Underline

Markdown has no underline, so Tisty has two plus signs.

++underlined++

• Exactly two + on each side. The words inside cannot start or end with a space.
• The walls cannot touch a letter, a digit or another + on their outer side, so C++, i++ and a ++ b ++ c are never underlines.
• An underline cannot cross the edge of a bold or a link: both walls sit inside the same one.
• Other readers show ++underlined++ as it is. When a document leaves Tisty as plain Markdown — Copy as Markdown, or written out to a folder — the walls are dropped and the words stay.