:root {
  --bg: #ffffff;
  --bg-soft: #f4f6fa;
  --text: #1f2328;
  --muted: #6b7280;
  --border: #e3e6ec;
  --accent: #1a73e8;
  --accent-soft: #e8f0fe;
  --topbar-h: 56px;
  --drawer-w: 300px;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111418;
    --bg-soft: #1b2027;
    --text: #e6e8eb;
    --muted: #9aa3ad;
    --border: #2b323b;
    --accent: #8ab4f8;
    --accent-soft: #1c2b44;
  }
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}
a { color: var(--accent); }

/* Barra superior */
.topbar {
  position: sticky; top: 0; z-index: 30;
  height: var(--topbar-h);
  display: flex; align-items: center; gap: 8px;
  padding: 0 8px;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
}
#menu-btn {
  width: 44px; height: 44px;
  font-size: 22px;
  border: 0; border-radius: 10px;
  background: transparent; color: var(--text);
  cursor: pointer;
}
#menu-btn:active { background: var(--bg-soft); }
.brand { font-weight: 700; text-decoration: none; color: var(--text); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }

/* Menú lateral */
#drawer {
  position: fixed; top: var(--topbar-h); bottom: 0; left: 0; z-index: 25;
  width: min(var(--drawer-w), 85vw);
  overflow-y: auto;
  padding: 12px 8px 40px;
  background: var(--bg-soft);
  border-right: 1px solid var(--border);
  transform: translateX(-100%);
  transition: transform .2s ease;
}
body.menu-open #drawer { transform: none; }
#overlay {
  position: fixed; inset: var(--topbar-h) 0 0 0; z-index: 20;
  background: rgba(0, 0, 0, .4);
}
#drawer .home { display: block; padding: 10px 12px; border-radius: 8px; text-decoration: none; color: var(--text); font-weight: 600; }
#drawer details { margin-top: 6px; }
#drawer summary {
  display: flex; justify-content: space-between; align-items: center; gap: 8px;
  padding: 10px 12px; border-radius: 8px;
  font-weight: 600; cursor: pointer; list-style: none;
}
#drawer summary::-webkit-details-marker { display: none; }
#drawer summary::before { content: "▸"; color: var(--muted); }
#drawer details[open] > summary::before { content: "▾"; }
#drawer summary span:first-child { flex: 1; }
.count { font-size: 12px; font-weight: 600; color: var(--muted); background: var(--bg); padding: 2px 8px; border-radius: 999px; }
#drawer ul { list-style: none; margin: 0; padding: 0 0 0 16px; }
#drawer li a, #drawer li .pending { display: block; padding: 8px 12px; border-radius: 8px; font-size: 15px; line-height: 1.35; }
#drawer li a { color: var(--text); text-decoration: none; }
#drawer li .pending { color: var(--muted); opacity: .6; }
#drawer a.active { background: var(--accent-soft); color: var(--accent); font-weight: 600; }

/* Contenido */
main { max-width: 760px; margin: 0 auto; padding: 16px 16px 48px; }
.crumb { margin: 8px 0 0; font-size: 13px; color: var(--muted); }
h1 { font-size: 1.6rem; line-height: 1.25; margin: 4px 0 16px; }
h2 { font-size: 1.25rem; margin-top: 2rem; padding-bottom: 4px; border-bottom: 1px solid var(--border); }
h3 { font-size: 1.1rem; }
blockquote { margin: 1rem 0; padding: 8px 14px; border-left: 4px solid var(--accent); background: var(--accent-soft); border-radius: 0 8px 8px 0; }
blockquote p { margin: 4px 0; }
code { background: var(--bg-soft); padding: 1px 5px; border-radius: 4px; font-size: .9em; }
pre { background: var(--bg-soft); padding: 12px; border-radius: 8px; overflow-x: auto; font-size: 13px; }
pre code { background: none; padding: 0; }
img { max-width: 100%; height: auto; border-radius: 10px; background: #fff; }
hr { border: 0; border-top: 1px solid var(--border); margin: 2rem 0; }

/* Tablas: scroll horizontal en pantallas chicas */
table { display: block; overflow-x: auto; border-collapse: collapse; font-size: 14px; margin: 1rem 0; }
th, td { border: 1px solid var(--border); padding: 8px 10px; vertical-align: top; min-width: 110px; }
th { background: var(--bg-soft); text-align: left; }

/* Preguntas de autoevaluación */
main details {
  margin: 10px 0;
  border: 1px solid var(--border); border-radius: 10px;
  background: var(--bg-soft);
}
main details summary { padding: 12px 14px; cursor: pointer; }
main details[open] summary { border-bottom: 1px solid var(--border); }
main details p { margin: 0; padding: 12px 14px; }

/* Anterior / Siguiente */
.pager { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-top: 40px; }
.pager a { display: block; padding: 12px; border: 1px solid var(--border); border-radius: 10px; text-decoration: none; color: var(--text); font-size: 14px; }
.pager small { display: block; color: var(--accent); font-weight: 600; }
.pager .next { text-align: right; grid-column: 2; }

/* Tarjetas de la portada */
.cards { display: grid; gap: 12px; margin: 16px 0; padding: 0; list-style: none; }
.cards li { border: 1px solid var(--border); border-radius: 12px; padding: 14px; background: var(--bg-soft); }
.cards h3 { margin: 0 0 6px; }
.progress { height: 6px; border-radius: 999px; background: var(--border); overflow: hidden; margin: 8px 0; }
.progress span { display: block; height: 100%; background: var(--accent); }
.cards ol { margin: 8px 0 0; padding-left: 20px; font-size: 15px; }
.cards .pending { color: var(--muted); }

/* Escritorio: menú fijo a la izquierda */
@media (min-width: 900px) {
  #menu-btn, #overlay { display: none !important; }
  #drawer { transform: none; }
  main { margin-left: var(--drawer-w); margin-right: auto; padding-left: 40px; max-width: calc(760px + var(--drawer-w)); }
}