Question

Missing a colon (' ') between the property and value in the (property) (value) declaration

Answer 1

Missing a closing quote for the string value.
Missing a colon (':') between the property and value in the "(property) : (value)" declaration.
The CSS looks like this

div.master-page
{
padding: 10px;
}

div.master-page div.master-page
{
position: relative;
margin: -20px;
}
Here is an image of the error