style.css

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  background-color: #4b4b4b;
  font-family: sans-serif;
  perspective: 1000px;
}

.content {
  background-color: #1b1b1b;
  border: 1px solid #1b1b1b;
  position: relative;
  padding-bottom: 5rem;
  transform-origin: center left;
  transition: transform 0.3s ease-in-out;
}

/* JavaScript */
.content.active {
  transform: translateX(200px) rotateY(20deg);
}

.container {
  max-width: 500px;
  margin: 0 auto;
  margin-top: 7rem;
  padding: 5rem;
  background: #292929;
  color: #fff;
}

.container h1 {
  margin-bottom: 5rem;
}

form {
  display: flex;
  flex-direction: column;
  justify-content: center;
}

form label {
  margin-bottom: 5px;
}

form label .special {
  color: #ffa31a;
}

form input {
  margin-bottom: 2rem;
  outline: none;
  height: 30px;
  padding: 15px;
}

.sidebar {
  background: #808080;
  color: #fff;
  padding: 10px 30px;
  position: fixed;
  top: 0;
  left: 0;
  width: 200px;
  height: 100%;
  transform: translateX(-200px);
  transition: transform 0.3s ease-in-out;
  z-index: 100;
}

/* JavaScript */
.sidebar.active {
  transform: translateX(0);
}

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

.sidebar ul li {
  margin: 20px 0;
}

.sidebar ul li a {
  color: #fff;
  text-decoration: none;
}

.sidebar ul li a:hover {
  text-decoration: underline;
}

.sidebar .menu .fa-bars {
  display: block;
}

.sidebar .menu .fa-times {
  display: none;
}

/* JavaScript */
.sidebar.active .menu .fa-bars {
  display: none;
}

.sidebar.active .menu .fa-times {
  display: block;
}

.menu {
  background-color: crimson;
  color: #fff;
  border: none;
  font-size: 16px;
  position: absolute;
  top: 0;
  right: -30px;
  height: 30px;
  width: 30px;
  outline: none;
}