body {
  margin: 0;
}

/* use this to put borders around things... */
.thin_border {
	border: 1px solid black;
}

div {
  border: 1px solid gray;
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  float: left;
}

@media (min-width: 750px) {
  .responsive {
    display: inline-block;
    width: 400px;
  }
}

@media (min-width: 1000px) {
  .responsive {
    display: inline;
    width: 500px;
  }

}

@media (min-width: 500px) {
  body {
    background: #ff8060;
  }
}

@media (min-width: 1000px) {
  body {
    background: #80e0a0;
  }
}