style.css

* {
  padding: 0;
  margin: 2px;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: "Franklin Gothic Medium", "Arial Narrow", Arial, sans-serif;
}

.nav-bar {
  display: flex;
  margin-top: 10px;
  margin-bottom: 10px;
  padding-left: 20px;
  padding-right: 20px;
  width: 90%;
  border: 3px solid rgb(0, 0, 0);
}

.nav-bar.listBtn {
  cursor: pointer;
  transition: all 0.5s ease;
}

.nav-bar.listBtn :hover {
  transform: scale(0.98);
  color: aqua;
}

.nav-item {
  display: flex;
  margin-left: auto;
  margin-right: 30px;
}

.nav-item > ul {
  display: flex;
  margin-left: auto;
}

.nav-item > ul > li {
  display: flex;
  margin-right: 10px;
  align-items: center;
  list-style: none;
  cursor: pointer;
}

li > hr {
  border: 1px solid #000;
  align-items: center;
  height: 20px;
  margin-left: 5px;
}

li > a {
  font-size: 17px;
  font-weight: 400;
  line-height: 24px;
}

.nav-bar a {
  list-style-type: none;
  text-decoration: none;
}

.date_time {
  display: flex;
  justify-content: flex-end;
  margin-bottom: 30px;
  margin-top: -10px;
  margin-left: auto;
  margin-right: 7%;
  font-size: 18px;
  font-weight: 300;
  line-height: 24px;
}

section {
  width: 80%;
}

.booklist {
  display: none;
}

.addbooks {
  display: none;
}

.contact {
  display: none;
  max-width: 500px;
}

.active {
  display: block !important;
}

header {
  display: flex;
  background-color: #fff;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 100%;
  position: fixed;
  top: 0;
  left: 0;
}

.container {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 100%;
  margin-top: 200px;
  margin-bottom: 200px;
}

.container h2 {
  margin: 6px;
}

.list-section {
  width: 100%;
  border: 3px solid #000;
  padding-right: 5px;
}

.bookBlock {
  width: 100%;
  display: flex;
  font-size: 17px;
  font-weight: 400;
  line-height: 24px;
  padding-left: 20px;
  padding-right: 0;
  margin-bottom: 10px;
}

.bookBlock:nth-child(odd) {
  background-color: rgb(209, 208, 208);
}

.contact_header {
  text-align: center;
  margin-bottom: 20px;
}

.contact ul {
  max-width: 80%;
  margin: 20px 40px;
  margin-left: 100px !important;
  text-align: left;
  width: 90%;
}

.contact ul > li + li {
  margin-top: 10px;
}

form {
  display: flex;
  flex-direction: column;
  max-width: 400px;
  margin: auto;
}

form > * + * {
  margin-top: 20px;
}

.heading {
  font-size: 20px;
  font-weight: bold;
  text-align: center;
  margin-bottom: 10px;
}

input {
  border: 2px solid black;
  width: 100%;
}

button {
  border: 3px solid black;
  margin-bottom: 10px;
  align-self: flex-end;
  box-shadow: 2px 2px #000;
  background-color: #fff;
  padding: 5px 10px;
}

.remove-btn {
  height: 30px;
  font-size: 17px;
  font-weight: 400;
  line-height: 24px;
  border: 2px solid black;
  background-color: #fff;
  align-self: center;
  margin-top: 12px;
  margin-left: auto;
  margin-right: 18px;
  font-family: "Franklin Gothic Medium", "Arial Narrow", Arial, sans-serif;
  box-shadow: 3px 3px #000;
}

footer {
  display: flex;
  background-color: #fff;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  position: fixed;
  width: 100%;
  bottom: 0;
  left: 0;
}