.site-header {
    position: sticky;
    top: 0;
    z-index: 1;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 24px;
    background-image: linear-gradient(var(--primary-bg-color) 50%, #00000000);
    border-bottom: 0px solid var(--public-accent-color);
    font-family: var(--english-font);
    font-size: 1.2rem;
    color: var(--secondary-text-color);

    overflow: visible;
}


/* PCナビ */
.header-nav {
    display: flex;
    align-items: center;
    gap: 20px
}

.header-nav a {
    text-decoration: none;
    color: var(--secondary-text-color);
    position: relative;
}

.header-nav a::after {
    content: "";
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 0.05rem;
    background: var(--secondary-text-color);
    transition: width var(--transition);
}

.header-nav a:hover::after {
    width: 100%
}

/* ハンバーガー */
.nav-toggle {
    display: none;
    width: 40px;
    height: 40px;
    border: 0;
    background: transparent;
    padding: 8px;
    cursor: pointer
}

.nav-toggle .bar {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--secondary-text-color);
    margin: 4px 0;
    transition: var(--transition)
}

/* オーバーレイ */
.nav-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, .45);
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition);
    z-index: 999;
}

body.nav-open main {

    filter: blur(6px);

}
body.nav-open .nav-overlay {
    opacity: 1;
    pointer-events: auto;
}



/* 背景スクロール固定 */
body.nav-open {
    overflow: hidden
}

/* スマホ時：右ドロワー */
@media (max-width:980px) {
    .header-nav {
        flex-direction: column;
        gap: 16px;
        position: fixed;
        top: 0;
        right: 0;
        width: 180px;
        height: 100%;
        background: var(--primary-bg-color);
        padding: 80px 24px 24px;
        box-shadow: -4px 0 12px rgba(0, 0, 0, .6);
        transform: translateX(100%);
        transition: transform var(--transition);
        z-index: 1001;
    }

    .header-nav.is-open {
        transform: translateX(0)
    }

    .header-nav a::after {
        display: block
    }

    .nav-toggle {
        display: inline-block
    }
}