fix redundancy

src/_Button.sass

@@ -10,7 +10,6 @@ input[type='submit']
 	background-color: $color-primary
 	border: .1rem solid $color-primary
 	border-radius: .4rem
-	box-sizing: border-box
 	color: $color-initial
 	cursor: pointer
 	display: inline-block

src/_Form.sass

@@ -16,7 +16,6 @@ select
 	border: .1rem solid $color-quaternary
 	border-radius: .4rem
 	box-shadow: none
-	box-sizing: border-box
 	height: 3.8rem
 	padding: .6rem 1.0rem // The .6rem vertically centers text on FF, ignored by Webkit
 	width: 100%

src/_Grid.sass

@@ -4,7 +4,6 @@
 
 // .container is main centered wrapper with a max width of 1120rem (1120px)
 .container
-	box-sizing: border-box
 	margin: 0 auto
 	max-width: 112.0rem
 	padding: 0 2.0rem