/*
  Apariencia académica de CSS / LAB (v13).
  Este archivo define la presentación general, la jerarquía visual, la navegación
  y la armonía cromática entre los modos claro, oscuro y descanso.
  Los ejemplos de cada tema conservan sus estilos pedagógicos para enseñar CSS puro.
*/
:root {
  color-scheme: light;
  --bg: #f6f8fb;
  --surface: #ffffff;
  --surface-raised: #edf2f7;
  --line: #d8e2ed;
  --text: #1e293b;
  --muted: #59677b;
  --accent: #2563eb;
  --accent-rgb: 37, 99, 235;
  --accent-ink: #1d4ed8;
  --accent-soft: color-mix(in srgb, var(--accent) 11%, var(--surface));
  --accent-contrast: #ffffff;
  --line-strong: color-mix(in srgb, var(--line) 64%, var(--text));
  --purple: #7c3aed;
  --orange: #ea580c;
  --mint: #0f766e;
  --chrome: #ffffff;
  --toolbar-bg: rgb(255 255 255 / 0.96);
  --code-bg: #162032;
  --code-text: #e2e8f0;
  --sidebar: 0px;
  --radius: 8px;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.07), 0 2px 4px -2px rgb(0 0 0 / 0.05);
}

html[data-theme="light"] {
  color-scheme: light;
  --bg: #f6f8fb;
  --surface: #ffffff;
  --surface-raised: #edf2f7;
  --line: #d8e2ed;
  --text: #1e293b;
  --muted: #59677b;
  --chrome: #ffffff;
  --toolbar-bg: rgb(255 255 255 / 0.96);
  --toolbar-veil: rgb(255 255 255 / 0.76);
  --code-bg: #162032;
  --code-text: #e2e8f0;
}

html[data-theme="dark"] {
  color-scheme: dark;
  --bg: #0f172a;
  --surface: #1e293b;
  --surface-raised: #28364b;
  --line: #334358;
  --text: #f8fafc;
  --muted: #9aa8bc;
  --chrome: #162032;
  --toolbar-bg: rgb(22 32 50 / 0.96);
  --toolbar-veil: rgb(15 23 42 / 0.72);
  --code-bg: #0b121e;
  --code-text: #dbeafe;
}

html[data-theme="rest"] {
  color-scheme: light;
  --bg: #f4eee2;
  --surface: #fbf6ee;
  --surface-raised: #ede3d1;
  --line: #d8cbb7;
  --text: #3c3427;
  --muted: #726654;
  --chrome: #fbf6ee;
  --toolbar-bg: rgb(251 246 238 / 0.97);
  --toolbar-veil: rgb(244 238 226 / 0.86);
  --code-bg: #e6dcce;
  --code-text: #3c3427;
}

body {
  background-color: var(--bg);
  background-image: radial-gradient(rgb(var(--accent-rgb) / 0.04) 1px, transparent 1px);
  background-size: 24px 24px;
  font-size: 16px;
  letter-spacing: -0.01em;
}

h1,
h2,
h3 {
  letter-spacing: -0.03em;
  font-weight: 700;
}

h2 {
  font-size: clamp(28px, 3.2vw, 40px);
  line-height: 1.18;
}

h3 {
  font-size: 22px;
  line-height: 1.25;
}

:focus-visible {
  outline: 2px solid var(--accent-ink);
  outline-offset: 3px;
}

/* Navegación: barra institucional superior y menú horizontal ergonómico */
.sidebar {
  position: static;
  inset: auto;
  width: 100%;
  height: auto;
  display: block;
  padding: 16px max(24px, calc((100% - 1100px) / 2));
  overflow: visible;
  border-right: 0;
  border-bottom: 1px solid var(--line);
  background: var(--chrome);
}

.brand {
  display: inline-flex;
  align-items: center;
  width: fit-content;
  gap: 10px;
  font-size: 20px;
  font-weight: 700;
  letter-spacing: -0.025em;
  color: var(--text);
  text-decoration: none;
}

.brand-symbol {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  font-family: var(--mono);
  font-weight: 700;
  color: var(--accent-ink);
  background: rgb(var(--accent-rgb) / 0.12);
  padding: 2px 8px;
  border-radius: 6px;
  line-height: 1.1;
  transition: transform 0.25s ease;
}

