style.css

* {
  font-family: Verdana, Geneva, Tahoma, sans-serif;
}

.heading {
  text-align: center;
}

input[type="text"] {
  border: 1px solid black;
  border-radius: 2px;
  margin-bottom: 10px;
  padding: 4px 6px;
  width: 100%;
  box-sizing: border-box;
}

.book-list {
  border: 3px solid black;
  margin-bottom: 10px;
  height: 60vh;
  overflow-y: scroll;
}

.book-list div {
  display: flex;
  flex-direction: row;
  justify-content: space-between;
  box-sizing: border-box;
  padding: 2px 5px;
}

.book-list div:nth-child(odd) {
  background-color: rgba(200, 200, 200, 0.4);
}

button {
  all: unset;
  border: 3px solid black;
  padding: 4px 12px;
}

form {
  margin: 20px auto;
  display: flex;
  flex-direction: column;
  box-sizing: border-box;
  width: 50%;
}

button.btn {
  display: flex;
  align-self: flex-end;
  width: 40px;
}

nav {
  outline: 1px solid black;
  justify-content: space-between;
  padding: 2px 30px;
}

nav,
.main-links {
  display: flex;
  flex-direction: row;
  box-sizing: border-box;
}

nav p {
  font-weight: bold;
}

.main-links {
  padding: 2px 10px;
}

.main-links li {
  list-style: none;
  padding: 0 20px;
}

.main-links li .middle {
  border-left: 1px solid black;
  border-right: 1px solid black;
  padding: 0 20px;
}

.main-links li a {
  text-decoration: none;
  color: black;
}

div#date {
  display: flex;
  flex-direction: row;
  justify-content: flex-end;
  margin-top: 10px;
  margin-bottom: 20px;
}

footer {
  border: 1px solid black;
  padding: 15px 20px;
  position: relative;
  box-sizing: border-box;
  bottom: 0;
  text-align: center;
}

/* add book page style */
.add-book {
  padding: 50px 0;
  text-align: center;
  margin-bottom: 30px;
  height: 50vh;
}

.add-book h1 {
  margin-bottom: 50px;
}

/* contact info style */
.contact-info {
  padding: 50px 15%;
  margin-bottom: 30px;
  height: 50vh;
}

.contact-info h2 {
  text-align: center;
  margin-bottom: 30px;
}

.contact-info ul li {
  padding: 5px 0;
}

/* dynamically assigned styles */
li a.active {
  color: blue;
}

.hide {
  display: none;
}

.reveal {
  display: block;
}