body {
  margin: 0;
  font-family: system-ui, sans-serif;
  background: #f4f4f4;
  color: #222;
  text-align: center;
  transition: background 0.3s, color 0.3s;
}

body.dark {
  background: #121212;
  color: #eee;
}

.container {
  max-width: 600px;
  margin: auto;
  padding: 2rem;
}

.container section {
  text-align: left;
  margin-bottom: 1.5rem;
  line-height: 1.6;
  font-size: 1rem;
  color: inherit;
}

.container section h2 {
  margin-top: 0;
  margin-bottom: 0.5rem;
  font-weight: 700;
  font-size: 1.2rem;
}

.container section p {
  margin: 0 0 1rem 0;
}

.container section p:last-child {
  margin-bottom: 0;
}

.avatar {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  margin-bottom: 1rem;
}

.links a {
  display: inline-block;
  margin: 0.5rem;
  text-decoration: none;
  color: #0066cc;
  font-weight: bold;
  transition: color 0.3s;
}

.links a:hover {
  color: #004a99;
}

body.dark .links a {
  color: #66b2ff;
}

body.dark .links a:hover {
  color: #3399ff;
}

.books {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-top: 1rem;
}

.books a {
  display: flex;
  align-items: center;
  gap: 1rem;
  text-decoration: none;
  background: white;
  padding: 1rem;
  border-radius: 10px;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
  color: inherit;
  transition: background 0.3s;
}

.books a:hover {
  background: #eaeaea;
}

body.dark .books a {
  background: #1e1e1e;
  box-shadow: 0 2px 5px rgba(255, 255, 255, 0.05);
}

body.dark .books a:hover {
  background: #2a2a2a;
}

.books img {
  width: 60px;
  height: auto;
  border-radius: 5px;
}

.book-text {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  text-align: left;
  flex: 1;
}

.books .title {
  font-weight: bold;
  margin: 0;
}

.amazon-link {
  font-size: 0.9rem;
  color: #0066cc;
  margin: 0.2rem 0 0;
}

body.dark .amazon-link {
  color: #66b2ff;
}

.impressum section a,
.impressum section a:visited {
  color: #0066cc;
  transition: color 0.3s;
}

.impressum section a:hover,
.impressum section a:focus {
  color: #004a99;
}

body.dark .impressum section a,
body.dark .impressum section a:visited {
  color: #66b2ff;
}

body.dark .impressum section a:hover,
body.dark .impressum section a:focus {
  color: #3399ff;
}

.back-button {
  text-align: center;
  margin-top: 2em;
  margin-bottom: 0;
}

.back-button .btn {
  display: inline-block;
  background-color: #333;
  color: #fff;
  padding: 0.6em 1.2em;
  border-radius: 6px;
  text-decoration: none;
  transition: background 0.3s;
}

.back-button .btn:hover {
  background-color: #555;
}

.footer {
  text-align: center;
  font-size: 0.85rem;
  color: #888;
  margin: 1rem 0 0;
  padding: 0.5rem 0;
  border-top: 1px solid #ccc;
}

body.dark .footer {
  color: #aaa;
  border-top: 1px solid #444;
}

.footer a {
  color: #0066cc;
  text-decoration: none;
}

.footer a:hover {
  text-decoration: underline;
}

body.dark .footer a {
  color: #66b2ff;
}

@media (max-width: 500px) {
  .books a {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }

  .book-text {
    align-items: center;
    text-align: center;
  }
}