What are the blue numbers on the character's stats screen?

My Petra is an assassin, doing a very good job of her role.
While looking at her stats, I noticed some of them have blue text, rather than black text, notably her speed and defense.
At first I thought, that must be the max stat this class can get.

However when I went into battle she leveled up, and her speed went up by 1.
Afterwards, I used a speed increasing item, and it still went up by 1, so it looks like it is not the cap for that stat.

Does anyone know what these blue stats mean?

Solution 1:

The blue numbers refer to boosted stats.

This can happen for various reasons, such as equipped skills, items, or Battalions, being the target of a Rally, or being dismounted, among others.

Conversely, stats that are being hindered are red.

You can see what exactly is boosting (or hindering) each stat, by pressing the X button (Details) and moving your cursor towards the colored stat.

According to the screenshot (the Detail window is in the lower center), Dorothea has 18 Charm + 1 from the Merchant Military Battalion, for a total of 19 Charm.

You can only see those details during battle, however, as they won't display when viewed from the student roster.