Add authentication pages and routing;

src/scss/components/_header.scss

@@ -1,11 +1,45 @@
 // Header
 
-@use '../base/settings' as *;
-@use '../utilities/mixins' as *;
+@use "../base/settings" as *;
+@use "../utilities/mixins" as *;
 
 header {
-    padding: $section-padding;
-    h1 {
-        @include flatten;
+  padding: $section-padding;
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  border-bottom: 1px solid $grey;
+
+  h1 {
+    @include flatten;
+
+    a {
+      text-decoration: none;
+      color: $dark;
+
+      &:hover {
+        color: $yellow;
+      }
     }
-}
+  }
+
+  nav {
+    ul {
+      @include flatten(true);
+      display: flex;
+      gap: 1rem;
+
+      li {
+        a {
+          text-decoration: none;
+          color: $dark;
+          font-weight: bold;
+
+          &:hover {
+            color: $yellow;
+          }
+        }
+      }
+    }
+  }
+}