/* ==========================================================
   rejilladeacero.com — Hoja de estilos
   Énfasis: rojo y gris · Fondos: gris, blanco y negro
   Mobile-first
   ========================================================== */

:root {
  --rojo: #C41E28;
  --rojo-hover: #A3161F;
  --rojo-claro: #E8454E;
  --gris-acero: #6B7177;
  --gris-medio: #A9AEB3;
  --gris-fondo: #EDEEEF;
  --gris-linea: #D5D8DB;
  --blanco: #FFFFFF;
  --negro: #1A1C1E;
  --negro-2: #26292C;
  --texto: #24272A;
  --texto-suave: #50565C;

  --f-display: "Barlow Condensed", "Arial Narrow", "Roboto Condensed", Arial, sans-serif;
  --f-body: "Barlow", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;

  --wrap: 1180px;
  --pad: clamp(1.25rem, 4vw, 2.5rem);
  --sec: clamp(3.5rem, 8vw, 6.5rem);
  --radius: 4px;
  --header-h: 68px;
}

/* ---------- Base ---------- */
*, *::before, *::after { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 12px);
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: var(--f-body);
  font-size: 1.0625rem;
  line-height: 1.65;
  color: var(--texto);
  background: var(--blanco);
  -webkit-font-smoothing: antialiased;
}

img, svg { max-width: 100%; height: auto; display: block; }

h1, h2, h3 {
  font-family: var(--f-display);
  line-height: 1.08;
  margin: 0 0 .6em;
  letter-spacing: -.005em;
}
h2 { font-size: clamp(2rem, 4.6vw, 3rem); font-weight: 700; }
h3 { font-size: 1.4rem; font-weight: 600; }
p { margin: 0 0 1.1em; }

a { color: var(--rojo); text-underline-offset: 3px; text-decoration-thickness: 1px; }
a:hover { color: var(--rojo-hover); text-decoration-thickness: 2px; }

:focus-visible {
  outline: 3px solid var(--rojo-claro);
  outline-offset: 3px;
}

.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--pad);
}
.narrow { max-width: 860px; }

.skip-link {
  position: absolute;
  left: 1rem;
  top: -100px;
  z-index: 200;
  background: var(--rojo);
  color: var(--blanco);
  padding: .6rem 1rem;
  border-radius: var(--radius);
}
.skip-link:focus { top: 1rem; }

/* ---------- Botones ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: .75rem 1.6rem;
  font-family: var(--f-display);
  font-size: 1.15rem;
  font-weight: 600;
  letter-spacing: .02em;
  text-decoration: none;
  border-radius: var(--radius);
  border: 2px solid transparent;
  transition: background-color .2s, color .2s, border-color .2s;
}
.btn-red { background: var(--rojo); color: var(--blanco); }
.btn-red:hover { background: var(--rojo-hover); color: var(--blanco); }
.btn-ghost { border-color: var(--gris-medio); color: var(--blanco); }
.btn-ghost:hover { border-color: var(--blanco); color: var(--blanco); background: rgba(255,255,255,.08); }
.btn-white { background: var(--blanco); color: var(--rojo); }
.btn-white:hover { background: var(--negro); color: var(--blanco); }
.btn-lg { font-size: 1.3rem; padding: 1rem 2.2rem; }

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--negro);
  border-bottom: 3px solid var(--rojo);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: var(--header-h);
  position: relative;
}

.brand {
  display: flex;
  align-items: center;
  gap: .65rem;
  color: var(--blanco);
  text-decoration: none;
}
.brand:hover { color: var(--blanco); }
.brand-mark { width: 38px; height: 38px; color: var(--gris-medio); }
.brand-text {
  font-family: var(--f-display);
  font-weight: 800;
  font-size: 1.55rem;
  line-height: 1;
  display: flex;
  flex-direction: column;
}
.brand-sub {
  font-weight: 500;
  font-size: .95rem;
  color: var(--gris-medio);
  letter-spacing: .04em;
}

