/* ================================================================
   IIS — Apuntes interactivos
   Rediseño basado en el lenguaje visual de giupponi.dev
   (brutalist-minimal, dark, Space Grotesk + Doto, acento rojo)
================================================================ */

@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@300;400;500;600;700&family=Space+Mono:wght@400;700&family=Doto:wght@400;700;900&display=swap');

:root {
  --bg: #000000;
  --bg-soft: #0a0a0a;
  --bg-card: #111111;
  --muted: #1a1a1a;
  --border: #222222;
  --border-strong: #333333;
  --text: #ffffff;
  --text-dim: #999999;
  --text-disabled: #666666;
  --accent: #f59e0b;
  --accent-2: #ffffff;
  --ok: #4a9e5c;
  --warn: #d2a915;
  --err: #ef4444;
  --success: #00c758;
  --code-bg: #0a0a0a;
  --radius: 12px;
  --radius-sm: 6px;
  --font-sans: 'Space Grotesk', 'DM Sans', system-ui, sans-serif;
  --font-mono: 'Space Mono', 'JetBrains Mono', 'SF Mono', monospace;
  --font-display: 'Doto', 'Space Mono', monospace;
}

* { box-sizing: border-box; }

html, body {
  margin: 0; padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-weight: 400;
  line-height: 1.65;
  letter-spacing: -0.005em;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a { color: var(--text); text-decoration: underline; text-decoration-color: var(--border-strong); text-underline-offset: 4px; transition: color .15s, text-decoration-color .15s; }
a:hover { color: var(--accent); text-decoration-color: var(--accent); }

.container { max-width: 1100px; margin: 0 auto; padding: 3rem 1.5rem 6rem; }

/* ======================= TOP NAV ======================= */
.top-nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(0,0,0,0.75);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: 0.9rem 1.5rem;
  display: flex; gap: 1rem; align-items: center; justify-content: space-between;
  font-size: 0.85rem;
  font-family: var(--font-mono);
}
.top-nav a { text-decoration: none; }
.top-nav .crumb { color: var(--text-dim); text-transform: uppercase; letter-spacing: 0.08em; font-size: 0.75rem; }
.top-nav .crumb strong { color: var(--text); font-weight: 700; }
.top-nav .nav-links { display: flex; gap: 1.25rem; }
.top-nav .nav-links a { color: var(--text-dim); text-transform: uppercase; letter-spacing: 0.08em; font-size: 0.75rem; }
.top-nav .nav-links a:hover { color: var(--accent); }

/* ========================= HERO ========================= */
.hero {
  background: transparent;
  border: none;
  border-radius: 0;
  padding: 4rem 0 2.5rem;
  margin-bottom: 2rem;
  position: relative;
  border-bottom: 1px solid var(--border);
}
.hero::before { display: none; }

.hero .chip {
  display: inline-block;
  padding: 0.35rem 0.75rem;
  background: transparent;
  color: var(--text-dim);
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  font-size: 0.7rem;
  font-weight: 500;
  font-family: var(--font-mono);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 1.75rem;
}

.hero h1 {
  margin: 0 0 1rem;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(2.75rem, 8vw, 6rem);
  line-height: 0.95;
  letter-spacing: -0.02em;
  text-transform: uppercase;
  color: var(--text);
}

.hero p.sub {
  color: var(--text-dim);
  margin: 0;
  font-size: 1.05rem;
  max-width: 60ch;
  font-weight: 300;
  line-height: 1.55;
}

/* ========================= HEADINGS ========================= */
h2 {
  font-size: clamp(1.75rem, 3.5vw, 2.25rem);
  font-weight: 300;
  letter-spacing: -0.015em;
  margin-top: 4rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border);
  position: relative;
}
h2::before {
  content: ""; position: absolute; left: 0; bottom: -1px;
  width: 48px; height: 1px; background: var(--accent);
}

h3 {
  color: var(--text);
  font-size: 1.15rem;
  font-weight: 500;
  letter-spacing: -0.01em;
  margin-top: 2rem;
}

h4 { color: var(--text); font-weight: 500; }

p { color: var(--text); }

/* ========================= CARDS ========================= */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem 1.75rem;
  margin: 1rem 0;
  transition: border-color .2s, transform .2s;
}
.card:hover { border-color: var(--border-strong); }
.card.accent { border-left: 2px solid var(--accent); }
.card.ok { border-left: 2px solid var(--ok); }
.card.warn { border-left: 2px solid var(--warn); }
.card.err { border-left: 2px solid var(--err); }

a.card { display: block; text-decoration: none; color: inherit; }
a.card:hover { border-color: var(--accent); transform: translateY(-2px); }
a.card:hover h3 { color: var(--accent) !important; }

