In section 1.3, why is this important?, 'base direction' is marked as definition in third paragraph, but it seems for me this part is not a definition of 'base direction' (rather a state of how important it is). So, it might be better to have some state to define the term.
Also, I feel a link (or mention) to section 3.2 is better to be included, that some may not be noticed that 'base direction' is not a direction of characters/glyphs but a direction of base point for text layout - such as start point of text layout.
In section 1.3, why is this important?, 'base direction' is marked as definition in third paragraph, but it seems for me this part is not a definition of 'base direction' (rather a state of how important it is). So, it might be better to have some state to define the term.
Also, I feel a link (or mention) to section 3.2 is better to be included, that some may not be noticed that 'base direction' is not a direction of characters/glyphs but a direction of base point for text layout - such as start point of text layout.