.site-header{--header-height:72px;position:sticky;top:0;z-index:1000;background:rgba(5,5,10,0.9);backdrop-filter:blur(8px);border-bottom:1px solid var(--color-divider);} 
.site-header__inner{position:relative;z-index:2;display:grid;grid-template-columns:1fr auto 1fr;align-items:center;min-height:var(--header-height);gap:var(--space-3);} 
.nav{display:flex;gap:var(--space-4);align-items:center;} 
.nav a{font-family:var(--font-heading);font-size:var(--fs-sm);text-transform:uppercase;letter-spacing:0.05em;position:relative;} 
.nav a::after{content:"";position:absolute;left:0;bottom:-4px;width:0;height:2px;background:var(--color-accent-cyan);transition:0.2s;} 
.nav a:hover::after{width:100%;} 
.brand{display:flex;justify-content:center;} 
.brand__link{display:flex;align-items:center;gap:0.6rem;} 
.brand__logo{width:52px;height:auto;} 
.brand__text{font-family:var(--font-heading);font-size:1.2rem;letter-spacing:0.06em;} 
.nav-toggle{display:none;position:absolute;right:var(--space-4);top:50%;transform:translateY(-50%);width:44px;height:44px;align-items:center;justify-content:center;} 
.nav-toggle span{display:block;width:22px;height:2px;background:var(--color-accent-cyan);margin:4px 0;transition:transform 0.2s ease,opacity 0.2s ease;} 
.nav-toggle[aria-expanded="true"] span:nth-child(1){transform:translateY(6px) rotate(45deg);} 
.nav-toggle[aria-expanded="true"] span:nth-child(2){opacity:0;} 
.nav-toggle[aria-expanded="true"] span:nth-child(3){transform:translateY(-6px) rotate(-45deg);} 
.mobile-menu{position:absolute;top:100%;right:0;left:0;z-index:1;height:calc(100dvh - var(--header-height));background:var(--color-bg-primary);padding:var(--space-5);overflow-y:auto;} 
.mobile-menu__nav{display:flex;flex-direction:column;gap:var(--space-4);} 
.mobile-menu a{font-family:var(--font-heading);font-size:var(--fs-lg);} 
body.menu-open{overflow:hidden;}
@media(max-width:900px){
.nav{display:none;}
.nav-toggle{display:flex; flex-direction: column;}
.site-header__inner{grid-template-columns:1fr;justify-items:center;}
.brand__logo{width:40px;}
.brand__text{font-size:1rem;}
.mobile-menu{padding:var(--space-4) var(--space-3);}
}