/* ============================================================
   PROMPT ENGINEERING MASTER COURSE — Carbón + Ámbar
   © Alonso J. Núñez — GS·RUN
   ============================================================ */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;900&family=JetBrains+Mono:wght@400;600&display=swap');

/* === TEMA OSCURO (default) — Carbón + Ámbar dorado === */
:root, [data-theme="dark"] {
  /* Backgrounds */
  --bg-deep:        #0F1115;
  --bg:             #161A20;
  --bg-card:        rgba(30, 35, 42, 0.65);
  --bg-card-hover:  rgba(36, 42, 50, 0.85);
  --bg-code:        rgba(12, 14, 18, 0.85);
  --bg-sidebar:     rgba(18, 22, 28, 0.85);

  /* Glass / borders */
  --glass:          rgba(245, 165, 36, 0.04);
  --glass-border:   rgba(245, 165, 36, 0.12);
  --glass-hover:    rgba(245, 165, 36, 0.08);
  --grid-line:      rgba(245, 165, 36, 0.04);

  /* Texto cálido (no glacial) */
  --text:           #E8E6E3;
  --text-dim:       #9A958E;
  --text-muted:     #6B665E;

  /* Acentos firma — ámbar dorado profundo, NO amarillo chillón */
  --accent:         #F5A524;
  --accent-soft:    #FFC56C;
  --accent-deep:    #C77D0B;
  --accent-glow:    rgba(245, 165, 36, 0.22);
  --accent2:        #E0840F;       /* ámbar quemado, segundo plano */
  --accent2-glow:   rgba(224, 132, 15, 0.18);

  /* Colores semánticos */
  --green:          #6EBE7F;
  --red:            #E05F5F;
  --yellow:         #E0B843;
  --orange:         #D4784A;
  --gray-accent:    #8A857C;
  --gray-soft:      #6E6960;

  --radius:         14px;
  --radius-sm:      8px;
  --transition:     0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --font:           'Inter', system-ui, -apple-system, sans-serif;
  --mono:           'JetBrains Mono', 'Fira Code', monospace;
}

/* === TEMA CLARO — Papel + Ámbar profundo === */
[data-theme="light"] {
  /* Backgrounds — papel cálido, no glacial */
  --bg-deep:        #FAF9F6;
  --bg:             #F4F2EC;
  --bg-card:        rgba(255, 255, 255, 0.85);
  --bg-card-hover:  rgba(255, 255, 255, 0.95);
  --bg-code:        rgba(28, 25, 20, 0.95);
  --bg-sidebar:     rgba(248, 246, 240, 0.92);

  /* Glass / borders ámbar profundo (contraste accesible WCAG) */
  --glass:          rgba(199, 125, 11, 0.05);
  --glass-border:   rgba(199, 125, 11, 0.18);
  --glass-hover:    rgba(199, 125, 11, 0.1);
  --grid-line:      rgba(199, 125, 11, 0.05);

  /* Texto */
  --text:           #1A1A1A;
  --text-dim:       #5C5852;
  --text-muted:     #908A82;

  /* Acentos — más profundos que en oscuro para legibilidad */
  --accent:         #C77D0B;
  --accent-soft:    #F5A524;
  --accent-deep:    #8F5708;
  --accent-glow:    rgba(199, 125, 11, 0.20);
  --accent2:        #B86A05;
  --accent2-glow:   rgba(184, 106, 5, 0.15);

  /* Semánticos ajustados */
  --green:          #4F8B5F;
  --red:            #B83838;
  --yellow:         #B89020;
  --orange:         #B85A20;
  --gray-accent:    #6B665E;
  --gray-soft:      #908A82;
}

/* Smooth transition al cambiar tema */
html, body, #app, #sidebar, #main, .card, .nav-link, .btn,
.exercise-panel, .sim-panel, pre, .code-block, .copy-btn {
  transition: background-color 0.4s ease, color 0.4s ease,
              border-color 0.4s ease, box-shadow 0.4s ease;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font); background: var(--bg);
  color: var(--text); overflow-x: hidden;
  line-height: 1.7; min-height: 100vh;
}

