feat(join-us): add sign up button for membership

Changes include various styling for the new button and reorgnization of
current tabs.

_data/nav.yml

@@ -1,25 +1,27 @@
 # header links
 header:
-  - title: "Our Work"
-    url: "/our-work/"
-    description: "Link to Southern New Hampshire's Work"
-    subpages:
-      - title: "Working Groups"
-        url: "/working-groups/"
   - title: "About Us"
     description: "About how we work and what we believe"
     subpages:
+      - title: "Our Work"
+        url: "/our-work/"
+        description: "Link to Southern New Hampshire's Work"
       - title: "Working Groups"
         url: "/working-groups/"
   - title: "Statements"
     url: "/blog/"
     description: "Link to Southern New Hampshire's Chapter Statements"
-  - title: "Get Involved"
-    url: "/get-involved/"
-    description: "Check out what Southern New Hampshire DSA is working on. Join DSA!"
   - title: "Events Calendar"
     url: "/calendar/"
     description: "Chapter Events Calendar"
+  - title: "Get Involved"
+    url: "/get-involved/"
+    description: "How to get involved with our chapter"
+
+join:
+  title: "JOIN US"
+  url: "https://act.dsausa.org/donate/membership/"
+  description: "Check out what Southern New Hampshire DSA is working on. Join DSA!"
 
 # footer links
 footer:

_includes/header.html

@@ -43,6 +43,9 @@
         </li>
         {%- endif -%}
         {%- endfor -%}
+          <li class="nav-item">
+            <a class="btn-join" href="{{ site.data.nav.join.url }}" target="_blank" title="{{ site.data.nav.join.title }}">{{ site.data.nav.join.title }}</a>
+          </li>
       </ul>
       {% if site.search == true %}
       {%- include search-providers/search_form.html -%}

_sass/bootswatch/dist/united/_variables.scss

@@ -51,3 +51,7 @@ $font-family-sans-serif:      "Ubuntu", -apple-system, BlinkMacSystemFont, "Sego
 
 $table-dark-bg:               $dark !default;
 $table-dark-border-color:     darken($dark, 5%) !default;
+
+
+// navigation bar colors
+$navbar-dark-color: white;

_sass/dsa/buttons.scss

@@ -3,15 +3,15 @@
     color: white;
     font-size: var(--size-xs);
 
-    &:hover{ 
+    &:hover{
         background: var(--red-tint-1);
     }
 }
 
 .btn-secondary {
     color: var(--red);
     font-size: var(--size-xs);
-    font-weight: bolder;
+    font-weight: 600;
     border: 1px solid transparent;
     background: transparent !important;
 
@@ -20,4 +20,26 @@
         color: var(--red) !important;
         background: transparent !important;
     }
-}
+}
+
+.nav-item .btn-join {
+    background-color: var(--white);
+    border-radius: 8px;
+    color: black;
+    display: block;
+    font-family: Ubuntu Condensed, sans-serif;
+    font-size: var(--size-sm);
+    font-weight: 800;
+    padding: .25rem .5rem;
+}
+
+.navbar-nav {
+    color: white;
+    display: flex;
+    align-items: center;
+}
+
+.nav-item {
+    display: flex;
+    align-items: center;
+}