.site-header.is-sticky {
    position: fixed;
    height: 92px;
    background: rgba(255, 255, 255, .8);
    border-bottom: 1px solid rgba(73, 71, 69, .12);
    box-shadow: 0 8px 28px rgba(45, 43, 40, .06);
    -webkit-backdrop-filter: blur(12px);
    backdrop-filter: blur(12px);
    animation: header-slide-down .42s cubic-bezier(.22, .61, .36, 1) both;
}

.site-header.is-sticky .brand img { width: 56px; height: 56px; }
.site-header.is-sticky .header-logo-text { height: 58px; }

.header-actions .line-button {
    width: 48px;
    height: 48px;
    padding: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid #aaa;
    font-size: 12px;
    line-height: 1;
    letter-spacing: .08em;
    text-indent: .08em;
}

.header-actions .inquiry-button {
    width: 198px;
    height: 48px;
}

.inquiry-button svg {
    width: 18px;
    height: 14px;
    fill: none;
    stroke: currentColor;
    stroke-width: 1.25;
    stroke-linecap: round;
    stroke-linejoin: round;
}

@keyframes header-slide-down {
    from { transform: translateY(-100%); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

@media (max-width: 900px) {
    .site-header { position: fixed; }
    .site-header.is-sticky { height: 72px; background: rgba(255, 255, 255, .8); }
    .site-header.is-sticky .brand img { width: 46px; height: 46px; }
}

@media (prefers-reduced-motion: reduce) {
    .site-header.is-sticky { animation: none; }
}