diff --git a/_mixins.sass b/_mixins.sass
index ea60fe1..964e4b2 100644
--- a/_mixins.sass
+++ b/_mixins.sass
@@ -5,6 +5,23 @@
   right: 0
   bottom: 0
 
+/*
+ * $size: all, top, right, bottom, left
+ */
+@mixin border($size: 1px, $color: black, $side: all)
+  border: 0
+  -webkit-appearance: none
+  @if $side == 'all'
+    box-shadow: inset 0 0 0 $size $color
+  @else if $side == 'top'
+    box-shadow: inset 0 $size 0 0 $color
+  @else if $side == 'right'
+    box-shadow: inset -#{$size} 0 0 0 $color
+  @else if $side == 'left'
+    box-shadow: inset $size 0 0 0 $color
+  @else if $side == 'bottom'
+    box-shadow: inset 0 -#{$size} 0 0 $color
+
 @mixin animationRotate($speed: 1s)
   @keyframes animationRotate
       from