demo.css

.center {
  text-align: center;
}

.page_wrapper {
  border: 2px solid #50525e;
  border-radius: 6px;
  max-width: 1200px;
  margin: 0 auto;
}

.flex-item {
  margin: 25px 50px;
}

.flexdemo .flex-container-rows,
.flexdemo .flex-container-cols {
  background-color: #50525E;
  border-radius: 8px;
  min-height: 120px;
  margin-top: 5px;
}

.flexdemo .flex-container-cols {
  min-height: 230px;
}

.flexdemo .flex-item {
  min-width: 50px;
  min-height: 50px;
  border-radius: 6px;
  margin: 5px;
  text-align: center;
  color: #50525E;
  font-weight: bold;
}

.no-flexbox .flexdemo .flex-item {
  width: 50px;
  height: 50px;
}

.flexdemo .flex-container-rows .flex-item {
  background-color: #00FFF6;
}

.flexdemo .flex-container-cols .flex-item {
  background-color: #A85EAD;
}