diff --git a/.gitignore b/.gitignore
index c2ca8cb..ce48c16 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,4 +2,5 @@ dist/demo
 node_modules
 *.sass-cache
 .publish
-.DS_Store
\ No newline at end of file
+.DS_Store
+.idea
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9ca459c..584c505 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+## v1.3.2
+
+* Fix validation issues for .optional-prop mixin in Less version.
+
 ## v1.3.1
 
 * Update files in dist folder
@@ -34,4 +38,4 @@
 
 ## v1.0.0
 
-* Add IE10 to "dinosaur mode" and set it to "false" by default
\ No newline at end of file
+* Add IE10 to "dinosaur mode" and set it to "false" by default
diff --git a/README.md b/README.md
index bdfbcb7..4d9b2e7 100644
--- a/README.md
+++ b/README.md
@@ -27,7 +27,7 @@ with browserify:
 
 ## Configure
 
-Overwrite default values for generic typography:
+### Overwrite default values for generic typography
 ```
 $initialize-box-sizing: border-box;
 $initialize-font-family: sans-serif;
@@ -35,12 +35,19 @@ $initialize-font-size: 1em;
 $initialize-line-height: 1.4;
 ```
 
-Microsoft [dropped support](https://www.microsoft.com/en-us/WindowsForBusiness/End-of-IE-support) for IE8, IE9 & IE10. If you still have to support these old dinosaur browsers, just set dinosaur mode to true.
+### Options
+
+```
+$initialize-print-styles: true;
+$initialize-html5-boilerplate-overwrites: true;
+```
+
+Microsoft [dropped support](https://www.microsoft.com/en-us/WindowsForBusiness/End-of-IE-support) for IE8, IE9 & IE10. If you still have to support these old dinosaur browsers, just set dinosaur mode to true. This option is set to false by default.
 ```
 $initialize-dinosaur-mode: true;
 ```
 
-Optional values:
+### Optional values
 ```
 $initialize-color: #000;
 $initialize-block-margins: 0 0 0.75em;
@@ -51,7 +58,3 @@ $initialize-heading-color: #000;
 $initialize-heading-font-family: sans-serif;
 $initialize-heading-margins: 1em 0 0.75em;
 ```
-
-```
-$initialize-print-styles: true;
-```
\ No newline at end of file
diff --git a/bower.json b/bower.json
index ade8227..ea37d8d 100644
--- a/bower.json
+++ b/bower.json
@@ -1,6 +1,6 @@
 {
   "name": "initialize-css",
-  "version": "1.3.1",
+  "version": "1.3.2",
   "homepage": "http://jeroenoomsnl.github.io/initialize-css/",
   "authors": [
     "Jeroen Ooms (@jeroenooms)"
diff --git a/dist/_initialize.scss b/dist/_initialize.scss
index a004f8c..c4dbd9b 100644
--- a/dist/_initialize.scss
+++ b/dist/_initialize.scss
@@ -1,5 +1,5 @@
 /*!
- * Initialize.css (v1.3.1) is a complete and customizable collection of CSS best practices based on Normalize.css and HTML5 Boilerplate.
+ * Initialize.css (v1.3.2) is a complete and customizable collection of CSS best practices based on Normalize.css and HTML5 Boilerplate.
  * http://jeroenoomsnl.github.io/initialize-css
  *
  * HTML5 Boilerplate: https://github.com/h5bp/html5-boilerplate
@@ -24,6 +24,7 @@ $initialize-line-height: 1.4 !default;
 //
 $initialize-dinosaur-mode: false !default; // toggle support for IE8, IE9 & IE10
 $initialize-print-styles: false !default; // toggle HTML5 Boilerplate print styles
+$initialize-html5-boilerplate-overwrites: false !default; // toggle HTML5 Boilerplate overwrites
 
 //
 // Optional values
@@ -57,10 +58,10 @@ $initialize-block-margins: null !default;
 
 /**
  * 1. Set default font family to $initialize-font-family (default: sans-serif)
- * 2. Prevent iOS and IE text size adjust after device orientation change,
- *    without disabling user zoom
+ * 2. Prevent adjustments of font size after orientation changes in IE and iOS.
  * 3. Configurable defaults
  */
+
 html {
   @include optional-prop('color', $initialize-color);
   @include optional-prop('box-sizing', $initialize-box-sizing);
@@ -72,17 +73,19 @@ html {
   -webkit-text-size-adjust: 100%; /* 2 */
 }
 
-/*
- * Remove default margin
+/**
+ * Remove the margin in all browsers
  */
+
 body {
   margin: 0;
 }
 
-/*
+/**
  * Inheriting box-sizing
  * https://css-tricks.com/inheriting-box-sizing-probably-slightly-better-best-practice/
  */
+
 *, *:before, *:after {
   box-sizing: inherit;
 }
@@ -93,66 +96,74 @@ body {
    HTML5 display defenitions
    ========================================================================== */
 
-/*
- * Correct `block` display not defined for any HTML5 element in IE 8/9.
- * Correct `block` display not defined for `details` or `summary` in IE 10/11
- * and Firefox.
- * Correct `block` display not defined for `main` in IE 11.
+/**
+ * Add the correct display in IE 9-.
+ * 1. Add the correct display in Edge, IE, and Firefox.
+ * 2. Add the correct display in IE.
  */
+
 @if $initialize-dinosaur-mode == true {
   article,
   aside,
-  details,
+  details, /* 1 */
   figcaption,
   figure,
   footer,
   header,
   hgroup,
-  main,
+  main, /* 2 */
   menu,
   nav,
   section,
-  summary {
+  summary /* 1 */ {
     display: block;
   }
 } @else {
-  details,
-  main,
-  summary {
+  details, /* 1 */
+  main,  /* 2 */
+  summary /* 1 */ {
     display: block;
   }
 }
 
-/*
- * 1. Correct `inline-block` display not defined in IE 8/9.
- * 2. Normalize vertical alignment of `progress` in Chrome, Firefox, and Opera.
- */
-audio,
-canvas,
-progress,
-video {
-  @if $initialize-dinosaur-mode == true {
-    display: inline-block; /* 1 */
-  }
-  vertical-align: baseline; /* 2 */
+@if $initialize-dinosaur-mode == true {
+    /**
+     * Add the correct display in IE 9-.
+     */
+
+    audio,
+    canvas,
+    progress,
+    video {
+        display: inline-block;
+    }
 }
 
-/*
- * Prevent modern browsers from displaying `audio` without controls.
- * Remove excess height in iOS 5 devices.
+/**
+ * Add the correct display in iOS 4-7.
  */
+
 audio:not([controls]) {
   display: none;
   height: 0;
 }
 
