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

.menu-btn {
  display: flex;
  flex-direction: column;
  cursor: pointer;
  padding: 10px;
}

.bar {
  width: 30px;
  height: 3px;
  background-color: #333;
  margin: 3px 0;
  transition: 0.4s;
}

.menu {
  position: fixed;
  top: 0;
  left: -250px;
  width: 250px;
  height: 100%;
  background-color: #f0f0f0;
  box-shadow: 2px 0px 10px rgba(0, 0, 0, 0.2);
  transition: 0.4s;
}

.menu ul {
  list-style: none;
  padding: 0;
  margin: 30px 0 0 0;
}

.menu li {
  padding: 10px;
}

.menu a {
  text-decoration: none;
  color: #333;
  font-weight: bold;
  font-size: 18px;
}

.menu-btn.open .bar:nth-child(1) {
  transform: rotate(-45deg) translate(-5px, 6px);
}

.menu-btn.open .bar:nth-child(2) {
  opacity: 0;
}

.menu-btn.open .bar:nth-child(3) {
  transform: rotate(45deg) translate(-5px, -6px);
}

.menu.open {
  left: 0;
}