css: refactor CSS to use Tailwind-style utility classes.

Refactor CSS to use standard Tailwind-style utility classes instead of
ad-hoc rules. This eliminates a lot of single-purpose rules for specific
UI elements and standardizes margins to be more consistent throughout
the site.

Utility classes are defined manually on an as-needed basis instead of
importing Tailwind as a whole. Naming conventions mostly follow
Tailwind's conventions, otherwise they follow Bootstrap.

* https://tailwindcss.com/docs/
* https://getbootstrap.com/docs/5.0/utilities/spacing/

app/views/static/_backtrace.html.erb

@@ -1,6 +1,6 @@
 <%# backtrace %>
 
-<ul class="backtrace">
+<ul class="backtrace font-monospace p-4 mb-4">
   <% if defined?(exception) %>
     <li><%= exception.class.to_s %> exception raised</li>
   <% end %>

app/views/static/privacy_policy.html.erb

@@ -8,7 +8,7 @@
   <div id="a-privacy-policy" class="prose fixed-width-container">
     <h1>Privacy Policy</h1>
 
-    <p class="summary">Last updated: July 5, 2020</p>
+    <p><em>Last updated: July 5, 2020</em></p>
 
     <p>This privacy policy describes what information <%= @app_name %>
     (collectively "we", "us", "our") collects about you when you use our website
@@ -25,7 +25,7 @@
 
     <h6>Information You Provide To Us</h6>
 
-    <p class="summary">Summary: We collect information you directly give us.</p>
+    <p><em>Summary: We collect information you directly give us.</em></p>
 
     <p>We collect information you directly provide to us when you use our
     Services. What information we collect depends on how you use our Services.
@@ -76,9 +76,9 @@
 
     <h6>Information We Collect Automatically</h6>
 
-    <p class="summary">Summary: We collect some information about you
+    <p><em>Summary: We collect some information about you
     automatically, including your IP address, information about your computer,
-    and information about your site usage.</p>
+    and information about your site usage.</em></p>
 
     <ul class="list-bulleted">
       <li><strong>Log and usage data</strong>. We may log information about you
@@ -100,9 +100,9 @@
 
     <h6>Information We Collect From Other Sources</h6>
 
-    <p class="summary">Summary: If you choose to link other sites to your
+    <p><em>Summary: If you choose to link other sites to your
     <%= @app_name %> account, we will receive profile information about you
-    from those sites.</p>
+    from those sites.</em></p>
 
     <p>We may receive information about you from other sources and combine that
     information with other information we have about you. For example, we may
@@ -114,8 +114,8 @@
 
     <h4>How We Use Your Information</h4>
 
-    <p class="summary">Summary: We use your information to provide services to
-    you, to operate the Site, and to enforce our Terms of Service.</p>
+    <p><em>Summary: We use your information to provide services to
+    you, to operate the Site, and to enforce our Terms of Service.</em></p>
 
     <p>We use your information to:</p>
 
@@ -173,10 +173,10 @@
 
     <h4>How Information About You Is Shared</h4>
 
-    <p class="summary">Summary: Most activity on <%= @app_name %> is public. We
+    <p><em>Summary: Most activity on <%= @app_name %> is public. We
     won't share your information with advertisers without your consent. We
     won't share information about you with third parties, except as required
-    under certain conditions.</p>
+    under certain conditions.</em></p>
 
     <p>When you use the Site, certain information about you may be shared with
     other users, with Site moderators or other authorized users, or with the
@@ -312,9 +312,9 @@
 
     <h6>How We Handle Linked Accounts</h6>
 
-    <p class="summary">Summary: If you link other sites to your <%= @app_name %>
+    <p><em>Summary: If you link other sites to your <%= @app_name %>
     account, we will receive profile information about you from those sites. We
-    won't disclose any information about you to those sites.</p>
+    won't disclose any information about you to those sites.</em></p>
 
     <p>We may offer you the ability to sign up or login using third-party
     social media accounts (such as your Google or Twitter accounts), or to link
@@ -352,8 +352,8 @@
 
     <h6>Deleting Your Account</h6>
 
-    <p class="summary">Summary: You may deactivate your account, but we may
-    retain your IP address and your public contributions to the Site.</p>
+    <p><em>Summary: You may deactivate your account, but we may
+    retain your IP address and your public contributions to the Site.</em></p>
 
     <p>If you would like to delete your account, you may request your
     account to be deactivated <%= link_to "here", maintenance_user_deletion_path %>.</p>
@@ -409,9 +409,9 @@
 
     <h6>Data Retention</h6>
 
-    <p class="summary">Summary: We keep your information for as long as
+    <p><em>Summary: We keep your information for as long as
     necessary to fulfill the purposes outlined in this privacy policy, unless
-    otherwise required by law.</p>
+    otherwise required by law.</em></p>
 
     <p>We store the information we collect for as long as it is necessary for
     the purpose(s) for which we originally collected it. We may retain certain
@@ -426,7 +426,7 @@
 
     <h6>International Data Transfers</h6>
 
-    <p class="summary">Summary: We store data in the United States and operate under US law.</p>
+    <p><em>Summary: We store data in the United States and operate under US law.</em></p>
 
     <p>We are based in the United States and we process and store information
     on servers located in the United States. We may store information on
@@ -439,9 +439,9 @@
 
     <h6>Information Security</h6>
 
-    <p class="summary">Summary: We take reasonable measures to secure your
+    <p><em>Summary: We take reasonable measures to secure your
     data. We will promptly notify you of breaches of your personal
-    information.</p>
+    information.</em></p>
 
     <p>We take reasonable measures to protect your personal information from
     loss, theft, misuse, unauthorized access, disclosure, alteration, or
@@ -461,7 +461,7 @@
 
     <h6>Changes to this Policy</h6>
 
-    <p class="summary">Summary: We may update this policy from time to time.</p>
+    <p><em>Summary: We may update this policy from time to time.</em></p>
 
     <p>We may update this Privacy Policy from time to time. The updated policy
     will be indicated by a new "Last updated" date at the top of this page. If

app/views/static/site_map.html.erb

@@ -1,8 +1,8 @@
 <% page_title "Site Map" %>
 
 <div id="c-static">
-  <div id="a-site-map" class="fixed-width-container">
-    <section>
+  <div id="a-site-map" class="fixed-width-container space-y-4 md:flex md:space-y-0">
+    <section class="flex-auto space-y-4">
       <ul>
         <li><h2>Posts</h2></li>
         <li><%= link_to_wiki "Help", "help:posts" %></li>
@@ -44,7 +44,7 @@
         <li><%= link_to("Changes", artist_versions_path) %></li>
       </ul>
     </section>
-    <section>
+    <section class="flex-auto space-y-4">
       <ul>
         <li><h2>Tags</h2></li>
         <li><%= link_to_wiki "Help", "help:tags" %></li>
@@ -75,7 +75,7 @@
         <li><%= link_to("Missed Searches", missed_searches_explore_posts_path) %></li>
       </ul>
     </section>
-    <section>
+    <section class="flex-auto space-y-4">
       <ul>
         <li><h2>Comments</h2></li>
         <li><%= link_to_wiki "Help", "help:comments" %></li>
@@ -107,7 +107,7 @@
         <li><%= link_to("Changes", artist_commentary_versions_path) %></li>
       </ul>
     </section>
-    <section>
+    <section class="flex-auto space-y-4">
       <ul>
         <li><h2>Profile</h2></li>
         <% if CurrentUser.is_anonymous? %>