/* ============================================================
   Estadística Aplicada a los Negocios Internacionales
   Hoja de estilos principal — book.css
   ============================================================ */

:root {
  --azul:   #003366;
  --azul2:  #0066B3;
  --dorado: #B48C00;
  --gris:   #F5F6F8;
  --verde:  #007850;
  --rojo:   #B41E1E;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: #1a1a2e;
  background: #fff;
}

/* ── Sidebar ─────────────────────────────────────────────── */
.sidebar {
  position: fixed;
  top: 0; left: 0;
  width: 270px; height: 100vh;
  background: var(--azul);
  color: #fff;
  overflow-y: auto;
  z-index: 200;
  display: flex;
  flex-direction: column;
}

.sidebar-brand {
  padding: 1.4rem 1.2rem 1rem;
  border-bottom: 1px solid rgba(255,255,255,.15);
}

.sidebar-brand .uni {
  font-size: .72rem;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: var(--dorado);
  font-weight: 700;
}

.sidebar-brand .book-title {
  font-size: .9rem;
  font-weight: 700;
  line-height: 1.3;
  margin-top: .25rem;
}

.sidebar-brand .author {
  font-size: .72rem;
  color: rgba(255,255,255,.6);
  margin-top: .2rem;
}

.sidebar nav { flex: 1; padding: .6rem 0; }

.sidebar nav a {
  display: flex;
  align-items: center;
  gap: .6rem;
  padding: .55rem 1.2rem;
  color: rgba(255,255,255,.8);
  text-decoration: none;
  font-size: .82rem;
  border-left: 3px solid transparent;
  transition: all .18s;
}

.sidebar nav a:hover,
.sidebar nav a.active {
  background: rgba(255,255,255,.1);
  color: #fff;
  border-left-color: var(--dorado);
}

.sidebar nav .ch-num {
  min-width: 20px;
  font-weight: 700;
  color: var(--dorado);
  font-size: .8rem;
}

.sidebar-footer {
  padding: .8rem 1.2rem;
  font-size: .68rem;
  color: rgba(255,255,255,.4);
  border-top: 1px solid rgba(255,255,255,.1);
}

/* ── Main content ────────────────────────────────────────── */
.main {
  margin-left: 270px;
  min-height: 100vh;
}

.content {
  max-width: 860px;
  padding: 2.5rem 3rem 4rem;
}

/* ── Chapter header ──────────────────────────────────────── */
.ch-header {
  margin-bottom: 2rem;
  padding-bottom: 1.2rem;
  border-bottom: 3px solid var(--azul);
}

.ch-label {
  font-size: .72rem;
  font-weight: 700;
  letter-spacing: .12em;
  color: var(--dorado);
  text-transform: uppercase;
}

.ch-title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--azul);
  line-height: 1.2;
  margin: .3rem 0 .5rem;
}

.ch-subtitle {
  font-size: .95rem;
  color: #555;
  font-style: italic;
}

/* ── Typography ──────────────────────────────────────────── */
h2 {
  font-size: 1.35rem;
  color: var(--azul);
  margin: 2.2rem 0 .7rem;
  padding-bottom: .35rem;
  border-bottom: 1.5px solid #dde3ec;
}

h3 {
  font-size: 1.1rem;
  color: var(--azul2);
  margin: 1.6rem 0 .5rem;
}

h4 {
  font-size: .95rem;
  color: var(--dorado);
  font-weight: 700;
  margin: 1.2rem 0 .35rem;
}

p { margin: .65rem 0; }

ul, ol { padding-left: 1.5rem; margin: .6rem 0; }
li { margin: .3rem 0; }

strong { color: var(--azul); }

/* ── Boxes ───────────────────────────────────────────────── */
.box {
  border-radius: 6px;
  padding: 1.1rem 1.4rem;
  margin: 1.3rem 0;
}

.box .box-title {
  font-size: .75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .08em;
  margin-bottom: .5rem;
}

.box-formula {
  background: #fff;
  border: 2px solid var(--azul2);
}

.box-formula .box-title { color: var(--azul2); }

.box-concepto {
  background: var(--gris);
  border-left: 4px solid var(--dorado);
}

.box-concepto .box-title { color: var(--dorado); }

.box-caso {
  background: #dce8fa;
  border: 1.5px solid var(--azul);
  border-radius: 6px;
}

.box-caso .box-title { color: var(--azul); }

.box-advertencia {
  background: #fff3f3;
  border-left: 4px solid var(--rojo);
}

.box-advertencia .box-title { color: var(--rojo); }

.box-verde {
  background: #edfbf4;
  border-left: 4px solid var(--verde);
}

.box-verde .box-title { color: var(--verde); }

.box-dorado {
  background: #fdf8e8;
  border-left: 4px solid var(--dorado);
}

.box-dorado .box-title { color: var(--dorado); }

/* ── Objectives ──────────────────────────────────────────── */
.objectives {
  background: #ebf0f8;
  border: 1.5px solid var(--azul);
  border-radius: 6px;
  padding: 1.2rem 1.5rem;
  margin-bottom: 2rem;
}

.objectives .obj-title {
  font-weight: 700;
  font-size: .8rem;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: var(--azul);
  margin-bottom: .8rem;
}

.objectives ol { padding-left: 1.2rem; margin: 0; }
.objectives li { margin: .4rem 0; font-size: .9rem; }

