.session-hero { padding: var(--space-5) 0 var(--space-4); border-bottom: 1px solid var(--border); }
.session-hero .num { font-family: var(--font-display); font-size: 3rem; color: var(--blue-royal); }
.session-hero h1 { font-size: clamp(1.8rem, 4vw, 2.6rem); margin-top: var(--space-1); }
.session-hero .quote { color: var(--text-dim); font-style: italic; max-width: 640px; }
.session-hero .badges { display: flex; gap: 8px; flex-wrap: wrap; margin-top: var(--space-2); }
.session-hero__trace-wrap { margin-top: var(--space-2); opacity: 0.6; }
.session-hero__trace-wrap svg { display: block; width: 100%; max-width: 280px; height: auto; }

.session-section { padding: var(--space-5) 0; }
.session-section h2 { font-size: 1.6rem; margin-bottom: var(--space-3); }
.session-section + .session-section { border-top: 1px solid var(--border); }

.content-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 12px; }
.content-list li {
  background: var(--bg-panel); border: 1px solid var(--border); border-radius: var(--radius);
  padding: var(--space-2) var(--space-3);
}

.reference-block { display: grid; gap: var(--space-3); margin-top: var(--space-2); }
.reference-block .formula-item .formula-label { color: var(--text-dim); font-size: 0.85rem; margin-bottom: 4px; }
.table-wrap { overflow-x: auto; }
.table-caption { color: var(--text-dim); font-size: 0.85rem; margin-bottom: 6px; }

.session-nav { display: flex; justify-content: space-between; gap: var(--space-2); padding: var(--space-4) 0; flex-wrap: wrap; }

.safety-box { border: 1px solid var(--signal-amber); border-radius: var(--radius-lg); padding: var(--space-3); background: rgba(255,177,61,0.06); }
.safety-box h3 { color: var(--signal-amber); }

.diagram { margin: 0; }
.diagram img { width: 100%; max-width: 420px; border-radius: var(--radius); border: 1px solid var(--border); }
.diagram figcaption { margin-top: 6px; }
.diagram--wide img { max-width: 640px; display: block; margin: 0 auto; }

/* ---- Modelo 3D + ficha técnica (hero) ---- */
.hero-model { display: flex; gap: var(--space-3); align-items: stretch; flex-wrap: wrap; }
.hero-model .model-slot { flex: 1 1 340px; width: auto; max-width: 460px; align-self: flex-start; }
.spec-card {
  flex: 1 1 260px; min-width: 240px;
  background: var(--bg-panel); border: 1px solid var(--border); border-radius: var(--radius-lg);
  padding: var(--space-3); display: flex; flex-direction: column;
}
.spec-card__eyebrow { font-family: var(--font-mono); font-size: 0.66rem; letter-spacing: 0.14em; text-transform: uppercase; color: var(--signal-amber); margin-bottom: 4px; }
.spec-card__title { font-family: var(--font-display); font-weight: 600; font-size: 1.15rem; margin-bottom: 12px; padding-bottom: 10px; border-bottom: 1px solid var(--border); }
.spec-list { display: grid; gap: 10px; font-family: var(--font-mono); font-size: 0.84rem; align-content: start; }
.spec-row { display: flex; justify-content: space-between; gap: 14px; align-items: baseline; }
.spec-k { color: var(--text-dim); white-space: nowrap; }
.spec-v { color: var(--text); text-align: right; }
.spec-v .hl { color: var(--blue-bright); }

/* ---- Lección explicativa ---- */
.concept { max-width: 760px; }
.concept p { font-size: 1.02rem; }
.concept .diagram { margin-top: var(--space-2); }
.concept code, .callout code { font-family: var(--font-mono); color: var(--blue-bright); background: var(--bg-panel-2); padding: 1px 6px; border-radius: 4px; font-size: 0.9em; }
.concept .value-hl { color: var(--signal-amber); font-family: var(--font-mono); }

