Your Tumblr blog includes a Customize mode with options to revise the presentation of your posts. Adding Cascading Style Sheets code will style your blog’s elements. For example, if you want to adjust the line height of your posts, insert a code in the Add Custom CSS section. This code will include a percentage value that you can adjust to increase or decrease the leading space between the lines of text and update your blog’s look.

CSS Line Height

Log in to your Dashboard, select the blog and then click the "Customize" button in the header to bring up the Customize sidebar. Scroll down and click "Advanced Options" to open the Advanced sidebar. Insert this code in the Add Custom CSS section:

p { line-height: 300%; }

Change "300" for the preferred value. For example, type "500" for a larger line height. Do not enter a negative value for this percentage. Avoid inserting smaller values that can cause the lines to overlap. The preview of the new line height displays on the blog layout. Click "Save," click the arrow button to return to the Customize sidebar and then click "Exit" to return to your revised blog.