/* ==================== 01｜頁首導覽 ==================== */
.site-header { position: sticky; z-index: 1000; top: 0; height: 80px; display: flex; align-items: center; justify-content: space-between; gap: 28px; padding: 0 max(var(--page-gutter), calc((100% - var(--content-width)) / 2)); background: rgba(255,250,239,.92); border-bottom: 1px solid rgba(164,91,69,.13); box-shadow: 0 10px 30px rgba(60,30,20,.06); backdrop-filter: blur(12px); }
.brand { min-width: 0; flex: 0 1 500px; }
.brand img { width: clamp(330px, 36vw, 520px); max-height: 48px; object-fit: contain; object-position: left center; }
.site-nav { display: flex; align-items: center; gap: 22px; white-space: nowrap; }
.site-nav a { position: relative; font-size: 16px; font-weight: 800; }
.site-nav a:not(.nav-signup)::after { content: ""; position: absolute; right: 0; bottom: -8px; left: 0; height: 2px; background: var(--color-red); transform: scaleX(0); transition: .2s; }
.site-nav a:hover::after { transform: scaleX(1); }
.site-nav .nav-signup { padding: 10px 18px; color: white; background: var(--color-red); border-radius: var(--radius-button); }
.menu-button { display: none; width: 44px; height: 44px; padding: 10px; border: 0; background: transparent; cursor: pointer; }
.menu-button i { display: block; height: 2px; margin: 5px 0; background: var(--color-red-dark); }