diff --git a/spec.txt b/spec.txt
@@ -1286,9 +1286,9 @@ bar
.
An [info string](#info-string) can be provided after the opening code fence.
-Opening and closing spaces will be stripped, and the first word
-is used here to populate the `class` attribute of the enclosing
-`pre` tag.
+Opening and closing spaces will be stripped, and the first word, prefixed
+with `language-`, is used as the value for the `class` attribute of the
+`code` element within the enclosing `pre` element.
.
```ruby
@@ -1297,7 +1297,7 @@ def foo(x)
end
```
.
-<pre class="ruby"><code>def foo(x)
+<pre><code class="language-ruby">def foo(x)
return 3
end
</code></pre>
@@ -1310,7 +1310,7 @@ def foo(x)
end
~~~~~~~
.
-<pre class="ruby"><code>def foo(x)
+<pre><code class="language-ruby">def foo(x)
return 3
end
</code></pre>
@@ -1320,7 +1320,7 @@ end
````;
````
.
-<pre class=";"><code></code></pre>
+<pre><code class="language-;"></code></pre>
.
Info strings for backtick code blocks cannot contain backticks:
@@ -3720,7 +3720,7 @@ blocks](#fenced-code-block):
foo
```
.
-<pre class="foo+bar"><code>foo
+<pre><code class="language-foo+bar">foo
</code></pre>
.
@@ -3813,7 +3813,7 @@ code blocks, including raw HTML, URLs, [link titles](#link-title), and
foo
```
.
-<pre class="föö"><code>foo
+<pre><code class="language-föö">foo
</code></pre>
.