*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

    :root {
      --black: #000000;
      --dark-gray: #404040;
      --mid-gray: #808080;
      --light-gray: #D9D9D9;
      --off-white: #F5F5F5;
      --white: #FFFFFF;
      --red: #FF0000;
      --red-dark: #ff0000;
      --font: Calibri, Carlito, "Segoe UI", Arial, sans-serif;
      --max-w: 860px;
    }

    html { scroll-behavior: smooth; font-size: 16px; }
    body { font-family: var(--font); color: var(--black); background: var(--white); line-height: 1.7; -webkit-font-smoothing: antialiased; }
    img { max-width: 100%; display: block; }
    a { color: inherit; text-decoration: none; }
    ul { padding-left: 1.2rem; }
    p { margin-bottom: 1rem; }

    h1, h2, h3, h4 { font-family: var(--font); font-weight: 700; line-height: 1.2; letter-spacing: -0.01em; }
    h1 { font-size: clamp(2rem, 5vw, 3rem); }
    h2 { font-size: clamp(1.3rem, 3vw, 1.8rem); margin-bottom: 0.9rem; }

    .btn {
      display: inline-block;
      font-family: var(--font);
      font-size: 0.9rem;
      font-weight: 700;
      letter-spacing: 0.04em;
      text-transform: uppercase;
      padding: 14px 28px;
      border: 2px solid transparent;
      cursor: pointer;
      transition: background 0.15s, color 0.15s, border-color 0.15s;
      white-space: nowrap;
    }
    .btn--primary { background: var(--red); color: var(--white); border-color: var(--red); }
    .btn--primary:hover { background: var(--red-dark); border-color: var(--red-dark); }
    .btn--secondary { background: transparent; color: var(--black); border-color: var(--black); }
    .btn--secondary:hover { background: var(--black); color: var(--white); }

    .site-header {
      position: sticky; top: 0; z-index: 100;
      background: var(--white);
      border-bottom: 1px solid var(--light-gray);
    }
    .site-header__inner {
      max-width: 1160px; margin: 0 auto; padding: 0 24px;
      height: 64px; display: flex; align-items: center;
      justify-content: space-between; gap: 24px;
    }
    .site-header__logo { display: flex; align-items: center; gap: 10px; flex-shrink: 0; }
    .site-header__logo-img { height: 32px; width: auto; }
    .site-header__logo-text { display: flex; flex-direction: column; line-height: 1.1; }
.brand-p2p { font-size: 1rem; font-weight: 700; color: var(--black); letter-spacing: -0.01em; }
    .brand-p2p span { color: var(--red); }

    .site-nav { display: flex; }
    .site-nav__list { display: flex; gap: 4px; list-style: none; }
    .site-nav__list a {
      display: block; padding: 8px 14px;
      font-size: 0.82rem; font-weight: 600;
      letter-spacing: 0.04em; text-transform: uppercase;
      color: var(--dark-gray);
      border-bottom: 2px solid transparent;
      transition: color 0.12s, border-color 0.12s;
    }
    .site-nav__list a:hover,
    .site-nav__list a[aria-current="page"] { color: var(--black); border-bottom-color: var(--red); }

    .lang-switcher {
      display: flex; align-items: center; gap: 2px; flex-shrink: 0;
      border: 1px solid rgba(0,0,0,0.15); border-radius: 4px;
      padding: 3px 4px; background: rgba(255,255,255,0.06);
    }
    .lang-switcher__item {
      display: flex; align-items: center; gap: 4px;
      padding: 3px 6px; border-radius: 3px;
      font-size: 0.68rem; font-weight: 700;
      letter-spacing: 0.06em; text-transform: uppercase;
      color: var(--dark-gray);
      transition: background 0.12s, color 0.12s;
    }
    .lang-switcher__item svg { width: 16px; height: 11px; display: block; border-radius: 1px; }
    .lang-switcher__item:hover { background: rgba(0,0,0,0.06); color: var(--black); }
    .lang-switcher__item.is-active { background: var(--black); color: var(--white); }
    .lang-switcher__sep { width: 1px; height: 14px; background: rgba(0,0,0,0.12); flex-shrink: 0; }

