namaste/html/sass/mdb/pro/_checkbox.scss

/***************
   Checkboxes
***************/
[type="checkbox"] {
  @extend %hide-radio-checkbox;
  + label {
    @extend %base-radio-checkbox-label;
    &:before {
      content: '';
      position: absolute;
      top: 0;
      left: 0;
      width: 17px;
      height: 17px;
      z-index: 0;
      border: 1.5px solid #8a8a8a;
      border-radius: 1px;
      margin-top: 2px;
      @include transition(.2s);
    }
  }

  &:checked {
    + label:before {
      top: -4px;
      left: -3px;
      width: 12px;
      height: 22px;
      border-style: solid;
      border-width: 2px;
      border-color: transparent $radio-fill-color $radio-fill-color transparent;
      @include transform(rotate(40deg));
      -webkit-backface-visibility: hidden;
      @include transform-origin(100% 100%);
    }
  }

  &:indeterminate {
    + label:before {
      left: -10px;
      top: -11px;
      width: 10px;
      height: 22px;
      border: none;
      border-right: 2px solid $radio-fill-color;
      @include transform(rotate(90deg));
      -webkit-backface-visibility: hidden;
      @include transform-origin(100% 100%);
    }
  }

  &:disabled {
    &:checked + label:before {
      border-color: transparent $input-disabled-color $input-disabled-color transparent;
    }  
    &:not(:checked) + label:before {
      border: none;
      margin-left: 2px; 
      margin-top: 2px; 
      background-color: $input-disabled-color;
    }
    &:indeterminate + label:before {
      border-right: 2px solid $input-disabled-color;
      margin-left: 0;
      margin-top: 0;
      background-color: transparent;
    }     
  }

  &[class*='filled-in'] {

    + label:after, + label:before {
      content: '';
      left: 0;
      position: absolute;
      /* .1s delay is for check animation */
      transition: border .25s, background-color .25s, width .20s .1s, height .20s .1s, top .20s .1s, left .20s .1s;
      z-index: 1;
      border-style: solid;
      border-width: 2px;
    }
    + label:after {
      border-radius: 2px;
      height: 20px;
      width: 20px;
    }
    + label:before {
      @include transform(rotateZ(37deg));
      @include transform-origin(100% 100%); // ? 20% 40%
    }

    &:not(:checked) {
      + label:before {
        width: 0;
        height: 0;
        border-style: 3px;
        border-color: transparent;
        left: 6px;
        top: 10px;
      }
      + label:after {
        background-color: transparent;
        border-color: $radio-empty-color;
        top: 0;
        z-index: 0;
      }
    }

    &:checked {
      + label:before {
        top: 0;
        left: 1px;
        width: 8px;
        height: 13px;
        border-color: transparent $input-bg-color $input-bg-color transparent;
      }
      + label:after {
        border-color: $secondary-color;
        background-color: $secondary-color;
        z-index: 0;
      }
    }

    &:disabled {
      &:not(:checked) {
        + label:before {
          background-color: transparent;
          border-color: $input-disabled-solid-color;    
        }
        + label:after {
          border-color: transparent;
          background-color: $input-disabled-solid-color;
        }
      }
      &:checked {
        + label:before {
          background-color: transparent;
        }
        + label:after {
          background-color: $input-disabled-solid-color;
          border-color: $input-disabled-solid-color;
        }
      }

    }

  }

  &.filled-in-danger {
    &:checked + label:after {
      background-color: red;
      border-color: red;
    }
  }

}