*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }

/* Transición suave (cross-fade) entre páginas: el circuito de fondo no "parpadea"
   al navegar. Navegadores sin soporte lo ignoran. */
@view-transition { navigation: auto; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: 0.01ms !important; animation-iteration-count: 1 !important; transition-duration: 0.01ms !important; }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.15;
  margin: 0 0 var(--space-2);
}

p { margin: 0 0 var(--space-2); color: var(--text); }
a { color: var(--blue-bright); }
code, .formula, .data-table { font-family: var(--font-mono); }

.visually-hidden {
  position: absolute; width: 1px; height: 1px; overflow: hidden;
  clip: rect(0 0 0 0); white-space: nowrap;
}

a:focus-visible, button:focus-visible, .btn:focus-visible {
  outline: 2px solid var(--blue-bright);
  outline-offset: 3px;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-3);
}

/* Header / nav */
.site-header {
  position: sticky; top: 0; z-index: 20;
  height: var(--header-h);
  display: flex; align-items: center;
  background: rgba(10, 14, 26, 0.85);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}
.site-header .container { display: flex; align-items: center; justify-content: space-between; width: 100%; }
.site-header__brand { display: flex; align-items: center; gap: var(--space-1); font-family: var(--font-display); font-weight: 600; color: var(--text); text-decoration: none; }
.site-header__brand img { height: 40px; width: auto; }
/* Distintivo de nivel: este curso es el "Básico" del temario de Telemetría */
.level-badge {
  font-family: var(--font-mono); font-style: normal;
  font-size: 0.62rem; font-weight: 600; letter-spacing: 0.14em;
  text-transform: uppercase; line-height: 1;
  padding: 4px 8px; border-radius: 999px;
  color: var(--signal-amber);
  background: rgba(255, 177, 61, 0.1);
  border: 1px solid rgba(255, 177, 61, 0.5);
}

.nav-dots { display: flex; gap: 8px; list-style: none; margin: 0; padding: 0; }
.nav-dots a {
  display: block; width: 10px; height: 10px; border-radius: 50%;
  background: var(--border); text-indent: -9999px; overflow: hidden;
  transition: background 0.2s ease, transform 0.2s ease;
}
.nav-dots a:hover { background: var(--blue-bright); }
.nav-dots a.is-done { background: var(--signal-amber); }
.nav-dots a.is-current { background: var(--blue-royal); transform: scale(1.35); }
/* Sesión 6+ (bonus): rombo con contorno ámbar para distinguirla del resto */
.nav-dots a.nav-dot--bonus { border-radius: 2px; background: transparent; border: 1.5px solid var(--signal-amber); transform: rotate(45deg); }
.nav-dots a.nav-dot--bonus.is-current { background: var(--signal-amber); transform: rotate(45deg) scale(1.35); }
.nav-dots a.nav-dot--bonus.is-done { background: var(--signal-amber); }
.nav-dots a.nav-dot--bonus:hover { border-color: var(--blue-bright); }

/* Buttons */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 22px; border-radius: var(--radius);
  font-family: var(--font-body); font-weight: 600; font-size: 0.95rem;
  text-decoration: none; border: 1px solid transparent; cursor: pointer;
  transition: background 0.2s ease, border-color 0.2s ease, transform 0.15s ease;
}
.btn--primary { background: var(--blue-royal); color: #fff; }
.btn--primary:hover { background: var(--blue-bright); transform: translateY(-1px); }
.btn--ghost { background: transparent; border-color: var(--border); color: var(--text); }
.btn--ghost:hover { border-color: var(--blue-bright); color: var(--blue-bright); }
.btn--signal { background: var(--signal); color: var(--bg); border-color: var(--signal); box-shadow: 0 4px 18px -4px var(--signal); }
.btn--signal:hover { filter: brightness(1.06); transform: translateY(-1px); box-shadow: 0 6px 24px -4px var(--signal); }

/* Cards */
.card {
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-3);
  transition: border-color 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
}
.card:hover {
  border-color: var(--blue-royal);
  transform: translateY(-3px);
  box-shadow: 0 12px 30px -18px rgba(37, 71, 224, 0.6);
}
.card--alert:hover { border-color: var(--signal-amber); box-shadow: 0 12px 30px -18px rgba(255, 177, 61, 0.5); }

/* Badges */
.badge {
  display: inline-flex; align-items: center; gap: 6px;
  font-family: var(--font-mono); font-size: 0.78rem; letter-spacing: 0.02em;
  padding: 4px 10px; border-radius: 999px;
  background: var(--bg-panel-2); color: var(--text-dim); border: 1px solid var(--border);
}

/* Callouts */
.callout {
  border-left: 3px solid var(--blue-royal);
  background: var(--bg-panel);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: var(--space-3);
}
.callout--alert { border-left-color: var(--signal-amber); }

/* Tables (datasheet look) */
.data-table { width: 100%; border-collapse: collapse; font-size: 0.9rem; }
.data-table th, .data-table td {
  text-align: left; padding: 10px 14px; border-bottom: 1px solid var(--border);
}
.data-table th { color: var(--text-dim); font-weight: 600; text-transform: uppercase; font-size: 0.75rem; letter-spacing: 0.04em; }