-/*
- * Address `[hidden]` styling not present in IE 8/9/10.
- * Hide the `template` element in IE 8/9/10/11, Safari, and Firefox < 22.
+/**
+ * Add the correct vertical alignment in Chrome, Firefox, and Opera.
  */
-[hidden],
-template {
-  display: none;
+
+progress {
+    vertical-align: baseline;
+}
+
+/**
+ * Add the correct display in IE 10-.
+ * 1. Add the correct display in IE.
+ */
+
+template, /* 1 */
+[hidden] {
+    display: none;
 }
 
 
@@ -161,22 +172,25 @@ template {
    Links
    ========================================================================== */
 
-/*
- * Remove the gray background color from active links in IE 10.
+/**
+ * 1. Remove the gray background on active links in IE 10.
+ * 2. Remove gaps in links underline in iOS 8+ and Safari 8+.
  */
-@if $initialize-dinosaur-mode == true {
-  a {
-    background-color: transparent;
-  }
+a {
+    @if $initialize-dinosaur-mode == true {
+        background-color: transparent; /* 1 */
+    }
+    -webkit-text-decoration-skip: objects; /* 2 */
 }
 
-/*
- * Improve readability of focused elements when they are also in an
- * active/hover state.
+/**
+ * Remove the outline on focused links when they are also active or hovered
+ * in all browsers (opinionated).
  */
+
 a:active,
 a:hover {
-  outline: 0;
+    outline-width: 0;
 }
 
 
@@ -185,85 +199,92 @@ a:hover {
    Text-level semantics
    ========================================================================== */
 
-/*
- * Address inconsistent styling of `abbr[title]`.
- * 1. Correct styling in Firefox 39 and Opera 12.
- * 2. Correct missing styling in Chrome, Edge, IE, Opera, and Safari.
+/**
+ * 1. Remove the bottom border in Firefox 39-.
+ * 2. Add the correct text decoration in Chrome, Edge, IE, Opera, and Safari.
  */
+
 abbr[title] {
-  border-bottom: none; /* 1 */
-  text-decoration: underline; /* 2 */
-  text-decoration: underline dotted; /* 2 */
+    border-bottom: none; /* 1 */
+    text-decoration: underline; /* 2 */
+    text-decoration: underline dotted; /* 2 */
 }
 
-/*
- * Address inconsistent styling of b and strong.
- * 1. Correct duplicate application of `bolder` in Safari 6.0.2.
- * 2. Correct style set to `bold` in Edge 12+, Safari 6.2+, and Chrome 18+.
+/**
+ * Prevent the duplicate application of `bolder` by the next rule in Safari 6.
  */
 
 b,
 strong {
-  font-weight: inherit; /* 1 */
+    font-weight: inherit;
 }
 
+/**
+ * Add the correct font weight in Chrome, Edge, and Safari.
+ */
+
 b,
 strong {
-  font-weight: bolder; /* 2 */
+    font-weight: bolder;
 }
 
-/*
- * Address styling not present in Safari and Chrome.
+/**
+ * Add the correct font style in Android 4.3-.
  */
+
 dfn {
-  font-style: italic;
+    font-style: italic;
 }
 
-/*
- * Address variable `h1` font-size and margin within `section` and `article`
- * contexts in Firefox 4+, Safari, and Chrome.
+/**
+ * Correct the font size and margin on `h1` elements within `section` and
+ * `article` contexts in Chrome, Firefox, and Safari.
  */
+
 h1 {
-  font-size: 2em;
-  margin: 0.67em 0;
+    font-size: 2em;
+    margin: 0.67em 0;
 }
 
-
 @if $initialize-dinosaur-mode == true {
-  /*
+  /**
   * Address styling not present in IE 8/9.
   */
+
   mark {
     background: #ff0;
     color: #000;
   }
 }
-/*
- * Address inconsistent and variable font size in all browsers.
+
+
+/**
+ * Add the correct font size in all browsers.
  */
 
 small {
-  font-size: 80%;
+    font-size: 80%;
 }
 
-/*
- * Prevent `sub` and `sup` affecting `line-height` in all browsers.
+/**
+ * Prevent `sub` and `sup` elements from affecting the line height in
+ * all browsers.
  */
 
 sub,
 sup {
-  font-size: 75%;
-  line-height: 0;
-  position: relative;
-  vertical-align: baseline;
+    font-size: 75%;
+    line-height: 0;
+    position: relative;
+    vertical-align: baseline;
 }
 
-sup {
-  top: -0.5em;
+sub {
+    bottom: -0.25em;
 }
 
-sub {
-  bottom: -0.25em;
+sup {
+    top: -0.5em;
 }
 
 
@@ -272,22 +293,22 @@ sub {
    Embedded content
    ========================================================================== */
 
-
 @if $initialize-dinosaur-mode == true {
-  /*
-   * Remove border when inside `a` element in IE 8/9/10.
-   */
-  img {
-    border: 0;
-  }
+    /**
+     * Remove the border on images inside links in IE 10-.
+     */
+
+    img {
+        border-style: none;
+    }
 }
 
-/*
- * Correct overflow not hidden in IE 9/10/11.
+/**
+ * Hide the overflow in IE.
  */
 
 svg:not(:root) {
-  overflow: hidden;
+    overflow: hidden;
 }
 
 
@@ -296,45 +317,36 @@ svg:not(:root) {
    Grouping content
    ========================================================================== */
 
-/*
- * Address margin not present in IE 8/9 and Safari.
- */
-
-figure {
-  margin: 1em 40px;
-}
-
-/*
- * Address inconsistent styling of `hr`.
- * 1. Correct `box-sizing` set to `border-box` in Firefox.
- * 2. Correct `overflow` set to `hidden` in IE 8/9/10/11 and Edge 12.
+/**
+ * 1. Correct the inheritance and scaling of font size in all browsers.
+ * 2. Correct the odd `em` font sizing in all browsers.
  */
 
-hr {
-  box-sizing: content-box; /* 1 */
-  height: 0; /* 1 */
-  overflow: visible; /* 2 */
+code,
+kbd,
+pre,
+samp {
+    font-family: monospace, monospace; /* 1 */
+    font-size: 1em; /* 2 */
 }
 
-/*
- * Contain overflow in all browsers.
+/**
+ * Add the correct margin in IE 8.
  */
 
