@media only screen and (min-width: 500px) and (max-width: 768px) {
  /* For tablets: */
  .main:before {
    height: 300px;
    left: 200px;
    top: -140px; }
  .top-grid {
    margin: 120px 50px 0 50px; }
  .session-btn {
    margin-left: 50px; } }