ant-design/style/components/button.less

@import "../mixins/index";
@btn-prefix-cls: ~"@{css-prefix}btn";

// Button styles
// -----------------------------
.@{btn-prefix-cls} {
  .btn;
  .btn-default;

  &-primary {
    .btn-primary;

    .@{btn-prefix-cls}-group &:not(:first-child):not(:last-child) {
      border-right-color: @btn-group-border;
      border-left-color: @btn-group-border;
    }

    .@{btn-prefix-cls}-group &:first-child {
      &:not(:last-child) {
        border-right-color: @btn-group-border;
        &[disabled] {
          border-right-color: @btn-default-border;
        }
      }
    }

    .@{btn-prefix-cls}-group &:last-child:not(:first-child),
    .@{btn-prefix-cls}-group & + .@{btn-prefix-cls} {
      border-left-color: @btn-group-border;
      &[disabled] {
        border-left-color: @btn-default-border;
      }
    }
  }

  &-ghost {
    .btn-ghost;
  }

  &-dashed {
    .btn-dashed;
  }

  &-circle,
  &-circle-outline {
    .btn-circle(@btn-prefix-cls);
  }

  &:after {
    font-family: anticon;
    content: "\e6a1";
    position: absolute;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.5s ease;
  }

  &&-loading {
    padding-left: 29px;
    pointer-events: none;
    opacity: 0.75;
    .anticon {
      margin-left: -14px;
      .transition(all .3s @ease-in-out);
    }
  }

  &-sm&-loading {
    padding-left: 24px;
    .anticon {
      margin-left: -17px;
    }
  }

  &-group {
    .btn-group(@btn-prefix-cls);
  }

  &:not(&-circle)&-icon-only {
    padding-left: 8px;
    padding-right: 8px;
  }

  // To ensure that a space will be placed between character and `Icon`.
  > .@{iconfont-css-prefix} + span,
  > span + .@{iconfont-css-prefix} {
    margin-left: 0.5em;
  }

  &-clicked:before {
  	content: '';
  	position: absolute;
  	top: -1px;
  	left: -1px;
  	bottom: -1px;
  	right: -1px;
  	border-radius: inherit;
    border: 0 solid @primary-color;
  	opacity: 0.4;
    animation: buttonEffect 0.32s ease forwards;
  }
}

@keyframes buttonEffect {
	to {
		opacity: 0;
    top: -5px;
  	left: -5px;
  	bottom: -5px;
  	right: -5px;
    border-width: 5px;
	}
}