Bootstrap/docs/assets/scss/_masthead.scss

.bd-masthead {
  position: relative;
  padding: 3rem ($grid-gutter-width / 2) 2rem;
  color: $bd-purple-light;
  text-align: center;
  background-image: -webkit-linear-gradient(135deg, darken($bd-purple, 20%), $bd-purple, lighten(saturate($bd-purple, 5%), 15%));
  background-image:         linear-gradient(135deg, darken($bd-purple, 20%), $bd-purple, lighten(saturate($bd-purple, 5%), 15%));
  filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#{ie-hex-str(darken($bd-purple, 20%))}', endColorstr='#{ie-hex-str(lighten(saturate($bd-purple, 5%), 15%))}', gradientType='1');   /* For IE9 */

  .bd-booticon {
    margin: 0 auto 2rem;
    color: $bd-purple-light;
    border-color: $bd-purple-light;
  }

  h1 {
    font-weight: 300;
    line-height: 1;
  }

  .lead {
    margin-left: auto;
    margin-right: auto;
    margin-bottom: 2rem;
    font-size: 1.25rem;
    color: #fff;
  }

  .version {
    margin-top: -1rem;
    margin-bottom: 2rem;
  }

  .btn {
    width: 100%;
    padding: 1rem 2rem;
    font-size: 1.25rem;
    font-weight: 500;
    color: $bd-yellow;
    border-color: $bd-yellow;

    &:hover {
      color: $bd-graphite;
      background-color: $bd-yellow;
      border-color: $bd-yellow;
    }
  }

  .carbonad {
    margin-bottom: -2rem !important;
  }

  @include media-breakpoint-up(sm) {
    padding-top: 8rem;
    padding-bottom: 2rem;

    .btn {
      width: auto;
    }

    .carbonad {
      margin-bottom: 0 !important;
    }
  }

  @include media-breakpoint-up(md) {
    padding-bottom: 4rem;

    .bd-header {
      margin-bottom: 4rem;
    }

    h1 {
      font-size: 4rem;
    }

    .lead {
      font-size: 1.5rem;
    }

    .carbonad {
      margin-top: 3rem !important;
    }
  }

  @include media-breakpoint-up(lg) {
    .lead {
      width: 85%;
      font-size: 2rem;
    }
  }
}