/* Canvas REMOVED — using CSS-only elegant backgrounds */

/* === BACKGROUND ELEMENTS === */
.bg-gradient {
  position: fixed; top: 0; left: 0; width: 100%; height: 100%;
  z-index: 0; pointer-events: none;
  background:
    radial-gradient(ellipse 80% 60% at 20% 15%, rgba(212,168,83,0.06) 0%, transparent 60%),
    radial-gradient(ellipse 60% 80% at 85% 75%, rgba(224,138,58,0.05) 0%, transparent 60%),
    radial-gradient(ellipse 50% 50% at 50% 50%, rgba(180,140,80,0.03) 0%, transparent 70%);
}
.bg-grid {
  position: fixed; top: 0; left: 0; width: 100%; height: 100%;
  z-index: 0; pointer-events: none; opacity: 0.25;
  background-image:
    linear-gradient(rgba(255,255,255,0.015) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.015) 1px, transparent 1px);
  background-size: 48px 48px;
}
.bg-orb {
  position: fixed; border-radius: 50%; pointer-events: none; z-index: 0;
  filter: blur(80px); opacity: 0.18;
  animation: orbFloat 14s ease-in-out infinite;
}
.bg-orb-1 {
  width: 500px; height: 500px;
  background: radial-gradient(circle, rgba(212,168,83,0.5) 0%, transparent 70%);
  top: -15%; left: 5%;
  animation-delay: 0s;
}
.bg-orb-2 {
  width: 400px; height: 400px;
  background: radial-gradient(circle, rgba(224,138,58,0.45) 0%, transparent 70%);
  bottom: -10%; right: -5%;
  animation-delay: -5s;
}
.bg-orb-3 {
  width: 350px; height: 350px;
  background: radial-gradient(circle, rgba(200,160,100,0.35) 0%, transparent 70%);
  top: 40%; left: 55%;
  animation-delay: -9s;
}
@keyframes orbFloat {
  0%, 100% { transform: translate(0, 0) scale(1); }
  25% { transform: translate(30px, -20px) scale(1.08); }
  50% { transform: translate(-15px, 25px) scale(0.94); }
  75% { transform: translate(-25px, -10px) scale(1.04); }
}

/* APP LAYOUT */
#app {
  position: relative; z-index: 1;
  display: flex; min-height: 100vh;
}
#sidebar {
  width: 300px; min-width: 300px;
  background: rgba(8,8,25,0.85);
  backdrop-filter: blur(20px);
  border-right: 1px solid var(--glass-border);
  padding: 20px 0; height: 100vh;
  position: sticky; top: 0; overflow-y: auto;
  z-index: 10; transition: transform var(--transition);
}
#sidebar-logo {
  padding: 0 24px 20px; border-bottom: 1px solid var(--glass-border);
  margin-bottom: 12px;
}
#sidebar-logo h2 {
  font-size: 18px; font-weight: 700;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}
#sidebar-logo span {
  font-size: 11px; color: var(--text-dim); display: block;
  margin-top: 2px; letter-spacing: 1px; text-transform: uppercase;
}
.nav-module { margin: 4px 0; }
.nav-module-title {
  padding: 8px 24px; font-size: 10px; text-transform: uppercase;
  letter-spacing: 1.5px; color: var(--text-muted); font-weight: 700;
}
.nav-link {
  display: flex; align-items: center; gap: 10px;
  padding: 8px 24px 8px 32px; font-size: 13px;
  color: var(--text-dim); text-decoration: none;
  border-left: 2px solid transparent;
  transition: all var(--transition); cursor: pointer;
  position: relative;
}
.nav-link::before {
  content: ''; position: absolute; left: 0; top: 0; bottom: 0;
  width: 2px; background: linear-gradient(180deg, var(--accent), var(--accent2));
  transform: scaleY(0); transition: transform var(--transition);
}
.nav-link:hover { color: var(--text); background: var(--glass); }
.nav-link.active {
  color: var(--accent);
  background: linear-gradient(90deg, rgba(180,160,120,0.08), transparent);
}
.nav-link.active::before { transform: scaleY(1); }
.nav-link .nav-icon { font-size: 14px; width: 20px; text-align: center; }
.nav-link .nav-check {
  margin-left: auto; font-size: 10px; opacity: 0;
  transition: opacity var(--transition);
}
.nav-link.completed .nav-check { opacity: 1; color: var(--green); }

