What does it mean for the Header style font size to be a percent?

I’m creating a document with Writer. I belatedly inserted some headers and noticed that they were not the same font size. I could see this looking at the tool bar’s font size tool when I clicked on each header. These are both the same header style but somehow not identical. Perplexed I opened up the Style dialog and looked at the Font tab to see what size was there. What I find is that the size is a percent. This makes no sense to me. Percent of what? A font is not relative to some other thing.

I tried the Help button but it dumped me into a part of the help the did not seem relevant.

Can someone
first enlighten me on the percent thing and
second explain how I can get all my header to match?

First, you’re not talking about headers (the information repeated unchanged at top of each page) but about headings or titles for the outline of your documents.

Paragraph styles are organised in a hierarchy (think of a genealogical chart) where descendant styles initially inherit their attributes from the immediate ancestor (and recursively up to the unique ultimate root). At each stage, attributes may be changed and override the definition in the ancestor.

To have an idea of the built-in hierarchy, open the style sidepane (F11 if not already displayed) and select Hierarchical from the bottom drop-down menu.

When font size is involved, you generally design your styles such that headings are larger than discourse text and also headings for more global titles are larger than those for less important titles.

Imagine now that proof-reading estimated that headings needed more distinctive appearance compared to discourse. You decide then to enlarge the heading font size. If you want to keep the relative importance of the various heading levels, you must change the size in every Heading n style. This is not user-friendly.

To address this question, font size can be specified as %-values instead of absolute point sizes. These %-values are applied to the font size of the ancestor style. Thus, when the font size changes in the ancestor, font sizes in the descendants are automatically updated. This is one of the magics of styles.

All Heading n descend from Heading which itself descend from Default Paragraph Style.

Discourse text should be formatted with Text Body which descend from Default Paragraph Style.

This “genealogy” explains why in Writer Default Paragraph Style should never be used for anything (contrary to M$ Word). Default Paragraph Style purpose is to assign attributes common to all other styles (before override).

Discrepancy between headings

Check that your headers have the same style. If so, this means you have somehow manually changed the font size. To make sure, select the full paragraph content (triple- or quadruple-click if several sentences) and Ctrl+M or Format>Clear direct formatting. If the formatting changes, you definitely applied a manual variation.

In Writer, manually applied attributes override those from the styles.

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Pretty good answer. I need to be more mindful of my formatting & proactive with a plan.

You left me with one question. When I inserted the Headings, I simply started a new paragraph following existing text (enter key at EOL) & then applied the Heading style. There was no messing with the font but the new line did assume whatever format was already there. Did this in 2 places & got different results.

So I’m wondering what did I do wrong?

I’m not clear on how the inheritance works.
Does the style inherit the parental style’s values as defined in style manager? That is does percentage apply to font size in generic style “Heading”?
Or is inheritance from the style (possible manually modified) of text to which style is applied? That is if text was “Default Paragraph Style” & font manually modified, does that effect Headings?
If the first then I can’t explain my different result.
If the later, must I constantly use the “Clear direct formatting” to be sure the text is virgin?

If applying a style has no effect, there is some direct formatting which must be cleared with Ctrl+M.

Inheritance works between styles, not between text and styles or vice versa.

If you manually modify attributes “locally”, this does not affect other occurrences. Only modifying styles will propagate to all instances so styled. Therefore, direct formatting any paragraph has no consequence on headings (whatever style they have).

But if you change Default Paragraph Style style, it propagate to all other styles because it is the common ancestor, unless a style has explicitly changed the attribute (what I call an override). It affects Heading (and Heading n) as well as Text Body.

Changing Heading affects Heading n but not Text Body.

To keep things tidy, once you style your document, don’t use direct formatting any more (unless you perfectly know the consequences of doing so and accept them).

Percent of what? A font is not relative to some other thing.

When you write your text, you probably use the style Textbody (Liberation Sans, 12 pt).

The percentage then refers to 12 pt, i think.

(A consideration of mine that I have not been able to read up on either.)