.brand:hover .brand-symbol {
  transform: rotate(-8deg) scale(1.08);
}

.brand small {
  display: inline-block;
  margin: 0 0 0 10px;
  font-size: 9.5px;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--muted);
  opacity: 0.85;
}

.index-label,
.sidebar-bottom {
  display: none;
}

.chapter-nav {
  width: 100%;
  display: flex;
  gap: 6px;
  margin-top: 14px;
  padding-top: 12px;
  padding-bottom: 6px;
  border-top: 1px solid var(--line);
  overflow-x: auto;
  scrollbar-width: thin;
  scrollbar-color: var(--line) transparent;
  scroll-behavior: smooth;
  -webkit-overflow-scrolling: touch;
}

.chapter-nav a {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  min-height: 36px;
  padding: 6px 12px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 500;
  white-space: nowrap;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--surface);
  text-decoration: none;
  transition:
    color 0.18s ease,
    background-color 0.18s ease,
    border-color 0.18s ease,
    transform 0.18s ease,
    box-shadow 0.18s ease;
}

.chapter-nav a > span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 700;
  color: var(--accent-ink);
  background: rgb(var(--accent-rgb) / 0.1);
  padding: 1px 6px;
  border-radius: 4px;
  margin-right: 7px;
}

.chapter-nav a i {
  display: none;
}

.chapter-nav a:hover {
  color: var(--text);
  background: var(--surface-raised);
  border-color: rgb(var(--accent-rgb) / 0.4);
  transform: translateY(-1px);
}

.chapter-nav a.active {
  color: var(--accent-ink);
  background: rgb(var(--accent-rgb) / 0.1);
  border-color: var(--accent);
  font-weight: 600;
  box-shadow: 0 1px 4px rgb(var(--accent-rgb) / 0.15);
}

.chapter-nav a.active > span {
  background: var(--accent);
  color: #ffffff;
}

.page-shell {
  margin-left: 0;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 30;
  min-height: 58px;
  padding: 9px max(24px, calc((100% - 1100px) / 2));
  background: var(--toolbar-bg);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
}

.breadcrumb {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--muted);
}

.breadcrumb span {
  color: var(--accent-ink);
  margin: 0 4px;
}

.toolbar {
  gap: 8px;
  flex-wrap: wrap;
  justify-content: flex-end;
  align-items: center;
}

.appearance-control,
.icon-button,
.theme-button,
.explain-button {
  min-height: 38px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--surface);
  color: var(--text);
  font-size: 12px;
  font-weight: 500;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  padding: 7px 11px;
  cursor: pointer;
  transition: all 0.18s ease;
}

.appearance-control:hover,
.icon-button:hover,
.theme-button:hover,
.explain-button:hover {
  background: var(--surface-raised);
  border-color: rgb(var(--accent-rgb) / 0.45);
  transform: translateY(-1px);
}

.appearance-control:active,
.icon-button:active,
.theme-button:active,
.explain-button:active {
  transform: scale(0.98);
}

.appearance-control {
  min-width: 144px;
  padding-left: 10px;
  overflow: hidden;
}

.appearance-control > span {
  color: var(--accent-ink);
  font-size: 14px;
}

.appearance-control select {
  flex: 1;
  width: auto;
  min-width: 0;
  max-width: 100%;
  border: 0;
  background: transparent;
  color: var(--text);
  font-size: 12px;
  font-weight: 500;
  outline: 0;
  cursor: pointer;
  padding: 6px 8px 6px 2px;
}

.appearance-control select:focus-visible {
  outline: 0;
}

select option {
  background: #ffffff;
  color: #1f2937;
}

html[data-theme="dark"] select option {
  background: #1e293b;
  color: #f8fafc;
}

.appearance-control:focus-within {
  border-color: var(--accent-ink);
  box-shadow: inset 0 0 0 1px var(--accent-ink);
}

.palette-dot {
  display: inline-block;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 6px rgb(var(--accent-rgb) / 0.6);
  transition: background 0.3s ease, transform 0.2s ease;
}