-pre {
-  overflow: auto;
+figure {
+    margin: 1em 40px;
 }
 
-/*
- * 1. Correct inheritance and scaling of font-size for preformatted text.
- * 2. Address odd `em`-unit font size rendering in all browsers.
+/**
+ * 1. Add the correct box sizing in Firefox.
+ * 2. Show the overflow in Edge and IE.
  */
 
-code,
-kbd,
-pre,
-samp {
-  font-family: monospace, monospace; /* 1 */
-  font-size: 1em; /* 2 */
+hr {
+    box-sizing: content-box; /* 1 */
+    height: 0; /* 1 */
+    overflow: visible; /* 2 */
 }
 
 
@@ -343,244 +355,244 @@ samp {
    Forms
    ========================================================================== */
 
-/*
- * Known limitation: by default, Chrome and Safari on OS X allow very limited
- * styling of `select`, unless a `border` property is set.
- */
-
-/*
- * 1. Correct font properties not being inherited.
- * 2. Address margins set differently in Firefox 4+, Safari, and Chrome.
+/**
+ * 1. Change font properties to `inherit` in all browsers (opinionated).
+ * 2. Remove the margin in Firefox and Safari.
  */
 
 button,
 input,
-optgroup,
 select,
 textarea {
-  font: inherit; /* 1 */
-  margin: 0; /* 2 */
+    font: inherit; /* 1 */
+    margin: 0; /* 2 */
 }
 
-/*
- * Address `overflow` set to `hidden` in IE 8/9/10/11.
+/**
+ * Restore the font weight unset by the previous rule.
  */
 
-button {
-  overflow: visible;
+optgroup {
+    font-weight: bold;
 }
 
-/*
- * Address inconsistent `text-transform` inheritance for `button` and `select`.
- * All other form control elements do not inherit `text-transform` values.
- * Correct `button` style inheritance in Firefox, IE 8/9/10/11, and Opera.
- * Correct `select` style inheritance in Firefox.
+/**
+ * Show the overflow in IE.
+ * 1. Show the overflow in Edge.
  */
 
 button,
-select {
-  text-transform: none;
+input { /* 1 */
+    overflow: visible;
 }
 
-/*
- * 1. Avoid the WebKit bug in Android 4.0.* where (2) destroys native `audio`
- *    and `video` controls.
- * 2. Correct inability to style clickable `input` types in iOS.
- * 3. Improve usability and consistency of cursor style between image-type
- *    `input` and others.
+/**
+ * Remove the inheritance of text transform in Edge, Firefox, and IE.
+ * 1. Remove the inheritance of text transform in Firefox.
  */
 
 button,
-html input[type="button"], /* 1 */
-input[type="reset"],
-input[type="submit"] {
-  -webkit-appearance: button; /* 2 */
-  cursor: pointer; /* 3 */
+select { /* 1 */
+    text-transform: none;
 }
 
-/*
- * Re-set default cursor for disabled elements.
+/**
+ * 1. Prevent a WebKit bug where (2) destroys native `audio` and `video`
+ *    controls in Android 4.
+ * 2. Correct the inability to style clickable types in iOS and Safari.
  */
 
-button[disabled],
-html input[disabled] {
-  cursor: default;
+button,
+html [type="button"], /* 1 */
+[type="reset"],
+[type="submit"] {
+    -webkit-appearance: button; /* 2 */
 }
 
-/*
- * Remove inner padding and border in Firefox 4+.
+/**
+ * Remove the inner border and padding in Firefox.
  */
 
 button::-moz-focus-inner,
-input::-moz-focus-inner {
-  border: 0;
-  padding: 0;
+[type="button"]::-moz-focus-inner,
+[type="reset"]::-moz-focus-inner,
+[type="submit"]::-moz-focus-inner {
+    border-style: none;
+    padding: 0;
 }
 
-/*
- * Restore focus style in Firefox 4+ (unset by a rule above)
+/**
+ * Restore the focus styles unset by the previous rule.
  */
 
 button:-moz-focusring,
-input:-moz-focusring {
-  outline: 1px dotted ButtonText;
+[type="button"]:-moz-focusring,
+[type="reset"]:-moz-focusring,
+[type="submit"]:-moz-focusring {
+    outline: 1px dotted ButtonText;
 }
 
-/*
- * Address Firefox 4+ setting `line-height` on `input` using `!important` in
- * the UA stylesheet.
- */
+@if $initialize-html5-boilerplate-overwrites == false {
+    /**
+     * Change the border, margin, and padding in all browsers (opinionated).
+     */
 
-input {
-  line-height: normal;
+    fieldset {
+        border: 1px solid #c0c0c0;
+        margin: 0 2px;
+        padding: 0.35em 0.625em 0.75em;
+    }
 }
 
-@if $initialize-dinosaur-mode == true {
-  /*
-   * It's recommended that you don't attempt to style these elements.
-   * Firefox's implementation doesn't respect box-sizing, padding, or width.
-   *
-   * 1. Address box sizing set to `content-box` in IE 8/9/10.
-   * 2. Remove excess padding in IE 8/9/10.
-   */
-
-  input[type="checkbox"],
-  input[type="radio"] {
+/**
+ * 1. Correct the text wrapping in Edge and IE.
+ * 2. Correct the color inheritance from `fieldset` elements in IE.
+ * 3. Remove the padding so developers are not caught out when they zero out
+ *    `fieldset` elements in all browsers.
+ */
+
+legend {
     box-sizing: border-box; /* 1 */
-    padding: 0; /* 2 */
-  }
+    color: inherit; /* 2 */
+    display: table; /* 1 */
+    max-width: 100%; /* 1 */
+    padding: 0; /* 3 */
+    white-space: normal; /* 1 */
 }
 
-/*
- * Fix the cursor style for Chrome's increment/decrement buttons. For certain
- * `font-size` values of the `input`, it causes the cursor style of the
- * decrement button to change from `default` to `text`.
+/**
+ * Remove the default vertical scrollbar in IE.
  */
 
-input[type="number"]::-webkit-inner-spin-button,
-input[type="number"]::-webkit-outer-spin-button {
-  height: auto;
+textarea {
+    overflow: auto;
 }
 
-/*
- * Address `appearance` set to `searchfield` in Safari and Chrome.
- */
+@if $initialize-dinosaur-mode == true {
+    /**
+     * 1. Add the correct box sizing in IE 10-.
+     * 2. Remove the padding in IE 10-.
+     */
 
-input[type="search"] {
-  -webkit-appearance: textfield;
+    [type="checkbox"],
+    [type="radio"] {
+        box-sizing: border-box; /* 1 */
+        padding: 0; /* 2 */
+    }
 }
 
