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

html, body {
  font-size: 62.5%;
}

body {
  background: #F2E274;
  font-family: "Open Sans", Helvetica, Arial, sans-serif;
}

.demo {
  z-index: 1;
  overflow: hidden;
  position: absolute;
  left: 50%;
  top: 50%;
  width: 26rem;
  height: 44rem;
  margin-left: -13rem;
  margin-top: -22rem;
  border-radius: 0.5rem;
  background: #fff;
  box-shadow: 0.3rem 0.5rem 0.5rem rgba(0, 0, 0, 0.2);
}
.demo__overlay {
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.15);
  pointer-events: none;
  opacity: 0;
  -webkit-transition: opacity 0.4s 0.35s;
          transition: opacity 0.4s 0.35s;
}
.demo.menu-active .demo__overlay {
  opacity: 1;
  -webkit-transition: opacity 0.4s 0.4s;
          transition: opacity 0.4s 0.4s;
}
.demo__menu-btn {
  z-index: 3;
  position: absolute;
  left: 2rem;
  top: 2rem;
  width: 2.4rem;
  height: 1.6rem;
  -webkit-transition: -webkit-transform 0.4s 0.75s;
          transition: transform 0.4s 0.75s;
  cursor: pointer;
  -webkit-transform: translate3d(0, 0, 0);
          transform: translate3d(0, 0, 0);
}
.demo.menu-active .demo__menu-btn {
  -webkit-transition: -webkit-transform 0.4s;
          transition: transform 0.4s;
  -webkit-transform: translate3d(-2rem, 0, 0);
          transform: translate3d(-2rem, 0, 0);
}
.demo__menu-btn-line {
  position: absolute;
  left: 0;
  width: 100%;
  height: 0.2rem;
  background: #879BAF;
  -webkit-transition: width 0.4s 0.75s, -webkit-transform 0.4s 0.35s;
          transition: width 0.4s 0.75s, transform 0.4s 0.35s;
  -webkit-transform: translate3d(0, 0, 0);
          transform: translate3d(0, 0, 0);
}
.demo.menu-active .demo__menu-btn-line {
  width: 26rem;
  -webkit-transition: width 0.4s, -webkit-transform 0.4s 0.32s;
          transition: width 0.4s, transform 0.4s 0.32s;
}
.demo__menu-btn-line:nth-child(1) {
  top: 0;
}
.demo.menu-active .demo__menu-btn-line:nth-child(1) {
  -webkit-transform: translate3d(0, 4rem, 0);
          transform: translate3d(0, 4rem, 0);
}
.demo__menu-btn-line:nth-child(2) {
  top: 0.7rem;
}
.demo.menu-active .demo__menu-btn-line:nth-child(2) {
  -webkit-transform: translate3d(0, 9.5rem, 0);
          transform: translate3d(0, 9.5rem, 0);
}
.demo__menu-btn-line:nth-child(3) {
  top: 1.4rem;
}
.demo.menu-active .demo__menu-btn-line:nth-child(3) {
  -webkit-transform: translate3d(0, 15rem, 0);
          transform: translate3d(0, 15rem, 0);
}
.demo__menu-bg {
  z-index: 1;
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 24.8rem;
  background: #fff;
  border-bottom: 0.2rem solid #879BAF;
  -webkit-transform: scaleY(0.3);
      -ms-transform: scaleY(0.3);
          transform: scaleY(0.3);
  -webkit-transform-origin: 50% 0;
      -ms-transform-origin: 50% 0;
          transform-origin: 50% 0;
  opacity: 0;
  -webkit-transition: opacity 0.2s 0.55s, -webkit-transform 0.4s 0.35s;
          transition: opacity 0.2s 0.55s, transform 0.4s 0.35s;
  pointer-events: none;
}
.demo.menu-active .demo__menu-bg {
  pointer-events: auto;
  -webkit-transform: scaleY(1);
      -ms-transform: scaleY(1);
          transform: scaleY(1);
  opacity: 1;
  -webkit-transition: opacity 0.2s 0.4s, -webkit-transform 0.4s 0.4s;
          transition: opacity 0.2s 0.4s, transform 0.4s 0.4s;
}
.demo__menu-items {
  z-index: 2;
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  pointer-events: none;
}
.demo.menu-active .demo__menu-items {
  pointer-events: auto;
}
.demo__menu-item {
  height: 6rem;
  padding-left: 2rem;
  margin-bottom: 0.2rem;
  font-size: 1.8rem;
  line-height: 6rem;
  color: #7F91A4;
  background-color: rgba(127, 145, 164, 0);
  opacity: 0;
  -webkit-transform: translateX(-1rem);
      -ms-transform: translateX(-1rem);
          transform: translateX(-1rem);
  -webkit-transition: opacity 0.2s 0.15s, -webkit-transform 0.2s 0.15s;
          transition: opacity 0.2s 0.15s, transform 0.2s 0.15s;
  cursor: pointer;
}
.demo__menu-item.clicked {
  -webkit-animation: menuItemClicked 0.3s;
          animation: menuItemClicked 0.3s;
}
.demo.menu-active .demo__menu-item {
  opacity: 1;
  -webkit-transform: translateX(0);
      -ms-transform: translateX(0);
          transform: translateX(0);
}
.demo.menu-active .demo__menu-item:nth-child(1) {
  -webkit-transition: opacity 0.2s 0.4s, -webkit-transform 0.2s 0.4s;
          transition: opacity 0.2s 0.4s, transform 0.2s 0.4s;
}
.demo.menu-active .demo__menu-item:nth-child(2) {
  -webkit-transition: opacity 0.2s 0.55s, -webkit-transform 0.2s 0.55s;
          transition: opacity 0.2s 0.55s, transform 0.2s 0.55s;
}
.demo.menu-active .demo__menu-item:nth-child(3) {
  -webkit-transition: opacity 0.2s 0.7s, -webkit-transform 0.2s 0.7s;
          transition: opacity 0.2s 0.7s, transform 0.2s 0.7s;
}
.demo.menu-active .demo__menu-item:nth-child(4) {
  -webkit-transition: opacity 0.2s 0.85s, -webkit-transform 0.2s 0.85s;
          transition: opacity 0.2s 0.85s, transform 0.2s 0.85s;
}
.demo__section {
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  padding: 7rem 2rem 0;
  opacity: 0;
  -webkit-transition: opacity 0.4s;
          transition: opacity 0.4s;
  pointer-events: none;
}
.demo__section:after {
  content: "";
  position: absolute;
  left: 1rem;
  bottom: 1rem;
  width: 24rem;
  height: 17rem;
  border-radius: 0.5rem;
  background: #E7F6FB;
}
.demo__section.active-section {
  opacity: 1;
  pointer-events: auto;
}
.demo__section-heading {
  margin-bottom: 1.5rem;
  text-align: center;
  font-size: 2.2rem;
  text-transform: uppercase;
}
.demo__description {
  text-align: center;
  font-size: 1.5rem;
}

@-webkit-keyframes menuItemClicked {
  0% {
    background-color: #7F91A4;
  }
  100% {
    background-color: rgba(127, 145, 164, 0);
  }
}

@keyframes menuItemClicked {
  0% {
    background-color: #7F91A4;
  }
  100% {
    background-color: rgba(127, 145, 164, 0);
  }
}