.theme-button:hover .palette-dot {
  transform: scale(1.25);
}

main {
  width: 100%;
  max-width: 1100px;
  padding: 0 24px;
}

/* Portada */
.hero {
  grid-template-columns: minmax(0, 1.08fr) minmax(320px, 0.92fr);
  gap: 48px;
  padding: 60px 0 52px;
  align-items: center;
}

.hero h1 {
  max-width: 650px;
  margin-bottom: 20px;
  font-size: clamp(44px, 5.8vw, 66px);
  line-height: 1.06;
  letter-spacing: -0.045em;
  font-weight: 700;
}

.hero h1 em {
  color: var(--accent-ink);
  font-style: normal;
  background: linear-gradient(135deg, var(--accent-ink), var(--purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-asterisk,
.orbit,
.art-cross,
.floating-tag,
.sculpture-back {
  display: none;
}

.hero-copy > p {
  max-width: 570px;
  font-size: 16px;
  line-height: 1.7;
  color: var(--muted);
}

.hero-actions {
  display: flex;
  gap: 12px;
  margin: 28px 0 32px;
  flex-wrap: wrap;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 42px;
  padding: 10px 18px;
  font-size: 13px;
  font-weight: 600;
  border-radius: 6px;
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--text);
  text-decoration: none;
  cursor: pointer;
  transition:
    background-color 0.18s ease,
    border-color 0.18s ease,
    transform 0.18s ease,
    box-shadow 0.18s ease;
}

.button:hover {
  background: var(--surface-raised);
  border-color: rgb(var(--accent-rgb) / 0.5);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgb(0 0 0 / 0.08);
}

.button:active {
  transform: scale(0.98);
}

.button.accent {
  background: var(--accent);
  color: #ffffff;
  border-color: var(--accent);
  box-shadow: 0 4px 14px rgb(var(--accent-rgb) / 0.35);
}

.button.accent:hover {
  opacity: 0.94;
  box-shadow: 0 6px 18px rgb(var(--accent-rgb) / 0.45);
  transform: translateY(-2px);
}

.accent {
  color: #ffffff;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 20px;
  color: var(--muted);
  font-size: 13px;
}

.hero-art {
  min-height: 300px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background-color: var(--surface);
  background-image:
    linear-gradient(rgb(var(--accent-rgb) / 0.06) 1px, transparent 1px),
    linear-gradient(90deg, rgb(var(--accent-rgb) / 0.06) 1px, transparent 1px);
  background-size: 24px 24px;
  box-shadow: 0 8px 30px rgb(0 0 0 / 0.06);
}

.art-top,
.art-bottom {
  color: var(--muted);
}

.art-bottom > span:last-child {
  display: none;
}

.css-sculpture {
  top: 50%;
  width: 230px;
  height: 140px;
  transform: translate(-50%, -50%);
  animation: none;
}

.sculpture-front {
  display: grid;
  place-content: center;
  padding: 16px;
  border: 0;
  border-radius: 10px;
  background: var(--accent);
  color: #ffffff;
  box-shadow: 8px 8px 0 rgb(var(--accent-rgb) / 0.25);
  font-size: 78px;
  font-weight: 700;
  line-height: 1;
  text-align: center;
}

.sculpture-front span {
  margin-top: 7px;
  padding: 0;
  font-size: 9px;
  font-weight: 600;
  letter-spacing: 0.08em;
}

.topic-strip {
  display: flex;
  justify-content: flex-start;
  flex-wrap: wrap;
  gap: 10px 16px;
  padding: 18px 0;
  color: var(--muted);
  font-size: 12px;
}

.topic-strip b {
  font-size: 10px;
  font-weight: 700;
  color: var(--accent-ink);
}

/* Secciones y paneles */
.lab-section {
  padding: 64px 0;
  border-top: 1px solid var(--line);
}

.section-title {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  margin-bottom: 12px;
  flex-wrap: wrap;
}

.section-title .eyebrow,
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-bottom: 8px;
  color: var(--accent-ink);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.07em;
}

.section-badge {
  border-radius: 6px;
  padding: 5px 11px;
  color: var(--muted);
  background: var(--surface);
  border: 1px solid var(--line);
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 700;
}

