body {
  margin: 0;
  font-family: Arial, sans-serif;
}

.side-menu {
  position: fixed;
  top: 0;
  left: 0;
  height: 1000px;
  width: 50px;
  background-color: #888888;
  overflow-x: hidden;
  transition: width 0.3s ease;
  color: white;
}

.side-menu:hover {
  width: 200px;
}

.menu-label {
  writing-mode: vertical-rl;
  text-orientation: mixed;
  padding: 20px 10px;
  font-weight: bold;
  cursor: pointer;
  user-select: none;
  transition: opacity 0.3s ease;
}

.side-menu:hover .menu-label {
  opacity: 0;
  pointer-events: none;
}

.side-menu:hover .menu-list {
  display: block;
}

.menu-list {
  display: none;
  margin: 20px 0 0 10px;
  padding: 0;
  list-style: none;
}

.menu-list li {
  margin: 15px 0;
}

.menu-list button {
  width: 150px;
  padding: 10px 15px;
  background-color: #aaa;
  border: none;
  border-radius: 5px;
  cursor: pointer;
  color: black;
  font-size: 14px;
  transition: background-color 0.2s ease, color 0.2s ease;
}

.menu-list button:hover {
  background-color: orange;
  color: white;
}