style.css

:root {
  --primary-color: #b0daff;
  --secondary-color: #0f1420;
  --tertiary-color: #0a0e16;
  --text-color: #e0f4fc;
  --secondary-text-color: #7a858a;
}

* {font-family: 'Courier New', Courier, monospace;}

body {
  margin: 0;
  padding: 0;
  color: var(--primary-color);
  overflow-x: hidden;
  background-color: var(--secondary-color);
}

header {
  padding: 20px;
}

nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: var(--tertiary-color);
  padding: 25px;
  border-radius: 30px;
  box-shadow: rgba(0, 0, 0, 0.2) 0px 0px 8px 0px;
}

nav a {
  font-size: 24px;
  font-weight: bold;
  color: var(--primary-color);
  text-decoration: none;
}

nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
}

nav ul li {
  margin-left: 20px;
}

nav ul li a {
  color: var(--primary-color);
  text-decoration: none;
}

.article {
  text-align: justify;
  margin-left: auto;
  margin-right: auto;
  margin-bottom: 10px;
  width: 80%;
  
  color: var(--text-color);
}

hr {
  border: solid #e0e0e0 1px;
}

.header-text {
  color: var(--primary-color);
  margin-top: 50px;
  text-align: center;
}

.header-text h1 {
  font-size: 48px;
  font-weight: bold;
  margin-bottom: 20px;
}

.header-text p {
  font-size: 24px;
  margin-bottom: 40px;
}

.search-container {
  display: flex;
  justify-content: center;
}

.search-container form {
  display: flex;
  align-items: center;
  width: 500px;
  background-color: var(--tertiary-color);
  border-radius: 24px;
  box-shadow: rgba(0, 0, 0, 0.2) 0px 0px 20px 10px;
}

.search-container input[type="text"] {
  flex: 1;
  padding: 12px 24px;
  border: none;
  font-size: 16px;
  border-radius: 24px 0px 0px 24px;
  outline: none;
  background-color: var(--tertiary-color);
  color: var(--text-color);
}

.search-container button[type="submit"] {
  background-color: var(--tertiary-color);
  border: none;
  color: var(--text-color);
  padding: 12px 16px;
  font-size: 16px;
  cursor: pointer;
  border-radius: 0px 24px 24px 0px;
  transition: all 0.3s ease;
}

.search-container button[type="submit"]:hover {
  background-color: #010101;
}

footer {
  background-color: var(--tertiary-color);
  color: var(--primary-color);
  padding: 20px;
  text-align: center;
  bottom: 0;
  width: 100%;
  box-shadow: rgba(0, 0, 0, 0.2) 0px -2px 8px 0px;
}

table {
  border-collapse: collapse;
  padding: 7px;
  width: 100%
}

td, th {
  border: 2px solid #c9c9c9;
  background-color: var(--tertiary-color);
  text-align: center;
  padding: 10px;
}

code {
  font-family: 'Courier New', Courier, monospace;
  background-color: var(--tertiary-color);
  border-radius: 4px;
}

.logomark {
  width: 70px;
  margin-bottom: -10px;
}

.logomark, .logotype h1 {
  display: inline-block;
  color: #0a0e16;
}

#isbn-info {
  text-align: justify;
  margin-left: auto;
  margin-right: auto;
  margin-bottom: 20px;
  margin-top: 30px;
  width: 650px;
  opacity: 0;
  visibility: hidden;
  transition: 200ms ease;
}

#isbn-info.show {
  opacity: 1;
  visibility: visible;
}

#isbn-content {
  text-align: left;
  background-color: var(--tertiary-color);
  border-radius: 24px;
  color: var(--text-color);
  box-shadow: rgba(0, 0, 0, 0.2) 0px 0px 20px 10px;
  padding: 50px;
  min-height: 250px;
}

#isbn-details p {
  margin: 9px 0px;
  font-size: 18px;
  padding: 0;
}

#isbn-details a, #isbn-details a:visited, #isbn-details a:hover {
  color: var(--primary-color);
}

#isbn-x {
  cursor: pointer;
  color: var(--secondary-text-color);
}

#isbn-cover {
  height: 250px;
  margin-left: 15px;
  float: right;
}

#isbn-text {
  color: var(--secondary-text-color);
}