chess/assets/css/_board.scss

$board-size: 90vmin;

@mixin move-indicator {
  border-radius: 50%;
  content: "";
  display: block;
  height: 2%;
  position: absolute;
  right: 2%;
  width: 2%;
}

.board {
  background: lighten($black-square-color, 7%);
  border-collapse: unset;
  border-radius: 2.8%;
  border-spacing: 1px;
  box-shadow: 0 ($board-size / 200) ($board-size / 40) $board-shadow-color;
  color: $white-square-color;
  height: $board-size;
  padding: $board-size / 20;
  position: relative;
  width: $board-size;

  &.white-to-move::before {
    @include move-indicator;
    background: $white;
  }

  &.black-to-move::before {
    @include move-indicator;
    background: $black;
  }

  &.player-is-white.white-to-move::before,
  &.player-is-black.black-to-move::before {
    bottom: 2%;
  }

  &.player-is-white.black-to-move::before,
  &.player-is-black.white-to-move::before {
    top: 2%;
  }
}

.board-body {
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  grid-template-rows: repeat(8, 1fr);

  height: 100%;
  width: 100%;
}

.board-border-top,
.board-border-bottom {
  height: $board-size / 20;
}

%black-square {
  background-color: $black-square-color;

  &.selected {
    background-color: mix($black-square-color, $selected-square-color, 60%);
    box-shadow: 0 0 0 ($board-size / 400) $selected-outline-color;
  }

  &.available {
    background-color: mix($black-square-color, $available-square-color, 80%);
    box-shadow: 0 0 0 ($board-size / 400) $available-outline-color;
  }
}

%white-square {
  background-color: $white-square-color;

  &.selected {
    background-color: mix($white-square-color, $selected-square-color, 60%);
    box-shadow: 0 0 0 ($board-size / 400) $selected-outline-color;
  }

  &.available {
    background-color: mix($white-square-color, $available-square-color, 80%);
    box-shadow: 0 0 0 ($board-size / 400) $available-outline-color;
  }
}

.board-square {
  background-position: center;
  background-repeat: no-repeat;
  background-size: 100%;
  border-radius: 2%;
  margin: 0.5px;

  // This is to ensure the squares can be clicked on in PhantomJS
  // TODO: Figure out why we need this

  min-height: 20px;
  min-width: 20px;

  @include odd-between(1, 8) { @extend %white-square; }
  @include even-between(1, 8) { @extend %black-square; }

  @include odd-between(9, 16) { @extend %black-square; }
  @include even-between(9, 16) { @extend %white-square; }

  @include odd-between(17, 24) { @extend %white-square; }
  @include even-between(17, 24) { @extend %black-square; }

  @include odd-between(25, 32) { @extend %black-square; }
  @include even-between(25, 32) { @extend %white-square; }

  @include odd-between(33, 40) { @extend %white-square; }
  @include even-between(33, 40) { @extend %black-square; }

  @include odd-between(41, 48) { @extend %black-square; }
  @include even-between(41, 48) { @extend %white-square; }

  @include odd-between(49, 56) { @extend %white-square; }
  @include even-between(49, 56) { @extend %black-square; }

  @include odd-between(57, 64) { @extend %black-square; }
  @include even-between(57, 64) { @extend %white-square; }

  @each $colour in $colours {
    @each $piece in $pieces {
      &.#{$colour}.#{$piece} {
        background-image: url(/images/#{$piece}_#{$colour}.svg);
      }
    }
  }
}

// .board-square:nth-child(even) {
  // @include black-square;
// }

// .board-square:nth-child(odd) {
  // @include white-square;
// }

@media (min-width: 480px) {
  .board-square {
    margin: 1px;
  }

  .board-label {
    font-size: 0.8rem;
  }
}

@media (min-width: 768px) {
  .board-square {
    margin: 1.5px;
  }

  .board-label {
    font-size: 1rem;
  }
}