-/*
- * Remove inner padding and search cancel button in Safari and Chrome on OS X.
- * Safari (but not Chrome) clips the cancel button when the search input has
- * padding (and `textfield` appearance).
+/**
+ * Correct the cursor style of increment and decrement buttons in Chrome.
  */
 
-input[type="search"]::-webkit-search-cancel-button,
-input[type="search"]::-webkit-search-decoration {
-  -webkit-appearance: none;
+[type="number"]::-webkit-inner-spin-button,
+[type="number"]::-webkit-outer-spin-button {
+    height: auto;
 }
 
-/*
- * Define consistent border, margin, and padding.
+/**
+ * 1. Correct the odd appearance in Chrome and Safari.
+ * 2. Correct the outline style in Safari.
  */
 
-fieldset {
-  border: 1px solid #c0c0c0;
-  margin: 0 2px;
-  padding: 0.35em 0.625em 0.75em;
+[type="search"] {
+    -webkit-appearance: textfield; /* 1 */
+    outline-offset: -2px; /* 2 */
 }
 
-/*
- * 1. Correct `color` not being inherited in IE 8/9/10/11.
- * 2. Remove padding so people aren't caught out if they zero out fieldsets.
+/**
+ * Remove the inner padding and cancel buttons in Chrome and Safari on OS X.
  */
 
-legend {
-  border: 0; /* 1 */
-  padding: 0; /* 2 */
+[type="search"]::-webkit-search-cancel-button,
+[type="search"]::-webkit-search-decoration {
+    -webkit-appearance: none;
 }
 
-/*
- * Remove default vertical scrollbar in IE 8/9/10/11.
+/**
+ * Correct the text style of placeholders in Chrome, Edge, and Safari.
  */
 
-textarea {
-  overflow: auto;
+::-webkit-input-placeholder {
+    color: inherit;
+    opacity: 0.54;
 }
 
-/*
- * Restore font weight (unset by a rule above).
- * NOTE: the default cannot safely be changed in Chrome and Safari on OS X.
+/**
+ * 1. Correct the inability to style clickable types in iOS and Safari.
+ * 2. Change font properties to `inherit` in Safari.
  */
 
-optgroup {
-  font-weight: bold;
+::-webkit-file-upload-button {
+    -webkit-appearance: button; /* 1 */
+    font: inherit; /* 2 */
 }
 
 
 
-/* ==========================================================================
-   HTML5 Boilerplate optimizations 
-   ========================================================================== */
+@if $initialize-html5-boilerplate-overwrites == true {
+    /* ==========================================================================
+       HTML5 Boilerplate optimizations
+       ========================================================================== */
 
-/*
- * Remove text-shadow in selection highlight:
- * https://twitter.com/miketaylr/status/12228805301
- *
- * These selection rule sets have to be separate.
- * Customize the background color to match your design.
- */
+    /**
+     * Remove text-shadow in selection highlight:
+     * https://twitter.com/miketaylr/status/12228805301
+     *
+     * These selection rule sets have to be separate.
+     * Customize the background color to match your design.
+     */
 
-::selection {
-    background: #b3d4fc;
-    text-shadow: none;
-}
+    ::selection {
+        background: #b3d4fc;
+        text-shadow: none;
+    }
 
-/*
- * A better looking default horizontal rule
- */
+    /**
+     * A better looking default horizontal rule
+     */
 
-hr {
-    display: block;
-    height: 1px;
-    border: 0;
-    border-top: 1px solid #ccc;
-    margin: 1em 0;
-    padding: 0;
-}
+    hr {
+        display: block;
+        height: 1px;
+        border: 0;
+        border-top: 1px solid #ccc;
+        margin: 1em 0;
+        padding: 0;
+    }
 
-/*
- * Remove the gap between audio, canvas, iframes,
- * images, videos and the bottom of their containers:
- * https://github.com/h5bp/html5-boilerplate/issues/440
- */
+    /**
+     * Remove the gap between audio, canvas, iframes,
+     * images, videos and the bottom of their containers:
+     * https://github.com/h5bp/html5-boilerplate/issues/440
+     */
 
-audio,
-canvas,
-iframe,
-img,
-svg,
-video {
-    vertical-align: middle;
-}
+    audio,
+    canvas,
+    iframe,
+    img,
+    svg,
+    video {
+        vertical-align: middle;
+    }
 
-/*
- * Remove default fieldset styles.
- */
+    /**
+     * Remove default fieldset styles.
+     */
 
-fieldset {
-    border: 0;
-    margin: 0;
-    padding: 0;
-}
+    fieldset {
+        border: 0;
+        margin: 0;
+        padding: 0;
+    }
 
-/*
- * Allow only vertical resizing of textareas.
- */
+    /**
+     * Allow only vertical resizing of textareas.
+     */
 
-textarea {
-    resize: vertical;
+    textarea {
+        resize: vertical;
+    }
 }
 
 
@@ -589,7 +601,7 @@ textarea {
    Optional configurations
    ========================================================================== */
 
-/*
+/**
  * Headings
  */
 
@@ -599,7 +611,7 @@ h1, h2, h3, h4, h5, h6 {
   @include optional-prop('font-family', $initialize-heading-font-family);
 }
 
-/*
+/**
  * Block elements
  */
 
@@ -680,4 +692,3 @@ p, table, ul, ol, fieldset, blockquote, dl {
       }
   }
 }
-
diff --git a/dist/initialize.less b/dist/initialize.less
index 5442f1b..cb5343f 100644
--- a/dist/initialize.less
+++ b/dist/initialize.less
@@ -1,5 +1,5 @@
 /*!
- * Initialize.css (v1.3.1) is a complete and customizable collection of CSS best practices based on Normalize.css and HTML5 Boilerplate.
+ * Initialize.css (v1.3.2) is a complete and customizable collection of CSS best practices based on Normalize.css and HTML5 Boilerplate.
  * http://jeroenoomsnl.github.io/initialize-css
  *
  * HTML5 Boilerplate: https://github.com/h5bp/html5-boilerplate
@@ -9,7 +9,7 @@
 
 // ==========================================================================
 // Config
-// ========================================================================== 
+// ==========================================================================
 
 //
 // Predefined values
@@ -38,12 +38,12 @@
 
 // ==========================================================================
 // Helpers
-// ========================================================================== 
+// ==========================================================================
 
 //
 // Mixin for optional properties
 //
-.optional-prop(@property, @value) when (isstring(@value)), (iscolor(@value)), (isnumber(@value)) {
+.optional-prop(@property, @value) when not(@value=null) {
   @{property}: @value;
 }
 
