diff --git a/header-meta.html b/header-meta.html
index 7e8d3c6..67cd3c2 100644
--- a/header-meta.html
+++ b/header-meta.html
@@ -22,29 +22,34 @@
 {% endif %}
 <meta property="og:site_name"                      content="{{ site.name }}" />
 <meta property="twitter:site"                      content="{{ site.name }}" />
-{% if site.social.twitter %}
-<meta name="twitter:creator"                       content="@{{ site.social.twitter }}" /><!-- Tell twitter that this was made by {{ site.author.name }} -->
+{% if site.social.twitter-username | default: site.social.twitter %}
+<meta name="twitter:creator"                       content="@{{ site.social.twitter-username | default: site.social.twitter }}" /><!-- Tell twitter that this was made by {{ site.author.name }} -->
 {% endif %}
-<meta property="og:type"                           content="{% if page.type | default: site.type %}{{ page.type | default: site.type }}{% else %}website{% endif %}" />
+<meta property="og:type"                           content="{{ page.type | default: site.type | default: 'website' }}" />
 <meta property="og:url"                            content="{{ site.url }}{{ page.url }}" />
+{%- if site.author -%}
 <meta name="author"                                content="{{ site.author.name }}" />
 <meta property="profile:first_name"                content="{{ site.author.first-name }}" />
 <meta property="profile:last_name"                 content="{{ site.author.last-name }}" />
+{%- endif %}
+{%- if site.social.default-username -%}
 <meta property="profile:username"                  content="{{ site.social.default-username }}" />
+{%- endif %}
 <meta name="twitter:card"                          content="summary_large_image" /><!-- Tell twitter that this link can be presented as a large image with a summary -->
 <meta name="msapplication-TileImage"               content="/images/MS-Tile-Image.png" /><!-- When pinned as a tile for Windows' Start, this is the image -->
-<meta property="og:image"                          content="{{ page.social-preview-image-url | default: page.hero-image | default: '/images/Social-Preview.png' }}" /><!-- Image for sharing on social networks -->
-<meta property="twitter:image"                     content="{{ page.social-preview-image-url | default: page.hero-image | default: '/images/Social-Preview.png' }}" />
-<meta name="twitter:image:src"                     content="{{ page.social-preview-image-url | default: page.hero-image | default: '/images/Social-Preview.png' }}" />
-{% if site.theme-color %}
-<meta name="msapplication-TileColor"               content="{{ site.theme-color }}" /><!-- When pinned as a tile for Windows' Start, this is the tile's BG color -->
-<meta name="theme-color"                           content="{{ site.theme-color }}"/><!-- Color in Chrome address bar -->
-<meta name="apple-mobile-web-app-status-bar-style" content="{{ site.theme-color }}" /><!-- Color in Safari status bar -->
+<meta property="og:image"                          content="{{ page.social-preview-image-url | default: page.hero-image | default: site.social-preview-image-url | default: '/images/Social-Preview.png' }}" /><!-- Image for sharing on social networks -->
+<meta property="twitter:image"                     content="{{ page.social-preview-image-url | default: page.hero-image | default: site.social-preview-image-url | default: '/images/Social-Preview.png' }}" />
+<meta name="twitter:image:src"                     content="{{ page.social-preview-image-url | default: page.hero-image | default: site.social-preview-image-url | default: '/images/Social-Preview.png' }}" />
+{%- assign theme-color = site.brand.primary-color | default: site.theme-color %}
+{%- if theme-color %}
+<meta name="msapplication-TileColor"               content="{{ theme-color }}" /><!-- When pinned as a tile for Windows' Start, this is the tile's BG color -->
+<meta name="theme-color"                           content="{{ theme-color }}"/><!-- Color in Chrome address bar -->
+<meta name="apple-mobile-web-app-status-bar-style" content="{{ theme-color }}" /><!-- Color in Safari status bar -->
 {% endif %}
 {% if page.date %}
 <meta property="article:published_time"            content="{{ page.date }}" />
-{% endif %}
-{% if page.date-modified %}
+{%- endif %}
+{%- if page.date-modified %}
 <meta property="article:modified_time"             content="{{ page.date-modified }}" />
 {% endif %}