From 3efa49a770910f34a9e154d7817fc82cec15db28 Mon Sep 17 00:00:00 2001
From: kennylam <kennylam@protonmail.com>
Date: Wed, 20 Jan 2021 14:37:25 -0500
Subject: [PATCH] chore(masthead): update style docs (#4948)

### Description

Document CSS fix applied to [#4941](https://github.com/carbon-design-system/carbon-for-ibm-dotcom/pull/4941).

### Changelog

**New**

- add style comments documenting breakpoint fix

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<!-- *** "package: services": Services -->
<!-- *** "package: utilities": Utilities -->
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---
 packages/styles/scss/components/masthead/_masthead-l1.scss | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/packages/styles/scss/components/masthead/_masthead-l1.scss b/packages/styles/scss/components/masthead/_masthead-l1.scss
index 2094b28b5c7..42fddd239c3 100644
--- a/packages/styles/scss/components/masthead/_masthead-l1.scss
+++ b/packages/styles/scss/components/masthead/_masthead-l1.scss
@@ -26,6 +26,11 @@ $search-transition-timing: 95ms;
     transition-timing-function: $search-transition;
     overflow: visible;
 
+    // Exclude the target breakpoint itself (800px) by subtracting .02.
+    // This has been addressed in Carbon core, but only for breakpoint
+    // keywords, i.e. 'md', 'lg'.
+    // The calculation is not applied to numeric values.
+    // https://github.com/carbon-design-system/carbon/blob/master/packages/layout/scss/_breakpoint.scss#L172
     @include carbon--breakpoint-down(799.98px) {
       display: none;
     }