/* PROGRESS BAR */
#progress-bar {
  position: fixed; top: 0; left: 0; height: 3px;
  background: linear-gradient(90deg, var(--accent), var(--accent2), var(--gray-soft));
  z-index: 100; transition: width 0.5s ease;
  box-shadow: 0 0 10px var(--accent-glow), 0 0 20px var(--accent-glow);
}

/* MAIN */
#main {
  flex: 1; padding: 48px 60px; max-width: 950px;
  position: relative; z-index: 1;
}
#main section {
  margin-bottom: 80px; opacity: 0; transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
#main section.visible { opacity: 1; transform: translateY(0); }

/* TYPOGRAPHY */
h2 {
  font-size: 30px; font-weight: 800; margin-bottom: 8px;
  background: linear-gradient(135deg, var(--text), var(--gray-accent));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  letter-spacing: -0.5px;
}
h3 {
  font-size: 19px; font-weight: 700; margin: 32px 0 12px;
  color: var(--accent2); letter-spacing: -0.3px;
}
h4 { font-size: 15px; font-weight: 600; margin: 22px 0 8px; }
p { margin-bottom: 14px; color: var(--text-dim); }
.subtitle {
  color: var(--text-muted); font-size: 14px; margin-bottom: 24px;
}

/* CARDS — Glassmorphism */
.card {
  background: var(--bg-card); border: 1px solid var(--glass-border);
  border-radius: var(--radius); padding: 24px; margin: 20px 0;
  backdrop-filter: blur(12px);
  transition: all var(--transition);
  position: relative; overflow: hidden;
}
.card::before {
  content: ''; position: absolute; top: 0; left: 0; right:0; height:1px;
  background: linear-gradient(90deg, transparent, var(--accent-glow), transparent);
  opacity: 0; transition: opacity var(--transition);
}
.card:hover { background: var(--bg-card-hover); transform: translateY(-2px);
  box-shadow: 0 8px 32px rgba(0,0,0,0.3); }
.card:hover::before { opacity: 1; }
.card-title {
  font-size: 15px; font-weight: 700; margin-bottom: 10px;
  display: flex; align-items: center; gap: 8px;
}
.card-accent { border-color: rgba(180,160,120,0.25); }
.card-green { border-color: rgba(92,184,120,0.3); }
.card-orange { border-color: rgba(212,120,74,0.3); }

/* CODE */
pre, .code-block {
  background: rgba(5,5,20,0.8); border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm); padding: 16px 20px;
  margin: 14px 0; overflow-x: auto; font-family: var(--mono);
  font-size: 13px; line-height: 1.6; position: relative;
}
pre code { font-family: var(--mono); }
.copy-btn {
  position: absolute; top: 8px; right: 8px;
  background: var(--glass); border: 1px solid var(--glass-border);
  color: var(--text-dim); border-radius: 6px; padding: 4px 10px;
  font-size: 11px; cursor: pointer; font-family: var(--font);
  transition: all var(--transition);
}
.copy-btn:hover { background: var(--accent); color: #fff; border-color: var(--accent); }

/* TABLES */
.table-wrap {
  overflow-x: auto; margin: 20px 0; border-radius: var(--radius);
  border: 1px solid var(--glass-border);
}
table {
  width: 100%; border-collapse: collapse; font-size: 13px;
}
th {
  padding: 12px 16px; text-align: left;
  background: rgba(180,160,120,0.06);
  font-weight: 600; color: var(--accent2);
  font-size: 11px; text-transform: uppercase; letter-spacing: 0.5px;
}
td {
  padding: 10px 16px; border-top: 1px solid var(--glass-border);
  color: var(--text-dim);
}
tr:hover td { background: var(--glass); }
tr:last-child td { border-bottom: none; }

/* COMPARISON 2-COL */
.compare {
  display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin: 24px 0;
}
.compare > div {
  background: var(--bg-card); border: 1px solid var(--glass-border);
  border-radius: var(--radius); padding: 24px;
  backdrop-filter: blur(12px);
}
.compare h4 { color: var(--accent); margin-bottom: 10px; display: flex; align-items: center; gap: 8px; }