.teacher-note {
  margin-top: var(--space-3);
  border-left: 3px solid var(--signal-amber);
  background: rgba(255, 177, 61, 0.06);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: var(--space-1) var(--space-2);
}
.teacher-note summary {
  cursor: pointer; color: var(--signal-amber);
  font-family: var(--font-mono); font-size: 0.82rem; letter-spacing: 0.02em;
  list-style: none; user-select: none;
}
.teacher-note summary::-webkit-details-marker { display: none; }
.teacher-note[open] summary { margin-bottom: 8px; }
.teacher-note p { margin: 0; font-size: 0.92rem; color: var(--text-dim); }
.teacher-note p + p { margin-top: 6px; }

/* ---- Rieles laterales (laptops y pantallas anchas) ---- */
.side-rail { display: none; }
/* En cuanto aparecen los rieles (≥1360px) la columna de contenido se estrecha para
   hacerles sitio: 960px en laptops angostas → 1120px de vuelta en monitores anchos
   (≥1760px, para conservar la vista amplia). El margen liberado se reparte entre un
   riel más ancho (gráficas menos aplastadas) y ~28px de aire con el borde. Solo
   afecta a #session-root, no al home. */
@media (min-width: 1360px) {
  #session-root { --max-width: clamp(960px, 40.6vw + 405px, 1120px); }
  .side-rail {
    display: flex; flex-direction: column;
    position: fixed; top: 120px; bottom: 32px;
    z-index: 5;
    /* Ocupa el margen disponible menos 48px = 20px de separación con el contenido
       + 28px de aire con el borde de la pantalla. Mín 96px (piso de legibilidad),
       máx 240px (tope en monitores anchos). */
    width: clamp(96px, calc((100vw - var(--max-width)) / 2 - 48px), 240px);
    overflow: auto; scrollbar-width: none;
  }
  .side-rail::-webkit-scrollbar { display: none; }
  /* Pegados al contenido con 20px de separación. */
  .side-rail--left  { right: calc(50% + (var(--max-width) / 2) + 20px); }
  .side-rail--right { left: calc(50% + (var(--max-width) / 2) + 20px); text-align: right; }
}
.side-rail__label {
  font-family: var(--font-mono); font-size: 0.7rem; letter-spacing: 0.14em;
  text-transform: uppercase; color: var(--text-dim); margin-bottom: 14px;
  padding-bottom: 10px; border-bottom: 1px solid var(--border); flex-shrink: 0;
}

/* Índice / scrollspy */
.spy { list-style: none; margin: 0; padding: 0; display: grid; gap: 3px; }
.spy a {
  display: block; padding: 9px 12px; border-left: 2px solid var(--border);
  color: var(--text-dim); text-decoration: none; font-size: 0.85rem; line-height: 1.35;
  transition: color 0.15s ease, border-color 0.15s ease, background 0.15s ease;
}
.spy a:hover { color: var(--text); background: rgba(108, 140, 255, 0.06); }
.spy a.is-active { color: var(--blue-bright); border-left-color: var(--blue-royal); background: rgba(37, 71, 224, 0.1); }

/* Avance de lectura (pie del riel izquierdo, anclado abajo) */
.rail-progress { margin-top: auto; flex-shrink: 0; }
.rail-progress__label { font-family: var(--font-mono); font-size: 0.66rem; letter-spacing: 0.1em; text-transform: uppercase; color: var(--text-dim); margin-bottom: 6px; }
.rail-progress__track { height: 4px; border-radius: 2px; background: var(--border); overflow: hidden; }
.rail-progress__fill { display: block; height: 100%; width: 0; background: var(--blue-royal); transition: width 0.15s linear; }

/* Ticker de telemetría */
.telem { display: grid; gap: 12px; font-family: var(--font-mono); flex-shrink: 0; }
.telem__row { display: flex; justify-content: space-between; gap: 8px; font-size: 0.82rem; }
.telem__k { color: var(--text-dim); }
.telem__v { color: var(--blue-bright); font-variant-numeric: tabular-nums; }
.telem__v.is-hot { color: var(--signal-amber); }
.telem__bar { height: 6px; border-radius: 3px; background: var(--border); overflow: hidden; margin-top: 4px; }
.telem__bar span { display: block; height: 100%; background: var(--blue-royal); transition: width 0.4s ease, background 0.4s ease; }