/* ========================= BLOCKQUOTE ========================= */
blockquote {
  margin: 1.5rem 0;
  padding: 1rem 1.5rem;
  border-left: 2px solid var(--accent);
  background: var(--bg-soft);
  color: var(--text);
  border-radius: 0;
  font-style: normal;
  font-weight: 300;
  font-size: 1.05rem;
  line-height: 1.55;
}

/* ========================= TABLE ========================= */
table {
  width: 100%; border-collapse: collapse;
  margin: 1.5rem 0;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  font-size: 0.95rem;
}
th, td { padding: 0.9rem 1.1rem; text-align: left; border-bottom: 1px solid var(--border); }
th {
  background: var(--bg-soft);
  color: var(--text-dim);
  font-weight: 500;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}
tr:last-child td { border-bottom: none; }
tr:hover td { background: var(--bg-soft); }

/* ========================= CODE ========================= */
code {
  background: var(--code-bg);
  color: var(--accent);
  padding: 0.15rem 0.45rem;
  border-radius: var(--radius-sm);
  font-size: 0.88em;
  font-family: var(--font-mono);
  border: 1px solid var(--border);
}
pre code { border: none; padding: 0; background: transparent; }
pre { background: var(--code-bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 1rem 1.25rem; overflow-x: auto; }

/* ========================= GRID ========================= */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}

/* ========================= KPI ========================= */
.kpi {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem 1.5rem;
  text-align: left;
  transition: border-color .2s;
}
.kpi:hover { border-color: var(--border-strong); }
.kpi .n {
  font-family: var(--font-display);
  font-size: 3rem;
  font-weight: 400;
  color: var(--text);
  display: block;
  line-height: 1;
  letter-spacing: -0.02em;
  margin-bottom: 0.5rem;
}
.kpi .l {
  color: var(--text-dim);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-family: var(--font-mono);
}

/* ========================= ACCORDION ========================= */
details {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.9rem 1.25rem;
  margin: 0.6rem 0;
  transition: border-color .15s;
}
details[open] { border-color: var(--border-strong); }
summary {
  cursor: pointer;
  font-weight: 500;
  color: var(--text);
  list-style: none;
  display: flex; align-items: center; gap: 0.5rem;
}
summary::before {
  content: '+';
  font-family: var(--font-mono);
  color: var(--accent);
  font-weight: 700;
  display: inline-block;
}
details[open] summary::before { content: '−'; }
summary::-webkit-details-marker { display: none; }
summary:hover { color: var(--accent); }
details > *:not(summary) { margin-top: 0.75rem; }

/* ========================= TABS ========================= */
.tabs { margin: 1.5rem 0; }
.tab-buttons {
  display: flex; gap: 0;
  border-bottom: 1px solid var(--border);
  flex-wrap: wrap;
}
.tab-btn {
  background: transparent;
  border: none;
  color: var(--text-dim);
  padding: 0.8rem 1.25rem;
  cursor: pointer;
  font-size: 0.85rem;
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  border-bottom: 1px solid transparent;
  margin-bottom: -1px;
  transition: all 0.15s;
}
.tab-btn.active { color: var(--text); border-bottom-color: var(--accent); }
.tab-btn:hover { color: var(--text); }
.tab-panel { display: none; padding: 1.25rem 0; }
.tab-panel.active { display: block; animation: fadeIn 0.3s; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(4px); } to { opacity: 1; transform: none; } }

/* ========================= QUIZ ========================= */
.quiz {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  margin: 2rem 0;
}
.quiz h3 { margin-top: 0; color: var(--text); }
.q {
  margin: 1.25rem 0;
  padding: 1.25rem;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
}
.q .question { font-weight: 500; margin-bottom: 0.85rem; }
.q .opts { display: flex; flex-direction: column; gap: 0.5rem; }
.q .opt {
  padding: 0.7rem 1rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.15s;
  background: var(--muted);
  font-family: var(--font-sans);
}
.q .opt:hover { border-color: var(--border-strong); background: var(--bg-card); }
.q .opt.selected { border-color: var(--text); background: var(--bg-card); }
.q .opt.correct { border-color: var(--ok); background: rgba(74,158,92,0.12); color: var(--ok); }
.q .opt.wrong { border-color: var(--err); background: rgba(215,25,33,0.12); color: var(--err); }
.q .explain {
  margin-top: 0.85rem;
  padding: 0.85rem 1rem;
  background: var(--muted);
  border-left: 2px solid var(--accent);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-size: 0.9rem;
  color: var(--text-dim);
  display: none;
}
.q .explain.show { display: block; }
.q .q-meta { margin-top: 0.85rem; color: var(--text-disabled); font-size: 0.75rem; text-align: right; font-family: var(--font-mono); text-transform: uppercase; letter-spacing: 0.08em; }

