_src/_sass/_header.scss

.site-header {
  width: 100%;
  position: fixed;
  z-index: 100;
  display: flex;
  justify-content: space-between;
  flex-direction: column;
  align-items: center;
  padding: 0 20px;
  background-color: rgba(0,0,0,.9);
  @media (min-width: $bp-medium) {
    flex-direction: row;
    position: absolute;
    background: transparent;
    &.sticky {
      position: fixed;
      left: 0;
      top: -80px;
      background-color: rgba(0,0,0,.9);
    }
    &--not-home {
      background-color: rgba(0,0,0,.9);
    }
  }
  .logo {
    font-size: 20px;
    font-weight: $font-weight-medium;
    line-height: 1;
    margin: 30px 0 0 0;
    @media (min-width: $bp-medium) {
      margin: 0;
    }
    .logo-mark {
      display: inline-block;
      height: 31px;
      width: 32px;
      background: transparent url(../img/SystemML-logo-white-32-cleaned.png) 0 0 no-repeat;
      margin-right: 20px;
    }
    a {
      color: #fff;
      display: flex;
      align-items: center;
      &:visited {
        color: #fff;
      }
    }
  }
}