header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    z-index: 99;
    transition: all 0.4s;
    background: transparent;
}
header.under {
    background: rgba(255, 255, 255, 0.8);
}
header.white {
    background: rgba(255, 255, 255, 0.8);
}

header .container {
    width: 80%;
    margin: auto;
    padding: 15px 0;
}

header .header_icon {
    width: 11vw;
    max-width: 180px;
    min-width: 150px;
    height: auto;
}

header .link_list .link_item {
    margin-right: 8.59375vw;
}
header .link_list .link_item:last-of-type {
    margin-right: unset;
}
@media screen and (min-width: 1280px) {
    header .link_list .link_item {
        margin-right: 115px;
    }
}

/* hamburger */
header .hamburger {
    width: 25px;
    height: 10px;
    position: relative;
    cursor: pointer;
    display: none;
    z-index: 99999;
}

header .hamburger span {
    height: 2px;
    background: var(--blue);
    transition: all 0.4s;
    position: absolute;
    content: "";
}

header .hamburger span:first-of-type {
    width: 100%;
    top: 0;
    bottom: 0;
    left: 0;
}

header .hamburger span:last-of-type {
    width: 80%;
    bottom: 0;
    right: 0;
}

header .hamburger.active span {
    background: var(--white);
}

header .hamburger.active span:first-of-type {
    transform: rotate(225deg);
    left: 0;
    right: 0;
    margin: auto;
}

header .hamburger.active span:last-of-type {
    width: 100%;
    transform: rotate(-225deg);
    top: 10%;
    left: 0;
    right: 0;
    margin: auto;
}

/* ============================================================================ */
/* responsive */
/* ============================================================================ */
@media screen and (max-width: 768px) {
    header .container {
        width: 95%;
    }

    header .link_list .link_item {
        margin-right: 4vw;
    }

    header .container {
        padding: 10px 0;
    }

    header .link_list {
        display: none;
    }

    header .hamburger {
        display: block;
    }
}