display: inline-block
position: relative
+div.board3
+ width: 33.33%
+ padding-bottom: 33.33%
+
div.board5
width: 20%
padding-bottom: 20%
+div.board6
+ width: 16.66%
+ padding-bottom: 16.66%
+
div.board7
width: 14.28%
padding-bottom: 14.28%
width: 8.33%
padding-bottom: 8.33%
+div.board19
+ width: 5.26%
+ padding-bottom: 5.26%
+
img.piece
width: 100%
z-index: 10
.in-shadow
filter: brightness(50%)
+.touch-hover
+ background-color: #C571E6 !important
+
.monochrome
border-bottom: 1px solid black
border-right: 1px solid black