/* ==========================================================================
   Site Header
   ========================================================================== */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 500;
    height: var(--header-height);
    display: flex;
    align-items: center;
    background: transparent;
    border-bottom: 1px solid transparent;
    transition: background var(--dur-mid) var(--ease-soft),
                border-color var(--dur-mid) var(--ease-soft),
                height var(--dur-mid) var(--ease-soft),
                backdrop-filter var(--dur-mid) var(--ease-soft);
}

.site-header.is-scrolled {
    height: var(--header-height-sm);
    background: rgba(248, 247, 245, 0.86);
    -webkit-backdrop-filter: saturate(140%) blur(10px);
    backdrop-filter: saturate(140%) blur(10px);
    border-bottom-color: var(--color-line-soft);
}

.site-header__inner {
    width: 100%;
    max-width: calc(var(--container-width) + var(--container-padding) * 2);
    margin-inline: auto;
    padding-inline: var(--container-padding);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.site-header__logo {
    display: inline-flex;
    align-items: center;
}

.site-header__logo img {
    width: clamp(160px, 16vw, 220px);
    height: auto;
}

.site-header__nav {
    display: none;
}

.site-header__nav-list {
    display: flex;
    align-items: center;
    gap: clamp(28px, 3vw, 56px);
}

.site-header__nav-link {
    position: relative;
    display: inline-block;
    padding: 8px 2px;
    font-family: var(--font-serif-en);
    font-size: 0.85rem;
    letter-spacing: var(--ls-label);
    color: var(--color-text);
}

.site-header__nav-link::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 0;
    height: 1px;
    background: currentColor;
    transition: width var(--dur-mid) var(--ease-soft);
}

.site-header__nav-link:hover::after,
.site-header__nav-link:focus-visible::after,
.site-header__nav-link[aria-current="page"]::after {
    width: 100%;
}

.site-header__nav-link--contact {
    padding: 10px 26px;
    border: 1px solid var(--color-dark-navy);
    color: var(--color-dark-navy);
    transition: background var(--dur-fast) var(--ease-soft), color var(--dur-fast) var(--ease-soft);
}

.site-header__nav-link--contact::after {
    display: none;
}

.site-header__nav-link--contact:hover,
.site-header__nav-link--contact:focus-visible {
    background: var(--color-dark-navy);
    color: var(--color-white);
}

/* ==========================================================================
   Hamburger toggle
   ========================================================================== */
.site-header__toggle {
    position: relative;
    z-index: 600;
    width: 40px;
    height: 32px;
    display: inline-flex;
    flex-direction: column;
    align-items: flex-end;
    justify-content: center;
    gap: 7px;
}

.site-header__toggle-line {
    display: block;
    width: 100%;
    height: 1px;
    background: var(--color-dark-navy);
    transition: transform var(--dur-fast) var(--ease-soft), opacity var(--dur-fast) var(--ease-soft), width var(--dur-fast) var(--ease-soft);
}

.site-header__toggle-line:nth-child(2) {
    width: 70%;
}

.site-header__toggle[aria-expanded="true"] .site-header__toggle-line {
    width: 100%;
}

.site-header__toggle[aria-expanded="true"] .site-header__toggle-line:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
}

.site-header__toggle[aria-expanded="true"] .site-header__toggle-line:nth-child(2) {
    opacity: 0;
}

.site-header__toggle[aria-expanded="true"] .site-header__toggle-line:nth-child(3) {
    transform: translateY(-8px) rotate(-45deg);
}

/* ==========================================================================
   Mobile fullscreen menu
   ========================================================================== */
.mobile-menu {
    position: fixed;
    inset: 0;
    z-index: 400;
    background: var(--color-off-white);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-12px);
    transition: opacity var(--dur-mid) var(--ease-soft), transform var(--dur-mid) var(--ease-soft), visibility 0s linear var(--dur-mid);
}

.mobile-menu.is-open {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
    transition: opacity var(--dur-mid) var(--ease-soft), transform var(--dur-mid) var(--ease-soft), visibility 0s;
}

.mobile-menu__inner {
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: calc(var(--header-height) + 20px) var(--container-padding) 60px;
}

.mobile-menu__list {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.mobile-menu__item {
    opacity: 0;
    transform: translateY(16px);
    transition: opacity var(--dur-mid) var(--ease-soft), transform var(--dur-mid) var(--ease-soft);
    transition-delay: calc(var(--item-index, 0) * 0.06s);
    border-bottom: 1px solid var(--color-line);
}

.mobile-menu.is-open .mobile-menu__item {
    opacity: 1;
    transform: translateY(0);
}

.mobile-menu__link {
    display: block;
    padding: 22px 4px;
    font-family: var(--font-serif-jp);
    font-size: clamp(1.6rem, 7vw, 2.2rem);
    letter-spacing: 0.08em;
    color: var(--color-dark-navy);
}

.mobile-menu__footer {
    margin-top: 48px;
    display: flex;
    flex-direction: column;
    gap: 10px;
    font-family: var(--font-serif-en);
    letter-spacing: var(--ls-wide);
    color: var(--color-text-soft);
}

@media (prefers-reduced-motion: reduce) {
    .mobile-menu,
    .mobile-menu__item {
        transition: none;
    }
}

@media (min-width: 1024px) {
    .site-header__nav {
        display: block;
    }

    .site-header__toggle {
        display: none;
    }

    .mobile-menu {
        display: none;
    }
}