@import url("https://fonts.googleapis.com/css2?family=Nunito:wght@600;700;800&family=Open+Sans:wght@400;600&display=swap");

:root {
  --color-primary: #2b9ba6;
  --color-primary-dark: #1e5f66;
  --color-primary-light: #4ecdc4;
  --color-accent: #f39c12;
  --color-bg: #f8fafc;
  --color-bg-white: #ffffff;
  --color-text: #1f2937;
  --color-text-light: #6b7280;
  --color-border: #e5e7eb;
  --color-surface: rgba(255, 255, 255, 0.94);
  --color-border-accent: rgba(43, 155, 166, 0.14);
  --font-heading: "Nunito", sans-serif;
  --font-body: "Open Sans", sans-serif;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --radius-xl: 1.5rem;
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
  --shadow-app-card: 0 12px 40px rgba(31, 41, 55, 0.08);
  --gradient-teal-deep: linear-gradient(135deg, var(--color-primary-light), var(--color-primary-dark));
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-body);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}
a { color: var(--color-primary); text-decoration: none; transition: color 0.2s ease; }
a:hover { color: var(--color-primary-dark); }
img { max-width: 100%; height: auto; display: block; }
.container { width: 100%; max-width: 1200px; margin: 0 auto; padding: 0 1rem; }

.app-header {
  background: rgba(255, 255, 255, 0.96);
  border-bottom: 1px solid var(--color-border-accent);
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(10px);
}
.header-content { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.logo { display: flex; align-items: center; gap: 0.75rem; text-decoration: none; color: inherit; }
.logo img { height: 40px; width: auto; }
.logo-text { font-family: var(--font-heading); font-size: 1.25rem; font-weight: 800; color: var(--color-primary-dark); }
.nav-desktop { display: none; gap: 0.35rem; flex-wrap: wrap; }
.nav-link {
  padding: 0.5rem 1rem;
  border-radius: var(--radius-md);
  font-weight: 600;
  color: var(--color-text);
}
.nav-link:hover { background: var(--color-bg); color: var(--color-primary); }
.nav-link.active { background: var(--color-primary); color: #fff; }

main { flex: 1; }
.landing-mesh {
  padding: clamp(5rem, 11vw, 8rem) 0 clamp(2.5rem, 6vw, 4.5rem);
  background:
    radial-gradient(circle at 14% 8%, rgba(243, 156, 18, 0.09), transparent 28%),
    radial-gradient(circle at 90% 4%, rgba(78, 205, 196, 0.12), transparent 30%),
    linear-gradient(to bottom, var(--color-bg-white), var(--color-bg));
}
.page-shell {
  padding: clamp(5rem, 11vw, 7rem) 0 clamp(2.5rem, 6vw, 4rem);
  background:
    radial-gradient(circle at 12% 10%, rgba(243, 156, 18, 0.078), transparent 28%),
    radial-gradient(circle at 88% 6%, rgba(78, 205, 196, 0.11), transparent 32%),
    linear-gradient(to bottom, var(--color-bg-white), var(--color-bg));
}
.page-intro { text-align: center; margin-bottom: clamp(1.75rem, 4vw, 3rem); max-width: 44rem; margin-inline: auto; }
.page-intro h1 {
  font-family: var(--font-heading);
  font-size: clamp(2rem, 5vw, 3.15rem);
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 0.65rem;
}
.page-intro .accent { color: var(--color-primary); }
.page-intro p { font-size: 1.05rem; color: var(--color-text-light); line-height: 1.7; }
.ui-eyebrow {
  display: inline-flex;
  align-items: center;
  padding: 0.42rem 0.85rem;
  border-radius: 999px;
  background: rgba(43, 155, 166, 0.12);
  color: var(--color-primary-dark);
  font-family: var(--font-heading);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.085em;
  text-transform: uppercase;
  margin-bottom: 0.85rem;
}

.categories-grid, .niveles-grid, .libros-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(272px, 1fr));
  gap: clamp(1.25rem, 3vw, 2rem);
}
.categories-grid { margin-bottom: clamp(2rem, 5vw, 3rem); }

