html,
body {
  padding: 0;
  margin: 0;
}

.my-header,
.my-footer {
  width: 100vw;
  height: 50px;
  line-height: 50px;
  color: black;
  text-align: left ;
}

.my-header {
  background: black;
  color: #fff;
}

.my-content {
  width: 100vw;
  height: calc(100vh - 100px);
  background: white;
  color: black;
  display: flex;
  justify-content: center;
  align-items: center;
}

.my-footer {
  background: #000000;
  color: #fff;
}