Style sheets: remove heading's indent

[ChristianGolz]

For document generating I have create my own style sheet template. The headings have a numbering (1., 1.1, 1.1.1 etc.) and an indent left. So it looks like this:

1. Heading 1
  1.1 Heading 2
    1.1.1 Heading 3
2. Heading 1
  2.1 Heading 2
    2.1.1 Heading 3

How can I remove the ident without changing the level of the heading? Every time I decrease the indent, the level will be increased, too.

How can I set the style fo the heading left-justified without indent?
Example:

1. Heading 1
1.1 Heading 2
1.1.1 Heading 3
2. Heading 1
2.1 Heading 2
2.1.1 Heading 3

[Eve]

Show the ruler (View | Horizontal Ruler)
Edit the heading style (Edit | Edit Style)
Drag the little indent arrows on the ruler to the desired position.
Click in the document somewhere to end style edit.
Repeat for headings 2-9.