:root {
  --primary: #6C63FF;
  --primary-light: #8B85FF;
  --dark-bg: #0D1117;
  --dark-surface: #161B22;
  --dark-card: #1C2333;
  --dark-card-hover: #252D3D;
  --dark-border-solid: #30363D;
  --text-primary: #E6EDF3;
  --text-secondary: #8B949E;
  --text-muted: #858D97;
  --espacio-1: .25rem;
  --espacio-2: .5rem;
  --espacio-3: .75rem;
  --espacio-4: 1rem;
  --espacio-5: 1.5rem;
  --espacio-6: 2rem;
  --espacio-7: 2.5rem;
  --espacio-8: 3rem;
  --espacio-9: 4rem;
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --shadow-card: 0 4px 24px rgba(0, 0, 0, .4);
  --font-heading: Poppins, sans-serif;
  --font-body: Inter, sans-serif;
}

*, *::before, *::after { box-sizing: border-box; }
html { color-scheme: dark; scroll-behavior: smooth; }
body { margin: 0; min-height: 100vh; background: var(--dark-bg); color: var(--text-primary); font: 1rem/1.65 var(--font-body); }
a { color: var(--primary-light); text-underline-offset: .2em; }
a:hover { color: var(--text-primary); }
a:focus-visible { outline: 3px solid var(--primary-light); outline-offset: 4px; border-radius: var(--radius-sm); }
h1, h2 { margin: 0; font-family: var(--font-heading); line-height: 1.18; }
h1 { max-width: 20ch; font-size: clamp(2rem, 5vw, 3.75rem); }
h2 { font-size: clamp(1.35rem, 3vw, 2rem); }
p { margin: 0; color: var(--text-secondary); }
img { display: block; max-width: 100%; height: auto; }

.skip-link { position: fixed; top: var(--espacio-3); left: var(--espacio-3); z-index: 10; padding: var(--espacio-2) var(--espacio-4); transform: translateY(-180%); background: var(--text-primary); color: var(--dark-bg); }
.skip-link:focus { transform: translateY(0); }
.site-header, .site-footer, .page-width { width: min(74rem, calc(100% - 2rem)); margin-inline: auto; }
.site-header { display: flex; align-items: center; justify-content: space-between; min-height: 4.5rem; border-bottom: 1px solid var(--dark-border-solid); }
.site-header a, .site-footer a { text-decoration: none; }
.brand { color: var(--text-primary); font: 700 1.25rem var(--font-heading); letter-spacing: .04em; }
.brand span { color: var(--primary-light); font-weight: 500; }
.site-footer { display: flex; justify-content: space-between; gap: var(--espacio-4); margin-top: var(--espacio-9); padding-block: var(--espacio-6); border-top: 1px solid var(--dark-border-solid); color: var(--text-muted); }
.page-width { padding-block: var(--espacio-5) var(--espacio-9); }
.breadcrumbs { display: flex; flex-wrap: wrap; gap: var(--espacio-2); margin-bottom: var(--espacio-8); color: var(--text-muted); font-size: .9rem; }
.eyebrow { color: var(--primary-light); font-weight: 700; letter-spacing: .08em; text-transform: uppercase; }
.catalog-intro { display: grid; gap: var(--espacio-4); max-width: 55rem; margin-bottom: var(--espacio-8); }
.catalog-intro > p:last-child, .lead { max-width: 70ch; font-size: clamp(1.05rem, 2vw, 1.25rem); }

.course-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 20rem), 1fr)); gap: var(--espacio-5); }
.course-card { overflow: hidden; border: 1px solid var(--dark-border-solid); border-radius: var(--radius-lg); background: var(--dark-card); box-shadow: var(--shadow-card); }
.course-card:focus-within, .course-card:hover { background: var(--dark-card-hover); }
.course-card__image { display: block; aspect-ratio: 7 / 3; overflow: hidden; }
.course-card__image img { width: 100%; height: 100%; object-fit: cover; }
.course-card__body { display: grid; gap: var(--espacio-3); padding: var(--espacio-5); }
.course-card__body h2 { font-size: 1.3rem; }
.course-card__body h2 a { color: var(--text-primary); text-decoration: none; }
.text-link { width: fit-content; font-weight: 700; }

