<div id="app-idea">A popup modal open and close without using JavaScript</div>
<div id="cover">
  <input type="checkbox" id="checkbox">
  <div id="label">Open the popup</div>
  <div id="modal">Do you accept Jesus Christ as your Lord and Savior?</div>
  <div id="yep">i accept</div>
</div>

* {
  outline: none;
}

body {
  margin: 0px;
  font-family: Roboto;
  background-color: #2196f3;
}

#app-idea {
  text-align: center;
  padding: 20px;
  padding-bottom: 25px;
  font-size: 32px;
  color: #fff;
  font-weight: bold;
  border-bottom: 1px solid #1978c4;
}

#cover {
  width: 188px;
  margin: 110px auto;
  position: relative;
}

#checkbox {
  position: absolute;
  top: 0px;
  left: 0px;
  width: 100%;
  height: 100%;
  margin: 0px;
  opacity: 0;
  cursor: pointer;
  z-index: 1;
}

#label {
  font-size: 20px;
  text-align: center;
  padding: 20px;
}

#label:after {
  content: "";
  position: fixed;
  top: 0px;
  left: 0px;
  width: 0px;
  height: 0px;
  background-color: #2196f3;
  z-index: 1;
}

#modal {
  right: 0px;
  left: 0px;
  max-width: 460px;
  font-size: 42px;
  padding: 25px;
  margin: 0 auto;
  border: 10px solid #f5f5f5;
}

#yep {
  width: 93px;
  font-size: 20px;
  text-align: center;
  text-transform: uppercase;
  padding: 20px;
  cursor: pointer;
}

#label,
#modal,
#yep {
  background-color: #fff;
  border-radius: 2px;
  box-shadow: 0px 20px 40px #1462a1;
}

#modal,
#yep {
  position: fixed;
  color: #2196f3;
  font-weight: bold;
  transform: scale(0);
  transition: 0.2s cubic-bezier(0, 0.79, 0.52, 1.28) transform;
  z-index: 1;
}

#checkbox:checked {
  left: auto;
  width: 133px;
  height: 64px;
  z-index: 3;
}

#yep,
#checkbox:checked {
  position: fixed;
  right: 30px;
}

#modal,
#yep,
#checkbox:checked {
  top: 114px;
}

#checkbox:checked + #label:after {
  width: 100%;
  height: 100%;
}

#checkbox:checked ~ #modal,
#checkbox:checked ~ #yep {
  transform: scale(1);
  z-index: 2;
}