/* BADGES */
.badge {
  display: inline-flex; align-items: center; gap: 4px;
  padding: 3px 12px; border-radius: 20px; font-size: 10px;
  font-weight: 700; text-transform: uppercase; letter-spacing: 0.5px;
}
.badge-claude { background: rgba(225,112,85,0.15); color: var(--orange); border: 1px solid rgba(225,112,85,0.3); }
.badge-ds { background: rgba(180,160,120,0.1); color: var(--accent); border: 1px solid rgba(180,160,120,0.25); }
.badge-both { background: rgba(140,140,150,0.1); color: var(--gray-accent); border: 1px solid rgba(140,140,150,0.25); }

/* TIPS / WARNINGS */
.tip, .warn {
  padding: 14px 18px; border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 18px 0; font-size: 13px; border-left: 3px solid;
  background: var(--glass);
}
.tip { border-color: var(--accent); }
.warn { border-color: var(--yellow); }

/* BUTTONS */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 10px 24px; border-radius: var(--radius-sm);
  font-weight: 600; font-size: 14px; border: none; cursor: pointer;
  transition: all var(--transition); font-family: var(--font);
  position: relative; overflow: hidden;
}
.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--gray-accent));
  color: #fff; box-shadow: 0 4px 15px var(--accent-glow);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 6px 25px var(--accent-glow); }
.btn-secondary {
  background: var(--glass); color: var(--text);
  border: 1px solid var(--glass-border);
}
.btn-secondary:hover { background: var(--glass-hover); }
.btn-success {
  background: linear-gradient(135deg, var(--green), #6db88c);
  color: #000; box-shadow: 0 4px 15px rgba(92,184,120,0.25);
}

/* EXERCISE PANELS */
.exercise-panel {
  background: var(--bg-card); border: 1px solid var(--glass-border);
  border-radius: var(--radius); padding: 28px; margin: 24px 0;
  backdrop-filter: blur(12px);
}
.exercise-panel h4 {
  font-size: 17px; color: var(--green); margin-bottom: 6px;
  display: flex; align-items: center; gap: 8px;
}
.exercise-panel .ex-desc { color: var(--text-dim); font-size: 13px; margin-bottom: 16px; }
.exercise-panel .ex-tabs {
  display: flex; gap: 6px; margin-bottom: 12px; flex-wrap: wrap;
}
.exercise-panel .ex-tab {
  padding: 8px 16px; border-radius: var(--radius-sm);
  font-size: 12px; font-weight: 600; cursor: pointer;
  background: var(--glass); border: 1px solid var(--glass-border);
  color: var(--text-dim); transition: all var(--transition);
}
.exercise-panel .ex-tab:hover { background: var(--glass-hover); color: var(--text); }
.exercise-panel .ex-tab.active {
  background: var(--accent); color: #fff; border-color: var(--accent);
}
.exercise-panel .editor-container {
  position: relative; margin: 12px 0;
}
.exercise-panel textarea.ex-editor {
  width: 100%; min-height: 120px; background: rgba(5,5,20,0.9);
  color: var(--text); border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm); padding: 16px;
  font-family: var(--mono); font-size: 13px; line-height: 1.6;
  resize: vertical; tab-size: 2;
  transition: border-color var(--transition);
}
.exercise-panel textarea.ex-editor:focus {
  outline: none; border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}
.exercise-panel .ex-output {
  margin-top: 16px; padding: 16px;
  background: rgba(5,5,20,0.9); border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm); font-family: var(--mono);
  font-size: 12px; min-height: 50px; white-space: pre-wrap;
  display: none; color: var(--text-dim);
}
.exercise-panel .ex-output.show { display: block; }
.exercise-panel .ex-score {
  display: flex; align-items: center; gap: 12px; margin-top: 12px;
}
.exercise-panel .ex-score-bar {
  flex: 1; height: 8px; background: var(--glass);
  border-radius: 4px; overflow: hidden;
}
.exercise-panel .ex-score-fill {
  height: 100%; border-radius: 4px;
  transition: width 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}
.exercise-panel .ex-score-text {
  font-size: 14px; font-weight: 700; min-width: 50px;
}

