Update colour classes

source/_partials/post/about-author.html.twig

@@ -3,7 +3,7 @@
 
     <div class="flex items-center">
         <div class="mr-4 flex-none leading-none">
-            <img src="{{ site.avatar.url }}" alt="Picture of Oliver" class="w-16 rounded-full border border-grey">
+            <img src="{{ site.avatar.url }}" alt="Picture of Oliver" class="w-16 rounded-full border border-gray">
         </div>
 
         <p class="mb-0">

source/_partials/post/feedback.html.twig

@@ -1,3 +1,3 @@
-<p class="mb-4 italic text-grey-dark">
+<p class="mb-4 italic text-gray-600">
     <b>Have feedback on this post?</b> <a href="mailto:{{ site.email }}?subject=Feedback: {{ page.title }}">Email me</a> or <a href="https://twitter.com/intent/tweet?text=@{{ site.twitter.name }}&url={{ site.url }}{{ page.url|url_encode }}">send me a tweet</a>.
 </p>

source/_partials/post/header.html.twig

@@ -1,7 +1,7 @@
 <div class="mb-8">
     <h1 class="leading-tight mb-2">{{ page.title }}</h1>
 
-    <p class="text-grey-dark">
+    <p class="text-gray-600">
         {% include 'posts/post-date' with { post: page } %}
     </p>
 </div>

source/_partials/post/tags.html.twig

@@ -4,7 +4,7 @@
     <ul class="list-reset flex flex-wrap">
         {% for tag in page.tags|sort %}
             <li>
-                <a href="/blog/tags/{{ tag }}" class="text-xs py-1 px-2 mr-1 mb-1 bg-grey-lighter text-grey-darker leading-none no-underline hover:underline focus:bg-grey-darker focus:text-white focus:outline-none">
+                <a href="/blog/tags/{{ tag }}" class="text-xs py-1 px-2 mr-1 mb-1 bg-gray-200 text-gray-800 leading-none no-underline hover:underline focus:bg-gray-800 focus:text-white focus:outline-none">
                     {{- tag -}}
                 </a>
             </li>