/* Sección 04 · Aprender y portada con propósito. Ver views/LearnView.js. */

.page--learn {
  position: fixed;
  z-index: 5;
  inset: var(--nav-h) 0 0 0;
  overflow-y: auto;
  background: var(--bg);
  padding: var(--space-5) var(--space-4) var(--space-6);
}

.learn { width: min(980px, 100%); margin: 0 auto; display: grid; gap: var(--space-5); }
.learn h2 { margin: 0 0 var(--space-3); font-size: 0.8rem; letter-spacing: 0.14em; text-transform: uppercase; color: var(--accent); }
.learn h3 { margin: 0 0 4px; font-size: 1rem; }
.learn p { margin: 0; }
.learn-lead { max-width: 68ch; font-size: 1.05rem; line-height: 1.55; color: var(--ink-muted); }
.learn-sub { margin: 0 0 var(--space-3); color: var(--ink-muted); font-size: var(--fs-body); }

.learn-cards, .learn-examples, .learn-limits { margin: 0; padding: 0; list-style: none; display: grid; gap: var(--space-3); }
.learn-cards { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }

/* Tarjetas desplegables: el texto corto siempre se ve; al abrir salen cómo leerlo, un ejemplo real y dónde lo ves. */
.lcard { border: 1px solid var(--line); border-radius: 12px; background: var(--surface); align-self: start; transition: border-color 0.2s; }
.lcard.open { border-color: var(--accent); }
.learn .lcard-h { margin: 0; font-size: inherit; }
.lcard-head {
  all: unset; box-sizing: border-box; width: 100%; cursor: pointer; text-transform: none; letter-spacing: normal; font-family: var(--font-text); color: var(--ink);
  display: grid; grid-template-columns: 44px minmax(0, 1fr) auto; gap: var(--space-3); align-items: start;
  padding: var(--space-4); border-radius: 12px;
}
.lcard-head:hover { background: color-mix(in srgb, var(--accent) 7%, transparent); }
.lcard-head:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.lcard-head .icon { width: 44px; height: 44px; color: var(--accent); }
.lcard-text { display: grid; gap: 4px; }
.lcard-title { font-size: 1rem; font-weight: 700; }
.lcard-sum { text-transform: none; letter-spacing: normal; }
.lcard-sum { color: var(--ink-muted); font-size: var(--fs-body); line-height: 1.5; font-weight: 400; }
/* Indicador de abierto (chevrón) y de «visto» (punto). */
.lcard-mark { width: 10px; height: 10px; margin-top: 8px; border-right: 2px solid var(--ink-muted); border-bottom: 2px solid var(--ink-muted); transform: rotate(45deg); transition: transform 0.25s; }
.lcard.open .lcard-mark { transform: rotate(225deg); margin-top: 14px; border-color: var(--accent); }
.lcard.seen .lcard-title::after { content: ""; display: inline-block; width: 6px; height: 6px; margin-left: 8px; border-radius: 50%; background: var(--state-ok); vertical-align: middle; }
.lcard-panel { display: grid; grid-template-rows: 0fr; transition: grid-template-rows 0.28s ease; }
.lcard.open .lcard-panel { grid-template-rows: 1fr; }
.lcard-inner { overflow: hidden; visibility: hidden; display: grid; gap: var(--space-3); padding: 0 var(--space-4); transition: visibility 0s 0.28s; }
.lcard.open .lcard-inner { visibility: visible; padding-bottom: var(--space-4); transition-delay: 0s; }
.lcard-layer { padding-left: var(--space-3); border-left: 2px solid var(--line-strong); }
.lcard-layer h4 { margin: 0 0 2px; font-size: var(--fs-small); letter-spacing: 0.08em; text-transform: uppercase; color: var(--accent); }
.lcard-layer p { color: var(--ink-muted); font-size: var(--fs-body); line-height: 1.55; }
.lcard-inner .btn { justify-self: start; }
.learn-hint { margin: calc(var(--space-3) * -1) 0 0; font-size: var(--fs-small); }

/* Índice de temas: queda a la vista al desplazarse. */
.learn-index { position: sticky; top: calc(var(--space-5) * -1); z-index: 2; display: flex; flex-wrap: wrap; gap: var(--space-2); padding: var(--space-2) 0; background: var(--bg); }
.learn-index button { padding: 6px 12px; border: 1px solid var(--line-strong); border-radius: 16px; background: transparent; color: var(--ink); font-size: var(--fs-small); cursor: pointer; }
.learn-index button:hover { border-color: var(--accent); color: var(--accent); }
@media (prefers-reduced-motion: reduce) { .lcard-panel, .lcard-mark, .lcard-inner { transition: none; } }

.learn-examples li {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  padding: var(--space-4);
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface);
}
.learn-examples p { color: var(--ink-muted); font-size: var(--fs-body); }
.learn-examples .btn { flex: none; }

.learn-limits { list-style: disc; padding-left: 20px; gap: var(--space-2); color: var(--ink-muted); max-width: 72ch; }
.learn-limits + .learn-sub { margin-top: var(--space-3); }
.learn > section > .btn { margin-top: var(--space-2); }

