body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  line-height: 1.6;
  background-color: #f9f9f9;
  color: #333;
}

/* Sidebar Navigation */
#navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 250px;
  height: 100%;
  background: #24292e; /* GitHub dark gray */
  padding: 20px;
  box-sizing: border-box;
  overflow-y: auto;
}

#navbar header {
  font-size: 20px;
  font-weight: bold;
  color: #fff;
  margin-bottom: 20px;
}

#navbar .nav-link {
  display: block;
  color: #ddd;
  text-decoration: none;
  margin: 8px 0;
  padding: 6px 10px;
  border-radius: 5px;
  transition: background 0.3s ease;
}

#navbar .nav-link:hover {
  background: #0366d6; /* GitHub blue */
  color: #fff;
}

/* Main Content Area */
#main-doc {
  margin-left: 270px; /* leave space for sidebar */
  padding: 20px 40px;
  max-width: 900px;
}

#main-doc header h2 {
  border-bottom: 2px solid #0366d6;
  padding-bottom: 5px;
  margin-top: 40px;
  color: #24292e;
}

#main-doc pre {
  background: #eee;
  padding: 10px;
  border-radius: 6px;
  overflow-x: auto;
}

/* Footer */
footer {
  text-align: center;
  margin: 40px 0;
  font-size: 14px;
  color: #777;
}

/* Responsive Design */
@media screen and (max-width: 768px) {
  #navbar {
    position: relative;
    width: 100%;
    height: auto;
  }

  #main-doc {
    margin-left: 0;
    padding: 15px;
  }
}