mdb-ui-kit/less/_checkboxes.less

// http://www.google.com/design/spec/components/selection-controls.html#selection-controls-checkbox
.form-horizontal .checkbox {
  padding-top: 20px;
}

.form-group-checkbox-variant(@placeholder-font-size, @line-height){
  .checkbox {
    label {
      font-size: @placeholder-font-size;
      line-height: @line-height;
      font-weight: normal;
    }
  }
}

.form-group {

  // default label size/location
  .form-group-checkbox-variant(@md-input-font-size-base, @md-input-line-height-base);

  // sm label size/location
  &.form-group-sm {
    .form-group-checkbox-variant(@md-input-font-size-small, @md-input-line-height-small);
  }

  // lg label size/location
  &.form-group-lg {
    .form-group-checkbox-variant(@md-input-font-size-large, @md-input-line-height-large);
  }

  .checkbox {
    label {
      cursor: pointer;
      padding-left: 0; // Reset for Bootstrap rule
      color: @checkbox-label-color;
    }

    // Hide native checkbox
    input[type=checkbox] {
      opacity: 0;
      position: absolute;
      margin: 0;
      z-index: -1;
      width: 0;
      height: 0;
      overflow: hidden;
      left: 0;
      pointer-events: none;
    }

    .checkbox-material {
      vertical-align: middle;
      position: relative;
      top: 3px;
      &:before {  // FIXME: document why this is necessary (doesn't seem to be on chrome)
        display: block;
        position: absolute;
        left: 0;
        content: "";
        background-color: rgba(0,0,0,.84);
        height: @checkbox-size;
        width: @checkbox-size;
        border-radius: 100%;
        z-index: 1;
        opacity: 0;
        margin: 0;
        transform: scale3d(2.3, 2.3, 1);
      }

      .check {
        position: relative;
        display: inline-block;
        width: @checkbox-size;
        height: @checkbox-size;
        border: 2px solid @checkbox-border-color;
        border-radius: 2px;
        overflow: hidden;
        z-index: 1;
      }
      .check:before {
        position: absolute;
        content: "";
        transform: rotate(45deg);
        display: block;
        margin-top: -4px;
        margin-left: 6px;
        width: 0;
        height: 0;
        box-shadow:
          0 0 0 0,
          0 0 0 0,
          0 0 0 0,
          0 0 0 0,
          0 0 0 0,
          0 0 0 0,
          0 0 0 0 inset;
        animation: checkbox-off @checkbox-animation-check forwards;
      }
    }

    input[type=checkbox]:focus + .checkbox-material .check:after {
      opacity: 0.2;
    }
    input[type=checkbox]:checked + .checkbox-material .check:before {
      box-shadow:
        0 0 0 10px,
        10px -10px 0 10px,
        32px 0px 0 20px,
        0px 32px 0 20px,
        -5px 5px 0 10px,
        20px -12px 0 11px;
      animation: checkbox-on @checkbox-animation-check forwards;
    }

    input[type=checkbox]:not(:checked) + .checkbox-material:before {
      animation: rippleOff @checkbox-animation-ripple;
    }
    input[type=checkbox]:checked + .checkbox-material:before {
      animation: rippleOn @checkbox-animation-ripple;
    }

    // Ripple effect on click
    input[type=checkbox]:not(:checked) + .checkbox-material .check:after {
      animation: rippleOff @checkbox-animation-ripple forwards;
    }
    input[type=checkbox]:checked + .checkbox-material .check:after {
      animation: rippleOn @checkbox-animation-ripple forwards;
    }

    // Style for disabled inputs
    fieldset[disabled] &,
    fieldset[disabled] & input[type=checkbox],
    input[type=checkbox][disabled]:not(:checked) ~ .checkbox-material .check:before,
    input[type=checkbox][disabled]:not(:checked) ~ .checkbox-material .check,
    input[type=checkbox][disabled] + .circle {
      opacity: 0.5;
    }
    input[type=checkbox][disabled] + .checkbox-material .check:after {
      background-color: @lightbg-text;
      transform: rotate(-45deg);
    }

    .variations(~" input[type=checkbox]:checked + .checkbox-material .check:after", background-color, @success);
    .variations(~" input[type=checkbox]:checked + .checkbox-material .check:before", color, @checkbox-checked-color);
    .variations(~" input[type=checkbox]:checked + .checkbox-material .check", color, @checkbox-checked-color);
    .variations(~" input[type=checkbox]:checked + .checkbox-material .check", border-color, @checkbox-checked-color);
  }
}

@keyframes checkbox-on {
  0% {
    box-shadow:
      0 0 0 10px,
      10px -10px 0 10px,
      32px 0px 0 20px,
      0px 32px 0 20px,
      -5px 5px 0 10px,
      15px 2px 0 11px;
  }
  50% {
    box-shadow:
      0 0 0 10px,
      10px -10px 0 10px,
      32px 0px 0 20px,
      0px 32px 0 20px,
      -5px 5px 0 10px,
      20px 2px 0 11px;
  }
  100% {
    box-shadow:
      0 0 0 10px,
      10px -10px 0 10px,
      32px 0px 0 20px,
      0px 32px 0 20px,
      -5px 5px 0 10px,
      20px -12px 0 11px;
  }
}
@keyframes checkbox-off {
  0% {
    box-shadow:
      0 0 0 10px,
      10px -10px 0 10px,
      32px 0px 0 20px,
      0px 32px 0 20px,
      -5px 5px 0 10px,
      20px -12px 0 11px,
      0 0 0 0 inset;
  }

  25% {
    box-shadow:
      0 0 0 10px,
      10px -10px 0 10px,
      32px 0px 0 20px,
      0px 32px 0 20px,
      -5px 5px 0 10px,
      20px -12px 0 11px,
      0 0 0 0 inset;
  }
  50% {
    transform: rotate(45deg);
    margin-top: -4px;
    margin-left: 6px;
    width: 0px;
    height: 0px;
    box-shadow:
      0 0 0 10px,
      10px -10px 0 10px,
      32px 0px 0 20px,
      0px 32px 0 20px,
      -5px 5px 0 10px,
      15px 2px 0 11px,
      0 0 0 0 inset;
  }
  51% {
    transform: rotate(0deg);
    margin-top: -2px;
    margin-left: -2px;
    width: 20px;
    height: 20px;
    box-shadow:
      0 0 0 0,
      0 0 0 0,
      0 0 0 0,
      0 0 0 0,
      0 0 0 0,
      0 0 0 0,
      0px 0px 0 10px inset;
  }
  100% {
    transform: rotate(0deg);
    margin-top: -2px;
    margin-left: -2px;
    width: 20px;
    height: 20px;
    box-shadow:
      0 0 0 0,
      0 0 0 0,
      0 0 0 0,
      0 0 0 0,
      0 0 0 0,
      0 0 0 0,
      0px 0px 0 0px inset;
  }
}
@keyframes rippleOn {
  0% {
    opacity: 0;
  }
  50% {
    opacity: 0.2;
  }
  100% {
    opacity: 0;
  }
}
@keyframes rippleOff {
  0% {
    opacity: 0;
  }
  50% {
    opacity: 0.2;
  }
  100% {
    opacity: 0;
  }
}