* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'fangsong';
        }

        body {
            height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            background-color: rgb(0, 0, 0);
        }

        .item {
            position: relative;
            margin: 50px;
            width: 300px;
            height: 80px;
            text-align: center;
            line-height: 80px;
            text-transform: uppercase;
            text-decoration: none;
            font-size: 35px;
            letter-spacing: 5px;
            color: aqua;
            overflow: hidden;
            -webkit-box-reflect: below 1px linear-gradient(transparent, rgba(6, 133, 133, 0.3));
        }

        .item:hover {
            background-color: aqua;
            box-shadow: 0 0 5px aqua,
                0 0 75px aqua,
                0 0 155px aqua;
            color: black;
        }

        .item span:nth-of-type(1) {
            position: absolute;
            left: -100%;
            width: 100%;
            height: 3px;
            background-image: linear-gradient(to left, aqua, transparent);
            animation: btnanmaiton 1s linear infinite;
        }

        @keyframes btnanmaiton {
            0% {
                left: -100%;
            }

            50%,
            100% {
                left: 100%;
            }
        }

        .item span:nth-of-type(2) {
            position: absolute;
            top: -100%;
            right: 0;
            width: 3px;
            height: 100%;
            background-image: linear-gradient(to top, aqua, transparent);
            animation: two 1s linear infinite;
            animation-delay: 0.25s;
        }

        @keyframes two {
            0% {
                top: -100%;
            }

            50%,
            100% {
                top: 100%;
            }
        }

        .item span:nth-of-type(3) {
            position: absolute;
            right: -100%;
            bottom: 0;
            width: 100%;
            height: 3px;
            background-image: linear-gradient(to right, aqua, transparent);
            animation: three 1s linear infinite;
            animation-delay: 0.5s;
        }

        @keyframes three {
            0% {
                right: -100%;
            }

            50%,
            100% {
                right: 100%;
            }
        }

        .item span:nth-of-type(4) {
            position: absolute;
            bottom: -100%;
            left: 0;
            width: 3px;
            height: 100%;
            background-image: linear-gradient(to bottom, aqua, transparent);
            animation: zuo 1s linear infinite;
            animation-delay: 0.75s;
        }

        @keyframes zuo {
            0% {
                bottom: -100%;
            }

            50%,
            100% {
                bottom: 100%;
            }
        }

        .item1 {
            filter: hue-rotate(100deg);
        }

        .item3 {
            filter: hue-rotate(250deg);
        }