.course-detail { display: grid; gap: var(--espacio-8); }
.course-hero { display: grid; grid-template-columns: 1.05fr .95fr; gap: var(--espacio-7); align-items: center; }
.course-hero__copy { display: grid; gap: var(--espacio-4); }
.course-hero > img { width: 100%; border: 1px solid var(--dark-border-solid); border-radius: var(--radius-lg); box-shadow: var(--shadow-card); }
.course-facts { display: flex; flex-wrap: wrap; gap: var(--espacio-4) var(--espacio-6); margin: var(--espacio-2) 0; }
.course-facts div { display: grid; gap: var(--espacio-1); }
.course-facts dt { color: var(--text-muted); font-size: .85rem; }
.course-facts dd { margin: 0; font-weight: 700; }
.primary-button { display: inline-flex; width: fit-content; align-items: center; justify-content: center; min-height: 3rem; padding: var(--espacio-3) var(--espacio-5); border-radius: var(--radius-md); background: var(--primary); color: var(--text-primary); font-weight: 700; text-decoration: none; }
.primary-button:hover { background: var(--primary-light); color: var(--dark-bg); }
.course-sections { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--espacio-5); }
.course-sections section { padding: var(--espacio-6); border: 1px solid var(--dark-border-solid); border-radius: var(--radius-lg); background: var(--dark-surface); }
.course-sections section:last-child:nth-child(odd) { grid-column: 1 / -1; }
.course-sections h2 { margin-bottom: var(--espacio-5); }
.check-list, .tag-list, .syllabus { margin: 0; padding: 0; }
.check-list { display: grid; gap: var(--espacio-3); list-style: none; }
.check-list li::before { content: "✓"; margin-right: var(--espacio-3); color: var(--primary-light); font-weight: 700; }
.tag-list { display: flex; flex-wrap: wrap; gap: var(--espacio-2); list-style: none; }
.tag-list li { padding: var(--espacio-2) var(--espacio-3); border: 1px solid var(--dark-border-solid); border-radius: 999px; background: var(--dark-card); }
.syllabus { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--espacio-3); list-style: none; }
.syllabus li { display: flex; gap: var(--espacio-3); align-items: center; padding: var(--espacio-3); border-bottom: 1px solid var(--dark-border-solid); }
.syllabus li span { display: grid; flex: 0 0 2rem; width: 2rem; height: 2rem; place-items: center; border-radius: 50%; background: var(--dark-card); color: var(--primary-light); font-weight: 700; }
.course-cta { display: grid; gap: var(--espacio-4); justify-items: start; padding: var(--espacio-7); border: 1px solid var(--primary); border-radius: var(--radius-lg); background: var(--dark-card); }
.related-courses { display: grid; gap: var(--espacio-4); }
.related-courses ul { display: flex; flex-wrap: wrap; gap: var(--espacio-3); margin: 0; padding: 0; list-style: none; }
.related-courses a { display: block; padding: var(--espacio-3) var(--espacio-4); border: 1px solid var(--dark-border-solid); border-radius: var(--radius-md); background: var(--dark-surface); font-weight: 700; }

@media (max-width: 48rem) {
  .course-hero, .course-sections, .syllabus { grid-template-columns: 1fr; }
  .course-hero__copy { order: 2; }
  .course-sections section:last-child:nth-child(odd) { grid-column: auto; }
  .site-footer { flex-direction: column; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

@media (prefers-contrast: more) {
  .course-card, .course-sections section, .course-cta { border-width: 2px; }
  .eyebrow, .text-link { text-decoration: underline; }
}