html {
  box-sizing: border-box;
}

*, *:before, *:after {
  box-sizing: inherit;
}

.contentBox-single .mainBox {
  margin: auto;
  position: relative;
}
@media screen and (min-width: 641px) {
  .contentBox-single .mainBox {
    min-width: 750px;
    max-width: 1200px;
    width: auto;
  }
}

#popup {
  position: fixed;
  z-index: 100;
  width: 100%;
  height: 100%;
  left: 0;
  top: 0;
  background-color: rgba(0, 0, 0, 0.5);
}
#popup .content {
  vertical-align: middle;
  display: inline-block;
}
#popup .close {
  position: absolute;
  right: 0;
  top: 70px;
  color: #fff;
  font-size: 52px;
}
@media screen and (max-width: 640px) {
  #popup {
    display: none;
  }
}