/* ===== Nexyron IA — estilos ===== */
:root {
  --bg: #f8fafc;
  --surface: #ffffff;
  --text: #1e293b;
  --muted: #64748b;
  --border: #e2e8f0;
  --primary: #4f46e5;
  --primary-dark: #3730a3;
  --accent: #06b6d4;
  --soft: #eef2ff;
  --radius: 14px;
  --shadow: 0 4px 20px rgba(15, 23, 42, .06);
  --max: 1120px;
  --read: 740px;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b1120;
    --surface: #111a2e;
    --text: #e2e8f0;
    --muted: #94a3b8;
    --border: #1e293b;
    --primary: #818cf8;
    --primary-dark: #a5b4fc;
    --soft: #1a2342;
    --shadow: 0 4px 20px rgba(0, 0, 0, .3);
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Ubuntu, sans-serif;
  font-size: 17px;
  line-height: 1.7;
}
img { max-width: 100%; height: auto; }
a { color: var(--primary); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { color: var(--primary-dark); }
.container { max-width: var(--max); margin: 0 auto; padding: 0 20px; }
.skip { position: absolute; left: -999px; }
.skip:focus { left: 10px; top: 10px; background: var(--surface); padding: 8px 12px; z-index: 99; }

/* ===== Cabecera ===== */
.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 50;
}
.header-inner { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.logo { font-weight: 800; font-size: 1.25rem; color: var(--text); text-decoration: none; display: flex; align-items: center; gap: 8px; }
.logo span.dot { width: 12px; height: 12px; border-radius: 50%; background: linear-gradient(135deg, var(--primary), var(--accent)); display: inline-block; }
.nav ul { list-style: none; margin: 0; padding: 0; display: flex; gap: 26px; }
.nav a { color: var(--text); text-decoration: none; font-weight: 500; }
.nav a:hover, .nav a[aria-current="page"] { color: var(--primary); }
.menu-toggle { display: none; }
.menu-btn { display: none; font-size: 1.6rem; cursor: pointer; user-select: none; }

@media (max-width: 760px) {
  .menu-btn { display: block; }
  .nav { display: none; position: absolute; top: 64px; left: 0; right: 0; background: var(--surface); border-bottom: 1px solid var(--border); }
  .nav ul { flex-direction: column; gap: 0; padding: 8px 20px 16px; }
  .nav li a { display: block; padding: 10px 0; }
  .menu-toggle:checked ~ .nav { display: block; }
}

/* ===== Hero ===== */
.hero {
  padding: 80px 0 64px;
  background: radial-gradient(circle at 20% 10%, var(--soft), transparent 60%);
  text-align: center;
}
.hero h1 { font-size: clamp(2rem, 5vw, 3.2rem); line-height: 1.15; margin: 0 0 18px; letter-spacing: -0.02em; }
.hero h1 em { font-style: normal; background: linear-gradient(90deg, var(--primary), var(--accent)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero p { color: var(--muted); font-size: 1.15rem; max-width: 640px; margin: 0 auto 28px; }
.btn { display: inline-block; background: var(--primary); color: #fff; padding: 12px 24px; border-radius: 999px; text-decoration: none; font-weight: 600; }
.btn:hover { background: var(--primary-dark); color: #fff; }
.btn.secondary { background: transparent; color: var(--primary); border: 2px solid var(--primary); margin-left: 8px; }

