.a {
  top: 0px;
  left: 0px;
  background: none;
  height: 100%;
  width: 100%;
  /*IMPORTANTE*/
  display: flex;
  justify-content: center;
  align-items: center;
  position: absolute;

}

@media (min-width: 600px) {

  body, html {

  margin:0px 0px 0px 0px;
  background-image: url("background.jpg");
  background-attachment: fixed;
  background-size: cover; 
  }

  .b {
  background: none;
  width: 50%;
  height: 50%;
  align-items: center;
  display: flex;
  justify-content: center;
  box-shadow: -.2em .2em .9em;

}
}

@media (max-width: 600px) {

  body, html {
 
  margin:0px 0px 0px 0px;
  background-image: url("backgroundmobile.jpg");
  background-attachment: fixed;
  background-size: cover; 
}

  .b {
  background: none;
  width: 90%;
  height: 70%;
  align-items: center;
  display: flex;
  justify-content: center;
  box-shadow: -.2em .2em .9em;

}

  }


table{
width: 100%;
background-color:rgba(255,255,255,.4);
height: 100%;
text-align: center;
font: 120% sans-serif;
color:white;
text-shadow:  0em 0em 1em black;
}
table, tr, td {
 border-spacing: 0px;
}

tr{
border-bottom: 5px solid black;
}

.bot:hover{
  background-color: rgba(0,120,250,.5);
  color:#15e4d3;
  text-shadow:  0em 0em 1em black;
}
.bot{
  width:100%; height: 50%;

}


tr.border_bottom td {
  border-bottom:1pt solid black;
}

#cliente{
width: 80px

}