Comments break end of line semicolons
If there’s a comment at the end of line, the semi colon is included after the comment, rather than before.
E.g.:
padding-bottom 56.25% /* 16:9 */
Renders as:
padding-bottom: 56.25% /* 16:9 */;
When it should be:
padding-bottom: 56.25%; /* 16:9 */