Semantics
ARIA roles and attributes: when you need them and when you do not
ARIA is the one technology in web accessibility that lets you make a page actively worse than it was without it. A wrong role tells assistive software something untrue, and the user acts on it.
Tables: the part of SC 1.3.1 that breaks most often
Opening hours. Monday, 09:00 to 17:00. You look at it once and you know which time belongs to which day, because the two sit on the same row.
SC 1.3.1 - What does "Info and Relationships" mean?
You can see that a line is a heading because it is big and bold. You can see that three lines belong together because they each start with a bullet. You can see which column a number belongs to because it sits underneath the word “Price”. None of that is visible to a screen reader. It only knows what the code says. Success criterion 1.3.1 is the rule that closes that gap: the structure a sighted visitor perceives must also be available in the markup.