div.accordion-basic div.container{
  position: relative;
  margin:2em;
}
div.accordion-basic input{
  position: absolute;
  left: 0;
  top: 0;
  height: 100%;
  width: 100%;
  opacity:0;
  visibility: 0;
}
div.accordion-basic h4{
  background:steelblue;
  color:white;
  padding:1em;
  position: relative;
}
div.accordion-basic label::before{
  content:"";
  display: inline-block;
  border: 15px solid transparent;
  border-left:20px solid white;
}
div.accordion-basic label{
  cursor: pointer;
  position: relative;
  display: flex;
  align-items: center;
}
div.accordion-basic div.paragraph{
  max-height:0px;
  overflow: hidden;
  transition:max-height 0.5s;
  background-color: white;
  box-shadow:0 0 10px 0 rgba(0, 0, 0, 0.2);
}
div.accordion-basic div.paragraph p {
  padding:2em;
}
div.accordion-basic input:checked ~ h4 label::before{
  border-left:15px solid transparent;
  border-top:20px solid white;
  margin-top:12px;
  margin-right:10px;
}
div.accordion-basic input:checked ~ h4 ~ div.paragraph{
  max-height:100px;
}