/* ========================= FLASHCARDS ========================= */
.flashcards { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 1rem; margin: 1.5rem 0; }
.flashcard { perspective: 1200px; min-height: 260px; cursor: pointer; }
.flashcard-inner { position: relative; width: 100%; height: 100%; min-height: inherit; transition: transform 0.6s; transform-style: preserve-3d; }
.flashcard.flipped .flashcard-inner { transform: rotateY(180deg); }
.flashcard-front, .flashcard-back {
  position: absolute; inset: 0;
  backface-visibility: hidden;
  border-radius: var(--radius); padding: 1.1rem 1.2rem;
  border: 1px solid var(--border);
  overflow: auto;
}
.flashcard-front {
  background: var(--bg-card); color: var(--text); font-weight: 600;
  font-size: 1rem; letter-spacing: -0.01em;
  display: flex; align-items: center; justify-content: center; text-align: center;
}
.flashcard-back {
  background: var(--accent); color: #fff;
  transform: rotateY(180deg);
  border-color: var(--accent);
  font-size: 0.82rem; line-height: 1.45;
  text-align: left;
  display: block;
}
.flashcard-back p { margin: 0 0 0.5rem; }
.flashcard-back p:last-child { margin-bottom: 0; }
.flashcard-back ul, .flashcard-back ol { margin: 0.25rem 0; padding-left: 1.1rem; }
.flashcard-back li { margin-bottom: 0.2rem; }
.flashcard-back strong { color: #fff; }
.flashcard-back code { background: rgba(0,0,0,0.25); color: #fff; border-color: rgba(255,255,255,0.2); }
.flashcard-back::-webkit-scrollbar { width: 6px; }
.flashcard-back::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.35); border-radius: 3px; }

/* ========================= MERMAID / DIAGRAMS ========================= */
.mermaid { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.25rem; margin: 1.25rem 0; text-align: center; }
.diagram { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.5rem; margin: 1.5rem 0; text-align: center; }
.diagram svg { width: 100%; height: auto; max-width: 100%; display: block; margin: 0 auto; }
.diagram figcaption { color: var(--text-dim); font-size: 0.8rem; margin-top: 0.85rem; font-family: var(--font-mono); text-transform: uppercase; letter-spacing: 0.08em; }
.diagram.diagram-light { background: #f8fafc; }
.diagram.diagram-light figcaption { color: #475569; }
.diagram img { width: 100%; height: auto; max-width: 100%; display: block; margin: 0 auto; }

/* ========================= TIMELINE ========================= */
.timeline { position: relative; padding-left: 2rem; margin: 1.5rem 0; }
.timeline::before { content: ""; position: absolute; left: 0.5rem; top: 0; bottom: 0; width: 1px; background: var(--border-strong); }
.timeline-item { position: relative; padding: 0.5rem 0 1.25rem; }
.timeline-item::before {
  content: ""; position: absolute; left: -1.75rem; top: 1rem;
  width: 10px; height: 10px; border-radius: 50%;
  background: var(--accent); box-shadow: 0 0 0 3px var(--bg);
}
.timeline-item .date {
  color: var(--text-dim);
  font-weight: 500;
  font-size: 0.75rem;
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

/* ========================= CHART ========================= */
.chart-box { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.5rem; margin: 1.5rem 0; }
.chart-box h4 { margin: 0 0 1rem; color: var(--text); font-weight: 500; }

/* ========================= KEYPOINTS ========================= */
.keypoints {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-left: 2px solid var(--accent);
  border-radius: var(--radius);
  padding: 1.75rem;
  margin-top: 2.5rem;
}
.keypoints h3 { margin-top: 0; color: var(--text); }
.keypoints ul { padding-left: 1.25rem; }
.keypoints li { margin: 0.5rem 0; color: var(--text); }
.keypoints li::marker { color: var(--accent); }