.section-intro {
  max-width: 780px;
  margin-bottom: 26px;
  font-size: 15px;
  line-height: 1.7;
  color: var(--muted);
}

.panel,
.syntax-card,
.experiment,
.playground-toolbar,
.preview-panel,
.source-panel,
.color-concepts article {
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--surface);
  box-shadow: 0 2px 8px rgb(0 0 0 / 0.04);
  transition:
    border-color 0.2s ease,
    box-shadow 0.2s ease;
}

.panel,
.syntax-card {
  padding: 24px;
}

.experiment {
  margin-top: 24px;
}

.experiment-bar,
.editor-panel-bar {
  background: var(--surface-raised);
  border-bottom: 1px solid var(--line);
  padding: 12px 18px;
  border-radius: 10px 10px 0 0;
}

/* Controles de formulario refinados */
input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 6px;
  border-radius: 9999px;
  background: var(--line);
  cursor: pointer;
  margin: 12px 0 20px;
  outline: none;
  transition: background 0.2s ease;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--accent-ink);
  border: 2px solid var(--surface);
  box-shadow: 0 1px 4px rgb(0 0 0 / 0.25);
  cursor: pointer;
  transition:
    transform 0.15s ease,
    background-color 0.15s ease;
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.2);
}

input[type="range"]::-moz-range-thumb {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--accent-ink);
  border: 2px solid var(--surface);
  box-shadow: 0 1px 4px rgb(0 0 0 / 0.25);
  cursor: pointer;
  transition: transform 0.15s ease;
}

input[type="range"]::-moz-range-thumb:hover {
  transform: scale(1.2);
}

output {
  display: inline-block;
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 600;
  color: var(--accent-ink);
  background: rgb(var(--accent-rgb) / 0.1);
  padding: 2px 7px;
  border-radius: 4px;
  white-space: nowrap;
}

select {
  border: 1px solid var(--line);
  border-radius: 6px;
  background-color: var(--surface);
  color: var(--text);
  padding: 8px 12px;
  font-size: 13px;
  transition:
    border-color 0.2s ease,
    box-shadow 0.2s ease;
}

select:hover {
  border-color: rgb(var(--accent-rgb) / 0.5);
}

select:focus-visible {
  outline: 2px solid var(--accent-ink);
  outline-offset: 1px;
  border-color: var(--accent-ink);
}

/* Sección de selectores */
.selector-definition {
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(260px, 0.7fr);
  gap: 20px;
  align-items: center;
  margin-bottom: 24px;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--surface);
  box-shadow: 0 2px 8px rgb(0 0 0 / 0.04);
}

.selector-definition p {
  margin: 9px 0 0;
  color: var(--text);
}

.selector-definition pre {
  margin: 0;
}

.selector-steps {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  margin-bottom: 18px;
}

.selector-steps span {
  display: flex;
  align-items: center;
  gap: 9px;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  color: var(--muted);
  font-size: 12px;
  background: var(--surface);
}

.selector-steps b {
  display: grid;
  flex: 0 0 24px;
  height: 24px;
  place-items: center;
  border-radius: 50%;
  background: var(--accent);
  color: #ffffff;
  font: 11px var(--mono);
  font-weight: 700;
}

#selectorControls {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 8px;
  padding: 0;
  border: 0;
  background: transparent;
}

#selectorControls .selector-choice {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  justify-content: center;
  gap: 3px;
  min-width: 0;
  min-height: 64px;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--bg);
  color: var(--text);
  text-align: left;
  cursor: pointer;
  transition: all 0.18s ease;
}

#selectorControls .selector-choice code {
  max-width: 100%;
  color: inherit;
  font-size: 12px;
  font-weight: 700;
  overflow-wrap: anywhere;
}

#selectorControls .selector-choice small {
  color: inherit;
  font: 10.5px var(--font);
  opacity: 0.8;
}

#selectorControls .selector-choice:hover {
  background: var(--surface-raised);
  border-color: rgb(var(--accent-rgb) / 0.4);
  transform: translateY(-1px);
}

#selectorControls .selector-choice[aria-pressed="true"] {
  background: var(--accent);
  color: #ffffff;
  border-color: var(--accent);
  box-shadow: 0 2px 8px rgb(var(--accent-rgb) / 0.3);
}