.category-card, .nivel-card, .libro-card {
  background: var(--color-surface);
  border-radius: var(--radius-xl);
  border: 1px solid var(--color-border-accent);
  box-shadow: var(--shadow-app-card);
  padding: 2rem 1.5rem;
  text-align: center;
  text-decoration: none;
  color: inherit;
  transition: transform 0.28s ease, box-shadow 0.28s ease, border-color 0.28s ease;
  display: flex;
  flex-direction: column;
  align-items: center;
}
.category-card:hover, .nivel-card:hover, .libro-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-xl);
  border-color: rgba(43, 155, 166, 0.32);
}
.category-icon, .nivel-icon {
  width: 5rem;
  height: 5rem;
  border-radius: var(--radius-xl);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.25rem;
  color: #fff;
  font-size: 2rem;
}
.cnes-gradient { background: var(--gradient-teal-deep); }
.cultura-gradient { background: linear-gradient(135deg, var(--color-primary-dark), var(--color-primary)); }
.parv-gradient { background: linear-gradient(135deg, #4ecdc4, #2b9ba6); }
.prim-gradient { background: linear-gradient(135deg, #2b9ba6, #1e5f66); }
.tc-gradient { background: linear-gradient(135deg, #1e5f66, #123c36); }
.ct-gradient { background: linear-gradient(135deg, #f39c12, #d97706); }
.muted-card { opacity: 0.72; pointer-events: none; }

.category-card h3, .nivel-card h3, .libro-card h3 {
  font-family: var(--font-heading);
  font-size: 1.28rem;
  font-weight: 800;
  margin-bottom: 0.65rem;
}
.category-card p, .nivel-card p, .libro-card p { color: var(--color-text-light); font-size: 0.92rem; line-height: 1.65; }
.nivel-stats, .libro-meta { display: flex; justify-content: center; gap: 0.5rem; flex-wrap: wrap; margin-top: 0.75rem; }
.nivel-stats span, .libro-meta span {
  background: rgba(43, 155, 166, 0.08);
  color: var(--color-primary-dark);
  font-weight: 700;
  font-size: 0.78rem;
  padding: 0.32rem 0.72rem;
  border-radius: 999px;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1rem;
}
.stat-item {
  text-align: center;
  padding: 1.4rem 1rem;
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border-accent);
  box-shadow: var(--shadow-md);
}
.stat-number {
  font-family: var(--font-heading);
  font-size: 1.95rem;
  font-weight: 800;
  color: var(--color-primary-dark);
  margin-bottom: 0.35rem;
  line-height: 1;
}
.stat-label { font-size: 0.8125rem; color: var(--color-text-light); font-weight: 600; }

.back-row { margin-bottom: 1rem; }
.back-row a {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  font-weight: 700;
  color: var(--color-primary-dark);
  font-family: var(--font-heading);
}

.app-footer {
  background: var(--color-primary-dark);
  color: #fff;
  padding: 3rem 0 1.5rem;
  margin-top: auto;
}
.footer-content {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
  padding-bottom: 2rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}
.footer-logo { height: 50px; margin-bottom: 1rem; }
.footer-description { font-size: 0.875rem; opacity: 0.85; line-height: 1.6; max-width: 320px; }
.footer-links { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 2rem; }
.footer-section h4 { font-size: 1rem; font-weight: 700; margin-bottom: 1rem; color: var(--color-primary-light); }
.footer-section ul { list-style: none; }
.footer-section li { margin-bottom: 0.5rem; font-size: 0.875rem; opacity: 0.85; }
.footer-section a { color: #fff; opacity: 0.85; }
.footer-section a:hover { opacity: 1; }
.footer-bottom { padding-top: 1.5rem; text-align: center; font-size: 0.875rem; opacity: 0.65; }

.libro-card { padding: 1.25rem; text-align: left; align-items: stretch; }
.libro-cover {
  aspect-ratio: 3/4;
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 2.5rem;
  margin-bottom: 1rem;
}
.libro-code { font-size: 0.72rem; font-family: ui-monospace, monospace; color: var(--color-text-light); }
.libro-author { font-size: 0.85rem; color: var(--color-text-light); margin: 0.35rem 0 0.75rem; }

@media (min-width: 768px) {
  .nav-desktop { display: flex; }
  .footer-content { grid-template-columns: 1fr 2fr; }
}