.site-header{background:var(--color-surface-primary);border-bottom:1px solid var(--color-border-default);position:sticky;top:0;z-index:50}
.header-inner{display:flex;align-items:center;justify-content:space-between;gap:var(--space-4);min-height:72px}
.brand{display:flex;align-items:center;gap:0.75rem;text-decoration:none}
.brand-logo{width:48px;height:auto}
.brand-text{font-family:var(--font-heading);font-weight:700;color:var(--color-text-primary);font-size:1.2rem}

.nav-toggle{display:none;flex-direction:column;gap:4px;padding:0.5rem;border:1px solid var(--color-border-default);border-radius:var(--radius)}
.nav-toggle-line{width:20px;height:2px;background:var(--color-text-primary)}

.nav{display:block}
.nav-list{list-style:none;display:flex;gap:2rem;margin:0;padding:0;align-items:center}
.nav-list li{margin:0}
.nav-list a{color:var(--color-text-primary);font-weight:500}
.nav-list a:hover{color:var(--color-accent-primary);text-decoration:underline}

@media (max-width:900px){
  .nav-toggle{display:flex}
  .nav{position:absolute;top:100%;left:0;width:100%;background:var(--color-surface-primary);border-bottom:1px solid var(--color-border-default);display:none}
  .nav.open{display:block}
  .nav-list{flex-direction:column;align-items:flex-start;padding:1rem;gap:1rem}
}