body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  margin: 0;
  padding: 0;
  background-color: #f0f8ff;
  display: flex;
}

nav {
  background-color: #a2d9ff;
  color: #fff;
  width: 250px;
  height: 100vh;
  padding: 20px;
  box-sizing: border-box;
  position: fixed;
  top: 0;
  left: 0;
  transition: left 0.3s ease, transform 0.3s ease;
  z-index: 100;
  box-shadow: 3px 0 7px rgba(0, 0, 0, 0.1);
  border-radius: 0 15px 15px 0;
  overflow: hidden;
  transform-style: preserve-3d;
}

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

nav li {
  margin-bottom: 10px;
}

nav a {
  color: #fff;
  text-decoration: none;
  display: block;
  padding: 12px 15px;
  border-radius: 20px;
  transition: background-color 0.3s ease, transform 0.3s ease;
  margin: 5px 0;
  transform-style: preserve-3d;
}

nav a:hover {
  background-color: #29b6f6;
  transform: translateX(3px) translateZ(5px);
  box-shadow: 2px 2px 5px rgba(0, 0, 0, 0.2);
}

#content {
  padding: 20px;
  flex: 1;
  margin-left: 250px;
  transition: margin-left 0.3s ease;
}

nav.hidden {
  left: -250px;
  transform: translateX(0);
}

#content.hidden {
  margin-left: 0;
}

@media (max-width: 768px) {
  nav {
    width: 200px;
    left: -200px;
    border-radius: 0;
  }

  #content {
    margin-left: 0;
  }

  nav.hidden {
    left: 0;
  }

  #content.hidden {
    margin-left: 200px;
  }
}