.useful{background-color:#e8e8e8;display:flex;flex-wrap:wrap;height:100vh;align-items:start;align-content:start}.useful h1{padding:100px;font-size:40px}.useful .useful-box{width:100%;display:flex;flex-wrap:wrap;justify-content:center}.useful .useful-box a{position:relative;display:inline-block;width:450px;margin:20px}.useful .useful-box a div img{border-radius:15px}.useful .useful-box a div p{position:absolute;top:0;left:0;width:50%;height:50px;font-size:15px;background-color:rgba(0,0,0,.5);color:#fff;display:flex;justify-content:center;align-items:center;opacity:0;transition:opacity .3s ease;border-radius:15px 0 15px 0}.useful .useful-box a:hover div p{opacity:1}