.flex-container {
  padding: 0;
  margin: 0;
  list-style: none;
  /* max-height: 400px; */
  /* height:500px; */
  display: -webkit-box;
  display: -moz-box;
  display: -ms-flexbox;
  display: -webkit-flex;
  display: flex;
  -webkit-flex-flow: column wrap;
  justify-content: space-around;
  flex-direction: column;
}

.flex-item {
  display: flex;
}

.ex-col {
  width: 100%;
  max-width: 420px;
  /* background: white; */
  padding: 20px;
  color: #555;

}

.ex-col h2 {
  font-size: 1.1em;
  line-height: 1.3em;
  text-align: center;
  font-weight: bold;
  margin: 0 0 10px;
  padding: 0 0 10px;
  border-bottom: 1px solid slategray;
  width: 100%;
  font-weight: bold;
  color: white;
}

.ex-col h2>small {
  display: block;
  font-size: .9rem;
  line-height: 1.3rem;
  font-weight: normal;
  color: white;
}

.ex-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-gap: 10px;
  color: white;
}


/* The list item element. Must be FLEX */

.ex-list>li {
  display: flex;
  align-items: center;
  min-height: 70px;
}


/* The list heading element */

.ex-list h3 {
  font-size: 1em;
  line-height: 1.4em;
  padding: 6px 8px;
  border: 1px solid slategray;
  display: flex;
  align-items: center;
  /*  Set flex size to 50% of the parent element width.
              This is a good way to make sure it is always 50% */
  flex-basis: 100%;
  max-width: 50%;
  cursor: pointer;
  margin: 0;
}

.ex-list h3>small {
  font-size: .6em;
  line-height: 1em;
  color: lightgray;
  margin: 0 0 0 .5em;
}


/* The sub-menu element. Initial state is display:none */

.ex-list-sub {
  display: none;
  list-style: none;
  padding: 0 0 0 20px;
  margin: 0;
  position: relative;
  flex-basis: 100%;
  max-width: 100%;
  /* width: 80px; */
  transition: opacity .4s ease-out;
  border: 1px solid gray;
  border-left: none;
  font-size: .8em;
}

.ex-list-sub:before {
  content: "";
  display: block;
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  width: 10px;
  background: gray;
}

.ex-list-sub>li:not(:first-child) {
  border-top: 1px solid gray;
}

.ex-list-sub>li>a {
  display: block;
  /* padding: 6px 8px; */
  color: inherit;
  text-decoration: none;
  transition: background .2s;
}

.ex-list-sub>li>a:hover {
  background: #efefef;
}


/* THE HOVER ACTION */


/*  Set the hover on the parent element.
            Has to be the parent because otherwise the pop-up would disappear when you hover over it */

.ex-list>li:hover .ex-list-sub {
  display: block;
}