Reorganise normalize.css and edit comments

Update comments in line with any changes browsers have introduced.

Minor reordering of rulesets.

normalize.css

@@ -1,7 +1,26 @@
 /*! normalize.css v2.1.3 | MIT License | git.io/normalize */
 
-/* ==========================================================================
+/**
-   HTML5 display definitions
+ * 1. Set default font family to sans-serif.
+ * 2. Prevent iOS text size adjust after orientation change, without disabling
+ *    user zoom.
+ */
+
+html {
+  font-family: sans-serif; /* 1 */
+  -ms-text-size-adjust: 100%; /* 2 */
+  -webkit-text-size-adjust: 100%; /* 2 */
+}
+
+/**
+ * Remove default margin.
+ */
+
+body {
+  margin: 0;
+}
+
+/* HTML5 display definitions
    ========================================================================== */
 
 /**
@@ -56,32 +75,7 @@ template {
   display: none;
 }
 
-/* ==========================================================================
+/* Links
-   Base
-   ========================================================================== */
-
-/**
- * 1. Set default font family to sans-serif.
- * 2. Prevent iOS text size adjust after orientation change, without disabling
- *    user zoom.
- */
-
-html {
-  font-family: sans-serif; /* 1 */
-  -ms-text-size-adjust: 100%; /* 2 */
-  -webkit-text-size-adjust: 100%; /* 2 */
-}
-
-/**
- * Remove default margin.
- */
-
-body {
-  margin: 0;
-}
-
-/* ==========================================================================
-   Links
    ========================================================================== */
 
 /**
@@ -101,20 +95,9 @@ a:hover {
   outline: 0;
 }
 
-/* ==========================================================================
+/* Text-level semantics
-   Typography
    ========================================================================== */
 
-/**
- * Address variable `h1` font-size and margin within `section` and `article`
- * contexts in Firefox 4+, Safari 5, and Chrome.
- */
-
-h1 {
-  font-size: 2em;
-  margin: 0.67em 0;
-}
-
 /**
  * Address styling not present in IE 8/9, Safari 5, and Chrome.
  */
@@ -141,13 +124,13 @@ dfn {
 }
 
 /**
- * Address differences between Firefox and other browsers.
+ * Address variable `h1` font-size and margin within `section` and `article`
+ * contexts in Firefox 4+, Safari 5, and Chrome.
  */
 
-hr {
+h1 {
-  -moz-box-sizing: content-box;
+  font-size: 2em;
-  box-sizing: content-box;
+  margin: 0.67em 0;
-  height: 0;
 }
 
 /**
@@ -159,26 +142,6 @@ mark {
   color: #000;
 }
 
-/**
- * Correct font family set oddly in Safari 5 and Chrome.
- */
-
-code,
-kbd,
-pre,
-samp {
-  font-family: monospace, serif;
-  font-size: 1em;
-}
-
-/**
- * Contain overflow in all browsers.
- */
-
-pre {
-  overflow: auto;
-}
-
 /**
  * Address inconsistent and variable font size in all browsers.
  */
@@ -207,8 +170,7 @@ sub {
   bottom: -0.25em;
 }
 
-/* ==========================================================================
+/* Embedded content
-   Embedded content
    ========================================================================== */
 
 /**
@@ -227,8 +189,7 @@ svg:not(:root) {
   overflow: hidden;
 }
 
-/* ==========================================================================
+/* Grouping content
-   Figures
    ========================================================================== */
 
 /**
@@ -239,34 +200,48 @@ figure {
   margin: 1em 40px;
 }
 
-/* ==========================================================================
+/**
-   Forms
+ * Address differences between Firefox and other browsers.
+ */
+
+hr {
+  -moz-box-sizing: content-box;
+  box-sizing: content-box;
+  height: 0;
+}
+
+/**
+ * Contain overflow in all browsers.
+ */
+
+pre {
+  overflow: auto;
+}
+
+/**
+ * Address odd `em`-unit font size rendering in all browsers.
+ */
+
+code,
+kbd,
+pre,
+samp {
+  font-family: monospace, monospace;
+  font-size: 1em;
+}
+
+/* Forms
    ========================================================================== */
 
