           opacity: 0;
        }
        .cur .div4 {
            opacity: 1;
            transform: translateY(0);
            transition: all 1s;
        }
    </style>
</head>
<body>
    <div class="wp">
        <div class="wp-inner">
            <div class="page page1">
                <div class="div1">1</div>
            </div>
            <div class="page page2">
                <div class="div2">2</div>
            </div>
            <div class="page page3">
                <div class="div3">3</div>