@media (max-width: 768px) {
  .display-3 {
    font-size: 2.5rem;
  }
}

@media screen and (min-width: 1024px) {
  .main-menu .navbar-nav>li>a {
    font-size: 14px;
  }
  .display-3 {
    font-size: 3.5rem;
  }
}

@media screen and (min-width: 1366px) {
  .main-menu .navbar-nav>li>a {
    font-size: 15px;
  }
  .display-3 {
    font-size: 3.5rem;
  }
}
@media screen and (min-width: 1920px) {

  .main-menu .navbar-nav>li>a {
    font-size: 16px;
  }
  .display-3 {
    font-size: 3.5rem;
  }
}

 @media only screen and (max-width: 1920px) and (max-height: 1080px) and (-webkit-device-pixel-ratio: 1.25) {
  .main-menu .navbar-nav>li>a {
    font-size: 15px;
  }
  .display-3 {
    font-size: 3.5rem;
  }
 }

 @media only screen and (max-width: 1920px) and (max-height: 1080px) and (-webkit-device-pixel-ratio: 1.50) {
  .main-menu .navbar-nav>li>a {
    font-size: 14px;
  }.display-3 {
    font-size: 3.5rem;
  }
 }