.pantalla{
    display: -webkit-flex;
    display: flex;
    -webkit-flex-direction: column;
    flex-direction: column;
    /*width: 500px;*/
    padding: 10px;
    border: 0px;
    margin: 0px;
    background-color:#E9E6E6  ;
  }
  .pantalla input[type=text] {
    padding: 10px 10px;
    margin: 1px;
    box-sizing: border-box;
    border: none;
    background-color: #3CBC8D;
    color: white;
    font: bold 1.5em/1.5em HelveticaNeue, Arial;
    -webkit-align-self: center;
    align-self: center;
  }
  .teclas{
    -webkit-flex-direction: column;
    flex-direction: column;
    padding: 10px;
    border: 0px;
    margin: 1px;
    background-color:transparent;
    -webkit-align-self: center;
    align-self: center;
  }
  .button { 
    border: 1px solid #dedede;
    border-radius: 3px;
    color: #555;
    display: inline-block;
    font: bold 1.5em/1.5em HelveticaNeue, Arial;
    padding: 8px 11px;
    text-decoration: none;
    width: 70px;
    height:70px;
  }

  .button.white{
    background: #f5f5f5;
    border-color: #dedede #d8d8d8 #d3d3d3;
    box-shadow: 0 1px 1px #eaeaea, inset 0 1px 0 #fbfbfb;
    color: #555;
    text-shadow: 0 1px 0 #fff;
    background: -moz-linear-gradient(top,  #f9f9f9, #f0f0f0);
    background: -webkit-linear-gradient(top,  #f9f9f9, #f0f0f0);
    background: o-linear-gradient(top,  #f9f9f9, #f0f0f0);
    background: ms-linear-gradient(top,  #f9f9f9, #f0f0f0);
    background: linear-gradient(top,  #f9f9f9, #f0f0f0);
    filter:  progid:DXImageTransform.Microsoft.gradient(startColorstr='#f9f9f9', endColorstr='#f0f0f0');
  }

  .button.white:hover{
      background: #f4f4f4;
      border-color: #c7c7c7 #c3c3c3 #bebebe;
      box-shadow: 0 1px 1px #ebebeb, inset 0 1px 0 #f3f3f3;
      text-shadow: 0 1px 0 #fdfdfd;
      background: -moz-linear-gradient(top,  #efefef, #f8f8f8);
      background: -webkit-linear-gradient(top,  #efefef, #f8f8f8);
      background: -o-linear-gradient(top,  #efefef, #f8f8f8);
      background: -ms-linear-gradient(top,  #efefef, #f8f8f8);
      background: linear-gradient(top,  #efefef, #f8f8f8);
      filter:  progid:DXImageTransform.Microsoft.gradient(startColorstr='#efefef', endColorstr='#f8f8f8');
}