/* SIMULATOR */
.sim-panel {
  background: var(--bg-card); border: 1px solid var(--glass-border);
  border-radius: var(--radius); padding: 28px; margin: 24px 0;
  backdrop-filter: blur(12px);
}
.sim-panel h4 { font-size: 17px; color: var(--accent2); margin-bottom: 6px; }
.sim-controls {
  display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin: 16px 0;
}
.sim-control {
  display: flex; flex-direction: column; gap: 4px;
}
.sim-control label {
  font-size: 11px; text-transform: uppercase;
  letter-spacing: 1px; color: var(--text-muted); font-weight: 700;
}
.sim-control select, .sim-control input {
  background: rgba(5,5,20,0.9); color: var(--text);
  border: 1px solid var(--glass-border); border-radius: var(--radius-sm);
  padding: 10px 14px; font-family: var(--font); font-size: 13px;
}
.sim-control select:focus, .sim-control input:focus {
  outline: none; border-color: var(--accent);
}
.sim-toggle-group { display: flex; gap: 8px; flex-wrap: wrap; }
.sim-toggle {
  padding: 6px 14px; border-radius: 20px; font-size: 11px;
  font-weight: 600; cursor: pointer; transition: all var(--transition);
  background: var(--glass); border: 1px solid var(--glass-border);
  color: var(--text-dim); user-select: none;
}
.sim-toggle.on {
  background: var(--accent); color: #fff; border-color: var(--accent);
  box-shadow: 0 0 12px var(--accent-glow);
}
.sim-output-panel {
  margin-top: 20px; padding: 20px;
  background: rgba(5,5,20,0.9); border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm); min-height: 100px;
  display: none; font-family: var(--mono); font-size: 12px;
  white-space: pre-wrap; position: relative; overflow: hidden;
}
.sim-output-panel.show { display: block; animation: fadeSlideUp 0.4s ease; }
.sim-quality {
  position: absolute; top: 10px; right: 10px; padding: 4px 12px;
  border-radius: 20px; font-size: 10px; font-weight: 700;
  font-family: var(--font); text-transform: uppercase;
}
.sim-stats {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px;
  margin-top: 16px;
}
.sim-stat {
  text-align: center; padding: 12px; background: var(--glass);
  border-radius: var(--radius-sm); border: 1px solid var(--glass-border);
}
.sim-stat-val {
  font-size: 24px; font-weight: 700;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}
.sim-stat-label { font-size: 10px; text-transform: uppercase; color: var(--text-muted); margin-top: 4px; }

/* DIAGRAMS */
.diagram-canvas-wrap {
  background: var(--bg-card); border: 1px solid var(--glass-border);
  border-radius: var(--radius); margin: 24px 0; overflow: hidden;
  position: relative;
}
.diagram-canvas-wrap canvas { width: 100%; height: 300px; display: block; }

/* QUIZ */
.quiz-panel {
  background: var(--bg-card); border: 1px solid var(--glass-border);
  border-radius: var(--radius); padding: 28px; margin: 24px 0;
  backdrop-filter: blur(12px);
}
.quiz-question { font-size: 16px; font-weight: 600; margin-bottom: 16px; }
.quiz-option {
  display: flex; align-items: center; gap: 12px;
  padding: 12px 16px; margin: 6px 0;
  background: var(--glass); border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm); cursor: pointer;
  transition: all var(--transition); font-size: 13px;
}
.quiz-option:hover { background: var(--glass-hover); }
.quiz-option.selected { border-color: var(--accent); background: rgba(180,160,120,0.08); }
.quiz-option.correct { border-color: var(--green); background: rgba(92,184,120,0.12); }
.quiz-option.wrong { border-color: var(--red); background: rgba(224,85,85,0.1); }
.quiz-feedback { padding: 14px; border-radius: var(--radius-sm); margin-top: 12px; display: none; font-size: 13px; }
.quiz-feedback.show { display: block; }
.quiz-progress {
  display: flex; justify-content: space-between; align-items: center;
  margin-top: 16px; font-size: 12px; color: var(--text-muted);
}

/* ANIMATIONS */
@keyframes fadeSlideUp {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}
@keyframes glow {
  0%, 100% { box-shadow: 0 0 5px var(--accent-glow); }
  50% { box-shadow: 0 0 20px var(--accent-glow), 0 0 40px var(--accent2-glow); }
}

/* GLOWING ORB */
.glow-orb {
  position: absolute; border-radius: 50%;
  filter: blur(60px); pointer-events: none; z-index: 0;
  animation: pulse 4s ease-in-out infinite;
}