@@ -517,7 +517,7 @@ optgroup {
 
 
 /* ==========================================================================
-   HTML5 Boilerplate optimizations 
+   HTML5 Boilerplate optimizations
    ========================================================================== */
 
 /*
diff --git a/package.json b/package.json
index 2cda5d0..e9ae89b 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "initialize-css",
-  "version": "1.3.1",
+  "version": "1.3.2",
   "homepage": "http://jeroenoomsnl.github.io/initialize-css/",
   "description": "Initialize.css is a complete and customizable collection of CSS best practices based on Normalize.css and HTML5 Boilerplate. Available in CSS and configurable SASS (SCSS) and LESS format.",
   "author": {
@@ -11,26 +11,26 @@
   "main": "dist/_initialize.scss",
   "repository": "https://github.com/jeroenoomsNL/initialize-css.git",
   "devDependencies": {
-    "browser-sync": "^2.10.1",
-    "gulp": "^3.9.0",
-    "gulp-autoprefixer": "^3.1.0",
+    "browser-sync": "^2.18.2",
+    "gulp": "^3.9.1",
+    "gulp-autoprefixer": "^3.1.1",
     "gulp-cssmin": "^0.1.7",
-    "gulp-filter": "^3.0.1",
+    "gulp-filter": "^4.0.0",
     "gulp-gh-pages": "^0.5.4",
-    "gulp-if": "^2.0.0",
-    "gulp-jshint": "^2.0.0",
-    "gulp-load-plugins": "^1.1.0",
-    "gulp-plumber": "^1.0.1",
+    "gulp-if": "^2.0.2",
+    "gulp-jshint": "^2.0.4",
+    "gulp-load-plugins": "^1.4.0",
+    "gulp-plumber": "^1.1.0",
     "gulp-rename": "^1.2.2",
     "gulp-replace": "^0.5.4",
-    "gulp-ruby-sass": "^2.0.6",
-    "gulp-size": "^2.0.0",
-    "gulp-sourcemaps": "^1.6.0",
-    "gulp-uglify": "^1.5.1",
+    "gulp-ruby-sass": "^2.1.1",
+    "gulp-size": "^2.1.0",
+    "gulp-sourcemaps": "^2.2.1",
+    "gulp-uglify": "^2.0.0",
     "gulp-util": "^3.0.7",
-    "jshint": "^2.8.0",
-    "jshint-stylish": "^2.1.0",
-    "rimraf": "^2.4.4"
+    "jshint": "^2.9.4",
+    "jshint-stylish": "^2.2.1",
+    "rimraf": "^2.5.4"
   },
   "keywords": [
     "css",
diff --git a/src/styles/initialize.less b/src/styles/initialize.less
index 5442f1b..cb5343f 100644
--- a/src/styles/initialize.less
+++ b/src/styles/initialize.less
@@ -1,5 +1,5 @@
 /*!
- * Initialize.css (v1.3.1) is a complete and customizable collection of CSS best practices based on Normalize.css and HTML5 Boilerplate.
+ * Initialize.css (v1.3.2) is a complete and customizable collection of CSS best practices based on Normalize.css and HTML5 Boilerplate.
  * http://jeroenoomsnl.github.io/initialize-css
  *
  * HTML5 Boilerplate: https://github.com/h5bp/html5-boilerplate
@@ -9,7 +9,7 @@
 
 // ==========================================================================
 // Config
-// ========================================================================== 
+// ==========================================================================
 
 //
 // Predefined values
@@ -38,12 +38,12 @@
 
 // ==========================================================================
 // Helpers
-// ========================================================================== 
+// ==========================================================================
 
 //
 // Mixin for optional properties
 //
-.optional-prop(@property, @value) when (isstring(@value)), (iscolor(@value)), (isnumber(@value)) {
+.optional-prop(@property, @value) when not(@value=null) {
   @{property}: @value;
 }
 
@@ -517,7 +517,7 @@ optgroup {
 
 
 /* ==========================================================================
-   HTML5 Boilerplate optimizations 
+   HTML5 Boilerplate optimizations
    ========================================================================== */
 
 /*
diff --git a/src/styles/initialize.scss b/src/styles/initialize.scss
index a004f8c..c4dbd9b 100644
--- a/src/styles/initialize.scss
+++ b/src/styles/initialize.scss
@@ -1,5 +1,5 @@
 /*!
- * Initialize.css (v1.3.1) is a complete and customizable collection of CSS best practices based on Normalize.css and HTML5 Boilerplate.
+ * Initialize.css (v1.3.2) is a complete and customizable collection of CSS best practices based on Normalize.css and HTML5 Boilerplate.
  * http://jeroenoomsnl.github.io/initialize-css
  *
  * HTML5 Boilerplate: https://github.com/h5bp/html5-boilerplate
@@ -24,6 +24,7 @@ $initialize-line-height: 1.4 !default;
 //
 $initialize-dinosaur-mode: false !default; // toggle support for IE8, IE9 & IE10
 $initialize-print-styles: false !default; // toggle HTML5 Boilerplate print styles
+$initialize-html5-boilerplate-overwrites: false !default; // toggle HTML5 Boilerplate overwrites
 
 //
 // Optional values
@@ -57,10 +58,10 @@ $initialize-block-margins: null !default;
 
 /**
  * 1. Set default font family to $initialize-font-family (default: sans-serif)
- * 2. Prevent iOS and IE text size adjust after device orientation change,
- *    without disabling user zoom
+ * 2. Prevent adjustments of font size after orientation changes in IE and iOS.
  * 3. Configurable defaults
  */
+
 html {
   @include optional-prop('color', $initialize-color);
   @include optional-prop('box-sizing', $initialize-box-sizing);
@@ -72,17 +73,19 @@ html {
   -webkit-text-size-adjust: 100%; /* 2 */
 }
 
-/*
- * Remove default margin
+/**
+ * Remove the margin in all browsers
  */
+
 body {
   margin: 0;
 }
 
-/*
+/**
  * Inheriting box-sizing
  * https://css-tricks.com/inheriting-box-sizing-probably-slightly-better-best-practice/
  */
+
 *, *:before, *:after {
   box-sizing: inherit;
 }
@@ -93,66 +96,74 @@ body {
    HTML5 display defenitions
    ========================================================================== */
 
