:root {
  --bg: #f4efde;
  --bg-soft: #ece3c8;
  --ink: #1f241f;
  --ink-soft: #3e473f;
  --primary: #2f4f2d;
  --accent: #a35f2d;
  --line: #d0c39f;
  --card: #fffaf0;
  --shadow: 0 14px 34px rgba(20, 20, 12, 0.12);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: "Manrope", system-ui, -apple-system, Segoe UI, sans-serif;
  color: var(--ink);
  line-height: 1.6;
  background: var(--bg);
}
body.theme-home {
  background:
    radial-gradient(1100px 650px at 10% 0%, #d6e5cf 0%, transparent 60%),
    radial-gradient(900px 650px at 90% 0%, #f2d8bd 0%, transparent 50%),
    var(--bg);
}
body.theme-fundamentos {
  background:
    radial-gradient(1000px 550px at 15% 0%, #d2e8e8 0%, transparent 55%),
    radial-gradient(800px 600px at 88% 0%, #f4e3c4 0%, transparent 50%),
    var(--bg);
}
body.theme-mecanicas {
  background:
    radial-gradient(1000px 560px at 12% 0%, #d9e3cc 0%, transparent 55%),
    radial-gradient(900px 580px at 92% 0%, #eed5cb 0%, transparent 50%),
    var(--bg);
}
body.theme-estrategia {
  background:
    radial-gradient(1000px 550px at 12% 0%, #cfdcf0 0%, transparent 55%),
    radial-gradient(840px 590px at 90% 0%, #ecd6b5 0%, transparent 50%),
    var(--bg);
}
body.theme-practica {
  background:
    radial-gradient(1020px 590px at 10% 0%, #d9ebd0 0%, transparent 58%),
    radial-gradient(860px 600px at 90% 0%, #f0d7b8 0%, transparent 52%),
    var(--bg);
}
.topbar {
  position: sticky;
  top: 0;
  z-index: 35;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  padding: .8rem 1rem;
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(8px);
  background: rgba(244, 239, 222, 0.88);
}
.brand {
  font-family: "Bebas Neue", sans-serif;
  letter-spacing: .06em;
  font-size: 1.95rem;
  color: var(--primary);
  text-decoration: none;
}
.nav {
  display: flex;
  gap: .55rem;
  flex-wrap: wrap;
}
.nav a {
  text-decoration: none;
  color: var(--ink-soft);
  font-family: "Space Grotesk", sans-serif;
  font-weight: 700;
  font-size: .88rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: .34rem .62rem;
  background: #fff8e8;
}
.nav a.active {
  color: #fefaf1;
  background: var(--primary);
  border-color: var(--primary);
}
.container {
  width: min(1160px, 92%);
  margin: 0 auto;
}
.hero {
  padding: 2.9rem 0 2rem;
  display: grid;
  grid-template-columns: 1.2fr .8fr;
  gap: 1.2rem;
  align-items: start;
}
.hero h1 {
  margin: 0;
  font-family: "Bebas Neue", sans-serif;
  font-size: clamp(2.6rem, 6.5vw, 5.8rem);
  line-height: .95;
  letter-spacing: .02em;
}
.hero p { margin: .8rem 0 0; max-width: 68ch; }
.hero-figure {
  border-radius: 20px;
  overflow: hidden;
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
  background: var(--card);
  padding: .5rem;
}
.hero-figure img {
  width: 100%;
  height: auto;
  display: block;
  object-fit: contain;
  object-position: center center;
}
.pill-row {
  margin-top: 1rem;
  display: flex;
  gap: .55rem;
  flex-wrap: wrap;
}
.pill-row span {
  border: 1px solid var(--line);
  background: #fdf7e8;
  border-radius: 999px;
  padding: .34rem .68rem;
  font-size: .82rem;
  font-weight: 700;
}
.cards {
  margin: .5rem 0 2rem;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: .9rem;
}
.preview-strip {
  margin: .6rem 0 2.4rem;
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--card);
  box-shadow: var(--shadow);
}
.preview-head h2 {
  margin: 0 0 .55rem;
  font-family: "Space Grotesk", sans-serif;
  font-size: 1.32rem;
}
.preview-head p {
  margin: 0 0 .95rem;
  color: var(--ink-soft);
}
