@media only screen and (min-device-width : 320px) and (max-device-width :576px) {
  body{
    overflow-x:hidden;
  }
  .one {
    height: 40vh;
  }
  .page1{
  background-image: none;
    background-color: #10176c; 
  background-attachment: fixed;
  background-repeat: no-repeat;
  width: 100%;
  height: 100%;
  color:#ffffff;
  background-size:100%;
    
}  
  .block-glag {
  margin-left: 0%;
}
  .page1, hr {
  border-color: #fff;
}
  block-text, h5{
    font-size: 45px;
  }
  block-text, h6{
    font-size: 38px;
  }
  block-text, p {
    font-size: 30px;
  }
  .nav {
    background-color: #073d64;
  } 
  .Irina,.katerina,.Dmitriy,.Alyona  {
    height: 75%;
  }
}
@media only screen and (min-device-width : 577px) and (max-device-width : 991px){
     .page1{
  background-attachment: fixed;
  background-repeat: no-repeat;
  width: 100%;
  height: 100%;
  color:#ffffff;
  background-size:160%; 
}
  block-text, h5{
    font-size: 40px;
  }
  block-text, h6{
    font-size: 33px;
  }
  block-text, p {
    font-size: 25px;
  }
  
  .block-glag {
  margin-left: -3%;
}
  .Irina,.katerina,.Dmitriy,.Alyona  {
    height: 75%;
  }
}
@media only screen and (min-device-width : 991px) and (max-device-width : 1200px) {
   .Irina  {
    height: 50%;
  }
.katerina{
   height: 50%;
}
.Alyona {
   height: 55%;
}
.Dmitriy {
   height: 50%; 
}
  big,small{
    margin:0px;
    float: left
  }
  .navbar-nav {
    margin-right: 10%;
  }
}

@media only screen and (min-device-width : 1120px) and (max-device-width : 1360px){
    .one {
    color: red;
       display: none;
  }
    
}