@headings-color: #fff;
@line-height-computed: 20px;
@screen-sm-min: 320;

.h1, .h2, .h3, .h4, .h5, .h6 {

  color: @headings-color;

  small,
  .small {

    line-height: 1;
    color: @headings-color;
  }
}
 .h1,
.h2,
.h3 {
  margin-top: @line-height-computed;
  margin-bottom: (@line-height-computed / 2);

  small,
  .small {
      color: red;
  }
}