<style>
.boxbtn {
  /*background-color: #4CAF50;*/
  /*color: white;*/
  /*padding: 16px;*/
  /*font-size: 16px;*/
  /*border: none;*/
}

.tool-box {
  position: relative;
  display: inline-block;
  font-size: 20px;
  left: 290px;
  width: 100%;
}

.tool-box-content {
  display: none;
  position: absolute;
  background-color: #f1f1f1;
  box-shadow: 0px 20px 16px 0px rgba(0,0,0,0.2);
  z-index: 1;
}

.tool-box-content a {
  color: black;
  padding: 15px 16px;
  text-decoration: none;
  display: block;
  font-size: 15px;
}

.tool-box-content a:hover {background-color: #ddd; text-decoration: none;}

.tool-box:hover .tool-box-content {display: block;}

.tool-box:hover .boxbtn {background-color: grey;}