Repository: rust-lang/mdBook (language: rust)

Issue:
Scrollbars are weird in Safari
<img width="1280" alt="图片" src="https://user-images.githubusercontent.com/1286674/110286020-294a2a80-801f-11eb-9c1e-c278b67c8a8a.png">



Discussion / hints:
Can you say more what is "weird" about it?
They are always present in Safari.
The scroll bars:
- Are blocky instead of round
- Are far wider than normal
- Have the same background as the main content in the sidebar which looks incredibly janky
- Do not disappear when not scrolling
- Displace the context horizontally, messing up the alignment of the page (see red annotations)

### Firefox

<img width="1641" alt="Screen Shot 2022-12-21 at 5 47 03 PM" src="https://user-images.githubusercontent.com/25210657/209037264-10b63034-405f-426b-b06a-0da38a148869.png">

### Safari

<img width="1728" alt="Screen Shot 2022-12-21 at 5 47 14 PM" src="https://user-images.githubusercontent.com/25210657/209037281-efd36897-86ad-46e1-be51-45db3aa182e9.png">


The visual weirdness of the scrollbars is super janky and off-putting, and this visual glitch is sufficient to make me not want to use mdBook. I'll see if I can make a minimal reproducible example or something later
<img width="1174" alt="Screenshot 2022-12-21 at 9 53 48 PM" src="https://user-images.githubusercontent.com/25210657/209067132-6fe44cc4-eaff-472c-bf38-171179543b57.png">

Yeah, so deleting all the chrome CSS for `::-webkit-scrollbar` fixes the issue alright, but also has the effect of making the sidebar scrollbar appear darkened. 

Fix patch:
diff --git a/src/theme/css/chrome.css b/src/theme/css/chrome.css
index 59eae11fd0..53a79ccf0f 100644
--- a/src/theme/css/chrome.css
+++ b/src/theme/css/chrome.css
@@ -2,12 +2,6 @@
 
 @import 'variables.css';
 
-::-webkit-scrollbar {
-    background: var(--bg);
-}
-::-webkit-scrollbar-thumb {
-    background: var(--scrollbar);
-}
 html {
     scrollbar-color: var(--scrollbar) var(--bg);
 }


Test patch: