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

/*html {
  font: 18px/1.65 sans-serif;
  text-align: center;
}*/

li {
  list-style-type: none;
}

a {
  text-decoration: none;    
  display: block;
  color: #333;
}

h2 {
  color: #333;
  padding: 10px 0;
}

.filter {
  margin: 30px 0 10px;
}

.filter a {
  display: inline-block;
  padding: 10px;
  position: relative;
  margin-right: 20px;
  margin-bottom: 20px;
  color: #fff;
}

.boxes {
  display: flex;
  flex-wrap: wrap;
}

.boxes a {
  width: 23%;
  border: 2px solid #fff;
  margin: 0 1% 20px 1%;
  line-height: 60px;
}

.all {
  background:  #0c6e59;

}

.green {
  background: #0c6e59;
}

.blue {
  background: lightblue;
}

.red {
  background: lightcoral;
}

.filter a.active:before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  display: inline-block;
  width: 0;
  height: 0;
  border-style: solid;
  border-width: 15px 15px 0 0;
  border-color: #fff transparent transparent transparent;
}

.is-animated {
  animation: .6s zoom-in;
}

@keyframes zoom-in {
  0% {
   transform: scale(.1);
  } 
  100% {
    transform: none;
  }
}