conditional formatting

Hallo!

I have to columns.
The one contains numbers or blanks or zeros.
The other needs to be formatted with color, depending on these rules:

if the first column contains a number other than 0, then it must be red
if the first column contains a number equal to zero, or is blank, then it must be blank-without color
if the second column contains the word 'yes', then, whether red or without color before, it must become blue.