It is necessary to make 2 blocks on the page that together would occupy the entire possible width. The right block is narrow and should not change its size when stretching or compressing the page, and the left block should occupy the rest of the width. I tried it on my own, but either the left block does not occupy the entire space, or squeezes the right one into a new line, but this should not be.
.div3 { max-width: 700px; } .div1 { height: 50px; max-width: 550px; background: #f99; width:100%; text-align:center; display: inline-block; float:left; } .div2 { height: 50px; background: #99f; display: inline-block; float: right; } <div class="div3"> <div class="div1">Резиновый блок</div> <div class="div2">Фиксированный</div> </div>