/* ========================= PAGER ========================= */
.pager { display: flex; justify-content: space-between; margin-top: 4rem; gap: 1rem; }
.pager a {
  flex: 1;
  background: var(--bg-card);
  border: 1px solid var(--border);
  padding: 1.25rem 1.5rem;
  border-radius: var(--radius);
  text-decoration: none;
  display: flex; flex-direction: column;
  transition: all 0.2s;
}
.pager a:hover { border-color: var(--accent); transform: translateY(-2px); }
.pager a.next { text-align: right; align-items: flex-end; }
.pager .label {
  color: var(--text-dim);
  font-size: 0.7rem;
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 0.3rem;
}
.pager .title { color: var(--text); font-weight: 500; }
.pager a:hover .title { color: var(--accent); }

/* ========================= PROGRESS ========================= */
.progress-bar {
  position: fixed; top: 0; left: 0; height: 2px;
  background: var(--accent);
  width: 0; z-index: 100; transition: width 0.1s;
}

/* ========================= BUTTONS ========================= */
.btn-primary, .btn-secondary {
  background: var(--text);
  color: var(--bg);
  border: 1px solid var(--text);
  padding: 0.7rem 1.4rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-weight: 500;
  font-size: 0.85rem;
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  transition: all 0.15s;
}
.btn-primary:hover { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn-primary:disabled { opacity: 0.3; cursor: not-allowed; }
.btn-secondary {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border-strong);
}
.btn-secondary:hover { border-color: var(--text); color: var(--text); background: var(--bg-card); }
.btn-secondary:disabled { opacity: 0.3; cursor: not-allowed; }

/* ========================= EXAM ========================= */
.exam-controls {
  display: flex; flex-wrap: wrap; gap: 1rem; align-items: center;
  margin-top: 1.25rem;
}
.exam-controls label {
  display: flex; align-items: center; gap: 0.5rem;
  color: var(--text-dim);
  font-size: 0.8rem;
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}
.exam-controls select {
  background: var(--bg-card);
  color: var(--text);
  border: 1px solid var(--border-strong);
  padding: 0.5rem 0.7rem;
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: 0.9rem;
}
.exam-bar {
  display: flex; align-items: center; gap: 1rem;
  background: rgba(17,17,17,0.9);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.85rem 1.1rem;
  margin-bottom: 1.25rem;
  position: sticky; top: 60px; z-index: 40;
}
.exam-timer {
  font-family: var(--font-mono);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--accent);
  min-width: 64px;
}
.exam-progress {
  flex: 1; height: 4px;
  background: var(--muted);
  border-radius: 2px;
  overflow: hidden;
}
.exam-progress > div {
  height: 100%;
  background: var(--accent);
  transition: width 0.2s;
}
.exam-counter {
  color: var(--text-dim);
  font-size: 0.8rem;
  font-weight: 500;
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

/* ========================= TRUE/FALSE ========================= */
.tf-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.1rem 1.35rem;
  margin: 0.75rem 0;
}
.tf-statement { font-weight: 400; margin-bottom: 0.85rem; color: var(--text); }
.tf-buttons { display: flex; gap: 0.5rem; }
.btn-tf {
  flex: 1;
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border-strong);
  padding: 0.6rem 1rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  transition: all 0.15s;
}
.btn-tf:hover { border-color: var(--text); color: var(--text); }
.btn-tf.active { background: var(--accent); color: #fff; border-color: var(--accent); }

/* ========================= MEDIA ========================= */
@media (max-width: 720px) {
  .container { padding: 1.25rem 1rem 4rem; }

  /* Top nav: apilar breadcrumb y links, reducir padding */
  .top-nav {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
    padding: 0.75rem 1rem;
  }
  .top-nav .nav-links { gap: 1rem; flex-wrap: wrap; }
  .top-nav .crumb,
  .top-nav .nav-links a { font-size: 0.7rem; }

  /* Hero más chico y con line-height más respirado */
  .hero { padding: 2rem 0 1.75rem; margin-bottom: 1.25rem; }
  .hero h1 { font-size: clamp(2rem, 11vw, 3.25rem); line-height: 1; word-break: break-word; }
  .hero p.sub { font-size: 0.95rem; }
  .hero .chip { font-size: 0.65rem; margin-bottom: 1.25rem; letter-spacing: 0.1em; }

  /* Headings */
  h2 { margin-top: 2.5rem; font-size: 1.5rem; }
  h3 { font-size: 1.05rem; margin-top: 1.5rem; }

  /* Cards con menos padding */
  .card { padding: 1.1rem 1.1rem; }
  .kpi { padding: 1.25rem 1.1rem; }
  .kpi .n { font-size: 2.25rem; }

  /* Grid: una columna en pantallas chicas */
  .grid { grid-template-columns: 1fr; gap: 0.75rem; }