/* Menú móvil (sin JavaScript) */
.menu-toggle {
  position: absolute;
  opacity: 0;
  width: 48px;
  height: 48px;
  right: var(--pad);
  margin: 0;
  cursor: pointer;
  z-index: 2;
}
.menu-button {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 48px;
  height: 48px;
  padding: 12px;
  border: 1px solid var(--negro-2);
  border-radius: var(--radius);
}
.menu-button span {
  display: block;
  height: 2px;
  background: var(--blanco);
  transition: transform .25s, opacity .2s;
}
.menu-toggle:focus-visible + .menu-button { outline: 3px solid var(--rojo-claro); outline-offset: 2px; }
.menu-toggle:checked + .menu-button span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.menu-toggle:checked + .menu-button span:nth-child(2) { opacity: 0; }
.menu-toggle:checked + .menu-button span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.main-nav {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background: var(--negro);
  border-bottom: 3px solid var(--rojo);
  max-height: 0;
  overflow: hidden;
  visibility: hidden;
  transition: max-height .3s ease, visibility .3s;
}
.menu-toggle:checked ~ .main-nav { max-height: 480px; visibility: visible; }
.main-nav ul {
  list-style: none;
  margin: 0;
  padding: .5rem var(--pad) 1.25rem;
}
.main-nav a {
  display: block;
  padding: .85rem 0;
  color: var(--blanco);
  font-family: var(--f-display);
  font-size: 1.25rem;
  font-weight: 500;
  text-decoration: none;
  border-bottom: 1px solid var(--negro-2);
}
.main-nav a:hover { color: var(--rojo-claro); }
.main-nav .nav-cta {
  margin-top: 1rem;
  text-align: center;
  background: var(--rojo);
  border-radius: var(--radius);
  border: 0;
}
.main-nav .nav-cta:hover { background: var(--rojo-hover); color: var(--blanco); }

@media (min-width: 960px) {
  .menu-toggle, .menu-button { display: none; }
  .main-nav {
    position: static;
    max-height: none;
    visibility: visible;
    overflow: visible;
    background: none;
    border: 0;
  }
  .main-nav ul { display: flex; align-items: center; gap: 1.75rem; padding: 0; }
  .main-nav a { padding: .4rem 0; border: 0; font-size: 1.1rem; }
  .main-nav .nav-cta { margin: 0; padding: .55rem 1.3rem; }
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  color: var(--blanco);
  background-color: var(--negro);
  /* Para usar una foto real: sube img/hero-rejilla.webp y cambia la URL de abajo */
  background-image:
    linear-gradient(100deg, rgba(26,28,30,.96) 0%, rgba(26,28,30,.82) 45%, rgba(26,28,30,.35) 100%),
    url("../img/hero-rejilla.svg");
  background-size: cover, cover;
  background-position: center, center;
  background-repeat: no-repeat;
  padding-block: clamp(4.5rem, 12vw, 9rem) clamp(3.5rem, 8vw, 6rem);
}
.hero-inner { max-width: var(--wrap); }
.hero-kicker {
  display: inline-block;
  font-family: var(--f-display);
  font-weight: 600;
  font-size: 1.1rem;
  color: var(--gris-medio);
  padding-left: .9rem;
  border-left: 4px solid var(--rojo);
  margin-bottom: 1.4rem;
}
.hero h1 {
  font-size: clamp(2.6rem, 7.5vw, 5.4rem);
  font-weight: 800;
  line-height: .98;
  max-width: 15ch;
  margin-bottom: .45em;
  text-wrap: balance;
}
.hero-sub {
  font-size: clamp(1.1rem, 2.2vw, 1.3rem);
  color: #D9DCDF;
  max-width: 58ch;
  margin-bottom: 2rem;
}
.hero-actions { display: flex; flex-wrap: wrap; gap: .9rem; margin-bottom: 3rem; }
.hero-facts {
  list-style: none;
  margin: 0;
  padding: 1.5rem 0 0;
  border-top: 1px solid rgba(255,255,255,.18);
  display: grid;
  gap: 1rem;
  max-width: 900px;
}
.hero-facts li { color: var(--gris-medio); font-size: .98rem; line-height: 1.35; }
.hero-facts strong {
  display: block;
  font-family: var(--f-display);
  font-size: 1.9rem;
  font-weight: 700;
  color: var(--blanco);
}
@media (min-width: 640px) {
  .hero-facts { grid-template-columns: repeat(3, 1fr); gap: 2rem; }
}
@media (max-width: 479px) {
  .hero-actions .btn { width: 100%; }
}

