How to change font size of all math types in a document at the same time. Suggest a solution in a combination with styles.
Not stupid. A (contorted) workaround when everything else fails.
I assume you mean all math formulae create with the *Math component (application).
Unfortunately, you can’t.
Math lags largely behind the other applications and has not received significant evolution for ages. In particular, the notion of style when composing formulas in Math is already rudimentary (and this is already an understatement).
When the formula is inserted into Writer, the structural details are not seen by Writer. This means even if there were “styles” similar to those found in Writer, Calc or Impress, they are not seen by the hosting application. Anyway, the “styles” are far away from the concept in Writer.
No Writer style will have an action on Math formulas.
Every formula is an independent object. Even if you reedit it in Math, it won’t inherit from Math “styles”. You must reapply manually the changes.
I’m afraid there is no user-friendly solution. I tried saving all formulas in a single .otf file (like I do with Draw illustrations) but there is no way then to insert a single designated formula into Writer.
The only known procedure is to customise/configure Math before creating the formulas so that they will use the customised font face, size, colour and other attributes. This works for “future” formulas but has no effect on existing ones.
PS: always mention OS name and LO version even if this seem irrelevant to you. There are subtle differences between platforms and releases.
Try this topic for a solution: Easy way to change fonts of all mathematical formulas (OLE)
The second solution you suggest is a excellent work. The file FormulaTools.otd by Regina contain a set of macros that work fine to me. I hope a day they included in the system because in my opinion the Markup Language for typing furmulae in writer and using Writer for typesetting mathematics is the best one in the garden of free softwere.
Build ID: 00(Build:2)
CPU threads: 2; OS: Linux 5.10; UI render: default; VCL: gtk3
Locale: el-GR (en_US.UTF-8); UI: el-GR
Debian package version: 1:7.0.4-4+deb11u1
Thank you very much!