.wmax {
  display: flex; }

.w730 {
  display: none; }

.w640 {
  display: none; }

.w400 {
  display: none; }

@media screen and (max-width: 730px) {
  .wmax {
    display: none; }

  .w730 {
    display: flex; } }
@media screen and (max-width: 640px) {
  .w730 {
    display: none; }

  .w640 {
    display: flex; } }
@media screen and (max-width: 400px) {
  .w640 {
    display: none; }

  .w400 {
    display: flex; }

  #menu {
    display: none; } }