feat(top-nav): stub out mobile styles

* Add new open and close icons
* Remove navigation.css in favor of header.css

Author: sarmstead

assets/images/icon__burger.svg

@@ -13,10 +13,9 @@
 
 /* Layout */
 @import './layout/reset.css';
-@import './layout/navigation.css';
 @import './layout/dropdown.css';
 @import './layout/container.css';
-/* @import './layout/header.css'; */
+@import './layout/header.css';
 @import './layout/footer.css';
 
 /* Pages */

assets/images/icon__close.svg

@@ -1,3 +1,59 @@
-header {
-  margin-bottom: 3rem;
+.navigation--top {
+    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
+
+    .navigation__inner {
+        align-items: center;
+        display: grid;
+        grid-template-areas: 'logo mobile-trigger membership';
+        grid-template-columns: 1fr repeat(2, max-content);
+        margin: auto;
+        max-width: var(--layout-inner-max-width);
+        padding: 8px 20px 8px 10px;
+        position: relative;
+    }
+
+    .navigation__logo {
+        box-shadow: none;
+        grid-area: logo;
+
+        img {
+            height: 75px;
+            width: 75px;
+        }
+    }
+
+    .navigation__mobile-menu-trigger {
+        background-color: white;
+        background-repeat: no-repeat;
+        background-size: contain;
+        border: none;
+        cursor: pointer;
+        grid-area: mobile-trigger;
+        height: 24px;
+        margin-right: 20px;
+        width: 24px;
+    }
+
+    .navigation__mobile-menu-trigger.closed {
+        background-image: url('/assets/images/icon__burger.svg');
+    }
+
+    .navigation__mobile-menu-trigger.open {
+        background-image: url('/assets/images/icon__close.svg');
+    }
+
+    .navigation__list {
+        display: none;
+        grid-area: list;
+    }
+
+    .navigation__membership {
+        grid-area: membership;
+    }
+
+    @media (min-width: 1440px) {
+        .navigation__mobile-menu-trigger {
+            display: none;
+        }
+    }
 }