docs(explanations): simplify section intro

Author: khuyentran1401

docs/docs/explanations/index.md

@@ -1,8 +1,6 @@
 # Explanations
 
-Conceptual guides that build a mental model of how Nebari works. Read these
-when you want to understand the *why* behind a design choice, not just the
-*how* of a workflow.
+Background on how Nebari works under the hood. Read these to understand the design and how the pieces fit together.
 
 - [NKP architecture](/docs/explanations/nkp-architecture): the layered stack
   that makes up the Nebari Kubernetes Platform, what the `nic` CLI does and