/* Mini-gráficas en vivo (columna de 3 que llena la altura sobrante del riel) */
.telem-charts { margin-top: var(--space-3); flex: 1; min-height: 0; display: flex; flex-direction: column; gap: var(--space-3); }
.mini-chart { flex: 1; min-height: 0; display: flex; flex-direction: column; text-align: left; }
.telem-spark__label { font-family: var(--font-mono); font-size: 0.64rem; letter-spacing: 0.06em; text-transform: uppercase; color: var(--text-dim); margin-bottom: 6px; }
.spark { flex: 1; min-height: 0; display: flex; flex-direction: column; }
.spark__area { flex: 1; min-height: 60px; display: flex; gap: 6px; }
.spark__yaxis {
  display: flex; flex-direction: column; justify-content: space-between;
  font-family: var(--font-mono); font-size: 0.62rem; color: var(--text-dim);
  text-align: right; width: 28px; padding: 1px 0;
}
.spark__plot {
  flex: 1; position: relative;
  border-left: 1px solid var(--border); border-bottom: 1px solid var(--border);
}
.spark__plot svg { position: absolute; inset: 0; width: 100%; height: 100%; }
.spark__xaxis {
  display: flex; justify-content: space-between; margin-left: 34px; margin-top: 4px;
  font-family: var(--font-mono); font-size: 0.62rem; color: var(--text-dim);
}

/* Laptops de poca altura: el bloque de valores tiene alto fijo, así que en pantallas
   bajas se comía ~75% del riel y aplastaba las gráficas. Aquí se compacta (menos gap,
   letra y barras más finas) y se ocultan las filas decorativas de GPS (LAT/LON), para
   que las mini-gráficas conserven ~la mitad del riel como en monitores altos (>820px,
   donde se mantiene el diseño amplio). */
@media (max-height: 820px) {
  .telem { gap: 7px; }
  .telem__row { font-size: 0.78rem; }
  .telem__bar { height: 5px; margin-top: 3px; }
  .telem-charts { margin-top: var(--space-2); gap: var(--space-2); }
  .spark__area { min-height: 44px; }
}
/* LAT/LON (filas decorativas) solo se ocultan cuando el alto está realmente justo
   (ventana normal de laptop). Con más aire —p. ej. la misma laptop en F11, ~768px—
   reaparecen porque ya caben sin aplastar las gráficas. */
@media (max-height: 720px) {
  .telem__row--aux { display: none; }
}
/* ===== Traza del hero (color del curso) ===== */
.session-hero__trace path, .circuit-trace path { stroke: var(--accent); }

/* ===== Actividad de diseño (papel/pizarrón + herramienta en línea) ===== */
.activity {
  border: 1px solid var(--border); border-left: 3px solid var(--accent);
  background: var(--bg-panel); border-radius: 0 var(--radius-lg) var(--radius-lg) 0;
  padding: var(--space-3); max-width: 820px;
}
.activity__head { display: flex; align-items: baseline; gap: var(--space-2); flex-wrap: wrap; }
.activity__head h2 { margin: 0; font-size: 1.35rem; }
.activity__time {
  font-family: var(--font-mono); font-size: 0.7rem; letter-spacing: 0.12em; text-transform: uppercase;
  color: var(--accent); border: 1px solid color-mix(in srgb, var(--accent) 50%, transparent);
  background: color-mix(in srgb, var(--accent) 12%, transparent);
  padding: 3px 9px; border-radius: 999px; white-space: nowrap;
}
.activity__prompt { margin-top: var(--space-2); font-size: 1.02rem; }
.activity__steps { margin: var(--space-2) 0 0; padding-left: 1.3rem; display: grid; gap: 8px; }
.activity__steps li { padding-left: 4px; }
.activity__output {
  margin-top: var(--space-3); padding: var(--space-2);
  border: 1px dashed color-mix(in srgb, var(--signal) 55%, var(--border));
  border-radius: var(--radius); background: color-mix(in srgb, var(--signal) 7%, transparent);
  display: flex; flex-direction: column; gap: 4px;
}
.activity__output-label {
  font-family: var(--font-mono); font-size: 0.66rem; letter-spacing: 0.12em; text-transform: uppercase;
  color: var(--signal);
}
.activity__hint { margin-top: var(--space-2); }
.activity__hint summary {
  cursor: pointer; color: var(--accent); font-family: var(--font-mono); font-size: 0.82rem;
  list-style: none; user-select: none;
}
.activity__hint summary::-webkit-details-marker { display: none; }
.activity__hint p { margin: 8px 0 0; font-size: 0.92rem; color: var(--text-dim); }

