diff --git a/docs/components/jumbotron.md b/docs/components/jumbotron.md
index af12996e60..9dd3c8294e 100644
--- a/docs/components/jumbotron.md
+++ b/docs/components/jumbotron.md
@@ -12,7 +12,7 @@ A lightweight, flexible component that can optionally extend the entire viewport
 <div class="jumbotron">
   <h1 class="display-3">Hello, world!</h1>
   <p class="lead">This is a simple hero unit, a simple jumbotron-style component for calling extra attention to featured content or information.</p>
-  <hr class="m-y-md">
+  <hr class="m-y-2">
   <p>It uses utility classes for typography and spacing to space content out within the larger container.</p>
   <p class="lead">
     <a class="btn btn-primary btn-lg" href="#" role="button">Learn more</a>
diff --git a/docs/components/navbar.md b/docs/components/navbar.md
index 532a1d3813..d5d911c1ba 100644
--- a/docs/components/navbar.md
+++ b/docs/components/navbar.md
@@ -241,7 +241,7 @@ Our collapse plugin allows you to use a `<button>` or `<a>` to toggle hidden con
 
 {% example html %}
 <div class="collapse" id="exCollapsingNavbar">
-  <div class="bg-inverse p-a">
+  <div class="bg-inverse p-a-1">
     <h4>Collapsed content</h4>
     <span class="text-muted">Toggleable via the navbar brand.</span>
   </div>
diff --git a/docs/examples/navbar-top-fixed/index.html b/docs/examples/navbar-top-fixed/index.html
index 58640e9144..bf4eeccdf4 100644
--- a/docs/examples/navbar-top-fixed/index.html
+++ b/docs/examples/navbar-top-fixed/index.html
@@ -21,7 +21,7 @@
 
     <div class="pos-f-t">
       <div class="collapse" id="navbar-header">
-        <div class="container-fluid bg-inverse p-a">
+        <div class="container-fluid bg-inverse p-a-1">
           <h3>Collapsed content</h3>
           <p>Toggleable via the navbar brand.</p>
         </div>
diff --git a/docs/examples/navbar-top/index.html b/docs/examples/navbar-top/index.html
index f89e1e412e..322c65684d 100644
--- a/docs/examples/navbar-top/index.html
+++ b/docs/examples/navbar-top/index.html
@@ -20,12 +20,12 @@
   <body>
 
     <div class="collapse" id="navbar-header">
-      <div class="container-fluid bg-inverse p-a">
+      <div class="container-fluid bg-inverse p-a-1">
         <h3>Collapsed content</h3>
         <p>Toggleable via the navbar brand.</p>
       </div>
     </div>
-    <div class="navbar navbar-light bg-faded navbar-static-top m-b">
+    <div class="navbar navbar-light bg-faded navbar-static-top m-b-1">
       <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbar-header">
         &#9776;
       </button>
diff --git a/docs/examples/sticky-footer-navbar/index.html b/docs/examples/sticky-footer-navbar/index.html
index be7722696b..a92dd2003e 100644
--- a/docs/examples/sticky-footer-navbar/index.html
+++ b/docs/examples/sticky-footer-navbar/index.html
@@ -23,7 +23,7 @@
     <!-- Fixed navbar -->
     <div class="pos-f-t">
       <div class="collapse" id="navbar-header">
-        <div class="container bg-inverse p-a">
+        <div class="container bg-inverse p-a-1">
           <h3>Collapsed content</h3>
           <p>Toggleable via the navbar brand.</p>
         </div>
@@ -56,7 +56,7 @@
 
     <!-- Begin page content -->
     <div class="container">
-      <div class="page-header m-t">
+      <div class="page-header m-t-1">
         <h1>Sticky footer with fixed navbar</h1>
       </div>
       <p class="lead">Pin a fixed-height footer to the bottom of the viewport in desktop browsers with this custom HTML and CSS. A fixed navbar has been added with <code>padding-top: 60px;</code> on the <code>body > .container</code>.</p>
diff --git a/docs/examples/sticky-footer/index.html b/docs/examples/sticky-footer/index.html
index 8321d151c5..3af8b13ff7 100644
--- a/docs/examples/sticky-footer/index.html
+++ b/docs/examples/sticky-footer/index.html
@@ -22,7 +22,7 @@
 
     <!-- Begin page content -->
     <div class="container">
-      <div class="page-header m-t">
+      <div class="page-header m-t-1">
         <h1>Sticky footer</h1>
       </div>
       <p class="lead">Pin a fixed-height footer to the bottom of the viewport in desktop browsers with this custom HTML and CSS.</p>
diff --git a/docs/getting-started/download.md b/docs/getting-started/download.md
index eb5caa4bc6..806eb7b3ab 100644
--- a/docs/getting-started/download.md
+++ b/docs/getting-started/download.md
@@ -6,7 +6,7 @@ group: getting-started
 
 **Bootstrap v{{ site.current_version}}** is available for download in several ways, including some of your favorite package managers. Choose from the options below to snag just what you need.
 
-<div class="row m-t-md">
+<div class="row m-t-2">
   <div class="col-sm-6">
 {% markdown %}
 ### Compiled
diff --git a/docs/index.html b/docs/index.html
index 2c0d18f7a4..3591dbd040 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -21,14 +21,14 @@ title: Bootstrap &middot; 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>