    .site-header__cta { flex-shrink: 0; }
    .nav-toggle { display: none; background: none; border: none; cursor: pointer; padding: 4px; color: var(--black); }

    @media (max-width: 768px) {
      .site-nav, .site-header__cta, .lang-switcher { display: none; }
      .nav-toggle { display: flex; align-items: center; }
    }

    .page-header {
      background: var(--black); color: var(--white);
      padding: 64px 24px 56px;
    }
    .page-header__inner { max-width: var(--max-w); margin: 0 auto; }
    .breadcrumb { display: flex; align-items: center; gap: 6px; font-size: 0.75rem; color: #888; margin-bottom: 20px; }
    .breadcrumb a { color: #888; }
    .breadcrumb a:hover { color: var(--light-gray); }
    .breadcrumb__sep { color: #555; }
    .page-header h1 { color: var(--white); margin-bottom: 16px; }
    .page-header__desc { font-size: 1.05rem; color: var(--light-gray); max-width: 720px; }

    .article-wrapper {
      padding: 64px 24px 40px;
      background: var(--white);
    }
    .article-inner { max-width: var(--max-w); margin: 0 auto; }

    .article-meta {
      display: flex;
      gap: 14px;
      flex-wrap: wrap;
      align-items: center;
      font-size: 0.78rem;
      font-weight: 700;
      letter-spacing: 0.08em;
      text-transform: uppercase;
      color: var(--mid-gray);
      margin-bottom: 30px;
      border-bottom: 1px solid var(--light-gray);
      padding-bottom: 14px;
    }

    .article-lead {
      font-size: 1.1rem;
      line-height: 1.75;
      color: var(--dark-gray);
      margin-bottom: 32px;
    }

    .article-content h2 {
      margin-top: 36px;
    }
    .article-content ul {
      margin: 8px 0 16px;
    }
    .article-content li {
      margin-bottom: 8px;
    }

    .article-figure {
      margin: 0 0 30px;
      border: 1px solid var(--light-gray);
      background: #fafafa;
      padding: 10px;
    }
    .article-figure img {
      width: 100%;
      height: auto;
      display: block;
    }
    .article-figure figcaption {
      font-size: 0.84rem;
      color: var(--mid-gray);
      margin-top: 10px;
      line-height: 1.5;
    }
    .article-figure--medium {
      max-width: 620px;
      margin-left: auto;
      margin-right: auto;
    }
    .article-figure--small {
      max-width: 460px;
      margin-left: auto;
      margin-right: auto;
    }

    .highlight-box {
      border-left: 4px solid var(--red);
      background: var(--off-white);
      padding: 20px;
      margin: 24px 0;
    }

    .article-nav {
      margin-top: 42px;
      padding-top: 18px;
      border-top: 1px solid var(--light-gray);
      display: flex;
      justify-content: space-between;
      gap: 14px;
      flex-wrap: wrap;
    }

    .final-cta {
      background: var(--black);
      color: var(--white);
      padding: 80px 24px;
      text-align: center;
    }
    .final-cta__inner { max-width: 720px; margin: 0 auto; }
    .final-cta .section-label {
      display: block;
      font-size: 0.7rem;
      font-weight: 700;
      letter-spacing: 0.15em;
      text-transform: uppercase;
      color: var(--red);
      margin-bottom: 12px;
    }
    .final-cta h2 { color: var(--white); margin-bottom: 16px; }
    .final-cta p { font-size: 1.05rem; color: var(--light-gray); margin-bottom: 36px; }

