html {
  box-sizing: border-box;
}

*, *::before, *::after {
  box-sizing: inherit; /* [1] */
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen-Sans,Ubuntu,Cantarell,"Helvetica Neue",sans-serif; /* [2] */
}

.header {
  width: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 80px;
  background-color: #525286;
  color: #FFFFFF;
  margin-bottom: 50px;
}

.container {
  width: 960px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-gap: 20px;
}

.socket {
  text-align: center;
  margin-bottom: 5px;
}

.button {
  height: 50px;
  line-height: 50px;
  width: 100%;
  text-decoration: none;
  text-align: center;
  font-size: 20px;
  box-shadow: 1px 1px black;
}