/* RESPONSIVE */
@media (max-width: 900px) {
  #app { flex-direction: column; }
  #sidebar { width: 100%; height: auto; position: static; min-width: auto; }
  #main { padding: 20px; }
  .compare { grid-template-columns: 1fr; }
  .sim-controls { grid-template-columns: 1fr; }
  .sim-stats { grid-template-columns: repeat(2, 1fr); }
}

/* SCROLLBAR */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--glass-border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }

/* HIGHLIGHT OVERRIDES */
.hljs { background: transparent !important; }

/* === SIDEBAR TOGGLES (lang + theme) — Beta 2026-05-07 === */
.sidebar-toggles {
  display: flex; align-items: center; justify-content: space-between;
  gap: 8px; margin-top: 12px;
}
.lang-toggle { display: flex; gap: 4px; }
.lang-btn {
  padding: 4px 12px; border-radius: 12px;
  border: 1px solid var(--glass-border); background: var(--glass);
  color: var(--text-dim); font-size: 10px; font-weight: 700;
  cursor: pointer; font-family: var(--font);
  transition: all var(--transition); letter-spacing: 0.5px;
}
.lang-btn:hover { border-color: var(--accent); color: var(--text); }
.lang-btn.active {
  background: var(--accent); color: #1A1A1A;
  border-color: var(--accent);
  box-shadow: 0 0 12px var(--accent-glow);
}
#theme-toggle {
  width: 30px; height: 26px; border-radius: 12px;
  border: 1px solid var(--glass-border); background: var(--glass);
  color: var(--text); font-size: 13px; cursor: pointer;
  display: inline-flex; align-items: center; justify-content: center;
  transition: all var(--transition); padding: 0;
}
#theme-toggle:hover {
  border-color: var(--accent); background: var(--glass-hover);
  box-shadow: 0 0 12px var(--accent-glow);
}

/* === FOOTER — © Alonso J. Núñez · GS·RUN === */
#site-footer {
  margin-top: 80px; padding: 40px 0 32px;
  border-top: 1px solid var(--glass-border);
  font-size: 12px; color: var(--text-muted);
}
#site-footer .footer-inner {
  display: flex; flex-direction: column; gap: 14px; align-items: center;
  text-align: center;
}
@media (min-width: 720px) {
  #site-footer .footer-inner {
    flex-direction: row; justify-content: space-between; align-items: center;
  }
}
.footer-brand {
  display: inline-flex; align-items: center; gap: 8px; flex-wrap: wrap;
  justify-content: center;
}
.footer-copy { font-weight: 600; color: var(--text-dim); letter-spacing: 0.3px; }
.footer-sep { color: var(--text-muted); opacity: 0.6; }
.footer-link {
  color: var(--accent); text-decoration: none; font-weight: 700;
  letter-spacing: 0.5px; transition: color var(--transition);
}
.footer-link:hover { color: var(--accent-soft); text-shadow: 0 0 8px var(--accent-glow); }
.footer-license { color: var(--text-muted); font-style: italic; font-size: 11px; }
.footer-links {
  display: inline-flex; gap: 18px; flex-wrap: wrap; justify-content: center;
}
.footer-links a {
  color: var(--text-dim); text-decoration: none; font-size: 12px;
  transition: color var(--transition);
}
.footer-links a:hover { color: var(--accent); }

/* === BG ORBS — ajuste para tema claro (más sutiles) === */
[data-theme="light"] .bg-orb { opacity: 0.08; filter: blur(100px); }
[data-theme="light"] .bg-grid { opacity: 0.4; }
[data-theme="light"] .bg-orb-1 { background: radial-gradient(circle, rgba(199,125,11,0.55) 0%, transparent 70%); }
[data-theme="light"] .bg-orb-2 { background: radial-gradient(circle, rgba(184,106,5,0.5) 0%, transparent 70%); }
[data-theme="light"] .bg-orb-3 { background: radial-gradient(circle, rgba(245,165,36,0.4) 0%, transparent 70%); }

/* Code block en tema claro: fondo oscuro mantiene legibilidad de syntax */
[data-theme="light"] pre,
[data-theme="light"] .code-block,
[data-theme="light"] .exercise-panel textarea.ex-editor,
[data-theme="light"] .exercise-panel .ex-output,
[data-theme="light"] .sim-control select,
[data-theme="light"] .sim-control input {
  background: var(--bg-code); color: #E8E6E3;
}
[data-theme="light"] pre code { color: #E8E6E3; }

