html {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(to right, #434343, #000000);
}

body {
  display: flex;
  max-width: 60vw;
  min-width: 600px;
  margin: 0 auto;
  flex-direction: column;
  align-items: center;
  margin-top: 50px;
  border: 4px solid black;
  background-color: #121212;
  color: rgba(255, 255, 255, 0.87);
}