Move `html` and `body` styles to 'ui.less'

Moving reset properties
- `font-family` and
- `font-size`

and opinionated
- `margin`
to ui.less.

All other properties from 'reset.less' don't apply to those elements.

Also
- consolidating body `background-color` and `color` in 'ui.less' and
- moving `html` affecting property there as well.

Bug: T205341
Bug: T217621
Change-Id: I4c545da76e6fdebced41e6e7e6eb89e4d97a8b24

resources/skins.minerva.base.styles/reset.less

@@ -4,7 +4,7 @@
 */
 @import '../../minerva.less/minerva.mixins';
 
-html, body, div, span,
+div, span,
 h1, h2, h3, h4, h5, h6, p, blockquote, pre,
 a, abbr, acronym, address, big, cite, code,
 del, ins, em, img,
@@ -37,10 +37,6 @@ button {
 	cursor: pointer;
 }
 
-body {
-	line-height: 1;
-}
-
 input {
 	line-height: normal;
 }

resources/skins.minerva.base.styles/ui.less

@@ -9,8 +9,20 @@ body {
 	height: 100%;
 }
 
+html {
+	// FIXME: Still from Eric Meyer's reset, that should be better fine-grained.
+	font-size: 100%;
+	// Support Safari: Prevent font scaling in landscape
+	-webkit-text-size-adjust: none;
+}
+
 body {
-	background-color: @chromeColor;
+	background-color: @skinContentBgColor;
+	color: @colorGray2;
+	// Support All Browsers: Remove `margin` (normalized)
+	margin: 0;
+	// FIXME: Still from Eric Meyer's reset, that should be good to go.
+	line-height: 1;
 }
 
 // FIXME: should we use .mw-body here instead?

resources/skins.minerva.content.styles/main.less

@@ -7,19 +7,12 @@
 //
 // Styleguide 1.
 
-html {
-	// prevent font scaling in landscape in Safari
-	-webkit-text-size-adjust: none;
-}
-
 @font-size-body: 100% * @fontScalingFactor;
 
 body {
 	font-family: @fontFamily;
 	font-size: @font-size-body;
 	line-height: 1.4;
-	color: @colorGray2;
-	background: #fff;
 	-webkit-tap-highlight-color: rgba( 0, 0, 0, 0.2 );
 }