.banner {
    height: 780px;
    background: url(../images/aboutUs.png) no-repeat center center/cover;
    /* animation: banner 1s linear infinite alternate;
    -webkit-animation: banner 1s linear infinite alternate; */
    color: #fff;
}

/* @keyframes banner {
    from {
        background: url(../images/aboutUs.png) no-repeat center center/cover;
    }
    to {
        background: url(../images/aboutUs-light.png) no-repeat center center/cover;
    }
}

@-webkit-keyframes banner {
    from {
        background: url(../images/aboutUs.png) no-repeat center center/cover;
    }
    to {
        background: url(../images/aboutUs-light.png) no-repeat center center/cover;
    }
} */
.banner-inner {
    text-align: center;
    padding-top: 190px;
}

.banner .title {
    font-size: 72px;
    color: #fff;
}

.banner .tip {
    font-size: 24px;
    padding: 20px 30px;
    display: inline-block;
    border-bottom: 1px solid #fff;
    margin-bottom: 30px;
    letter-spacing: 5px;
    color: #fff;
    border-top: 0;
    margin-top: 0;
}

.banner .text {
    font-size: 32px;
}

.menu {
    background-color: rgba(28, 35, 39, 0.6);
    margin-top: -63px;
}

.menu-item {
    width: 20%;
    padding: 16px 0;
    text-align: center;
    display: block;
    float: left;
    color: #fff;
    font-size: 24px;
}

.menu-item.active {
    background-color: #4fc1f1;
}

.menu-item:hover {
    background-color: #4fc1f1;
}

.main {
    padding: 100px 0;
}