How to Change the Width of the Reading List Sidebar in Safari

For the record, I know this is a silly hack.

Add a new item to the `~/Library/Preferences/com.apple.Safari.plist` file:

Key: `SidebarSplitViewDividerPosition`
Type: "Number"
Value: `400`

For the value, use whatever width you want in the number of pixels. I think I like 400.