-/*
- * Correct `block` display not defined for any HTML5 element in IE 8/9.
- * Correct `block` display not defined for `details` or `summary` in IE 10/11
- * and Firefox.
- * Correct `block` display not defined for `main` in IE 11.
+/**
+ * Add the correct display in IE 9-.
+ * 1. Add the correct display in Edge, IE, and Firefox.
+ * 2. Add the correct display in IE.
  */
+
 @if $initialize-dinosaur-mode == true {
   article,
   aside,
-  details,
+  details, /* 1 */
   figcaption,
   figure,
   footer,
   header,
   hgroup,
-  main,
+  main, /* 2 */
   menu,
   nav,
   section,
-  summary {
+  summary /* 1 */ {
     display: block;
   }
 } @else {
-  details,
-  main,
-  summary {
+  details, /* 1 */
+  main,  /* 2 */
+  summary /* 1 */ {
     display: block;
   }
 }
 
-/*
- * 1. Correct `inline-block` display not defined in IE 8/9.
- * 2. Normalize vertical alignment of `progress` in Chrome, Firefox, and Opera.
- */
-audio,
-canvas,
-progress,
-video {
-  @if $initialize-dinosaur-mode == true {
-    display: inline-block; /* 1 */
-  }
-  vertical-align: baseline; /* 2 */
+@if $initialize-dinosaur-mode == true {
+    /**
+     * Add the correct display in IE 9-.
+     */
+
+    audio,
+    canvas,
+    progress,
+    video {
+        display: inline-block;
+    }
 }
 
-/*
- * Prevent modern browsers from displaying `audio` without controls.
- * Remove excess height in iOS 5 devices.
+/**
+ * Add the correct display in iOS 4-7.
  */
+
 audio:not([controls]) {
   display: none;
   height: 0;
 }
 
-/*
- * Address `[hidden]` styling not present in IE 8/9/10.
- * Hide the `template` element in IE 8/9/10/11, Safari, and Firefox < 22.
+/**
+ * Add the correct vertical alignment in Chrome, Firefox, and Opera.
  */
-[hidden],
-template {
-  display: none;
+
+progress {
+    vertical-align: baseline;
+}
+
+/**
+ * Add the correct display in IE 10-.
+ * 1. Add the correct display in IE.
+ */
+
+template, /* 1 */
+[hidden] {
+    display: none;
 }
 
 
@@ -161,22 +172,25 @@ template {
    Links
    ========================================================================== */
 
-/*
- * Remove the gray background color from active links in IE 10.
+/**
+ * 1. Remove the gray background on active links in IE 10.
+ * 2. Remove gaps in links underline in iOS 8+ and Safari 8+.
  */
-@if $initialize-dinosaur-mode == true {
-  a {
-    background-color: transparent;
-  }
+a {
+    @if $initialize-dinosaur-mode == true {
+        background-color: transparent; /* 1 */
+    }
+    -webkit-text-decoration-skip: objects; /* 2 */
 }
 
-/*
- * Improve readability of focused elements when they are also in an
- * active/hover state.
+/**
+ * Remove the outline on focused links when they are also active or hovered
+ * in all browsers (opinionated).
  */
+
 a:active,
 a:hover {
-  outline: 0;
+    outline-width: 0;
 }
 
 
@@ -185,85 +199,92 @@ a:hover {
    Text-level semantics
    ========================================================================== */
 
-/*
- * Address inconsistent styling of `abbr[title]`.
- * 1. Correct styling in Firefox 39 and Opera 12.
- * 2. Correct missing styling in Chrome, Edge, IE, Opera, and Safari.
+/**
+ * 1. Remove the bottom border in Firefox 39-.
+ * 2. Add the correct text decoration in Chrome, Edge, IE, Opera, and Safari.
  */
+
 abbr[title] {
-  border-bottom: none; /* 1 */
-  text-decoration: underline; /* 2 */
-  text-decoration: underline dotted; /* 2 */
+    border-bottom: none; /* 1 */
+    text-decoration: underline; /* 2 */
+    text-decoration: underline dotted; /* 2 */
 }
 
-/*
- * Address inconsistent styling of b and strong.
- * 1. Correct duplicate application of `bolder` in Safari 6.0.2.
- * 2. Correct style set to `bold` in Edge 12+, Safari 6.2+, and Chrome 18+.
+/**
+ * Prevent the duplicate application of `bolder` by the next rule in Safari 6.
  */
 
 b,
 strong {
-  font-weight: inherit; /* 1 */
+    font-weight: inherit;
 }
 
+/**
+ * Add the correct font weight in Chrome, Edge, and Safari.
+ */
+
 b,
 strong {
-  font-weight: bolder; /* 2 */
+    font-weight: bolder;
 }
 
-/*
- * Address styling not present in Safari and Chrome.
+/**
+ * Add the correct font style in Android 4.3-.
  */
+
 dfn {
-  font-style: italic;
+    font-style: italic;
 }
 
-/*
- * Address variable `h1` font-size and margin within `section` and `article`
- * contexts in Firefox 4+, Safari, and Chrome.
+/**
+ * Correct the font size and margin on `h1` elements within `section` and
+ * `article` contexts in Chrome, Firefox, and Safari.
  */
+
 h1 {
-  font-size: 2em;
-  margin: 0.67em 0;
+    font-size: 2em;
+    margin: 0.67em 0;
 }
 
-
 @if $initialize-dinosaur-mode == true {
-  /*
+  /**
   * Address styling not present in IE 8/9.
   */
+
   mark {
     background: #ff0;
     color: #000;
   }
 }
-/*
- * Address inconsistent and variable font size in all browsers.
+
+
+/**
+ * Add the correct font size in all browsers.
  */
 
 small {
-  font-size: 80%;
+    font-size: 80%;
 }
 
-/*
- * Prevent `sub` and `sup` affecting `line-height` in all browsers.
+/**
+ * Prevent `sub` and `sup` elements from affecting the line height in
+ * all browsers.
  */
 
 sub,
 sup {
-  font-size: 75%;
-  line-height: 0;
-  position: relative;
-  vertical-align: baseline;
+    font-size: 75%;
+    line-height: 0;
+    position: relative;
+    vertical-align: baseline;
 }
 
-sup {
-  top: -0.5em;
+sub {
+    bottom: -0.25em;
 }
 
-sub {
-  bottom: -0.25em;
+sup {
+    top: -0.5em;
 }
 
 
@@ -272,22 +293,22 @@ sub {
    Embedded content
    ========================================================================== */
 
-
 @if $initialize-dinosaur-mode == true {
-  /*
-   * Remove border when inside `a` element in IE 8/9/10.
-   */
-  img {
-    border: 0;
-  }
+    /**
+     * Remove the border on images inside links in IE 10-.
+     */
+
+    img {
+        border-style: none;
+    }
 }
 
