* {
  box-sizing: border-box;
}

html, body {
    height: 100%;
}

body {
    margin: 0;
    min-height: 100vh;

    display: flex;
    flex-direction: column;

    background: #121212;
    color: #f5f5f5;
}

.site-header {
  padding: 40px 20px 25px;
  text-align: center;
  background: #1e1e1e;
  border-bottom: 1px solid #444;
}

.site-header h1 {
  margin: 0 0 20px;
  font-size: 2.4rem;
  font-weight: 600;
  color: #f5f5f5;
}

nav {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 22px;
}

nav a {
  color: #f5f5f5;
  text-decoration: none;
  font-size: 1rem;
  border-bottom: 2px solid transparent;
  padding-bottom: 4px;
}

nav a:hover {
  border-bottom-color: #f5f5f5;
}

main {
  flex: 1;
  width: 100%;
  max-width: none;
  margin: 80px 0;
  padding: 0 40px;
}

.intro {
  background: #1e1e1e;
  padding: 45px;
  border-radius: 16px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.06);
}

.intro h2 {
  margin-top: 0;
  font-size: 2rem;
  color: #f5f5f5;
}

.intro p {
  font-size: 1.1rem;
  line-height: 1.7;
  color: #f5f5f5;
}

footer {
  text-align: center;
  padding: 35px 20px;
  color: #aaa;
}

.social-links a {
  color: #f5f5f5;
  text-decoration: none;
}

.social-links a:hover {
  text-decoration: underline;
}

html {
  scroll-behavior: smooth;
}

.book {
    display: flex;
    gap: 40px;
    align-items: flex-start;
    margin-top: 40px;
}

.book-cover {
    flex: 0 0 220px;
}

.book-cover img {
    width: 100%;
    border-radius: 12px;
}

.book-content {
    flex: 1;
}

.book-content h3 {
    margin-top: 0;
}

.book-content h4 {
    margin-top: 40px;
}

.book-list {
    background: #222;
    border: 1px solid #3b3b3b;
    border-radius: 10px;
    padding: 24px;
    margin: 30px 0;
}

.book-list h3 {
    margin-top: 0;
}

.book-list p {
    color: #bdbdbd;
    margin-bottom: 18px;
}

.book-list ul {
    list-style: none;
    padding: 0;
    margin: 0;

    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 10px 24px;
}

.book-list li {
    margin: 0;
}

.book-list a {
    display: block;
    padding: 8px 12px;
    color: #e5e5e5;
    text-decoration: none;
    border-radius: 6px;
    transition: background 0.2s ease;
}

.book-list a:hover {
    background: #333;
}