Update examples to account for #18185

[skip sauce]

docs/index.html

@@ -21,14 +21,14 @@ title: Bootstrap · The world's most popular mobile-first and responsive f
     <p class="lead">Quickly include Bootstrap's CSS and JS into any project. Use your favorite package manager, download the source, or use the Bootstrap CDN.</p>
 
     <div class="row">
-      <div class="col-sm-6 m-b-lg">
+      <div class="col-sm-6 m-b-3">
         <h4>Managed dependencies</h4>
         <p>Include Bootstrap's source Sass and JavaScript files via Bower, Composer, Meteor, or npm. Package managed installs don't include documentation, but do include our Gruntfile and readme.</p>
         <p>
           <a class="btn btn-bs btn-outline" href="{{ site.baseurl }}/getting-started/download/#package-managers">View install methods</a>
         </p>
       </div>
-      <div class="col-sm-6 m-b-lg">
+      <div class="col-sm-6 m-b-3">
         <h4>Bootstrap CDN</h4>
         <p>When you just need to include Bootstrap's compiled CSS and JS, use the Bootstrap CDN, free from the Max CDN folks.</p>
 {% highlight html %}
@@ -52,17 +52,17 @@ title: Bootstrap &middot; The world's most popular mobile-first and responsive f
     <p class="lead">Bootstrap makes front-end web development faster and easier. It's made for folks of all skill levels, devices of all shapes, and projects of all sizes.</p>
 
     <div class="row">
-      <div class="col-sm-4 m-b-lg">
+      <div class="col-sm-4 m-b-3">
         <img src="assets/img/sass.png" alt="Sass support" class="img-fluid">
         <h4>Preprocessor</h4>
         <p>Bootstrap ships with vanilla CSS, but its source code utilizes <a href="http://sass-lang.com/">Sass</a>, a popular CSS preprocessor. Quickly get started with precompiled CSS or build on the source.</p>
       </div>
-      <div class="col-sm-4 m-b-lg">
+      <div class="col-sm-4 m-b-3">
         <img src="assets/img/devices.png" alt="Responsive across devices" class="img-fluid">
         <h4>One framework, every device.</h4>
         <p>Bootstrap easily and efficiently scales your websites and applications with a single code base, from phones to tablets to desktops with CSS media queries.</p>
       </div>
-      <div class="col-sm-4 m-b-lg">
+      <div class="col-sm-4 m-b-3">
         <img src="assets/img/components.png" alt="Components" class="img-fluid">
         <h4>Full of features</h4>
         <p>With Bootstrap, you get extensive and beautiful documentation for common HTML elements, dozens of custom HTML and CSS components, and awesome jQuery plugins.</p>