@media only screen and (max-width: 767px) {
  .intro-details{
    position: relative;
    text-align: left;
    padding: 50px;
  }
  .about-desc{text-align: center;}
  .social-icons{text-align: center;}
  .about-learn h3{padding-left: 0;text-align: center;}
}

@media only screen and (max-device-width: 425px) {
  .intro-section h1{font-size: 200%;}
  .screenshot img{width: 300px;}
  .portfolio-desc{width: 300px;}
  .contact-links a{
    font-size: 40px;
    padding: 20px;
  }
  footer{font-size: 15px;}
}

@media only screen and (max-device-width: 320px) {
  .screenshot img{width: 250px;}
}