Update docs

Author: mrmrs

docs/layout/floats/index.html

@@ -138,7 +138,7 @@ <h3 class="f5 book pt4 caps">Float With Images</h3>
         <p class="f3">Originally floats were used to wrap text around images as in the example below.</p>
         <div class="cf">
           <img src="/img/example-1.jpg" class="fl w4 mr3" alt="example 1">
-          <p class="measure mtn">
+          <p class="measure mt0">
             Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod
             tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At
             vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren,

docs/themes/opacity/index.html

@@ -73,7 +73,7 @@ <h3 class="f6 ttu tracked mt0">Opacity</h3>
       </article>
       <div class="ph3 ph5-ns pt4 pb5">
         <h3 class="f5 mb4 pb2 bb">Examples</h3>
-        <h4 class="f6 mt4">Opacity scale</h3>
+        <h4 class="f6 mt4">Opacity scale</h4>
         <code class="f6 db mv3"></code>
         <section class="cf">
           <div class="fl w-100 w-33-l pt4">