The parser is really persistent for user’s errors:
normal **bold ''bold-italic** italic'' normal
normal bold bold-italic italic normal
<p> normal <strong>bold <em>bold-italic</em></strong><em> italic</em> normal </p>
H~~2~~O H~~2~~SO~~4~~ = 2H^^+^^ + SO~~4~~^^2-^^ X = **Y** ^^$$((style=“color:red”))a+b+c^^$$ + Z
H2O
H2SO4 = 2H+ + SO42-
X = Y a+b+c + Z