Adjust the width of your Atlassian Content’s pages:
Go to the Theme Editor > Confluence Pages or Jira Issues and Requests.
The default width is 1200px (75 rem). You can set a new width by percentage (of window width), pixels, or rem. The width applies to all pages with this theme. If you want some pages on your site to have a different width, set different themes for these pages. Learn more about site themes and page themes.
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