.selector-tile small {
  margin-top: 6px;
  color: currentColor;
  font-size: 10px;
  line-height: 1.3;
  opacity: 0.78;
  text-align: center;
}

.selector-result {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(260px, 0.85fr);
  gap: 14px;
  padding-top: 22px;
  border-top: 1px solid var(--line);
}

.selector-result > div {
  min-width: 0;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--bg);
}

.selector-result strong {
  display: block;
  margin-top: 7px;
  font-size: 18px;
}

.selector-result p {
  margin: 6px 0 0;
  font-size: 13px;
}

.selector-result-code {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 8px;
  background: var(--code-bg) !important;
  color: var(--code-text);
}

.selector-result-code .panel-label {
  color: inherit;
  opacity: 0.65;
}

.selector-result-code > code {
  color: inherit;
  font-size: 12px;
  overflow-wrap: anywhere;
}

.selector-result-code > span:last-child {
  font-size: 11px;
  opacity: 0.75;
}

.selector-relations {
  margin-top: 26px;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--surface);
  box-shadow: 0 2px 8px rgb(0 0 0 / 0.04);
}

.selector-relations h3 {
  margin: 7px 0 17px;
}

.selector-relations-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
}

.selector-relations-grid article {
  min-width: 0;
  padding: 14px;
  border-left: 3px solid var(--accent);
  background: var(--surface-raised);
  border-radius: 0 6px 6px 0;
}

.selector-relations-grid article > code,
.selector-relations-grid article > strong {
  display: block;
}

.selector-relations-grid article > code {
  color: var(--accent-ink);
  font-size: 12px;
  overflow-wrap: anywhere;
}

.selector-relations-grid article > strong {
  margin-top: 6px;
  font-size: 13px;
}

.selector-relations-grid p {
  margin: 5px 0 0;
  font-size: 12px;
  line-height: 1.55;
}

.selector-advice {
  margin-top: 14px;
  padding: 15px 18px;
  border-left: 4px solid var(--accent);
  background: var(--surface-raised);
  border-radius: 0 6px 6px 0;
}

.selector-advice p {
  margin: 4px 0 0;
  font-size: 13px;
}

.selector-analogy {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  margin-bottom: 18px;
  padding: 18px;
  border-left: 4px solid var(--accent);
  background: var(--surface-raised);
  border-radius: 0 8px 8px 0;
}

.selector-analogy > span {
  font-size: 24px;
  line-height: 1;
}

.selector-analogy p {
  margin: 5px 0 0;
  color: var(--text);
  font-size: 14px;
}

.selector-first-example {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  margin-bottom: 14px;
}

.selector-first-example article {
  min-width: 0;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 7px;
  background: var(--surface);
}

.selector-first-example pre {
  min-height: 104px;
  margin-top: 10px;
  padding: 13px;
  font-size: 11px;
  line-height: 1.65;
}

.selector-first-example article > p:not(.aviso-demo) {
  margin: 10px 0 0;
  font-size: 12px;
}

.selector-demo-output {
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.selector-demo-output p {
  margin: 12px 0 0;
  color: var(--text);
}

.selector-demo-output .aviso-demo {
  color: var(--accent-ink);
  font-weight: 700;
}

.selector-demo-output small {
  margin-top: 12px;
  color: var(--muted);
  font-size: 11px;
  line-height: 1.5;
}

.selector-basic-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
}

.selector-basic-grid article {
  min-width: 0;
  padding: 16px;
  border: 1px solid var(--line);
  border-top: 3px solid var(--accent);
  background: var(--surface);
  border-radius: 0 0 6px 6px;
}

.selector-basic-grid article > code,
.selector-basic-grid article > strong {
  display: block;
}

.selector-basic-grid article > code {
  color: var(--accent-ink);
  font-size: 20px;
  font-weight: 700;
}

.selector-basic-grid article > strong {
  margin-top: 5px;
}

.selector-basic-grid p {
  margin: 6px 0;
  font-size: 13px;
}

.selector-basic-grid small {
  color: var(--muted);
  font-size: 11px;
}

#selectorControls.selector-control-groups {
  display: block;
  padding: 0;
  border: 0;
  background: transparent;
}

