.header{position:sticky;top:0;z-index:100;border-bottom:1px solid var(--border);background:var(--bg-header);backdrop-filter:saturate(160%) blur(10px);-webkit-backdrop-filter:saturate(160%) blur(10px);font-family:var(--font-sans);line-height:1.2;letter-spacing:normal}.header a,.header a:hover,.header a:focus{text-decoration:none}.header-content{display:flex;align-items:center;justify-content:space-between;gap:1rem;padding-block:0.9rem}.header-logo{display:flex;align-items:baseline;gap:0.55rem;min-height:44px}.header-logo .name{font-family:var(--font-sans);font-size:1rem;font-weight:600;letter-spacing:-0.02em;color:var(--text-primary)}.header-logo .title{font-family:var(--font-mono);font-size:0.68rem;font-weight:500;letter-spacing:0.14em;text-transform:uppercase;color:var(--text-muted,var(--text-secondary))}.nav{display:flex;align-items:center;gap:clamp(0.5rem,1.6vw,1.1rem)}.nav-divider{width:1px;height:18px;flex-shrink:0;margin-inline:0.35rem;background:var(--border)}.nav-link{position:relative;display:inline-flex;align-items:center;min-height:44px;font-family:var(--font-sans);font-size:0.92rem;font-weight:500;line-height:1.2;letter-spacing:normal;color:var(--text-secondary);padding:0.35rem 0.25rem;transition:color var(--dur-hover,0.2s) var(--ease-out,ease)}.nav-link.active,.nav-link[aria-current="page"]{color:var(--text-primary)}.nav-link.active::after,.nav-link[aria-current="page"]::after{content:"";position:absolute;inset-inline:0.25rem;bottom:-0.1rem;height:1px;background:var(--accent)}.nav-cta,.nav-cta[aria-current="page"]{display:inline-flex;align-items:center;min-height:44px;padding:0.5rem 0.95rem;font-size:0.875rem;font-weight:600;white-space:nowrap;background:var(--accent);border:1px solid var(--accent);border-radius:999px;color:var(--bg-primary);transition:background-color var(--dur-hover,0.2s) var(--ease-out,ease),border-color var(--dur-hover,0.2s) var(--ease-out,ease),transform 160ms var(--ease-out,cubic-bezier(0.23,1,0.32,1))}.nav-cta:active,.theme-toggle-btn:active,.mobile-menu-btn:active{transform:scale(0.97)}.theme-toggle-btn{display:inline-flex;align-items:center;justify-content:center;width:2.75rem;height:2.75rem;flex-shrink:0;padding:0;border:1px solid var(--border);border-radius:999px;background:transparent;color:var(--text-secondary);cursor:pointer;transition:border-color var(--dur-hover,0.2s) var(--ease-out,ease),color var(--dur-hover,0.2s) var(--ease-out,ease),transform 160ms var(--ease-out,cubic-bezier(0.23,1,0.32,1))}.sun-icon{display:block;color:var(--accent)}.moon-icon,[data-theme="light"] .sun-icon{display:none}[data-theme="light"] .moon-icon{display:block;color:var(--accent)}.mobile-menu-btn{display:none;flex-direction:column;align-items:center;justify-content:center;gap:6px;padding:0.5rem;border:1px solid var(--border);border-radius:var(--radius-sm,4px);background:transparent;cursor:pointer;transition:transform 160ms var(--ease-out,cubic-bezier(0.23,1,0.32,1))}.mobile-menu-btn span{display:block;width:20px;height:2px;background:var(--text-primary);transition:transform var(--dur-hover,0.2s) var(--ease-out,ease),opacity var(--dur-hover,0.2s) var(--ease-out,ease)}.mobile-menu-btn.open span:nth-child(1){transform:translateY(8px) rotate(45deg)}.mobile-menu-btn.open span:nth-child(2){opacity:0}.mobile-menu-btn.open span:nth-child(3){transform:translateY(-8px) rotate(-45deg)}.mobile-menu{display:flex;flex-direction:column;margin-top:1rem;border-top:1px solid var(--border);background:var(--bg-primary)}.mobile-menu[hidden]{display:none}.mobile-nav-link{display:flex;align-items:center;min-height:44px;padding:0.75rem 1rem;font-family:var(--font-sans);font-size:0.95rem;font-weight:500;letter-spacing:normal;color:var(--text-secondary);border-bottom:1px solid var(--border);transition:color var(--dur-hover,0.2s) var(--ease-out,ease)}.mobile-nav-link.active,.mobile-nav-link[aria-current="page"]{color:var(--text-primary)}@media (hover:hover) and (pointer:fine){.nav-link:hover{color:var(--text-primary)}.theme-toggle-btn:hover{border-color:var(--border-strong,var(--text-secondary));color:var(--text-primary)}.nav-cta:hover{background:color-mix(in oklab,var(--accent) 88%,white);border-color:color-mix(in oklab,var(--accent) 88%,white);color:var(--bg-primary)}.mobile-nav-link:hover{color:var(--text-primary)}}@media (max-width:768px){.nav{display:none}.mobile-menu-btn{display:flex}.mobile-menu-btn,.theme-toggle-btn{min-width:44px;min-height:44px}.header-logo{align-items:center;min-height:44px}}@media (prefers-reduced-motion:reduce){.header a,.header button,.mobile-menu-btn span{transition-duration:0.01ms}.nav-cta:active,.theme-toggle-btn:active,.mobile-menu-btn:active{transform:none}}