-/*
- * Correct overflow not hidden in IE 9/10/11.
+/**
+ * Hide the overflow in IE.
  */
 
 svg:not(:root) {
-  overflow: hidden;
+    overflow: hidden;
 }
 
 
@@ -296,45 +317,36 @@ svg:not(:root) {
    Grouping content
    ========================================================================== */
 
-/*
- * Address margin not present in IE 8/9 and Safari.
- */
-
-figure {
-  margin: 1em 40px;
-}
-
-/*
- * Address inconsistent styling of `hr`.
- * 1. Correct `box-sizing` set to `border-box` in Firefox.
- * 2. Correct `overflow` set to `hidden` in IE 8/9/10/11 and Edge 12.
+/**
+ * 1. Correct the inheritance and scaling of font size in all browsers.
+ * 2. Correct the odd `em` font sizing in all browsers.
  */
 
-hr {
-  box-sizing: content-box; /* 1 */
-  height: 0; /* 1 */
-  overflow: visible; /* 2 */
+code,
+kbd,
+pre,
+samp {
+    font-family: monospace, monospace; /* 1 */
+    font-size: 1em; /* 2 */
 }
 
-/*
- * Contain overflow in all browsers.
+/**
+ * Add the correct margin in IE 8.
  */
 
-pre {
-  overflow: auto;
+figure {
+    margin: 1em 40px;
 }
 
-/*
- * 1. Correct inheritance and scaling of font-size for preformatted text.
- * 2. Address odd `em`-unit font size rendering in all browsers.
+/**
+ * 1. Add the correct box sizing in Firefox.
+ * 2. Show the overflow in Edge and IE.
  */
 
-code,
-kbd,
-pre,
-samp {
-  font-family: monospace, monospace; /* 1 */
-  font-size: 1em; /* 2 */
+hr {
+    box-sizing: content-box; /* 1 */
+    height: 0; /* 1 */
+    overflow: visible; /* 2 */
 }
 
 
@@ -343,244 +355,244 @@ samp {
    Forms
    ========================================================================== */
 
-/*
- * Known limitation: by default, Chrome and Safari on OS X allow very limited
- * styling of `select`, unless a `border` property is set.
- */
-
-/*
- * 1. Correct font properties not being inherited.
- * 2. Address margins set differently in Firefox 4+, Safari, and Chrome.
+/**
+ * 1. Change font properties to `inherit` in all browsers (opinionated).
+ * 2. Remove the margin in Firefox and Safari.
  */
 
 button,
 input,
-optgroup,
 select,
 textarea {
-  font: inherit; /* 1 */
-  margin: 0; /* 2 */
+    font: inherit; /* 1 */
+    margin: 0; /* 2 */
 }
 
-/*
- * Address `overflow` set to `hidden` in IE 8/9/10/11.
+/**
+ * Restore the font weight unset by the previous rule.
  */
 
-button {
-  overflow: visible;
+optgroup {
+    font-weight: bold;
 }
 
-/*
- * Address inconsistent `text-transform` inheritance for `button` and `select`.
- * All other form control elements do not inherit `text-transform` values.
- * Correct `button` style inheritance in Firefox, IE 8/9/10/11, and Opera.
- * Correct `select` style inheritance in Firefox.
+/**
+ * Show the overflow in IE.
+ * 1. Show the overflow in Edge.
  */
 
 button,
-select {
-  text-transform: none;
+input { /* 1 */
+    overflow: visible;
 }
 
-/*
- * 1. Avoid the WebKit bug in Android 4.0.* where (2) destroys native `audio`
- *    and `video` controls.
- * 2. Correct inability to style clickable `input` types in iOS.
- * 3. Improve usability and consistency of cursor style between image-type
- *    `input` and others.
+/**
+ * Remove the inheritance of text transform in Edge, Firefox, and IE.
+ * 1. Remove the inheritance of text transform in Firefox.
  */
 
 button,
-html input[type="button"], /* 1 */
-input[type="reset"],
-input[type="submit"] {
-  -webkit-appearance: button; /* 2 */
-  cursor: pointer; /* 3 */
+select { /* 1 */
+    text-transform: none;
 }
 
-/*
- * Re-set default cursor for disabled elements.
+/**
+ * 1. Prevent a WebKit bug where (2) destroys native `audio` and `video`
+ *    controls in Android 4.
+ * 2. Correct the inability to style clickable types in iOS and Safari.
  */
 
-button[disabled],
-html input[disabled] {
-  cursor: default;
+button,
+html [type="button"], /* 1 */
+[type="reset"],
+[type="submit"] {
+    -webkit-appearance: button; /* 2 */
 }
 
-/*
- * Remove inner padding and border in Firefox 4+.
+/**
+ * Remove the inner border and padding in Firefox.
  */
 
 button::-moz-focus-inner,
-input::-moz-focus-inner {
-  border: 0;
-  padding: 0;
+[type="button"]::-moz-focus-inner,
+[type="reset"]::-moz-focus-inner,
+[type="submit"]::-moz-focus-inner {
+    border-style: none;
+    padding: 0;
 }
 
-/*
- * Restore focus style in Firefox 4+ (unset by a rule above)
+/**
+ * Restore the focus styles unset by the previous rule.
  */
 
 button:-moz-focusring,
-input:-moz-focusring {
-  outline: 1px dotted ButtonText;
+[type="button"]:-moz-focusring,
+[type="reset"]:-moz-focusring,
+[type="submit"]:-moz-focusring {
+    outline: 1px dotted ButtonText;
 }
 
-/*
- * Address Firefox 4+ setting `line-height` on `input` using `!important` in
- * the UA stylesheet.
- */
+@if $initialize-html5-boilerplate-overwrites == false {
+    /**
+     * Change the border, margin, and padding in all browsers (opinionated).
+     */
 
-input {
-  line-height: normal;
+    fieldset {
+        border: 1px solid #c0c0c0;
+        margin: 0 2px;
+        padding: 0.35em 0.625em 0.75em;
+    }
 }
 
-@if $initialize-dinosaur-mode == true {
-  /*
-   * It's recommended that you don't attempt to style these elements.
-   * Firefox's implementation doesn't respect box-sizing, padding, or width.
-   *
-   * 1. Address box sizing set to `content-box` in IE 8/9/10.
-   * 2. Remove excess padding in IE 8/9/10.
-   */
-
-  input[type="checkbox"],
-  input[type="radio"] {
+/**
+ * 1. Correct the text wrapping in Edge and IE.
+ * 2. Correct the color inheritance from `fieldset` elements in IE.
+ * 3. Remove the padding so developers are not caught out when they zero out
+ *    `fieldset` elements in all browsers.
+ */
+
+legend {
     box-sizing: border-box; /* 1 */
-    padding: 0; /* 2 */
-  }
+    color: inherit; /* 2 */
+    display: table; /* 1 */
+    max-width: 100%; /* 1 */
+    padding: 0; /* 3 */
+    white-space: normal; /* 1 */
 }
 