/* Sidebar bg explícito por tema (override del rgba hardcoded original) */
#sidebar { background: var(--bg-sidebar); }

/* === i18n lang blocks (Bug 2 fix 2026-05-07) ===
   Each section body is wrapped in two parallel <div.lang-block data-lang="..."> blocks.
   The active language attribute on <html> drives visibility. Default ES.
   If a section is marked [data-untranslated="1"] (no EN content yet), the ES
   block is shown even in EN mode as fallback while translations are pending. */
.lang-block { display: none; }
.lang-block[data-lang="es"] { display: block; }
html[data-i18n-lang="en"] .lang-block[data-lang="es"] { display: none; }
html[data-i18n-lang="en"] .lang-block[data-lang="en"] { display: block; }
html[data-i18n-lang="en"] section[data-untranslated="1"] .lang-block[data-lang="es"] { display: block; }
html[data-i18n-lang="en"] section[data-untranslated="1"] .lang-block[data-lang="en"] { display: none; }

/* ============================================================
   v2.0.0 — multi-page split components (2026-05-08)
   ============================================================ */

/* Hero (landing) */
.course-hero { text-align: center; padding: 60px 20px 40px; }
.hero-title { font-size: 42px; font-weight: 900; margin: 0 0 12px; letter-spacing: -0.02em; }
.hero-tagline { font-size: 17px; color: var(--text-dim); max-width: 720px; margin: 0 auto 20px; line-height: 1.5; }
.hero-meta { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; margin-top: 14px; }
.hero-pill { background: var(--glass); border: 1px solid var(--glass-border); padding: 6px 14px; border-radius: 999px; font-size: 13px; color: var(--text-dim); }

/* Block grid on landing */
.blocks-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 16px; margin: 16px 0 32px; }
.block-card { display: block; padding: 18px; background: var(--glass); border: 1px solid var(--glass-border); border-radius: 14px; text-decoration: none; color: var(--text); transition: transform .18s, border-color .18s, background .18s; }
.block-card:hover { transform: translateY(-2px); border-color: var(--accent); background: var(--glass-hover, var(--glass)); }
.block-card.is-stub { opacity: .65; }
.block-card-head { display: flex; align-items: flex-start; gap: 12px; margin-bottom: 10px; }
.block-icon { font-size: 26px; line-height: 1; }
.block-id { font-size: 11px; letter-spacing: 1.5px; color: var(--text-muted); text-transform: uppercase; font-weight: 700; }
.block-title { font-size: 15px; font-weight: 700; line-height: 1.3; margin-top: 2px; }
.block-card-meta { display: flex; gap: 8px; flex-wrap: wrap; font-size: 11px; color: var(--text-muted); margin-bottom: 10px; }
.block-card-objs { padding-left: 18px; margin: 0; font-size: 12px; color: var(--text-dim); line-height: 1.5; }
.block-card-objs li { margin: 3px 0; }
.block-stub { background: var(--orange, #d97706); color: #fff; padding: 1px 8px; border-radius: 6px; font-size: 10px; }

/* Difficulty levels (badges + sidebar markers) */
.block-level, .module-level, .sb-level {
  display: inline-block; padding: 1px 8px; border-radius: 6px;
  font-size: 10px; font-weight: 700; text-transform: uppercase; letter-spacing: .5px;
  vertical-align: middle;
}
.level-beginner, .sb-beginner { background: rgba(34,197,94,.18); color: #4ade80; }
.level-intermediate, .sb-intermediate { background: rgba(245,158,11,.18); color: #fbbf24; }
.level-advanced, .sb-advanced { background: rgba(239,68,68,.18); color: #f87171; }
.level-capstone, .sb-capstone { background: rgba(168,85,247,.18); color: #c084fc; }
.level-reading, .level-reference { background: rgba(99,102,241,.18); color: #818cf8; }
.sb-stub { background: rgba(217,119,6,.20); color: #fbbf24; padding: 1px 6px; border-radius: 5px; font-size: 9px; margin-left: 4px; }

