pco/app/uview-ui/components/u-button/vue.scss

// nvue下hover-class无效
$u-button-before-top: 50% !default;
$u-button-before-left: 50% !default;
$u-button-before-width: 100% !default;
$u-button-before-height: 100% !default;
$u-button-before-transform: translate(-50%, -50%) !default;
$u-button-before-opacity: 0 !default;
$u-button-before-background-color: #000 !default;
$u-button-before-border-color: #000 !default;
$u-button-active-before-opacity: .15 !default;
$u-button-icon-margin-left: 4px !default;
$u-button-plain-u-button-info-color: $u-info;
$u-button-plain-u-button-success-color: $u-success;
$u-button-plain-u-button-error-color: $u-error;
$u-button-plain-u-button-warning-color: $u-error;

.u-button {
  width: 100%;

  &__text {
    white-space: nowrap;
    line-height: 1;
  }

  &:before {
    position: absolute;
    top: $u-button-before-top;
    left: $u-button-before-left;
    width: $u-button-before-width;
    height: $u-button-before-height;
    border: inherit;
    border-radius: inherit;
    transform: $u-button-before-transform;
    opacity: $u-button-before-opacity;
    content: " ";
    background-color: $u-button-before-background-color;
    border-color: $u-button-before-border-color;
  }

  &--active {
    &:before {
      opacity: .15
    }
  }

  &__icon + &__text:not(:empty),
  &__loading-text {
    margin-left: $u-button-icon-margin-left;
  }

  &--plain {
    &.u-button--primary {
      color: $u-primary;
    }
  }

  &--plain {
    &.u-button--info {
      color: $u-button-plain-u-button-info-color;
    }
  }

  &--plain {
    &.u-button--success {
      color: $u-button-plain-u-button-success-color;
    }
  }

  &--plain {
    &.u-button--error {
      color: $u-button-plain-u-button-error-color;
    }
  }

  &--plain {
    &.u-button--warning {
      color: $u-button-plain-u-button-warning-color;
    }
  }
}