body {
  background-color: green;
  margin: 0px;
}
h1 {
  text-align: center;
  color: #FFF;
}
#track {
  position: relative;
  background-color: gray;
  padding: 30px 0px;
  border-top: 3px solid black;
  border-bottom: 3px solid black;
}

.car {
  position: relative;
  left: 0px;
  height: 58px;
  width: 83px;
  margin: 20px 0px;
  transition: all 1s linear;
  z-index: 1;
}
.car#car1 {
  background-image: url(car1.png);
}
.car#car2 {
  background-image: url(car2.png);
}
.car#car3 {
  background-image: url(car3.png);
}
#finish {
  position: absolute;
  height: 100%;
  width: 30px;
  background-color: white;
  right: 0px;
  top: 0px;
  z-index: 0;
  background-image: url(finish.jpg);
  background-size: 50px;
}

button {
  padding: 30px;
  margin: 50px auto;
}