@media screen and (max-width: 850px){

  .main-container {
    text-align: center;
  }

  .main-container nav li {
    float: none;
    display: inline-block;
  }

  .main-container nav {
    float: none;
    display: block;
    padding: 0;
    padding-top: 10px;
  }

}

@media screen and (max-width: 1200px){

  .aktionen article {
  width: 100%;
  margin-top: 30px;
  padding-top: 30px;
}

  .aktionen article {
    width: 100%;
  }

  article {
        width: 100%;
  }
}