.site-header{background:red;border-bottom:1px solid #e5e7eb;position:sticky;top:0;z-index:100}.header-container{max-width:1280px;margin:0 auto;padding:1rem 2rem;display:flex;justify-content:space-between;align-items:center}.logo{font-size:1.5rem;font-weight:700;color:#111;text-decoration:none}.main-nav ul{display:flex;gap:2rem;list-style:none;margin:0;padding:0}.main-nav a{color:#374151;text-decoration:none;font-weight:500;transition:color .2s}.main-nav a:hover{color:#111}@media(max-width:768px){.header-container{flex-direction:column;gap:1rem}.main-nav ul{gap:1rem}}