/* ============================================================
   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; 
}

html, body {
  width: 100%;
  height: 100%;
}

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;
  box-shadow: 2px 0 8px rgba(0, 0, 0, 0.15);
}

.sidebar-brand {
  padding: 1.4rem 1.2rem 1rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.15);
  flex-shrink: 0;
}

.sidebar-brand .uni {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--dorado);
  font-weight: 700;
}

.sidebar-brand .book-title {
  font-size: 0.9rem;
  font-weight: 700;
  line-height: 1.3;
  margin-top: 0.25rem;
}

.sidebar-brand .author {
  font-size: 0.72rem;
  color: rgba(255, 255, 255, 0.6);
  margin-top: 0.2rem;
}

.sidebar nav {
  flex: 1;
  padding: 0.6rem 0;
  overflow-y: auto;
}

.sidebar nav a {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.55rem 1.2rem;
  color: rgba(255, 255, 255, 0.8);
  text-decoration: none;
  font-size: 0.82rem;
  border-left: 3px solid transparent;
  transition: all 0.18s ease;
}

.sidebar nav a:hover {
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
  border-left-color: var(--dorado);
}

.sidebar nav a.active {
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
  border-left-color: var(--dorado);
  font-weight: 600;
}

.sidebar nav .ch-num {
  min-width: 20px;
  font-weight: 700;
  color: var(--dorado);
  font-size: 0.8rem;
  display: flex;
  align-items: center;
  justify-content: center;
}

.sidebar-footer {
  padding: 0.8rem 1.2rem;
  font-size: 0.68rem;
  color: rgba(255, 255, 255, 0.4);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  flex-shrink: 0;
}

/* ── 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: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--dorado);
  text-transform: uppercase;
}

.ch-title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--azul);
  line-height: 1.2;
  margin: 0.3rem 0 0.5rem;
}

.ch-subtitle {
  font-size: 0.95rem;
  color: #555;
  font-style: italic;
}

/* ── Typography ──────────────────────────────────────────── */
h2 {
  font-size: 1.35rem;
  color: var(--azul);
  margin: 2.2rem 0 0.7rem;
  padding-bottom: 0.35rem;
  border-bottom: 1.5px solid #dde3ec;
}

h3 {
  font-size: 1.1rem;
  color: var(--azul2);
  margin: 1.6rem 0 0.5rem;
}

h4 {
  font-size: 0.95rem;
  color: var(--dorado);
  font-weight: 700;
  margin: 1.2rem 0 0.35rem;
}

p {
  margin: 0.65rem 0;
}

ul, ol {
  padding-left: 1.5rem;
  margin: 0.6rem 0;
}

li {
  margin: 0.3rem 0;
}

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

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

.box .box-title {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 0.5rem;
}

.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: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--azul);
  margin-bottom: 0.8rem;
}

.objectives ol {
  padding-left: 1.2rem;
  margin: 0;
}

.objectives li {
  margin: 0.4rem 0;
  font-size: 0.9rem;
}

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

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.875rem;
}

thead th {
  background: var(--azul);
  color: #fff;
  padding: 0.55rem 0.8rem;
  text-align: left;
  font-weight: 600;
}

tbody td {
  padding: 0.5rem 0.8rem;
  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: 0.7rem 1.2rem;
  font-weight: 700;
  font-size: 0.9rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.tool-header .badge-interactive {
  background: var(--dorado);
  color: #fff;
  font-size: 0.65rem;
  padding: 0.15rem 0.45rem;
  border-radius: 3px;
  font-weight: 700;
  letter-spacing: 0.06em;
  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: 0.25rem;
}

.ctrl label {
  font-size: 0.75rem;
  font-weight: 700;
  color: #555;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

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

.ctrl input[type="number"],
.ctrl input[type="text"],
.ctrl select {
  padding: 0.35rem 0.55rem;
  border: 1.5px solid #bdc8d8;
  border-radius: 4px;
  font-size: 0.875rem;
  width: 110px;
}

.ctrl .val {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--azul2);
}

/* Canvas */
.canvas-wrap {
  background: #f9fbff;
  border: 1px solid #dde3ec;
  border-radius: 6px;
  overflow: hidden;
  margin: 0.8rem 0;
}

canvas {
  display: block;
}

/* Output strip */
.output-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem;
  margin-top: 1rem;
}

.output-card {
  background: var(--gris);
  border-radius: 6px;
  padding: 0.6rem 1rem;
  min-width: 120px;
  flex: 1;
}

.output-card .oc-label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  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: 0.35rem;
  padding: 0.42rem 0.9rem;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.825rem;
  font-weight: 700;
  transition: all 0.18s;
  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: 0.3rem 0.65rem;
  font-size: 0.75rem;
}

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

.step {
  display: flex;
  gap: 1rem;
  margin: 0.9rem 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: 0.8rem;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  margin-top: 0.1rem;
}

.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: 0.875rem;
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.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: 0.7rem;
}

/* Responsive */
@media (max-width: 900px) {
  .sidebar {
    display: none;
  }

  .main {
    margin-left: 0;
  }

  .hero {
    margin-left: 0 !important;
  }

  .content {
    padding: 1.5rem;
  }
}

/* MathJax display tweak */
.MJX-TeXAtom-ORD {
}

mjx-container {
  margin: 0.4rem 0;
}

/* Utility */
.text-muted {
  color: #777;
  font-size: 0.875rem;
}

.text-center {
  text-align: center;
}

.mt-1 {
  margin-top: 0.5rem;
}

.mt-2 {
  margin-top: 1rem;
}

.mt-3 {
  margin-top: 1.5rem;
}

.mb-1 {
  margin-bottom: 0.5rem;
}

.mb-2 {
  margin-bottom: 1rem;
}

.flex {
  display: flex;
}

.gap-1 {
  gap: 0.5rem;
}

.gap-2 {
  gap: 1rem;
}

.flex-wrap {
  flex-wrap: wrap;
}

.items-center {
  align-items: center;
}