@media screen and (max-width: 640px) {
  #banners {
    border-top: 1px solid #e1e1e4;
    padding: 100px 0 100px 0 !important;
  }
  
  #banners ul {
    width: 220px;
    margin: 0 auto !important;
    list-style-type: none;
  }
  
  #banners li {
    width: 220px;
    height: 120px;
    margin-bottom: 20px !important;
  }
  
  #banners li:last-child {margin-bottom: 0 !important;}  
}

@media screen and (min-width: 641px) {
  #banners {
    border-top: 1px solid #e1e1e4;
    padding: 100px 0;
    width: 100%;
    min-width: 1100px;
  }
  
  #banners ul {
    width: 1000px;
    margin: 0 auto;
    list-style-type: none;
    display: flex;
    justify-content: space-around;
  }
  
  #banners li {
    width: 220px;
    height: 120px;
    margin: 0 10px;
  }
  
  #banners li a img {
    transition: opacity 0.3s;
  }
  #banners li a:hover img, #banners li a:active img {
    opacity: 0.8;
  }
}