/* ===== Tabla de decisión ("cuándo usar qué") ===== */
.decision-table .data-table th:first-child,
.decision-table .data-table td:first-child { color: var(--accent); font-weight: 600; }

/* ===== Entregable ===== */
.deliverable-box {
  border: 1px solid var(--accent); border-radius: var(--radius-lg);
  padding: var(--space-3); background: color-mix(in srgb, var(--accent) 7%, transparent);
}
.deliverable__eyebrow {
  font-family: var(--font-mono); font-size: 0.66rem; letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--accent); margin-bottom: 4px;
}
.deliverable-box h3 { font-size: 1.3rem; margin: 0 0 var(--space-2); }
.deliverable__list { margin: 0 0 var(--space-2); padding-left: 1.2rem; display: grid; gap: 6px; }
.deliverable__format { margin: 0; font-family: var(--font-mono); font-size: 0.85rem; color: var(--text-dim); }

/* ===== Rúbrica ===== */
.rubric { display: grid; gap: 8px; max-width: 820px; }
.rubric__row {
  display: flex; justify-content: space-between; align-items: center; gap: var(--space-2);
  background: var(--bg-panel); border: 1px solid var(--border); border-radius: var(--radius);
  padding: var(--space-2);
}
.rubric__crit { flex: 1; }
.rubric__weight {
  flex-shrink: 0; font-family: var(--font-mono); font-weight: 600; font-variant-numeric: tabular-nums;
  color: var(--signal); border: 1px solid color-mix(in srgb, var(--signal) 50%, transparent);
  background: color-mix(in srgb, var(--signal) 10%, transparent);
  padding: 3px 10px; border-radius: 999px; font-size: 0.85rem;
}
/* ===== Firma del hero (§4): traza de bus (Intermedio) / cinta de secuencia (Avanzado) ===== */
.hero-signature { margin-top: var(--space-3); max-width: 560px; }
.hero-signature__eyebrow {
  font-family: var(--font-mono); font-size: 0.66rem; letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--text-dim); margin-bottom: 10px;
}
/* Analizador lógico I²C */
.hero-bus { width: 100%; height: auto; display: block; overflow: visible; }
.hero-bus__lbl { fill: var(--text-dim); font-family: var(--font-mono); font-size: 15px; }
.hero-bus .hero-bus__scl { stroke: var(--accent); }
.hero-bus .hero-bus__sda { stroke: var(--accent-2); }
.hero-bus__legend { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 10px; }
.hero-bus__field {
  font-family: var(--font-mono); font-size: 0.62rem; letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--text-dim); border: 1px solid var(--border); border-radius: 999px; padding: 3px 9px;
}
/* Cinta de secuencia */
.seq-tape { display: flex; flex-wrap: wrap; gap: 5px; }
.seq-cell {
  width: 30px; height: 34px; display: flex; align-items: center; justify-content: center;
  font-family: var(--font-mono); font-size: 0.72rem; font-variant-numeric: tabular-nums;
  color: var(--text); background: var(--bg-panel-2); border: 1px solid var(--border); border-radius: 5px;
  transition: background 0.35s ease, color 0.35s ease, border-color 0.35s ease;
}
.seq-cell--miss { color: var(--signal); border-color: var(--signal); background: transparent; }
.seq-cell--filled { color: var(--bg); background: var(--accent-2); border-color: var(--accent-2); }