app/node_modules/ng-zorro-antd/form/style/vertical.less

@import (reference) '../../style/themes/index';

@form-prefix-cls: ~'@{ant-prefix}-form';
@form-item-prefix-cls: ~'@{form-prefix-cls}-item';

// ================== Label ==================
.make-vertical-layout-label() {
  & when (@form-vertical-label-margin > 0) {
    margin: @form-vertical-label-margin;
  }
  padding: @form-vertical-label-padding;
  line-height: @line-height-base;
  white-space: initial;
  text-align: left;

  > label {
    margin: 0;

    &::after {
      display: none;
    }
  }
}

.make-vertical-layout() {
  .@{form-prefix-cls}-item .@{form-prefix-cls}-item-label {
    .make-vertical-layout-label();
  }
  .@{form-prefix-cls} {
    .@{form-prefix-cls}-item {
      flex-wrap: wrap;
      .@{form-prefix-cls}-item-label,
      .@{form-prefix-cls}-item-control {
        flex: 0 0 100%;
        max-width: 100%;
      }
    }
  }
}

.@{form-prefix-cls}-vertical {
  .@{form-item-prefix-cls} {
    &-row {
      flex-direction: column;
    }

    &-label > label {
      height: auto;
    }

    .@{form-prefix-cls}-item-control {
      width: 100%;
    }
  }
}

.@{form-prefix-cls}-vertical .@{form-item-prefix-cls}-label,
/* when labelCol is 24, it is a vertical form */
.@{ant-prefix}-col-24.@{form-item-prefix-cls}-label,
.@{ant-prefix}-col-xl-24.@{form-item-prefix-cls}-label {
  .make-vertical-layout-label();
}

@media (max-width: @screen-xs-max) {
  .make-vertical-layout();
  .@{ant-prefix}-col-xs-24.@{form-item-prefix-cls}-label {
    .make-vertical-layout-label();
  }
}

@media (max-width: @screen-sm-max) {
  .@{ant-prefix}-col-sm-24.@{form-item-prefix-cls}-label {
    .make-vertical-layout-label();
  }
}

@media (max-width: @screen-md-max) {
  .@{ant-prefix}-col-md-24.@{form-item-prefix-cls}-label {
    .make-vertical-layout-label();
  }
}

@media (max-width: @screen-lg-max) {
  .@{ant-prefix}-col-lg-24.@{form-item-prefix-cls}-label {
    .make-vertical-layout-label();
  }
}

@media (max-width: @screen-xl-max) {
  .@{ant-prefix}-col-xl-24.@{form-item-prefix-cls}-label {
    .make-vertical-layout-label();
  }
}