:root { --header-height: 72px; --navy: #00266f; --blue: #073cb7; --orange: #ff502e; --lime: #c8f333; }
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: var(--header-height); }
body { margin: 0; background: var(--blue); color: #fff; font-family: Arial, Helvetica, sans-serif; overflow-x: hidden; }
.skip-link { position: fixed; top: -60px; left: 12px; z-index: 2000; padding: 10px 14px; background: var(--lime); color: #00184c; border-radius: 6px; }
.skip-link:focus { top: 10px; }
.site-header { position: fixed; inset: 0 0 auto; z-index: 1000; min-height: var(--header-height); display: flex; align-items: center; gap: 24px; padding: 10px clamp(14px, 3.2vw, 62px); background: rgba(0, 28, 88, .92); border-bottom: 1px solid rgba(255,255,255,.16); backdrop-filter: blur(12px); transition: box-shadow .2s, background .2s; }
.site-header.scrolled { background: rgba(0, 22, 70, .98); box-shadow: 0 8px 25px rgba(0,0,0,.25); }
.brand { display: flex; align-items: center; gap: 7px; color: #fff; font-weight: 800; text-decoration: none; white-space: nowrap; }
.brand strong { color: var(--orange); font-size: 1.55rem; }
.countdown { display: flex; flex-direction: column; white-space: nowrap; }
.countdown > span { color: var(--lime); font-size: .61rem; font-weight: 800; letter-spacing: .05em; text-transform: uppercase; }
.countdown div { display: flex; align-items: baseline; gap: 4px; margin-top: 4px; }
.countdown b { font-size: .82rem; font-variant-numeric: tabular-nums; }
.countdown small { margin-right: 2px; color: var(--orange); font-size: .55rem; font-weight: 800; }
.nav-menu { display: flex; gap: clamp(10px, 1.45vw, 23px); align-items: center; margin-left: auto; }
.nav-menu a { color: #fff; font-size: .78rem; font-weight: 700; text-decoration: none; }
.nav-menu a:hover, .nav-menu a:focus-visible { color: var(--lime); }
.menu-toggle { display: none; margin-left: auto; padding: 8px; border: 0; background: transparent; cursor: pointer; }
.menu-toggle span { display: block; width: 26px; height: 3px; margin: 5px; border-radius: 3px; background: #fff; transition: .2s; }
main { padding-top: var(--header-height); }
section { position: relative; width: 100%; margin: 0; padding: 0; line-height: 0; scroll-margin-top: var(--header-height); }
#inicio { aspect-ratio: 1920 / 1555; }
#inscripcion { aspect-ratio: 1920 / 2895; }
#categorias { aspect-ratio: 1920 / 1888; }
#expo { aspect-ratio: 1920 / 1662; }
#carrera { aspect-ratio: 1920 / 1800; }
#recorrido { aspect-ratio: 1920 / 2080; }
#premios { aspect-ratio: 1920 / 5630; }
#normas { aspect-ratio: 1920 / 2869; }
picture, picture img { display: block; width: 100%; }
picture img { height: auto; margin: 0; }
.registration-button { position: absolute; top: 64%; left: 79%; transform: translate(-50%, -50%); z-index: 2; padding: clamp(9px, 1vw, 16px) clamp(20px, 2.5vw, 46px); color: #fff; background: var(--orange); border: 3px solid #fff; border-radius: 999px; box-shadow: 0 7px 22px rgba(0,0,0,.28); font-size: clamp(.8rem, 1.4vw, 1.3rem); font-weight: 900; line-height: 1; text-decoration: none; text-transform: uppercase; white-space: nowrap; }
.registration-button:hover, .registration-button:focus-visible { background: var(--navy); outline: 3px solid var(--lime); outline-offset: 3px; }
footer { padding: 26px 16px 32px; text-align: center; background: #00194d; }
footer p { margin: 0 0 5px; font-size: .85rem; }
footer a { color: var(--lime); font-size: .85rem; text-decoration: none; }
@media (min-width: 1921px) { main { max-width: 1920px; margin: 0 auto; box-shadow: 0 0 60px rgba(0,0,0,.35); } }
@media (max-width: 980px) {
  :root { --header-height: 64px; }
  .countdown { margin-left: auto; }
  .menu-toggle { display: block; margin-left: 0; }
  .nav-menu { position: fixed; top: var(--header-height); right: 0; width: min(82vw, 340px); height: calc(100dvh - var(--header-height)); flex-direction: column; justify-content: center; gap: 21px; padding: 28px; background: rgba(0,22,70,.99); transform: translateX(100%); transition: transform .25s ease; }
  .nav-menu.open { transform: translateX(0); }
  .nav-menu a { font-size: 1rem; }
  .menu-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(8px) rotate(45deg); }
  .menu-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
  .menu-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-8px) rotate(-45deg); }
}
@media (max-width: 520px) {
  .site-header { gap: 8px; padding-inline: 10px; }
  .brand span { display: none; }
  .brand strong { font-size: 1.3rem; }
  .countdown > span { font-size: .47rem; }
  .countdown b { font-size: .68rem; }
  .countdown small { font-size: .44rem; }
  .registration-button { left: 76%; padding: 7px 14px; border-width: 2px; font-size: .65rem; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } *, *::before, *::after { transition-duration: .01ms !important; } }