.header{position:fixed;top:0;left:0;right:0;height:72px;background:#fffffff2;backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);border-bottom:1px solid transparent;z-index:var(--z-fixed);transition:border-color var(--transition-base)}.header--scrolled{border-bottom:1px solid var(--color-gray-300)}.header__content{display:flex;align-items:center;justify-content:space-between;height:100%}.header__logo{font-size:var(--text-body-lg);font-weight:var(--font-bold);color:var(--color-black);letter-spacing:var(--tracking-normal);text-decoration:none;transition:opacity var(--transition-base)}.header__logo:hover{opacity:.7}.header__logo-text{display:inline-block}.header__nav{display:flex;gap:var(--space-2xl);align-items:center}.header__nav-link{position:relative;font-size:var(--text-body);font-weight:var(--font-medium);color:var(--color-gray-600);letter-spacing:var(--tracking-normal);text-decoration:none;padding-bottom:4px;transition:color var(--transition-base)}.header__nav-link:after{content:"";position:absolute;bottom:0;left:0;width:0;height:1px;background-color:currentColor;transition:width var(--transition-smooth)}.header__nav-link:hover{color:var(--color-black)}.header__nav-link:hover:after{width:100%}.header__nav-link--active{color:var(--color-black);border-bottom:var(--border-width-thick) solid var(--color-accent)}.header__nav-link--active:after{display:none}.theme-toggle{display:flex;align-items:center;justify-content:center;width:40px;height:40px;padding:0;border:1px solid var(--color-gray-300);background:transparent;color:var(--color-black);cursor:pointer;transition:all var(--transition-base)}.theme-toggle:hover{border-color:var(--color-black);background:var(--color-gray-50)}.theme-toggle:active{transform:scale(.95)}.header__menu-toggle{display:none;flex-direction:column;justify-content:space-between;width:24px;height:24px;padding:0;border:none;background:transparent;cursor:pointer}.header__menu-toggle span{display:block;width:100%;height:2px;background:var(--color-black);transition:all var(--transition-smooth)}.header__nav--mobile{position:fixed;top:72px;left:0;right:0;bottom:0;background:#fffffffa;backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);display:flex;flex-direction:column;align-items:center;justify-content:center;gap:var(--space-xl);padding:var(--space-3xl);transform:translate(100%);transition:transform var(--transition-smooth);z-index:var(--z-dropdown)}.header__nav--mobile.is-open{transform:translate(0)}.header__nav--mobile .header__nav-link{font-size:var(--text-h3);text-align:center}@media (min-width: 768px) and (max-width: 1023px){.header__nav{gap:var(--space-xl)}}@media (max-width: 767px){.header__nav{display:none}.header__menu-toggle,.header__nav--mobile{display:flex}}@media (min-width: 768px){.header__nav--mobile{display:none}}@media (prefers-reduced-motion: reduce){.header,.header__nav-link,.header__nav-link:after,.header__nav--mobile,.theme-toggle{transition:none}}[data-theme=dark] .header{background:#0a0a0af2;border-bottom-color:transparent}[data-theme=dark] .header--scrolled{border-bottom-color:var(--color-charcoal)}[data-theme=dark] .header__logo{color:var(--color-white)}[data-theme=dark] .header__nav-link{color:var(--color-gray-300)}[data-theme=dark] .header__nav-link:hover,[data-theme=dark] .header__nav-link--active{color:var(--color-white)}[data-theme=dark] .theme-toggle{border-color:var(--color-gray-600);color:var(--color-white)}[data-theme=dark] .theme-toggle:hover{border-color:var(--color-white);background:var(--color-charcoal)}[data-theme=dark] .header__nav--mobile{background:#0a0a0afa}[data-theme=dark] .header__menu-toggle span{background:var(--color-white)}