#app{
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
    box-sizing: border-box;
}
.box{
    position: relative;
    width: 60%;
    height: 650px;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
    padding: 20px 10px;
    box-sizing: border-box;
}
#app img{
    /* float: left; */
    width: 30%;
    height: auto;
    transition: all 0.6s;
}
#app img:nth-child(5):hover{
    /* opacity: .8; */
    transform: scale(0.9);
    cursor: pointer;
    transition: all 0.6s;
}
.bright{
  opacity: 1;
  filter: brightness(100%);
  -webkit-filter: brightness(100%);
}
.dark{
  opacity: 1;
  filter: brightness(50%);
  -webkit-filter: brightness(50%);
}


@media (max-width: 768px) {
  .box {
    width: 100%;
    height: auto;
  }
}