hover:text-foreground text-muted-foreground"
+              class="text-sm font-normal transition-colors hover:text-foreground text-muted-foreground mr-8"
               target={item.external ? "_blank" : undefined}
               rel={item.external ? "noopener noreferrer" : undefined}
               style="text-decoration: none"
@@ -52,10 +52,13 @@ import { navConfig } from '@/config/navigation'
 
           <a 
             href="/getting-started"
-            class="inline-flex items-center justify-center whitespace-nowrap rounded-full text-sm font-medium transition-colors focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring disabled:pointer-events-none disabled:opacity-50 bg-foreground text-background hover:bg-foreground/80 hover:text-background h-9 px-4 py-2"
+            class="inline-flex items-center justify-center whitespace-nowrap rounded-full text-sm font-light transition-colors focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring disabled:pointer-events-none disabled:opacity-50 bg-foreground text-background hover:bg-foreground/80 hover:text-background h-9 px-4 py-2 mr-6"
             style="text-decoration: none"
           >
             Get Started
+            <svg class="ml-1 h-3 w-3" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+              <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 5l7 7-7 7"></path>
+            </svg>
           </a>
           <ThemeToggle client:load />
         </nav>

src/components/Sidebar.astro

@@ -39,10 +39,10 @@ const currentPath = Astro.url.pathname
               <li>
                 <a
                   href={item.href}
-                  class={`block px-3 py-1.5 text-sm transition-colors hover:text-gray-900 rounded-md ${
+                  class={`block text-sm transition-colors hover:text-gray-900 rounded-xl ${
                     currentPath === item.href
-                      ? 'text-gray-900 font-medium bg-gray-100'
-                      : 'text-gray-600 font-normal hover:bg-gray-50'
+                      ? 'text-gray-900 font-medium bg-[#e8e8e8] px-3.5 py-2'
+                      : 'text-gray-600 font-normal hover:bg-gray-50 px-3 py-1.5'
                   }`}
                   style="text-decoration: none"
                 >