/* One header layout for the tester, guides, and concept page. */
.header.site-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    flex-shrink: 0;
    gap: 20px;
    min-height: 74px;
    height: auto;
    padding: 18px 32px;
    position: relative;
    top: auto;
    z-index: 10;
    background: #0d1320;
    border-bottom: 1px solid #263145;
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}
.header.site-header::after { content: none; }
.site-header .site-brand {
    display: flex;
    align-items: center;
    gap: 14px;
    min-width: 0;
    color: #f1f5f9;
    text-decoration: none;
    border-radius: 6px;
}
.site-header .site-brand-mark {
    display: flex;
    align-items: center;
    justify-content: center;
    flex: 0 0 36px;
    width: 36px;
    height: 36px;
    border-radius: 8px;
    background: linear-gradient(135deg, #a5b4fc, #818cf8);
}
.site-header .site-brand-mark img { display: block; width: 20px; height: 20px; }
.site-header .site-brand-copy { min-width: 0; }
.site-header .site-brand-name {
    display: block;
    margin: 0;
    padding: 0;
    color: #f1f5f9;
    font-size: 18px;
    font-weight: 700;
    line-height: 22px;
    letter-spacing: -.5px;
}
.site-header .site-brand-caption {
    margin: 0;
    padding: 0;
    color: #a6b3c8;
    font-size: 12px;
    font-weight: 400;
    line-height: 16px;
    letter-spacing: .2px;
    text-transform: none;
}
.site-header .header-nav { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; }
.site-header .header-link {
    display: inline-flex;
    align-items: center;
    min-height: 36px;
    padding: 6px 12px;
    border: 0;
    border-radius: 6px;
    color: #b6c2d6;
    background: transparent;
    font-size: 13px;
    font-weight: 500;
    line-height: 20px;
    text-decoration: none;
    transition: color .15s, background-color .15s;
}
.site-header .header-link:hover { color: #f1f5f9; background: #1a2335; }
.site-header .header-link[aria-current="page"] { color: #e0e7ff; background: #202b43; }
.site-header a:focus-visible { outline: 2px solid #a5b4fc; outline-offset: 4px; }
@media (max-width: 640px) {
    .header.site-header { padding: 16px; gap: 16px; }
    .site-header .header-nav { flex-basis: 100%; gap: 2px; }
    .site-header .header-link { padding: 6px 9px; font-size: 12px; }
}
@media (prefers-reduced-motion: reduce) {
    .site-header .header-link { transition: none; }
}