Follow these steps:

1. Navigate to the "Assets" tab
2. Click "Preset"
3. Hover over the "Tools" icon
4. Click the "Cog" icon to open the style settings
5. On the "About" tab, select a category other than "Custom"
6. Return to the "Preset" tab and hover over the icons
7. Hover over the "Tools" icon
8. Click the red "Make public" icon; the style is now public
9. To remove the style from public, click the blue "Remove from public" icon; the style has now been removed from public access

Tips:

• Only the "Owner" of a style can edit it
• If you want to edit a public style, click "Save as new" to create a custom style guide