  /* Tablas y código scrollables horizontalmente */
  table { display: block; overflow-x: auto; white-space: nowrap; font-size: 0.85rem; }
  th, td { padding: 0.65rem 0.85rem; }
  pre { font-size: 0.8rem; padding: 0.85rem 1rem; }

  /* Pager en una sola columna */
  .pager { flex-direction: column; margin-top: 2.5rem; }
  .pager a { padding: 1rem 1.1rem; }
  .pager a.next { text-align: left; align-items: flex-start; }

  /* Exam bar en mobile: top offset menor */
  .exam-bar { top: 0; flex-wrap: wrap; padding: 0.7rem 0.9rem; }
  .exam-timer { font-size: 1rem; min-width: 52px; }
  .exam-controls { gap: 0.65rem; }

  /* Blockquote menos padding */
  blockquote { padding: 0.85rem 1.1rem; font-size: 0.95rem; }

  /* Flashcards: siempre una columna */
  .flashcards { grid-template-columns: 1fr; }

  /* Tabs scroll horizontal */
  .tab-buttons { overflow-x: auto; flex-wrap: nowrap; }
  .tab-btn { white-space: nowrap; }

  /* Quiz options — padding reducido */
  .q { padding: 1rem; }
  .q .opt { padding: 0.6rem 0.85rem; font-size: 0.9rem; }

  /* Diagramas: scroll si hace falta */
  .diagram { padding: 1rem; overflow-x: auto; }
}

/* Prevención global de overflow horizontal */
html, body { overflow-x: hidden; max-width: 100%; }
img, svg, video, canvas { max-width: 100%; height: auto; }

/* ========================= THEME TOGGLE ========================= */
.theme-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background: transparent;
  border: 1px solid var(--border-strong);
  color: var(--text);
  padding: 0.35rem 0.7rem;
  border-radius: 999px;
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  transition: color .15s, border-color .15s, background .15s;
}
.theme-toggle:hover { border-color: var(--text); color: var(--accent); }
.theme-toggle svg { display: block; }

.theme-toggle--floating {
  position: fixed;
  top: 1rem; right: 1rem;
  z-index: 60;
  background: var(--bg-card);
}
@media (max-width: 720px) {
  .theme-toggle--floating { top: 0.75rem; right: 0.75rem; font-size: 0.65rem; padding: 0.3rem 0.6rem; }
}

/* ========================= LIGHT THEME ========================= */
:root[data-theme="light"] {
  --bg: #f5f5f5;
  --bg-soft: #ececec;
  --bg-card: #ffffff;
  --muted: #f0f0f0;
  --border: #e0e0e0;
  --border-strong: #cccccc;
  --text: #111111;
  --text-dim: #555555;
  --text-disabled: #888888;
  --accent: #b45309;
  --accent-2: #111111;
  --ok: #1f8a3b;
  --warn: #b8860b;
  --err: #b91c1c;
  --code-bg: #f0f0f0;
}

:root[data-theme="light"] .top-nav {
  background: rgba(245,245,245,0.85);
}
:root[data-theme="light"] .exam-bar {
  background: rgba(255,255,255,0.9);
}
:root[data-theme="light"] .flashcard-back {
  color: #fff;
}
:root[data-theme="light"] code {
  background: var(--code-bg);
  color: #b45309;
  border-color: var(--border);
}
:root[data-theme="light"] .q .opt.correct {
  background: rgba(31,138,59,0.12);
  color: #1f8a3b;
}
:root[data-theme="light"] .q .opt.wrong {
  background: rgba(185,28,28,0.12);
  color: #b91c1c;
}
:root[data-theme="light"] ::selection {
  background: var(--accent); color: #fff;
}
:root[data-theme="light"] .btn-primary { color: #fff; background: #111; border-color: #111; }
:root[data-theme="light"] .btn-primary:hover { background: var(--accent); border-color: var(--accent); color: #fff; }

/* Diagramas SVG que usan blancos/fills oscuros no se leen bien en claro —
   suavizar con un leve fondo oscuro de tarjeta para mantener contraste */
:root[data-theme="light"] .diagram { background: #0d1117; }
:root[data-theme="light"] .diagram figcaption { color: #8b949e; }
:root[data-theme="light"] .diagram.diagram-light { background: #f8fafc; }
:root[data-theme="light"] .diagram.diagram-light figcaption { color: #475569; }
:root[data-theme="light"] .mermaid { background: #0d1117; }

/* ========================= SELECTION ========================= */
::selection { background: var(--accent); color: #fff; }