.header { position:fixed; top:0; left:0; right:auto; width:100%; transition:height .34s cubic-bezier(.2,.72,.22,1),padding .34s cubic-bezier(.2,.72,.22,1),background .35s ease,border-color .35s ease,box-shadow .35s ease; }
.header.is-scrolled { top:0; left:0; width:100%; height:74px; padding:0 max(36px,calc((100vw - 1280px)/2)); background:rgba(1,31,120,.84); border-bottom:1px solid rgba(255,255,255,.2); box-shadow:0 9px 28px rgba(0,10,65,.18); backdrop-filter:blur(13px) saturate(1.12); -webkit-backdrop-filter:blur(13px) saturate(1.12); }
.header.is-scrolled:after { content:""; position:absolute; right:max(36px,calc((100vw - 1280px)/2)); bottom:-1px; left:max(36px,calc((100vw - 1280px)/2)); height:1px; background:linear-gradient(90deg,transparent,#F28209 32%,#F28209 68%,transparent); animation:header-trace 3.2s ease-in-out infinite; }
.header.is-scrolled .brand-logo { width:130px; transition:width .36s cubic-bezier(.2,.72,.22,1); }
.back-to-top { position:fixed; z-index:12; right:28px; bottom:28px; display:grid; width:42px; height:42px; padding:0; place-items:center; border:0; border-radius:50%; background:#F28209; color:#011F78; box-shadow:0 12px 26px rgba(0,10,65,.24); cursor:pointer; opacity:0; pointer-events:none; transform:translateY(12px) scale(.88); transition:opacity .25s ease,transform .25s cubic-bezier(.2,.72,.22,1),background .2s ease; }
.back-to-top.is-visible { opacity:1; pointer-events:auto; transform:none; }
.back-to-top:hover { background:#fff; transform:translateY(-3px); }
.back-to-top svg { width:19px; height:19px; fill:none; stroke:currentColor; stroke-width:2; stroke-linecap:round; stroke-linejoin:round; }
@keyframes header-trace { 0%,100% { opacity:.45; transform:scaleX(.72); } 50% { opacity:1; transform:scaleX(1); } }
@media(max-width:720px) { .header.is-scrolled { top:0; width:100%; height:64px; padding:0 18px; } .header.is-scrolled:after { right:18px; left:18px; } .header.is-scrolled .brand-logo { width:112px; } .back-to-top { right:16px; bottom:16px; width:38px; height:38px; } }
@media(prefers-reduced-motion:reduce) { .header,.header.is-scrolled { transition:none; } .header.is-scrolled:after { animation:none; } }