Describe the bug

When you first open up the widgets screen on a new site, the padding for the first widget area appears to be off.

To reproduce
Steps to reproduce the behavior:

1. Create a new test site.
2. Install Gutenberg and activate.
3. Go to Appearance > Widgets
4. See padding is off :)

Expected behavior

I expect each widget area to look the same.

Screenshots

GIF:

Screenshot for good measure:

Editor version (please complete the following information):

• WordPress version: 5.5.1
• Does the website has Gutenberg plugin installed, or is it using the block editor that comes by default? Gutenberg Plugin
• If the Gutenberg plugin is installed, which version is it? 9.1.1

Desktop (please complete the following information):

• OS: MacOS
• Browser: Chrome
• Version: 86.0.4240.75