diff --git a/_sass/2017/markdown/code.scss b/_sass/2017/markdown/code.scss
index 8b68bb859..cfb1e363f 100644
--- a/_sass/2017/markdown/code.scss
+++ b/_sass/2017/markdown/code.scss
@@ -34,6 +34,10 @@
     line-height: $code-line-height;
   }
 
+  pre.-wrap {
+    white-space: pre-wrap;
+  }
+
   pre > code {
     color: $base-head;
     max-height: auto;
diff --git a/cheatsheet-styles.md b/cheatsheet-styles.md
index 4ce7b8a21..4c432a750 100644
--- a/cheatsheet-styles.md
+++ b/cheatsheet-styles.md
@@ -45,8 +45,9 @@ See: [Tables](#tables-1)
 
 ### Code
 
-| `-setup` | Gray background |
 | `-box-chars` | Less line height<br>_for box drawing chars_ |
+| `-setup` | Gray background |
+| `-wrap` | Enables line-wrapping |
 
 See: [Code](#code-1)
 
@@ -197,6 +198,15 @@ function createNode(nodeName: string, options: { key: string }) {
 
 Long lines will have scrollbars.
 
+### Line wrapping
+
+```js
+<script>(function(d,s){if(window.Promise&&[].includes&&Object.assign&&window.Map)return;var js,sc=d.getElementsByTagName(s)[0];js=d.createElement(s);js.src='https://cdn.polyfill.io/v2/polyfill.min.js';sc.parentNode.insertBefore(js, sc);}(document,'script'))</script>
+```
+{: .-wrap}
+
+Add `-wrap` to wrap long lines.
+
 ## Lists
 {: .-three-column}
 
diff --git a/polyfill.io.md b/polyfill.io.md
new file mode 100644
index 000000000..41081ee6e
--- /dev/null
+++ b/polyfill.io.md
@@ -0,0 +1,53 @@
+---
+title: Polyfill.io
+category: JavaScript libraries
+updated: 2017-10-26
+layout: 2017/sheet
+intro: |
+  [Polyfill.io](https://polyfill.io) is a service that serves JavaScript polyfills.
+---
+
+## Usage
+
+### Default usage
+
+```html
+<script src="https://cdn.polyfill.io/v2/polyfill.min.js"></script>
+```
+{: .-wrap}
+
+This is the default script for Polyfill.io.
+
+### References
+
+- [API example](https://polyfill.io/v2/docs/api) _(polyfill.io)_
+- [List of features](https://polyfill.io/v2/docs/features) _(polyfill.io)_
+
+## Optimized
+
+### For modern browsers
+
+```html
+<script>(function(d,s){
+if(window.Promise&&[].includes&&Object.assign&&window.Map)return;
+var sc=d.getElementsByTagName(s)[0],js=d.createElement(s);
+js.src='https://cdn.polyfill.io/v2/polyfill.min.js';
+sc.parentNode.insertBefore(js, sc);
+}(document,'script'))</script>
+```
+
+This only includes polyfill.io when necessary, skipping it for modern browsers for faster load times.
+
+### Extra features
+
+```html
+<script>(function(d,s){
+if(window.fetch&&window.Promise&&[].includes&&Object.assign&&window.Map)return;
+var sc=d.getElementsByTagName(s)[0],js=d.createElement(s);
+js.src='https://cdn.polyfill.io/v2/polyfill.min.js?features=default,fetch';
+sc.parentNode.insertBefore(js, sc);
+}(document,'script'))</script>
+```
+{: data-line="2,4"}
+
+This is the same as the previous, but also adds a polyfill for `window.fetch()`. We add a `window.fetch` check and loads the additional `fetch` feature.