use spacing mixins

src/scss/_base.scss

@@ -40,14 +40,14 @@
 }
 
 body {
-  font-size: 100%;
+	font-size: 100%;
 	line-height: 1.6;
 
-  box-sizing: border-box;
+	box-sizing: border-box;
 
 	@include font-body;
 	color: $color-body;
-  background-color: $background-color;
+	background-color: $background-color;
 }
 
 h1,
@@ -62,25 +62,25 @@ h6 {
 
 h1 {
 	font-size: 2em;
-	margin-bottom: 1.6rem;
+	@include margin-b(1);
 	@include font-title(semi-bold);
 }
 
 h2 {
 	font-size: 1.6em;
-	margin-bottom: 1.6rem;
+	@include margin-b(1);
 	@include font-title(semi-bold);
 }
 
 h3 {
 	font-size: 1.4em;
-	margin-bottom: 1.6rem;
+	@include margin-b(1);
 	@include font-title(semi-bold);
 }
 
 h4, h5, h6 {
 	opacity: 0.8;
-	margin-bottom: 0.8rem;
+	@include margin-b(0.5);
 }
 
 h4 {
@@ -97,7 +97,7 @@ h6 {
 }
 
 p {
-	margin-bottom: 1.6rem;
+	@include margin-b(1);
 }
 
 a,

src/scss/_mixins.scss

@@ -38,6 +38,11 @@
 	@include pb($bottom);
 }
 
+@mixin pad-h($left, $right: $left) {
+	@include pl($left);
+	@include pr($right);
+}
+
 @mixin pad($amount-t, $amount-r: $amount-t, $amount-b: $amount-t, $amount-l: $amount-r) {
 	padding: #{$amount-t * $line-height}rem
 		#{$amount-r * $line-height}rem