body {
  font-family: 'Georgia', serif;
  margin: 0;
  background: #f4f4f4;
  color: #333;
}

#cover-page {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  height: 100vh;
  background: #007f3f;
  color: #fff;
  text-align: center;
}

#cover-page img {
  width: 250px;
  margin-bottom: 20px;
  border-radius: 10px;
  box-shadow: 0 4px 15px rgba(0,0,0,0.3);
}

#cover-page h1 {
  font-size: 2.5em;
  margin: 10px 0;
}

#cover-page h3 {
  margin-bottom: 30px;
}

#cover-page button {
  padding: 12px 25px;
  font-size: 18px;
  border: none;
  background: #fff;
  color: #007f3f;
  font-weight: bold;
  border-radius: 5px;
  cursor: pointer;
}

#cover-page button:hover {
  background: #eee;
}

#book-content {
  display: none;
  max-width: 800px;
  margin: 0 auto;
  padding: 20px;
}

.author img {
  width: 150px;
  border-radius: 50%;
  margin: 15px auto;
  display: block;
}

section.chapter {
  margin-bottom: 40px;
}

h2 {
  text-align: center;
  color: #007f3f;
}

footer {
  text-align: center;
  margin: 30px 0;
  color: #555;
}