html, body {
  width: 100%;
  height: 100%;
  padding: 0;
  margin: 0;
}

svg {
  display:block;
  margin:auto;    
  margin-top:50px;
}

.container {
  maxwidth: 970px;
}

h2, h3 {
  text-align: center;
}

.center {
  position: absolute;
  left: 50%;
  top: 50%;
  -webkit-transform: translate(-50%, -50%);
  transform: translate(-50%, -50%);
}

.line {
  fill: none;
  stroke: steelblue;
  stroke-width: 2px;
}