.site-header{border-bottom:1px solid var(--color-border);background-color:rgba(0,0,0,0.9);backdrop-filter:blur(10px);position:sticky;top:0;z-index:40}.site-header-inner{display:flex;align-items:center;justify-content:space-between;padding-top:var(--space-3);padding-bottom:var(--space-3);gap:var(--space-4)}.brand-lockup{display:flex;align-items:center;gap:var(--space-3);color:var(--color-neutral-100)}.brand-mark{width:32px;height:32px;border-radius:0;border:1px solid var(--color-primary);display:flex;align-items:center;justify-content:center;font-family:var(--font-mono);font-size:var(--font-size-xs);letter-spacing:0.16em;text-transform:uppercase;color:var(--color-primary);background:radial-gradient(circle at center,#111827 0,#020617 60%,#000 100%)}.brand-text{display:flex;flex-direction:column;gap:2px}.brand-name{font-size:var(--font-size-sm);letter-spacing:0.24em;text-transform:uppercase}.brand-tagline{font-family:var(--font-mono);font-size:var(--font-size-xs);color:var(--color-text-muted);letter-spacing:0.16em;text-transform:uppercase}.nav{display:flex;align-items:center;font-family:var(--font-mono);font-size:var(--font-size-xs);letter-spacing:0.16em;text-transform:uppercase}.nav-list{display:flex;align-items:center;gap:var(--space-6)}.nav-item a{color:var(--color-text-muted);position:relative;padding-bottom:2px}.nav-item a::after{content:"";position:absolute;left:0;bottom:0;width:0;height:1px;background-color:var(--color-primary);transition:width var(--transition-base)}.nav-item a:hover,.nav-item a:focus-visible{color:var(--color-neutral-100);text-decoration:none}.nav-item a:hover::after,.nav-item a:focus-visible::after{width:100%}.nav-item-cta .nav-download-link{padding:8px 14px;border-radius:0;border:1px solid var(--color-primary-soft);background:linear-gradient(135deg,var(--color-primary),var(--color-accent-rust));color:#fef2f2;box-shadow:var(--shadow-sm);display:inline-flex;align-items:center;gap:8px}.nav-item-cta .nav-download-link::before{content:"";width:8px;height:8px;border-radius:999px;background-color:var(--color-neutral-50);box-shadow:0 0 10px rgba(248,250,252,0.8)}.nav-item-cta .nav-download-link:hover,.nav-item-cta .nav-download-link:focus-visible{background:linear-gradient(135deg,#b91c1c,#9a3412);border-color:#7f1d1d;box-shadow:var(--shadow-hard);text-decoration:none}.nav-toggle{display:none;flex-direction:column;align-items:center;justify-content:center;gap:5px;width:40px;height:40px;border-radius:0;border:1px solid var(--color-border);background-color:#020617;color:var(--color-neutral-100);font-family:var(--font-mono);font-size:var(--font-size-2xs);letter-spacing:0.16em;text-transform:uppercase;position:relative;z-index:50}.nav-toggle span{display:block;width:16px;height:2px;background-color:var(--color-neutral-100);transition:transform var(--transition-base),opacity var(--transition-base)}.nav-toggle-label{font-size:0;position:absolute;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;width:1px;height:1px}.nav-toggle-icon{display:flex;flex-direction:column}.nav-toggle.is-active span:nth-of-type(1){transform:translateY(7px) rotate(45deg)}.nav-toggle.is-active span:nth-of-type(2){opacity:0}.nav-toggle.is-active span:nth-of-type(3){transform:translateY(-7px) rotate(-45deg)}@media (max-width:900px){.nav-toggle{display:flex}.nav{position:absolute;top:100%;left:0;right:0;bottom:auto;transform:translateY(-12px);opacity:0;pointer-events:none;visibility:hidden;transition:transform var(--transition-base),opacity var(--transition-base),visibility var(--transition-base);background-color:#020617;border-bottom:1px solid var(--color-border);z-index:45;box-shadow:0 18px 40px rgba(0,0,0,0.85)}.nav-list{flex-direction:column;align-items:flex-start;padding:var(--space-5) var(--space-4) var(--space-6);gap:var(--space-4);width:100%}.site-header-inner{position:relative}.site-header.nav-open .nav{transform:translateY(0);opacity:1;pointer-events:auto;visibility:visible}}@media (prefers-reduced-motion:reduce){.nav{transition:none}.nav-item a::after{transition:none}}