Add your own style to a notebooks stylesheet.

Open a notebooks stylesheet

Choose Format Edit Stylesheet... to open a notebooks stylesheet:

Add a new style

Type the name of a new style in the style name field, followed by :

Define the new style

Apply styles to the new style cell to define the style. For example, select the cell and choose Format Background Color Light Orange:

Close the stylesheet

Choose File Close () to close the stylesheet:

Select an item you want to apply the new style to

Select text, an expression or cells that you want to apply the new style to:

Open the custom style chooser

Select Format Style Other... () to open the custom style chooser:

Select the new style

Select the new style from the drop-down menu or type its name in the input field. The new style is applied to the selection:

Notes

Use a custom style programmatically with Style:
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Click for copyable input
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