.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    height: var(--header-h);
    background: #ffffff;
    border-bottom: 1px solid var(--border);
    transition: box-shadow 0.2s var(--ease);
}
.site-header.is-scrolled {
    box-shadow: var(--shadow-sm);
}

.site-header__inner {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
    height: 100%;
    gap: var(--space-4);
}
.site-header__inner > .site-nav { justify-self: center; }
.site-header__inner > .site-header__actions { justify-self: end; }

.logo {
    display: inline-flex;
    align-items: center;
    gap: var(--space-3);
    color: var(--text-0);
    line-height: 1;
}
.logo__mark {
    width: 46px;
    height: 46px;
    object-fit: contain;
    border-radius: 50%;
    background: #000;
}
.logo__text { display: flex; flex-direction: column; gap: 2px; }
.logo__name {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 1.2rem;
    letter-spacing: -0.01em;
    color: var(--text-0);
    line-height: 1;
}
.logo__sub {
    font-family: var(--font-sans);
    font-size: 0.7rem;
    color: var(--text-2);
    letter-spacing: 0.16em;
    text-transform: uppercase;
}

.site-nav {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    align-items: center;
    width: min(640px, 100%);
    gap: var(--space-4);
}
.site-nav a { justify-self: center; }
.site-nav a {
    color: var(--text-1);
    font-size: 0.92rem;
    font-weight: 500;
    position: relative;
    transition: color 0.18s var(--ease);
}
.site-nav a::after {
    content: "";
    position: absolute;
    left: 0; right: 0; bottom: -6px;
    height: 2px;
    background: var(--text-0);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.25s var(--ease);
}
.site-nav a:hover { color: var(--text-0); }
.site-nav a:hover::after { transform: scaleX(1); }

.site-header__actions {
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.icon-btn--menu { display: none; }

@media (max-width: 880px) {
    .site-header__inner {
        display: flex;
        justify-content: space-between;
    }

    .logo__sub { display: none; }
    .logo__mark { width: 40px; height: 40px; }

    .site-nav {
        display: none;
        position: fixed;
        top: var(--header-h);
        left: 0;
        right: 0;
        flex-direction: column;
        align-items: flex-start;
        gap: 0;
        background: var(--bg-0);
        padding: var(--space-4) var(--space-5) var(--space-6);
        border-bottom: 1px solid var(--border);
        box-shadow: var(--shadow-md);
        z-index: 90;
    }
    .site-nav.is-open { display: flex; }
    .site-nav a {
        width: 100%;
        padding: var(--space-3) 0;
        border-bottom: 1px solid var(--border);
        font-size: 1.05rem;
    }
    .site-nav a:last-child { border-bottom: none; }
    .site-nav a::after { display: none; }

    .icon-btn--menu { display: inline-flex; }
}