 /**
- * Define consistent border, margin, and padding.
+ * Known limitation: by default, Chrome and Safari on OS X allow very limited
+ * styling of `select`, unless a `border` property is set.
  */
 
-fieldset {
-  border: 1px solid #c0c0c0;
-  margin: 0 2px;
-  padding: 0.35em 0.625em 0.75em;
-}
-
 /**
- * 1. Correct `color` not being inherited in IE 8/9.
+ * 1. Correct color not being inherited.
- * 2. Remove padding so people aren't caught out if they zero out fieldsets.
+ *    Known issue: affects color of disabled elements.
- */
+ * 2. Correct font properties not being inherited.
-
-legend {
-  border: 0; /* 1 */
-  padding: 0; /* 2 */
-}
-
-/**
- * 1. Correct color not being inherited in all browsers.
- *    Known issue: `select` will not inherit color in Chrome and Safari on OS X.
- * 2. Correct font properties not being inherited in all browsers.
  * 3. Address margins set differently in Firefox 4+, Safari 5, and Chrome.
  */
 
@@ -280,15 +255,6 @@ textarea {
   margin: 0; /* 3 */
 }
 
-/**
- * Re-apply the `font-weight` to avoid modifying the default UX, and because
- * the default cannot be changed in Chrome and Safari on OS X.
- */
-
-optgroup {
-  font-weight: bold;
-}
-
 /**
  * Address `overflow` set to `hidden` in IE 8/9/10.
  */
@@ -297,20 +263,11 @@ button {
   overflow: visible;
 }
 
-/**
- * Address Firefox 4+ setting `line-height` on `input` using `!important` in
- * the UA stylesheet.
- */
-
-input {
-  line-height: normal;
-}
-
 /**
  * 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 Chrome, Safari 5+, and IE 8+.
+ * Correct `button` style inheritance in Firefox, IE 8+, and Opera
- * Correct `select` style inheritance in Firefox 4+ and Opera.
+ * Correct `select` style inheritance in Firefox.
  */
 
 button,
@@ -344,6 +301,28 @@ html input[disabled] {
 }
 
 /**
+ * Remove inner padding and border in Firefox 4+.
+ */
+
+button::-moz-focus-inner,
+input::-moz-focus-inner {
+  border: 0;
+  padding: 0;
+}
+
+/**
+ * Address Firefox 4+ setting `line-height` on `input` using `!important` in
+ * the UA stylesheet.
+ */
+
+input {
+  line-height: normal;
+}
+
+/**
+ * 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.
  */
@@ -379,8 +358,9 @@ input[type="search"] {
 }
 
 /**
- * Remove inner padding and search cancel button in Safari 5 and Chrome
+ * Remove inner padding and search cancel button in Safari and Chrome on OS X.
- * on OS X.
+ * Safari (but not Chrome) clips the cancel button when the search input has
+ * padding (and `textfield` appearance).
  */
 
 input[type="search"]::-webkit-search-cancel-button,
@@ -389,13 +369,23 @@ input[type="search"]::-webkit-search-decoration {
 }
 
 /**
- * Remove inner padding and border in Firefox 4+.
+ * Define consistent border, margin, and padding.
  */
 
-button::-moz-focus-inner,
+fieldset {
-input::-moz-focus-inner {
+  border: 1px solid #c0c0c0;
-  border: 0;
+  margin: 0 2px;
-  padding: 0;
+  padding: 0.35em 0.625em 0.75em;
+}
+
+/**
+ * 1. Correct `color` not being inherited in IE 8/9.
+ * 2. Remove padding so people aren't caught out if they zero out fieldsets.
+ */
+
+legend {
+  border: 0; /* 1 */
+  padding: 0; /* 2 */
 }
 
 /**
@@ -406,8 +396,16 @@ textarea {
   overflow: auto;
 }
 
-/* ==========================================================================
+/**
-   Tables
+ * Don't inherit the `font-weight` (applied by a rule above).
+ * NOTE: the default cannot safely be changed in Chrome and Safari on OS X.
+ */
+
+optgroup {
+  font-weight: bold;
+}
+
+/* Tables
    ========================================================================== */
 
 /**