Justifying Column Header Text
The Data Table Column element has a Class attribute, which affects both the data displayed in the column and the column header text. By default, column header text is centered, which may not suit you. The element's Column Header Class, allows you to justify the header text separately from the data.
The effectiveness of other style descriptors in these style classes, such as font-size or -weight, may vary depending on any other style settings that have been made for the table, its rows, and cells, including those set by Themes.