levels with "_:child_" elements

[jarekjsk]

hi, levels with ":child" elements. In the instruction you didn't make a space between (in your example) _span:only-child, so when I wrote on the same way as you it didn't work

[myCatsName]

I think they must have space before the colon, no space after.

for example plate :first-child will be OK for problem 15
but plate:first-child will not.

The instructions use a bad example