.header_box {
    width: 100%;
    /* padding: calc(9px + 0.5rem) 0; */
    background: #ffffff;
    position: fixed;
    top: 0;
    z-index: 100;
        box-shadow: 0px 5px 10px 0px #00000010;
}

.header {
    max-width: 1650px;
    width: 85%;
    margin: auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    height: calc(2px + 3rem);
}

.logo img {
    height: 100%;
}

.header_nav_box {
    display: flex;
    justify-content: flex-end;
    align-items: center;
    gap: calc(10px + 1rem);
}



.nav_item {
    width: 100%;
    line-height: calc(18px + 4rem);
    font-family: Microsoft YaHei;
    font-weight: 400;
    font-size: calc(6px + 0.5rem);
    color: #252525;
    text-align: center;
    border-bottom: calc(0px + 0.1rem) transparent solid;
    transition: .3s;
    padding: 0 calc(2px + 0.5rem);

}

.header_nav_box .header_active {
    background: #F5F5F5;
    color: #0072C1;
    border-bottom: calc(0px + 0.1rem) #0072C1 solid;
}

.header_nav_box .header_active .nav_item {
    color: #0072C1;
}

.nav_item:hover {
    background: #F5F5F5;
    color: #0072C1;
    border-bottom: calc(0px + 0.1rem) #0072C1 solid;
}

.language {
    display: flex;
    justify-content: flex-start;
    align-items: center;
    gap: calc(4px + 0.25rem);
}

.language img {
    width: calc(4px + 1rem);
    height: calc(4px + 1rem);
}

.language p {
    font-family: Microsoft YaHei;
    font-weight: 400;
    font-size: calc(6px + 0.5rem);
    color: #242424;
    opacity: 0.5;
}

.language p:nth-of-type(1) {
    opacity: 1;
}

.search {
    width: calc(5px + 1rem);
}

.search img {
    width: 100%;
}

.nav_2 {
    width: max-content;
    background-color: #ffffff;
    padding: calc(5px + 0.5rem);
    position: absolute;
    top: 100%;
    z-index: 100;
    display: none;

    .nav_2_item {
        line-height: calc(2px + 2rem);
        font-size: calc(6px + 0.5rem);
        color: #666666;
        transition: .5s;
    }

    .nav_2_item:hover {
        color: #0072C1;
    }
}

.div1:hover {
    .nav_2 {
        display: block;
    }
}