'flex' c })}> <img className={css({ border: 0 d })} /> </div> footer.js <div className={css({ background: 'black', a padding: 10, b display: 'grid' e })}> <div className={css({ display: 'flex',( c flexDirection: 'column' f })} /> </div> output HTML // header <div class='a b c'> <img class='d' /> </div> // footer <div class='a b e'> <div class='c f' /> </div> output CSS .a { background: black } .b { padding: 10px } .c { display: flex } .d { border: 0 } .e { display: grid } .f { flex-direction: column }