diff --git a/docs/components/reboot.md b/docs/components/reboot.md
index 98b8bc6e5a..d41e4e303c 100644
--- a/docs/components/reboot.md
+++ b/docs/components/reboot.md
@@ -11,7 +11,7 @@ Reboot builds upon Normalize, providing many HTML elements with somewhat opinion
 
 Here are our guidelines and reasons for choosing what to override in Reboot:
 
-- Use `rem`s and `em`s for units, nothing else.
+- Update some browser default values to use `rem`s instead of `em`s for scalable component spacing.
 - Avoid `margin-top`. Vertical margins can collapse, yielding unexpected results. More importantly though, a single direction of `margin` is a simpler mental model.
 - For easier scaling across device sizes, block elements should use `rem`s for `margin`s.
 - Keep declarations of `font`-related properties to a minimal, using `inherit` whenever possible.