* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

#changeGreet {
  max-width: 600px;
  width: 100%;
  margin: 30px auto;
  padding: 30px 0;
  text-align: center;
  border: 1px solid #ccc;
}
#changeGreet p {
  margin-bottom: 30px;
  font-size: 1.4em;
}
#changeGreet button {
  padding: 8px 16px;
  font-size: 1.1em;
  cursor: pointer;
  background: #00008b;
  color: #ffffff;
  box-shadow: 2px 2px 4px #333;
}
#changeGreet button:hover {
  background: #00488b;
}
#changeGreet button:active {
  transform: translateY(2px);
  box-shadow: 0 0 1px #333;
}