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

body {
  background: #fff;
  display: flex;
  min-height: 100vh;
  flex-direction: column;
  line-height: 2rem;
}

h1,
h2,
h3,
#date-time {
  color: #6290c3;
}

.container {
  flex: 1;
}

.book-container:nth-child(odd) {
  background: #f9f9f9;
}

.btn {
  background: #495867;
  color: #fff;
  box-shadow: 2px 2px 2px #000;
  transition: 0.5s;
}

.btn:hover {
  background: #577399;
  color: #fff;
}

.add-btn {
  float: right;
}

.add-book,
.contact {
  margin-top: 120px;
}