/* ---------- Secciones ---------- */
.section { padding-block: var(--sec); }
.section-white { background: var(--blanco); }
.section-gray { background: var(--gris-fondo); }
.section-black { background: var(--negro); color: #E4E6E8; }
.section-black h2, .section-black h3 { color: var(--blanco); }
.section-black a { color: var(--rojo-claro); }
.section-black a:hover { color: var(--blanco); }
.section-black .btn-red,
.section-black .btn-red:hover { color: var(--blanco); }
.section-red { background: var(--rojo); color: var(--blanco); }

.lead {
  font-size: 1.2rem;
  color: var(--texto-suave);
  max-width: 62ch;
  margin-bottom: 2.5rem;
}
.section-black .lead { color: var(--gris-medio); }

.prose { max-width: 66ch; }
.prose strong { color: var(--negro); }

.split { display: grid; gap: 3rem; }
@media (min-width: 900px) {
  .split { grid-template-columns: 1.4fr 1fr; gap: 4.5rem; align-items: start; }
  .split-reverse { grid-template-columns: 1.2fr 1fr; }
}

/* Ventajas */
.key-points {
  background: var(--gris-fondo);
  border-top: 4px solid var(--rojo);
  padding: 2rem 1.75rem;
}
.key-points h3 { font-size: 1.6rem; }
.key-points dl { margin: 0; }
.key-points dt {
  font-family: var(--f-display);
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--negro);
  margin-top: 1rem;
}
.key-points dt:first-child { margin-top: 0; }
.key-points dd { margin: .15rem 0 0; color: var(--texto-suave); font-size: .98rem; }

/* Tipos */
.types {
  display: grid;
  gap: 0;
  border-top: 1px solid var(--gris-linea);
}
.type {
  padding: 1.75rem 0;
  border-bottom: 1px solid var(--gris-linea);
}
.type h3 { color: var(--negro); }
.type h3::before {
  content: "";
  display: inline-block;
  width: 14px;
  height: 14px;
  margin-right: .6rem;
  background: var(--rojo);
  vertical-align: .05em;
}
.type p { margin: 0; color: var(--texto-suave); max-width: 60ch; }
@media (min-width: 760px) {
  .types { grid-template-columns: 1fr 1fr; column-gap: 3.5rem; }
}
.inline-cta { margin: 2.5rem 0 0; font-size: 1.1rem; font-weight: 500; }

/* Proceso */
.steps {
  list-style: none;
  counter-reset: paso;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 2rem;
}
.steps li {
  counter-increment: paso;
  position: relative;
  padding-top: 3.6rem;
  border-top: 3px solid var(--gris-acero);
}
.steps li::before {
  content: counter(paso);
  position: absolute;
  top: .8rem;
  left: 0;
  font-family: var(--f-display);
  font-size: 2.2rem;
  font-weight: 800;
  line-height: 1;
  color: var(--rojo);
}
.steps p { color: var(--texto-suave); margin: 0; }
@media (min-width: 760px) { .steps { grid-template-columns: repeat(2, 1fr); gap: 2.5rem; } }
@media (min-width: 1080px) { .steps { grid-template-columns: repeat(4, 1fr); } }

/* Especificaciones */
.table-scroll {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  border: 1px solid var(--negro-2);
  border-radius: var(--radius);
}
.spec-table {
  width: 100%;
  min-width: 560px;
  border-collapse: collapse;
  font-size: 1rem;
}
.spec-table caption {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}
.spec-table thead th {
  background: var(--rojo);
  color: var(--blanco);
  font-family: var(--f-display);
  font-size: 1.15rem;
  font-weight: 600;
  text-align: left;
  padding: .9rem 1.25rem;
}
.spec-table tbody th,
.spec-table tbody td {
  text-align: left;
  vertical-align: top;
  padding: .9rem 1.25rem;
  border-top: 1px solid var(--negro-2);
}
.spec-table tbody th {
  width: 32%;
  font-weight: 600;
  color: var(--blanco);
  background: var(--negro-2);
}
.spec-table tbody tr:nth-child(even) td { background: #212427; }