/* ── Tables ──────────────────────────────────────────────── */
.tbl-wrap { overflow-x: auto; margin: 1rem 0; }

table { width: 100%; border-collapse: collapse; font-size: .875rem; }

thead th {
  background: var(--azul);
  color: #fff;
  padding: .55rem .8rem;
  text-align: left;
  font-weight: 600;
}

tbody td {
  padding: .5rem .8rem;
  border-bottom: 1px solid #e0e6ef;
}

tbody tr:nth-child(even) td { background: var(--gris); }

/* ── Interactive tool container ──────────────────────────── */
.tool {
  border: 2px solid var(--azul2);
  border-radius: 8px;
  overflow: hidden;
  margin: 2rem 0;
}

.tool-header {
  background: var(--azul2);
  color: #fff;
  padding: .7rem 1.2rem;
  font-weight: 700;
  font-size: .9rem;
  display: flex;
  align-items: center;
  gap: .5rem;
}

.tool-header .badge-interactive {
  background: var(--dorado);
  color: #fff;
  font-size: .65rem;
  padding: .15rem .45rem;
  border-radius: 3px;
  font-weight: 700;
  letter-spacing: .06em;
  text-transform: uppercase;
}

.tool-body { padding: 1.4rem; }

/* Controls */
.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 1.2rem;
  margin-bottom: 1.2rem;
  align-items: flex-end;
}

.ctrl {
  display: flex;
  flex-direction: column;
  gap: .25rem;
}

.ctrl label {
  font-size: .75rem;
  font-weight: 700;
  color: #555;
  text-transform: uppercase;
  letter-spacing: .05em;
}

.ctrl input[type="range"] {
  accent-color: var(--azul2);
  width: 160px;
}

.ctrl input[type="number"],
.ctrl input[type="text"],
.ctrl select {
  padding: .35rem .55rem;
  border: 1.5px solid #bdc8d8;
  border-radius: 4px;
  font-size: .875rem;
  width: 110px;
}

.ctrl .val {
  font-size: .75rem;
  font-weight: 700;
  color: var(--azul2);
}

/* Canvas */
.canvas-wrap {
  background: #f9fbff;
  border: 1px solid #dde3ec;
  border-radius: 6px;
  overflow: hidden;
  margin: .8rem 0;
}

canvas { display: block; }

/* Output strip */
.output-strip {
  display: flex;
  flex-wrap: wrap;
  gap: .8rem;
  margin-top: 1rem;
}

.output-card {
  background: var(--gris);
  border-radius: 6px;
  padding: .6rem 1rem;
  min-width: 120px;
  flex: 1;
}

.output-card .oc-label {
  font-size: .7rem;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: #666;
  font-weight: 600;
}

.output-card .oc-value {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--azul);
  font-variant-numeric: tabular-nums;
}

.output-card .oc-value.green { color: var(--verde); }
.output-card .oc-value.gold  { color: var(--dorado); }

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: .35rem;
  padding: .42rem .9rem;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-size: .825rem;
  font-weight: 700;
  transition: all .18s;
  text-decoration: none;
}

.btn-primary { background: var(--azul2); color: #fff; }
.btn-primary:hover { background: var(--azul); }

.btn-success { background: var(--verde); color: #fff; }
.btn-success:hover { background: #005a3b; }

.btn-dorado { background: var(--dorado); color: #fff; }
.btn-dorado:hover { background: #8a6b00; }

.btn-outline {
  background: #fff;
  border: 1.5px solid #bdc8d8;
  color: #444;
}

.btn-outline:hover { background: var(--gris); }

.btn-sm { padding: .3rem .65rem; font-size: .75rem; }

/* Steps (pasoapaso) */
.steps { margin: 1rem 0; }

.step {
  display: flex;
  gap: 1rem;
  margin: .9rem 0;
  align-items: flex-start;
}

.step-num {
  min-width: 28px; height: 28px;
  border-radius: 50%;
  background: var(--azul2);
  color: #fff;
  font-weight: 700;
  font-size: .8rem;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  margin-top: .1rem;
}

.step-body { flex: 1; }

/* Chapter navigation */
.ch-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid #dde3ec;
}

.ch-nav a {
  color: var(--azul2);
  text-decoration: none;
  font-weight: 700;
  font-size: .875rem;
  display: flex;
  align-items: center;
  gap: .35rem;
}

.ch-nav a:hover { color: var(--azul); }

/* Summary box */
.summary {
  background: var(--gris);
  border: 1.5px solid #c0cee0;
  border-radius: 6px;
  padding: 1.2rem 1.5rem;
  margin: 2rem 0 1rem;
}

.summary .sum-title {
  font-weight: 700;
  color: var(--azul);
  margin-bottom: .7rem;
}

/* Responsive */
@media (max-width: 900px) {
  .sidebar { display: none; }
  .main { margin-left: 0; }
  .content { padding: 1.5rem; }
}

/* MathJax display tweak */
.MJX-TeXAtom-ORD { }
mjx-container { margin: .4rem 0; }

/* Utility */
.text-muted  { color: #777; font-size: .875rem; }
.text-center { text-align: center; }
.mt-1 { margin-top: .5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mb-1 { margin-bottom: .5rem; }
.mb-2 { margin-bottom: 1rem; }
.flex { display: flex; }
.gap-1 { gap: .5rem; }
.gap-2 { gap: 1rem; }
.flex-wrap { flex-wrap: wrap; }
.items-center { align-items: center; }