containerless-container.css

.site-content {
  @include clearfix();
  @include display(flex);
  @include flex-direction(row);
  @include flex-wrap(nowrap);
  @include justify-content(center);
  @include align-items(flex-start);
  @include align-content(flex-start);
}

.content-area {
  @include flex(0 1 auto);
  @include span-columns(9);
  float: none; // Shame
  max-width: $max-width * (strip-units(flex-grid(9, 12)) / 100);
}

.widget-area {
  @include flex(0 1 auto);
  @include span-columns(3);
  float: none; // Shame
  max-width: $max-width * (strip-units(flex-grid(3, 12)) / 100);
}