.preview-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: .85rem;
}
.preview-card {
  border: 1px solid var(--line);
  border-radius: 14px;
  background: #fef8ea;
  padding: .65rem;
  display: flex;
  flex-direction: column;
  gap: .45rem;
}
.preview-card img {
  width: 100%;
  height: 152px;
  border-radius: 10px;
  border: 1px solid #e6d9b7;
  object-fit: contain;
  background: #fff;
}
.preview-card h3 {
  margin: .2rem 0 0;
  font-family: "Space Grotesk", sans-serif;
  font-size: .95rem;
}
.preview-card p {
  margin: 0;
  color: var(--ink-soft);
  font-size: .9rem;
}
.preview-card a {
  margin-top: auto;
  text-decoration: none;
  font-weight: 800;
  color: var(--primary);
  font-size: .9rem;
}
.video-strip {
  margin: .6rem 0 2.6rem;
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--card);
  box-shadow: var(--shadow);
}
.video-head h2 {
  margin: 0 0 .55rem;
  font-family: "Space Grotesk", sans-serif;
  font-size: 1.32rem;
}
.video-head p {
  margin: 0 0 1rem;
  color: var(--ink-soft);
}
.video-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: .95rem;
}
.video-card {
  border: 1px solid var(--line);
  border-radius: 14px;
  background: #fef8ea;
  padding: .65rem;
}
.video-frame {
  position: relative;
  width: 100%;
  padding-top: 56.25%;
  overflow: hidden;
  border-radius: 10px;
  border: 1px solid #e6d9b7;
  background: #fff;
}
.video-frame iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: 0;
}
.video-card h3 {
  margin: .58rem 0 .28rem;
  font-family: "Space Grotesk", sans-serif;
  font-size: .98rem;
}
.video-card p {
  margin: 0;
  color: var(--ink-soft);
  font-size: .9rem;
}
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
  box-shadow: var(--shadow);
  padding: 1rem;
}
.card h2, .card h3 {
  margin: 0 0 .5rem;
  font-family: "Space Grotesk", sans-serif;
}
.card h2 { font-size: 1.15rem; }
.card h3 { font-size: 1rem; }
.card p { margin: 0 0 .6rem; }
.card a {
  text-decoration: none;
  font-weight: 700;
  color: var(--primary);
}
.layout {
  margin: 1rem 0 2.8rem;
  display: grid;
  grid-template-columns: 290px 1fr;
  gap: 1rem;
  align-items: start;
}
.toc {
  position: sticky;
  top: 76px;
  max-height: calc(100vh - 90px);
  overflow: auto;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  box-shadow: var(--shadow);
  padding: .9rem;
}
.toc h2 {
  margin: 0 0 .7rem;
  font-family: "Space Grotesk", sans-serif;
  font-size: 1rem;
}
.toc ol {
  margin: 0;
  padding-left: 1rem;
  display: grid;
  gap: .38rem;
  font-size: .92rem;
}
.toc a {
  text-decoration: none;
  color: var(--ink-soft);
}
.content {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
  box-shadow: var(--shadow);
  padding: 1rem 1.2rem;
  overflow: hidden;
  overflow-wrap: anywhere;
}
.chapter {
  border-bottom: 1px solid #e8dec5;
  padding: .65rem 0 1.25rem;
}
.chapter:last-child { border-bottom: 0; }
.chapter h2 {
  margin: 0 0 .8rem;
  font-family: "Bebas Neue", sans-serif;
  font-size: clamp(1.85rem, 3.3vw, 2.9rem);
  line-height: .98;
}
.chapter h3 {
  margin: 1.2rem 0 .55rem;
  color: var(--primary);
  font-family: "Space Grotesk", sans-serif;
  font-size: 1.02rem;
}
.chapter p { margin: 0 0 .85rem; }
.chapter ul,
.chapter ol {
  margin: .2rem 0 .95rem;
  padding-left: 1.2rem;
}
.chapter li { margin-bottom: .45rem; }
.chapter dl { margin: .2rem 0 .9rem; }
.chapter dt { font-weight: 800; margin-top: .5rem; }
.chapter dd { margin: .2rem 0 .5rem .8rem; }
.book-figure {
  margin: 1rem 0;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: #fdf7e9;
  padding: .7rem;
