Use h1 for guide titles

Currently the guides use the h1 tag for the guides logo instead of the
guides title. As the guides title is more important in describing the
content of a guide, the title should use the h1 instead.
This also move every other heading to a more important heading (h3 becomes h2, etc.).

This change should improve SEO for the guides.

Author: p8

guides/assets/stylesheets/main.css

@@ -530,53 +530,46 @@ a, a:link, a:visited {
 --------------------------------------- */
 
 h1 {
-  font-size: 2.5em;
-  line-height: 1;
-  margin: 0.6em 0 .2em;
-  font-weight: bold;
-}
-
-h2 {
   font-size: 2.1428em;
   line-height: 1;
   margin: 0.7em 0 .2333em;
   font-weight: bold;
 }
 
 @media screen and (max-width: 480px) {
-  h2 {
+  h1 {
     font-size: 1.45em;
   }
 }
 
-h3 {
+h2 {
   font-size: 1.7142em;
   line-height: 1.286;
   margin: 0.875em 0 0.2916em;
   font-weight: bold;
 }
 
 @media screen and (max-width: 480px) {
-  h3 {
+  h2 {
     font-size: 1.45em;
   }
 }
 
-h4 {
+h3 {
   font-size: 1.2857em;
   line-height: 1.2;
   margin: 1.6667em 0 .3887em;
   font-weight: bold;
 }
 
-h5 {
+h4 {
   font-size: 1em;
   line-height: 1.5;
   margin: 1em 0 .5em;
   font-weight: bold;
 }
 
-h6 {
+h5 {
   font-size: 1em;
   line-height: 1.5;
   margin: 1em 0 .5em;
@@ -600,15 +593,15 @@ h6 {
 :where(body[dir="rtl"]) #topNav strong { margin-left: 0.5em; }
 #topNav strong a {color: #FFF;}
 
-#header h1 {
+#header .header-logo {
   background: url(../images/rails_guides_logo_1x.png) no-repeat;
   width: 297px;
   text-indent: -9999em;
   margin: 0;
   padding: 0;
 }
-:where(body[dir="ltr"]) #header h1 { float: left; }
-:where(body[dir="rtl"]) #header h1 { float: right; }
+:where(body[dir="ltr"]) #header .header-logo { float: left; }
+:where(body[dir="rtl"]) #header .header-logo { float: right; }
 
 @media
 only screen and (-webkit-min-device-pixel-ratio: 2),
@@ -617,19 +610,19 @@ only screen and (     -o-min-device-pixel-ratio: 2/1),
 only screen and (        min-device-pixel-ratio: 2),
 only screen and (                min-resolution: 192dpi),
 only screen and (                min-resolution: 2dppx) {
-  #header h1 {
+  #header .header-logo {
     background: url(../images/rails_guides_logo_2x.png) no-repeat;
     background-size: 160%;
   }
 }
 
 @media screen and (max-width: 480px) {
-  #header h1 {
+  #header .header-logo {
     float: none;
   }
 }
 
-#header h1 a {
+#header .header-logo a {
   text-decoration: none;
   display: block;
   height: 77px;

guides/rails_guides/markdown.rb

@@ -98,17 +98,17 @@ def generate_structure
             hierarchy = []
 
             doc.children.each do |node|
-              if /^h[3-6]$/.match?(node.name)
+              if /^h[2-5]$/.match?(node.name)
                 case node.name
-                when "h3"
+                when "h2"
                   hierarchy = [node]
                   @headings_for_index << [1, node, node.inner_html]
-                when "h4"
+                when "h3"
                   hierarchy = hierarchy[0, 1] + [node]
                   @headings_for_index << [2, node, node.inner_html]
-                when "h5"
+                when "h4"
                   hierarchy = hierarchy[0, 2] + [node]
-                when "h6"
+                when "h5"
                   hierarchy = hierarchy[0, 3] + [node]
                 end
 
@@ -117,7 +117,7 @@ def generate_structure
               end
             end
 
-            doc.css("h3, h4, h5, h6").each do |node|
+            doc.css("h2, h3, h4, h5").each do |node|
               node.inner_html = "<a class='anchorlink' href='##{node[:id]}'>#{node.inner_html}</a>"
             end
           end

guides/rails_guides/markdown/epub_renderer.rb

@@ -25,9 +25,6 @@ def link(url, title, content)
       end
 
       def header(text, header_level)
-        # Always increase the heading level by 1, so we can use h1, h2 heading in the document
-        header_level += 1
-
         header_with_id = text.scan(/(.*){#(.*)}/)
         unless header_with_id.empty?
           %(<h#{header_level} id="#{header_with_id[0][1].strip}">#{header_with_id[0][0].strip}</h#{header_level}>)

guides/rails_guides/markdown/renderer.rb

@@ -33,9 +33,6 @@ def link(url, title, content)
       end
 
       def header(text, header_level)
-        # Always increase the heading level by 1, so we can use h1, h2 heading in the document
-        header_level += 1
-
         header_with_id = text.scan(/(.*){#(.*)}/)
         unless header_with_id.empty?
           %(<h#{header_level} id="#{header_with_id[0][1].strip}">#{header_with_id[0][0].strip}</h#{header_level}>)

guides/source/layout.html.erb

@@ -42,7 +42,7 @@
   </div>
   <div id="header">
     <div class="wrapper clearfix">
-      <h1><a href="index.html" title="Return to home page">Guides.rubyonrails.org</a></h1>
+      <div class="header-logo"><a href="index.html" title="Return to home page">Guides.rubyonrails.org</a></div>
       <ul class="nav">
         <li><a class="nav-item" href="index.html">Home</a></li>
         <li class="guides-index guides-index-large">