header {
    width: 100%;
    height: 80px;
    position: fixed;
    background: #E2EDF7 url("https://www.hljstm.org.cn/assets/museum_intro_bg.bf1eb369.png") no-repeat;
    top: 0;
    z-index: 999;
    color: #ffffff;
}

.top-bar {
    width: 1380px;
    height: 80px;
    margin: 0 auto;
    display: flex;
    align-items: center;
}

.top-bar-menu {
    flex: 1;
    display: flex;
    align-items: center;
    margin-left: 50px;
    font-weight: bold;
}

.menu-item {
    height: 100%;
    line-height: 80px;
    font-size: 18px;
    margin-right: 40px;
    cursor: pointer;
}

.menu-item a {
    color: inherit;
    text-decoration: none;
}

.menu-item a:hover {
    color: #1a64e0;
}

.menu-item-active a {
    color: #1a64e0;
}

.top-bar-logo {
    width: 160px;
    height: 44px;
}

.liu_you {
    -webkit-text-size-adjust: auto;
}

.top-bar-logo img {
    width: 100%;
    height: 100%;
}

@media screen and (max-width: 600px) {
    header {
    width: 100%;
    height: 180px!important;
    position: fixed;
    background: #E2EDF7 url("https://www.hljstm.org.cn/assets/museum_intro_bg.bf1eb369.png") no-repeat;
    top: 0;
    z-index: 999;
    color: #ffffff;
}
.top-bar {
    width: 100%;
    height: 180px!important;
    margin: 0 auto;
    display: flex;
    align-items: center;
}
.top-bar-menu {
    flex: 1;
    display: flex;
    /*align-items: center;*/
    flex-direction: row;
    flex-wrap: wrap;
    margin-left: 30px;
    font-weight: bold;
}

    .menu-item {
    height: 100%;
    /*line-height: 80px;*/
    font-size: 28px;
    margin-right: 20px;
    cursor: pointer;
    color: #333!important;
}
.menu-item a {
    color: inherit;
    text-decoration: none;
}

.menu-item a:hover {
    color: #1a64e0;
}

.menu-item-active a {
    color: #1a64e0;
}

.top-bar-logo {
    width: 160px;
    height: 44px;
}

.top-bar-logo img {
    width: 100%;
    height: 100%;
}

}