  overflow: hidden;
}
.book-figure img {
  width: 100%;
  display: block;
  max-height: 560px;
  object-fit: contain;
  background: #fff;
  border-radius: 8px;
  border: 1px solid #e6d9b7;
  margin-bottom: .55rem;
}
.book-figure img:last-of-type { margin-bottom: 0; }
.book-figure figcaption {
  margin-top: .48rem;
  color: var(--ink-soft);
  font-size: .88rem;
}
.formula {
  margin: .95rem 0;
  padding: .72rem;
  background: #f4ecd8;
  border: 1px solid var(--line);
  border-radius: 10px;
}
.formula pre {
  margin: 0;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  font-size: .9rem;
  white-space: pre-wrap;
  overflow-x: auto;
}
.page-links {
  display: flex;
  flex-wrap: wrap;
  gap: .6rem;
  margin-top: 1.1rem;
}
.page-links a {
  text-decoration: none;
  border: 1px solid var(--primary);
  color: var(--primary);
  border-radius: 999px;
  padding: .42rem .74rem;
  font-weight: 700;
}
.cta-links {
  display: flex;
  flex-wrap: wrap;
  gap: .68rem;
  margin-top: .9rem;
}
.cta-btn {
  text-decoration: none;
  border-radius: 999px;
  padding: .5rem .92rem;
  font-weight: 800;
  border: 1px solid var(--line);
  background: #fff8e8;
  color: var(--ink);
  transition: transform .16s ease, opacity .16s ease, box-shadow .16s ease;
}
.cta-btn:hover {
  transform: translateY(-1px);
  opacity: .96;
  box-shadow: var(--shadow);
}
.cta-btn.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fefaf1;
}
.cta-btn.play {
  background: var(--primary);
  border-color: var(--primary);
  color: #fffaf0;
}
.cta-btn.youtube {
  background: #c4302b;
  border-color: #c4302b;
  color: #fffaf0;
}
.lang-switch {
  position: static;
  text-decoration: none;
  background: #fff8e8;
  color: var(--ink);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: .42rem .74rem;
  font-family: "Space Grotesk", sans-serif;
  font-weight: 800;
  white-space: nowrap;
  box-shadow: 0 5px 12px rgba(20, 20, 12, 0.12);
  transition: transform .16s ease, opacity .16s ease;
}
.lang-switch:hover {
  transform: translateY(-1px);
  opacity: .96;
}
.footer {
  text-align: center;
  color: var(--ink-soft);
  font-size: .9rem;
  padding: 1.8rem 1rem 2.5rem;
}
@media (max-width: 980px) {
  .hero { grid-template-columns: 1fr; }
  .cards { grid-template-columns: 1fr; }
  .preview-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .video-grid { grid-template-columns: 1fr; }
  .layout { grid-template-columns: 1fr; }
  .toc { position: static; max-height: none; }
}
@media (max-width: 680px) {
  .topbar { flex-direction: column; align-items: flex-start; }
  .preview-grid { grid-template-columns: 1fr; }
  .cta-btn { width: 100%; text-align: center; }
  .lang-switch { align-self: flex-end; }
}


body.theme-historia {
  background:
    radial-gradient(1000px 550px at 12% 0%, #d9dfef 0%, transparent 55%),
    radial-gradient(840px 590px at 90% 0%, #eadfbc 0%, transparent 50%),
    var(--bg);
}
body.theme-magnitudes {
  background:
    radial-gradient(1020px 590px at 10% 0%, #d6e5cf 0%, transparent 58%),
    radial-gradient(860px 600px at 90% 0%, #e9d0c2 0%, transparent 52%),
    var(--bg);
}
.chapter h4 {
  margin: .95rem 0 .45rem;
  color: var(--ink-soft);
  font-family: "Space Grotesk", sans-serif;
  font-size: .95rem;
}


.formula.formula-block {
  overflow-x: auto;
  padding: .82rem .72rem;
}
.formula.formula-block mjx-container[jax="CHTML"] {
  margin: 0;
  font-size: 1.02em;
}


.toc li.toc-l2 a {
  padding-left: .55rem;
  font-size: .88rem;
}
.toc li.toc-l3 a {
  padding-left: 1rem;
  font-size: .84rem;
}