&[data-primary] {
background: #f00;
color: #fff;
}
&:not([data-primary]) {
background: #000;
color: #000;
}
styled.Button`
background: ${ifPrimary('#f00' : '#00f')};
color: ${ifPrimary('#fff' : '#000')};
padding: 0.5rem 1rem;
`;
// or
${ifProp('primary').then('#f00').else('#00f')}
CSS-MODULES: WHY THIS IS THE MOST SIGNIFICANT IMPROVEMENT TO CSS IN YEARS