/* Cómo decide la NASA y cómo leer los gráficos. */
.learn .learn-h3 { margin: var(--space-4) 0 4px; font-size: 1.05rem; }
.learn-steps { margin: 0 0 var(--space-3); padding-left: 24px; display: grid; gap: var(--space-2); max-width: 72ch; color: var(--ink-muted); line-height: 1.5; }
.learn-steps li::marker { color: var(--accent); font-weight: 700; }
.learn-scroll { overflow-x: auto; margin-top: var(--space-2); }
.learn-table { width: 100%; border-collapse: collapse; font-size: var(--fs-body); }
.learn-table th, .learn-table td { padding: 10px 12px; text-align: left; vertical-align: top; border-top: 1px solid var(--line); line-height: 1.45; }
.learn-table thead th { border-top: 0; color: var(--ink-muted); font-weight: 600; font-size: var(--fs-small); }
.learn-table tbody th { white-space: nowrap; }
.learn-table td { color: var(--ink-muted); min-width: 200px; }
.learn-note { margin-top: var(--space-4); padding: var(--space-4); border: 1px solid var(--line); border-left: 3px solid var(--accent); border-radius: 0 12px 12px 0; background: var(--surface); max-width: 80ch; }
.learn-note p { color: var(--ink-muted); line-height: 1.5; }
.learn-sources { margin: 0 0 var(--space-2); padding-left: 20px; display: grid; gap: 4px; font-size: var(--fs-small); }
.learn-sources a { color: var(--ink); text-underline-offset: 3px; }
.learn-sources a:hover { color: var(--accent); }
.learn-charts { margin: 0; padding: 0; list-style: none; display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: var(--space-3); }
.learn-charts li { padding: var(--space-4); border: 1px solid var(--line); border-radius: 12px; background: var(--surface); }
.learn-charts p { color: var(--ink-muted); font-size: var(--fs-body); line-height: 1.5; }

/* Portada: propósito y dos entradas. */
.hero-purpose { margin: -16px 0 0; max-width: 46ch; font-size: 1.05rem; line-height: 1.5; color: var(--ink-muted); }
.hero-actions { display: flex; flex-wrap: wrap; align-items: center; gap: var(--space-4) var(--space-5); }
.hero-link { color: var(--ink); font-size: 0.8rem; letter-spacing: 0.12em; text-transform: uppercase; text-underline-offset: 6px; }
.hero-link:hover { color: var(--accent); }
.learn-link { display: block; text-align: center; }

@media (max-width: 700px) {
  .learn-examples li { flex-direction: column; align-items: stretch; }
  .hero-purpose { margin-top: 0; font-size: 0.95rem; }
}

/* Miniaturas anotadas (views/learnFigures.js): esquemas con llamadas numeradas. */
.lfig { margin: 0; display: grid; gap: var(--space-2); }
.lfig svg { width: 100%; max-width: 420px; height: auto; border: 1px solid var(--line); border-radius: 8px; background: color-mix(in srgb, var(--bg) 70%, transparent); }
.lfig-key { margin: 0; padding-left: 22px; display: grid; gap: 4px; color: var(--ink-muted); font-size: var(--fs-small); line-height: 1.45; }
.lfig-key li::marker { color: var(--accent); font-weight: 700; }
.lfig figcaption { color: var(--ink-muted); font-size: var(--fs-small); font-style: italic; }
.lfig .fg-call circle { fill: var(--accent); }
.lfig .fg-call text { fill: var(--accent-ink); font: 700 11px var(--font-text); }
.lfig .fg-lbl { fill: var(--ink-muted); font: 11px var(--font-text); }
.lfig .fg-num { fill: var(--ink); font: 700 13px var(--font-mono); }
.lfig .fg-axis { stroke: var(--line-strong); stroke-width: 1.5; }
.lfig .fg-thr { stroke: var(--ink); stroke-width: 2; }
.lfig .fg-thr.dash { stroke-dasharray: 4 4; stroke: var(--ink-muted); }
.lfig .fg-track { fill: none; stroke: var(--viable); stroke-opacity: 0.25; stroke-width: 6; }
.lfig .fg-track.off { stroke: var(--off); stroke-opacity: 0.2; }
.lfig .fg-arc { fill: none; stroke: var(--viable); stroke-width: 6; stroke-linecap: round; }
.lfig .fg-dash { fill: none; stroke: var(--off); stroke-width: 4; stroke-dasharray: 5 6; }
.lfig .fg-ring { fill: none; stroke: #fff; stroke-width: 2; }
.lfig .fg-pt { fill: var(--viable); }
.lfig .fg-pt.off { fill: var(--off); }
.lfig .fg-ok { fill: var(--state-ok); }
.lfig .fg-bad { fill: var(--state-bad); }
.lfig .fg-mark { font: 700 14px var(--font-text); }
.lfig .fg-mark.ok { fill: var(--state-ok); }
.lfig .fg-mark.bad { fill: var(--state-bad); }
.lfig .fg-terrain { fill: var(--line-strong); stroke: var(--ink-muted); stroke-width: 1; }
.lfig .fg-line { stroke-width: 2.5; }
.lfig .fg-line.sun { stroke: var(--data-sun); }
.lfig .fg-line.earth { stroke: var(--data-earth-high); }
.lfig .fg-hid { stroke: var(--data-sun); stroke-width: 2.5; stroke-dasharray: 2 4; opacity: 0.6; }
.lfig .fg-sun { fill: var(--data-sun); }
.lfig .fg-earth { fill: var(--data-earth-high); }
.lfig .fg-gap { fill: none; stroke: var(--ink-muted); stroke-dasharray: 3 3; }
.lfig .fg-tk.ok { fill: var(--state-ok); }
.lfig .fg-tk.bad { fill: var(--ink-muted); opacity: 0.55; }
.lfig .fg-bar.a { fill: var(--viable); }
.lfig .fg-bar.b, .lfig .fg-bar.c { fill: var(--off); }
.lfig .fg-scale { fill: color-mix(in srgb, var(--accent) 35%, var(--line)); }