-/*
- * Fix the cursor style for Chrome's increment/decrement buttons. For certain
- * `font-size` values of the `input`, it causes the cursor style of the
- * decrement button to change from `default` to `text`.
+/**
+ * Remove the default vertical scrollbar in IE.
  */
 
-input[type="number"]::-webkit-inner-spin-button,
-input[type="number"]::-webkit-outer-spin-button {
-  height: auto;
+textarea {
+    overflow: auto;
 }
 
-/*
- * Address `appearance` set to `searchfield` in Safari and Chrome.
- */
+@if $initialize-dinosaur-mode == true {
+    /**
+     * 1. Add the correct box sizing in IE 10-.
+     * 2. Remove the padding in IE 10-.
+     */
 
-input[type="search"] {
-  -webkit-appearance: textfield;
+    [type="checkbox"],
+    [type="radio"] {
+        box-sizing: border-box; /* 1 */
+        padding: 0; /* 2 */
+    }
 }
 
-/*
- * Remove inner padding and search cancel button in Safari and Chrome on OS X.
- * Safari (but not Chrome) clips the cancel button when the search input has
- * padding (and `textfield` appearance).
+/**
+ * Correct the cursor style of increment and decrement buttons in Chrome.
  */
 
-input[type="search"]::-webkit-search-cancel-button,
-input[type="search"]::-webkit-search-decoration {
-  -webkit-appearance: none;
+[type="number"]::-webkit-inner-spin-button,
+[type="number"]::-webkit-outer-spin-button {
+    height: auto;
 }
 
-/*
- * Define consistent border, margin, and padding.
+/**
+ * 1. Correct the odd appearance in Chrome and Safari.
+ * 2. Correct the outline style in Safari.
  */
 
-fieldset {
-  border: 1px solid #c0c0c0;
-  margin: 0 2px;
-  padding: 0.35em 0.625em 0.75em;
+[type="search"] {
+    -webkit-appearance: textfield; /* 1 */
+    outline-offset: -2px; /* 2 */
 }
 
-/*
- * 1. Correct `color` not being inherited in IE 8/9/10/11.
- * 2. Remove padding so people aren't caught out if they zero out fieldsets.
+/**
+ * Remove the inner padding and cancel buttons in Chrome and Safari on OS X.
  */
 
-legend {
-  border: 0; /* 1 */
-  padding: 0; /* 2 */
+[type="search"]::-webkit-search-cancel-button,
+[type="search"]::-webkit-search-decoration {
+    -webkit-appearance: none;
 }
 
-/*
- * Remove default vertical scrollbar in IE 8/9/10/11.
+/**
+ * Correct the text style of placeholders in Chrome, Edge, and Safari.
  */
 
-textarea {
-  overflow: auto;
+::-webkit-input-placeholder {
+    color: inherit;
+    opacity: 0.54;
 }
 
-/*
- * Restore font weight (unset by a rule above).
- * NOTE: the default cannot safely be changed in Chrome and Safari on OS X.
+/**
+ * 1. Correct the inability to style clickable types in iOS and Safari.
+ * 2. Change font properties to `inherit` in Safari.
  */
 
-optgroup {
-  font-weight: bold;
+::-webkit-file-upload-button {
+    -webkit-appearance: button; /* 1 */
+    font: inherit; /* 2 */
 }
 
 
 
-/* ==========================================================================
-   HTML5 Boilerplate optimizations 
-   ========================================================================== */
+@if $initialize-html5-boilerplate-overwrites == true {
+    /* ==========================================================================
+       HTML5 Boilerplate optimizations
+       ========================================================================== */
 
-/*
- * Remove text-shadow in selection highlight:
- * https://twitter.com/miketaylr/status/12228805301
- *
- * These selection rule sets have to be separate.
- * Customize the background color to match your design.
- */
+    /**
+     * Remove text-shadow in selection highlight:
+     * https://twitter.com/miketaylr/status/12228805301
+     *
+     * These selection rule sets have to be separate.
+     * Customize the background color to match your design.
+     */
 
-::selection {
-    background: #b3d4fc;
-    text-shadow: none;
-}
+    ::selection {
+        background: #b3d4fc;
+        text-shadow: none;
+    }
 
-/*
- * A better looking default horizontal rule
- */
+    /**
+     * A better looking default horizontal rule
+     */
 
-hr {
-    display: block;
-    height: 1px;
-    border: 0;
-    border-top: 1px solid #ccc;
-    margin: 1em 0;
-    padding: 0;
-}
+    hr {
+        display: block;
+        height: 1px;
+        border: 0;
+        border-top: 1px solid #ccc;
+        margin: 1em 0;
+        padding: 0;
+    }
 
-/*
- * Remove the gap between audio, canvas, iframes,
- * images, videos and the bottom of their containers:
- * https://github.com/h5bp/html5-boilerplate/issues/440
- */
+    /**
+     * Remove the gap between audio, canvas, iframes,
+     * images, videos and the bottom of their containers:
+     * https://github.com/h5bp/html5-boilerplate/issues/440
+     */
 
-audio,
-canvas,
-iframe,
-img,
-svg,
-video {
-    vertical-align: middle;
-}
+    audio,
+    canvas,
+    iframe,
+    img,
+    svg,
+    video {
+        vertical-align: middle;
+    }
 
-/*
- * Remove default fieldset styles.
- */
+    /**
+     * Remove default fieldset styles.
+     */
 
-fieldset {
-    border: 0;
-    margin: 0;
-    padding: 0;
-}
+    fieldset {
+        border: 0;
+        margin: 0;
+        padding: 0;
+    }
 
-/*
- * Allow only vertical resizing of textareas.
- */
+    /**
+     * Allow only vertical resizing of textareas.
+     */
 
-textarea {
-    resize: vertical;
+    textarea {
+        resize: vertical;
+    }
 }
 
 
@@ -589,7 +601,7 @@ textarea {
    Optional configurations
    ========================================================================== */
 
-/*
+/**
  * Headings
  */
 
@@ -599,7 +611,7 @@ h1, h2, h3, h4, h5, h6 {
   @include optional-prop('font-family', $initialize-heading-font-family);
 }
 
-/*
+/**
  * Block elements
  */
 
@@ -680,4 +692,3 @@ p, table, ul, ol, fieldset, blockquote, dl {
       }
   }
 }
-