.formula {
  display: block; background: var(--bg-panel-2); border: 1px solid var(--border);
  border-radius: var(--radius); padding: var(--space-2); white-space: pre-wrap;
  color: var(--blue-bright); font-size: 0.95rem;
}

/* Checklist (errores comunes) */
.checklist { list-style: none; margin: 0; padding: 0; display: grid; gap: 10px; }
.checklist__item {
  position: relative;
  padding: 12px 16px 12px 38px;
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 0.95rem;
  line-height: 1.55;
  color: var(--text);
}
.checklist__item::before {
  content: "⚠";
  position: absolute;
  left: 14px;
  top: 12px;
  color: var(--signal-amber);
  font-size: 0.95rem;
  line-height: 1.55;
}
.checklist__item code, .deliverable-box code, .rubric code, .data-table code {
  font-family: var(--font-mono);
  color: var(--blue-bright);
  background: var(--bg-panel-2);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.88em;
}

/* Photo placeholders */
.photo-placeholder {
  display: flex; align-items: center; justify-content: center; text-align: center;
  aspect-ratio: 4 / 3; border: 2px dashed var(--border); border-radius: var(--radius);
  color: var(--text-dim); font-size: 0.85rem; padding: var(--space-2);
  background: repeating-linear-gradient(135deg, var(--bg-panel), var(--bg-panel) 10px, var(--bg-panel-2) 10px, var(--bg-panel-2) 20px);
}

/* Reveal animation hook: JS toggles .is-visible */
.reveal { opacity: 0; transform: translateY(24px); }
.reveal.is-visible { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; }
}

.site-footer {
  border-top: 1px solid var(--border);
  padding: var(--space-4) 0;
  color: var(--text-dim);
  font-size: 0.9rem;
}

/* ===== Fondo: Capa A — profundidad ambiental ===== */
.bg-ambient {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  overflow: hidden;
  background:
    radial-gradient(120% 80% at 50% -10%, rgba(37, 71, 224, 0.18), transparent 60%),
    radial-gradient(100% 60% at 50% 110%, rgba(10, 14, 26, 0.9), transparent 70%),
    var(--bg);
}
.bg-ambient::before,
.bg-ambient::after {
  content: "";
  position: absolute;
  width: 60vmax;
  height: 60vmax;
  border-radius: 50%;
  filter: blur(90px);
  opacity: 0.06;
  will-change: transform;
}
.bg-ambient::before {
  background: var(--blue-royal);
  top: -20vmax; left: -10vmax;
  animation: aurora-a 34s ease-in-out infinite alternate;
}
.bg-ambient::after {
  background: var(--blue-bright);
  bottom: -25vmax; right: -15vmax;
  animation: aurora-b 42s ease-in-out infinite alternate;
}
@keyframes aurora-a {
  from { transform: translate(0, 0) scale(1); }
  to   { transform: translate(12vmax, 8vmax) scale(1.15); }
}
@keyframes aurora-b {
  from { transform: translate(0, 0) scale(1.1); }
  to   { transform: translate(-10vmax, -6vmax) scale(1); }
}
@media (prefers-reduced-motion: reduce) {
  .bg-ambient::before, .bg-ambient::after { animation: none; }
}

/* ===== Fondo: circuito de Mónaco centrado (todas las páginas) ===== */
.bg-monaco {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}
.bg-monaco svg { width: min(92vw, 900px); height: auto; max-height: 86vh; overflow: visible; }
.bg-monaco .monaco-track { stroke-opacity: 0.32; stroke-dasharray: 1600; }
.bg-monaco .monaco-dot { opacity: 0.9; filter: drop-shadow(0 0 7px rgba(255, 177, 61, 0.95)); }

/* ===== Aviso "reducir movimiento" (animations.js lo inserta si aplica) ===== */
.reduced-motion-notice {
  position: fixed;
  left: 50%;
  bottom: var(--space-2);
  transform: translateX(-50%);
  z-index: 30;
  display: flex;
  align-items: center;
  gap: var(--space-2);
  max-width: min(92vw, 520px);
  padding: 10px 12px 10px 16px;
  background: var(--bg-panel);
  color: var(--text);
  border: 1px solid var(--border);
  border-left: 3px solid var(--signal-amber);
  border-radius: var(--radius);
  font-size: 0.85rem;
  line-height: 1.4;
  box-shadow: 0 12px 30px -14px rgba(0, 0, 0, 0.6);
}
.reduced-motion-notice strong { color: var(--signal-amber); font-weight: 600; }
.reduced-motion-notice button {
  flex-shrink: 0;
  width: 26px; height: 26px;
  display: inline-flex; align-items: center; justify-content: center;
  background: none; border: none; border-radius: 6px;
  color: var(--text-dim); font-size: 1.3rem; line-height: 1; cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease;
}
.reduced-motion-notice button:hover { background: var(--bg-panel-2); color: var(--text); }