    .site-footer { background: var(--dark-gray); color: var(--light-gray); padding: 56px 24px 32px; }
    .site-footer__inner { max-width: 1160px; margin: 0 auto; }
    .site-footer__grid {
      display: grid; grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 48px; padding-bottom: 48px; border-bottom: 1px solid #555;
    }
    .footer-brand__logo { display: flex; align-items: center; gap: 10px; margin-bottom: 16px; }
    .footer-brand__logo-mark {
      width: 32px; height: 32px; background: var(--white);
      display: flex; align-items: center; justify-content: center;
    }
    .footer-brand__logo-mark svg { width: 18px; height: 18px; stroke: var(--black); fill: none; stroke-width: 2; }
    .footer-brand__name { font-size: 1rem; font-weight: 700; color: var(--white); }
    .footer-brand__desc { font-size: 0.82rem; line-height: 1.6; color: #aaa; max-width: 280px; }
    .footer-col h4 { font-size: 0.7rem; font-weight: 700; letter-spacing: 0.15em; text-transform: uppercase; color: var(--white); margin-bottom: 16px; }
    .footer-col ul { list-style: none; display: flex; flex-direction: column; gap: 8px; padding-left: 0; }
    .footer-col ul li a { font-size: 0.82rem; color: #aaa; transition: color 0.12s; }
    .footer-col ul li a:hover { color: var(--white); }
    .footer-contact-item { display: flex; align-items: flex-start; gap: 10px; font-size: 0.82rem; color: #aaa; line-height: 1.4; margin-bottom: 10px; }
    .footer-contact-item svg { width: 14px; height: 14px; stroke: var(--mid-gray); fill: none; stroke-width: 2; flex-shrink: 0; margin-top: 2px; }
    .footer-contact-item a { color: #aaa; transition: color 0.12s; }
    .footer-contact-item a:hover { color: var(--white); }
    .site-footer__bottom { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding-top: 24px; font-size: 0.75rem; color: #777; flex-wrap: wrap; }
    .site-footer__bottom a { color: #777; transition: color 0.12s; }
    .site-footer__bottom a:hover { color: var(--light-gray); }

    @media (max-width: 900px) {
      .site-footer__grid { grid-template-columns: 1fr 1fr; gap: 32px; }
      .footer-brand { grid-column: 1 / -1; }
    }
    @media (max-width: 500px) {
      .site-footer__grid { grid-template-columns: 1fr; }
    }
  
    /* --- Categorías transversales --- */
    .entry-category {
      display: inline-block;
      font-size: 0.68rem; font-weight: 700;
      letter-spacing: 0.06em; text-transform: uppercase;
      padding: 3px 8px; border-radius: 2px;
    }
    .entry-category--validacion        { background: #f5f5f5; color: #ff0000; border: 1px solid #ff0000; }
    .entry-category--materiales        { background: #e8f0fc; color: #1a3f7a; border: 1px solid #b8ceee; }
    .entry-category--industrializacion { background: #eef7ee; color: #1a5c20; border: 1px solid #b6d9b6; }

    /* --- Artículos relacionados --- */
    .related-posts { padding: 64px 24px; background: var(--off-white, #f5f5f5); }
    .related-posts__inner { max-width: 900px; margin: 0 auto; }
    .related-posts__title {
      font-size: 1.05rem; font-weight: 700; letter-spacing: -0.01em;
      margin-bottom: 28px; padding-bottom: 14px;
      border-bottom: 1px solid var(--light-gray, #d9d9d9);
    }
    .related-grid {
      display: grid; grid-template-columns: 1fr 1fr; gap: 20px;
    }
    .related-card {
      background: #fff; border: 1px solid var(--light-gray, #d9d9d9); padding: 22px;
    }
    .related-card__cat  { margin-bottom: 10px; }
    .related-card__title { font-size: 0.95rem; font-weight: 700; line-height: 1.35; margin-bottom: 10px; }
    .related-card__title a { text-decoration: none; color: inherit; }
    .related-card__title a:hover { text-decoration: underline; }
    .related-card__excerpt { font-size: 0.84rem; color: var(--dark-gray, #404040); line-height: 1.5; margin-bottom: 14px; }
    .related-card__link {
      font-size: 0.75rem; font-weight: 700; letter-spacing: 0.05em;
      text-transform: uppercase; color: var(--red, #ff0000); text-decoration: none;
    }
    .related-card__link:hover { text-decoration: underline; }
    @media (max-width: 600px) { .related-grid { grid-template-columns: 1fr; } }