$weak-background: $gray-lighter !default;
$strong-border-color: darken($weak-background, 6.5%) !default;
$strong-border-radius: $border-radius-small !default;

.weak {
  background-color: $weak-background;
}

.strong {
  padding: 15px;
  background: white;
  border-radius: $strong-border-radius;
  border: 1px solid $strong-border-color;
}

$weak-background: $gray-lighter !default;
$strong-border-color: darken($weak-background, 6.5%) !default;
$strong-border-radius: $border-radius-small !default;

.weak {
  background-color: $weak-background;
}

.strong {
  padding: 15px;
  background: white;
  border-radius: $strong-border-radius;
  border: 1px solid $strong-border-color;

  & + .strong {
    margin-top: 10px;
  }
}

Add margin between multiple 'strong' components
Add margin between multiple 'strong' components