/* Module front-matter (top of every module page) */
.module-front-matter { padding: 16px 0 24px; border-bottom: 1px dashed var(--glass-border); margin-bottom: 28px; }
.module-meta { display: flex; gap: 10px; align-items: center; font-size: 12px; color: var(--text-muted); margin-bottom: 8px; }
.module-icon { font-size: 22px; }
.module-time { font-size: 12px; }
.module-title { font-size: 32px; font-weight: 900; margin: 4px 0 14px; letter-spacing: -0.01em; }
.module-objectives h3 { font-size: 13px; text-transform: uppercase; letter-spacing: 1.5px; color: var(--accent); margin-bottom: 8px; }
.module-objectives ul { padding-left: 20px; margin: 0; }
.module-objectives li { margin: 4px 0; line-height: 1.5; }

/* Module references (bottom of every module page) */
.module-references { margin-top: 60px; padding: 24px 0; border-top: 1px dashed var(--glass-border); }
.module-references h3 { font-size: 16px; margin-bottom: 12px; }
.references-list { padding-left: 20px; }
.references-list li { margin: 6px 0; line-height: 1.5; font-size: 14px; }
.references-list a { color: var(--accent); text-decoration: none; }
.references-list a:hover { text-decoration: underline; }

/* Sidebar (multi-page, generated from manifest) */
#sidebar { padding-bottom: 100px; }
.sb-modules { display: flex; flex-direction: column; gap: 2px; padding: 8px 0; }
.sb-module-link {
  display: flex; align-items: center; gap: 10px;
  padding: 9px 14px; text-decoration: none; color: var(--text-dim);
  border-left: 3px solid transparent;
  transition: background .15s, border-color .15s, color .15s;
  font-size: 13px;
}
.sb-module-link:hover { background: var(--glass); color: var(--text); }
.sb-module-link.active { color: var(--accent); border-left-color: var(--accent); background: var(--glass); font-weight: 600; }
.sb-icon { font-size: 16px; flex-shrink: 0; width: 22px; text-align: center; }
.sb-title { flex: 1; line-height: 1.3; }
.sb-foot { padding: 16px 14px; border-top: 1px solid var(--glass-border); margin-top: 16px; font-size: 12px; display: flex; flex-direction: column; gap: 6px; }
.sb-foot a { color: var(--text-dim); text-decoration: none; }
.sb-foot a:hover { color: var(--accent); }
.sb-version { color: var(--text-muted); font-size: 10px; margin-top: 6px; }

/* Glossary */
.glossary-search { margin-top: 16px; }
.glossary-search input {
  width: 100%; max-width: 460px; padding: 10px 14px;
  background: var(--glass); border: 1px solid var(--glass-border); border-radius: 10px;
  color: var(--text); font-size: 14px;
}
.glossary-search input:focus { outline: none; border-color: var(--accent); }
.glossary-list { padding-bottom: 80px; }
.glossary-letter { margin: 28px 0; }
.glossary-letter-head {
  display: inline-block; min-width: 40px; height: 40px; line-height: 40px; text-align: center;
  background: var(--accent); color: #000; font-weight: 900; border-radius: 8px;
  font-size: 18px; margin-bottom: 10px;
}
.glossary-term { padding: 12px 0; border-bottom: 1px dashed var(--glass-border); }
.glossary-term:last-child { border-bottom: none; }
.glossary-term h4 { margin: 0 0 6px; font-size: 15px; }
.glossary-block-link { font-size: 11px; color: var(--text-muted); text-decoration: none; margin-left: 8px; font-weight: normal; }
.glossary-block-link:hover { color: var(--accent); }
.glossary-term > .lang-block { font-size: 13px; line-height: 1.6; color: var(--text-dim); }

/* Course footer (landing) */
.course-footer { margin-top: 60px; padding: 30px 0; border-top: 1px solid var(--glass-border); text-align: center; font-size: 12px; color: var(--text-muted); line-height: 1.7; }
.course-footer a { color: var(--accent); text-decoration: none; }
.course-footer a:hover { text-decoration: underline; }

/* Responsive: collapse sidebar on small screens */
@media (max-width: 900px) {
  #app { flex-direction: column; }
  #sidebar { width: 100%; height: auto; position: relative; }
  .sb-modules { flex-direction: row; flex-wrap: wrap; }
  .sb-module-link { flex: 1 1 200px; border-left: none; border-bottom: 3px solid transparent; }
  .sb-module-link.active { border-left-color: transparent; border-bottom-color: var(--accent); }
  .blocks-grid { grid-template-columns: 1fr; }
  .hero-title { font-size: 30px; }
}