.site-header {
    position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
    height: var(--header-height);
    background: rgba(10, 22, 40, 0.95);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(255,255,255,0.08);
    transition: background var(--transition-normal), box-shadow var(--transition-normal);
}
.site-header.scrolled { box-shadow: 0 2px 20px rgba(0,0,0,0.3); }
.header-inner { display: flex; align-items: center; justify-content: space-between; height: 100%; }
.header-logo img { height: 44px; width: auto; }

.nav-list { display: flex; list-style: none; gap: var(--space-lg); }
.nav-list a {
    color: rgba(255,255,255,0.85); font-weight: 500; font-size: var(--font-size-sm);
    text-transform: uppercase; letter-spacing: 0.5px; padding: 0.5rem 0; position: relative;
}
.nav-list a:hover { color: var(--color-white); }
.nav-list a::after {
    content: ''; position: absolute; bottom: 0; left: 0; width: 0; height: 2px;
    background: var(--color-blue); transition: width var(--transition-normal);
}
.nav-list a:hover::after, .nav-list .current-menu-item a::after { width: 100%; }

.nav-toggle {
    display: none; flex-direction: column; gap: 5px;
    background: none; border: none; cursor: pointer; padding: 0.5rem;
}
.nav-toggle span { display: block; width: 24px; height: 2px; background: var(--color-white); transition: all var(--transition-normal); }
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

.site-main { margin-top: var(--header-height); }
.home .site-main { margin-top: 0; }
.home .site-header { background: transparent; border-bottom: none; }
.home .site-header.scrolled { background: rgba(10, 22, 40, 0.95); border-bottom: 1px solid rgba(255,255,255,0.08); }

@media (max-width: 768px) {
    .nav-toggle { display: flex; }
    .header-nav {
        position: fixed; top: var(--header-height); left: 0; right: 0; bottom: 0;
        background: rgba(10, 22, 40, 0.98); padding: var(--space-xl);
        transform: translateX(100%); transition: transform var(--transition-normal);
    }
    .header-nav.open { transform: translateX(0); }
    .nav-list { flex-direction: column; gap: var(--space-md); }
    .nav-list a { font-size: var(--font-size-lg); }
}