calc is a CSS3 function that provides the possibility to do simple math in CSS (add, subtract, divide, multiply). Without spaces
around operators, calc will have no effect.
More precisely, before an operator, there must be a single whitespace or a newline plus indentation. After an operator, there must be a single whitespace or a newline.
#div1 {
position: absolute;
width: calc(100%- 100px); /* Noncompliant; no space after the % sign */
}
#div1 {
position: absolute;
width: calc(100% - 100px);
}