[tbela99]

• the walker functions now use DFS instead of BFS
• disallow mixin inside rules or nested groups
• disallow layer inside mixin
• disallow contents outside mixin
• support dashed indent as unit

.module {
  margin-block: 1.5--bs;
  border-block: .5--bs;
  /* gives a vertical margin of 12px,
     and vertical border of 4px */
}

is rendered as

.module {
 margin-block: 1.5--bs;
 border-block: .5--bs
}