body {
  padding: 50px;
  width: 420px;
  margin: 0 auto;
  margin-top: 20px;
}
div.row {
  width: 320px;
}
.col-xs-3 {
  width: 70px;
  height: 50px;
  text-align: center;
  line-height: 2.2;
  font-size: 1.3em;
  background: #ecf0f1;
  padding: 5px;
  margin: 1.5px;
}
#clear {
  background: #e74c3c;
}
#equals {
  background: #3498db;
}
#calcBody {
  font-weight: bold;
  text-transform: uppercase;
  margin: 0 auto;
  text-align: center;
}
div#calcBody.container {
  width: 420px;
}
#screen {
  width: 288px;
  margin-right: 28px;
  margin-left: -12px;
  height: 50px;
  margin-top: 5px;
  margin-bottom: 5px;
  font-size: 2em;
  letter-spacing: 1.5px;
  border: 2px solid #3498db;
  padding: 5px;
  background: #fff;
  text-align: left;
}
#calcBodyCover {
  border: 10px solid #ecf0f1;
  padding: 3px;
  border-radius: 3%;
}
footer {
  text-align: center;
  margin: 0 auto;
  padding: 25px;
}
a {
  color: #3498db;
  text-decoration: none;
}
a:hover {
  text-decoration: none;
}
div#calcBody.container {
  width: 300px;
}