With Style Tags...
Include style tags directly in embedded HTML to style HTML elements:
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With an External CSS File...
Create a CSS file
Choose File ▶ New ▶ CSS to create a new CSS file:
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Define styles in the CSS file
Add style directives to the CSS file:
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Use the CSS file in embedded HTML
Link to the CSS file in a cloud-deployed HTML fragment to use its styles:
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Verify your styling
Click the URL of the deployed object to visit it:
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Notes
Embedded HTML has no effect on the desktop, but can be deployed to the cloud from the desktop:
Raw HTML rendered in a cloud notebook cannot call an external style file:
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External CSS files are effective only in deployed objects.