.spec-notes { display: grid; gap: 1.5rem; margin-top: 2.5rem; }
.note {
  border-left: 4px solid var(--gris-acero);
  padding: .25rem 0 .25rem 1.4rem;
}
.note p { margin: 0; color: #C9CDD1; }
.note strong { color: var(--blanco); }
@media (min-width: 860px) { .spec-notes { grid-template-columns: 1fr 1fr; gap: 3rem; } }

/* Aplicaciones */
.check-list { list-style: none; margin: 0; padding: 0; }
.check-list li {
  position: relative;
  padding: .55rem 0 .55rem 2rem;
  border-bottom: 1px solid var(--gris-linea);
}
.check-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 1.05rem;
  width: 14px;
  height: 8px;
  border-left: 3px solid var(--rojo);
  border-bottom: 3px solid var(--rojo);
  transform: rotate(-45deg);
}
.figure-grid { margin: 0; }
.detail-svg { width: 100%; border-radius: var(--radius); }
.figure-grid figcaption { margin-top: .75rem; font-size: .92rem; color: var(--texto-suave); }

/* Banda roja */
.band { text-align: left; }
.band h2 { color: var(--blanco); max-width: 22ch; }
.band p { font-size: 1.2rem; max-width: 56ch; margin-bottom: 2rem; color: #FBE3E4; }

/* FAQ */
.faq { border-top: 2px solid var(--negro); }
.faq details { border-bottom: 1px solid var(--gris-medio); }
.faq summary {
  list-style: none;
  cursor: pointer;
  position: relative;
  padding: 1.3rem 3rem 1.3rem 0;
  font-family: var(--f-display);
  font-size: 1.3rem;
  font-weight: 600;
  color: var(--negro);
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+";
  position: absolute;
  right: .25rem;
  top: 50%;
  transform: translateY(-50%);
  font-size: 1.8rem;
  font-weight: 500;
  color: var(--rojo);
  transition: transform .2s;
}
.faq details[open] summary::after { transform: translateY(-50%) rotate(45deg); }
.faq summary:hover { color: var(--rojo); }
.faq details p { margin: 0 0 1.4rem; color: var(--texto-suave); max-width: 68ch; }

/* CTA final */
.cta-final { border-top: 6px solid var(--rojo); }
.cta-inner { display: grid; gap: 2rem; align-items: center; }
.cta-inner h2 { max-width: 20ch; }
.cta-inner p { color: var(--gris-medio); font-size: 1.15rem; max-width: 52ch; margin: 0; }
@media (min-width: 860px) {
  .cta-inner { grid-template-columns: 1fr auto; gap: 4rem; }
}

/* ---------- Footer ---------- */
.site-footer {
  background: #111314;
  color: var(--gris-medio);
  padding-top: 3.5rem;
  font-size: .98rem;
}
.footer-grid { display: grid; gap: 2.5rem; padding-bottom: 2.5rem; }
@media (min-width: 760px) { .footer-grid { grid-template-columns: 2fr 1fr 1fr; } }
.footer-logo {
  font-family: var(--f-display);
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--blanco);
  margin-bottom: .5rem;
}
.footer-logo span { color: var(--rojo-claro); font-weight: 500; }
.footer-brand p:last-child { max-width: 44ch; }
.footer-title {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--blanco);
  margin-bottom: .8rem;
}
.site-footer ul { list-style: none; margin: 0; padding: 0; }
.site-footer li { margin-bottom: .5rem; }
.site-footer a { color: var(--gris-medio); text-decoration: none; }
.site-footer a:hover { color: var(--blanco); text-decoration: underline; }
.footer-bottom {
  border-top: 1px solid var(--negro-2);
  padding-block: 1.4rem;
  font-size: .88rem;
}
.footer-bottom p { margin: 0; }

/* ---------- Página 404 ---------- */
.error-page {
  min-height: 70vh;
  display: grid;
  place-items: center;
  text-align: center;
  padding-block: var(--sec);
}
.error-page h1 { font-size: clamp(3rem, 10vw, 6rem); color: var(--negro); }
.error-page p { color: var(--texto-suave); }

/* ---------- Accesibilidad / movimiento ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
}

/* ---------- Impresión ---------- */
@media print {
  .site-header, .hero-actions, .cta-final, .section-red { display: none; }
  .hero, .section-black { background: none; color: #000; }
  .hero h1, .section-black h2, .section-black h3 { color: #000; }
}