/* ===== Secciones y tarjetas ===== */
section { padding: 48px 0; }
.section-title { font-size: 1.7rem; margin: 0 0 8px; }
.section-sub { color: var(--muted); margin: 0 0 28px; }
.grid { display: grid; gap: 22px; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); }
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow);
  display: flex; flex-direction: column;
  transition: transform .2s;
}
.card:hover { transform: translateY(-3px); }
.card h3 { margin: 10px 0 8px; font-size: 1.2rem; line-height: 1.35; }
.card h3 a { color: var(--text); text-decoration: none; }
.card h3 a:hover { color: var(--primary); }
.card p { color: var(--muted); margin: 0 0 14px; flex: 1; }
.card .more { font-weight: 600; text-decoration: none; }
.tag { display: inline-block; font-size: .78rem; font-weight: 700; text-transform: uppercase; letter-spacing: .05em; color: var(--primary); background: var(--soft); padding: 3px 10px; border-radius: 999px; align-self: flex-start; }
.cats { display: grid; gap: 16px; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); }
.cat { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px; }
.cat strong { display: block; font-size: 1.05rem; margin-bottom: 4px; }
.cat span { color: var(--muted); font-size: .95rem; }

/* ===== Artículo ===== */
.article-wrap { max-width: var(--read); margin: 0 auto; padding: 32px 20px 56px; }
.breadcrumb { font-size: .9rem; color: var(--muted); margin-bottom: 18px; }
.breadcrumb a { color: var(--muted); }
.article-wrap h1 { font-size: clamp(1.9rem, 4.5vw, 2.6rem); line-height: 1.2; margin: 10px 0 14px; letter-spacing: -0.015em; }
.meta { color: var(--muted); font-size: .92rem; margin-bottom: 26px; }
.lead { font-size: 1.15rem; color: var(--muted); }
.article-wrap h2 { font-size: 1.55rem; margin: 42px 0 12px; line-height: 1.3; scroll-margin-top: 80px; }
.article-wrap h3 { font-size: 1.2rem; margin: 28px 0 8px; }
.toc { background: var(--soft); border-radius: var(--radius); padding: 18px 22px; margin: 24px 0; }
.toc strong { display: block; margin-bottom: 6px; }
.toc ol { margin: 0; padding-left: 20px; }
.toc a { text-decoration: none; }
.callout { border-left: 4px solid var(--primary); background: var(--surface); padding: 14px 18px; border-radius: 0 var(--radius) var(--radius) 0; margin: 22px 0; box-shadow: var(--shadow); }
.prompt { background: #0f172a; color: #e2e8f0; padding: 16px 18px; border-radius: 10px; font-family: ui-monospace, Consolas, monospace; font-size: .92rem; white-space: pre-wrap; overflow-x: auto; }
table { width: 100%; border-collapse: collapse; margin: 20px 0; font-size: .95rem; display: block; overflow-x: auto; }
th, td { border: 1px solid var(--border); padding: 10px 12px; text-align: left; vertical-align: top; }
th { background: var(--soft); }
.faq details { background: var(--surface); border: 1px solid var(--border); border-radius: 10px; padding: 12px 16px; margin-bottom: 10px; }
.faq summary { cursor: pointer; font-weight: 600; }
.author-box { display: flex; gap: 16px; align-items: center; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px; margin-top: 40px; }
.avatar { width: 56px; height: 56px; border-radius: 50%; background: linear-gradient(135deg, var(--primary), var(--accent)); color: #fff; display: grid; place-items: center; font-weight: 800; font-size: 1.3rem; flex-shrink: 0; }
.related { margin-top: 40px; }
.related ul { padding-left: 20px; }

/* ===== Páginas simples ===== */
.page { max-width: var(--read); margin: 0 auto; padding: 40px 20px 60px; }
.page h1 { font-size: 2.2rem; margin-top: 0; }

/* ===== Pie ===== */
.site-footer { background: var(--surface); border-top: 1px solid var(--border); padding: 40px 0 24px; margin-top: 40px; font-size: .95rem; }
.footer-grid { display: grid; gap: 28px; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); }
.site-footer h4 { margin: 0 0 10px; }
.site-footer ul { list-style: none; margin: 0; padding: 0; }
.site-footer li { margin-bottom: 6px; }
.site-footer a { color: var(--muted); text-decoration: none; }
.site-footer a:hover { color: var(--primary); }
.copy { color: var(--muted); text-align: center; margin-top: 28px; font-size: .88rem; }