.selector-control-heading {
  margin-bottom: 12px;
  color: var(--text);
  font-size: 14px;
}

.selector-button-grid {
  display: grid;
  gap: 8px;
}

.selector-button-grid.basic {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.selector-button-grid.advanced {
  grid-template-columns: repeat(5, minmax(0, 1fr));
  margin-top: 10px;
}

.selector-more {
  margin-top: 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--surface-raised);
}

.selector-more summary {
  padding: 11px 13px;
  color: var(--accent-ink);
  font-size: 12px;
}

.selector-more[open] {
  padding: 0 10px 10px;
}

.selector-more[open] summary {
  margin-inline: -10px;
  border-bottom: 1px solid var(--line);
}

.selector-tile {
  position: relative;
  min-height: 146px;
  padding: 22px 10px 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface-raised);
  transition: all 0.22s ease;
}

.selector-tile b {
  position: absolute;
  top: 8px;
  left: 9px;
  color: currentColor;
  font: 10px var(--mono);
}

.selector-example-text {
  color: var(--text);
  font-size: 17px;
  font-weight: 650;
}

.selector-tile code {
  max-width: 100%;
  margin-top: 7px;
  overflow-wrap: anywhere;
}

.selector-tile.matched {
  background: rgb(var(--accent-rgb) / 0.12);
  border-color: var(--accent);
  outline: 2px solid var(--accent);
  outline-offset: -2px;
  box-shadow: 0 4px 14px rgb(var(--accent-rgb) / 0.18);
  transform: translateY(-2px);
}

.selector-state {
  margin-top: 10px !important;
  padding: 4px 8px;
  border-radius: 4px;
  background: var(--surface-raised);
  color: var(--muted) !important;
  font-weight: 600;
  opacity: 1 !important;
}

.selector-tile.matched .selector-state {
  background: var(--accent);
  color: #ffffff !important;
}

.selector-reference {
  margin-top: 20px;
  border: 1px solid var(--line);
  border-radius: 7px;
  background: var(--surface);
}

.selector-reference summary {
  padding: 15px 18px;
  color: var(--accent-ink);
  font-size: 13px;
  font-weight: 600;
}

.selector-reference[open] {
  padding: 0 16px 16px;
}

.selector-reference[open] summary {
  margin-inline: -16px;
  border-bottom: 1px solid var(--line);
}

.selector-reference .selector-relations-grid {
  margin-top: 16px;
}

.section-enter {
  animation: none;
}

/* Laboratorio de Color y Contraste */
.color-display {
  border-radius: 10px;
  border: 1px solid var(--line);
  box-shadow: inset 0 0 0 1px rgb(0 0 0 / 0.08), 0 4px 16px rgb(0 0 0 / 0.06);
  transition:
    background 0.25s ease,
    color 0.25s ease;
}

.contrast-preview {
  border-radius: 10px;
  border: 1px solid var(--line);
  box-shadow: inset 0 0 0 1px rgb(0 0 0 / 0.08);
}

.generated-palette,
.color-code-card {
  border-radius: 8px;
}

.generated-palette button {
  border: 0;
  cursor: pointer;
  font-weight: 600;
  border-radius: 6px;
  transition:
    flex-grow 0.25s ease,
    transform 0.2s ease,
    filter 0.2s ease;
}

.generated-palette button:hover {
  flex-grow: 1.5;
  filter: brightness(1.06);
  z-index: 1;
}

.contrast-result > strong {
  font-size: 28px;
  font-weight: 800;
  font-family: var(--mono);
  color: var(--accent-ink);
}

.contrast-grade {
  display: inline-block;
  padding: 3px 9px;
  border-radius: 4px;
  font-size: 12px;
  font-weight: 700;
  background: rgb(var(--accent-rgb) / 0.12);
  color: var(--accent-ink);
  margin-bottom: 4px;
}

/* Editor HTML + CSS */
.playground-toolbar {
  padding: 18px 22px;
  border-radius: 10px;
  background: var(--surface);
}

.playground-grid,
.source-panels {
  gap: 14px;
}

/* Lienzo de visualización con soporte para dispositivos reales */
.preview-canvas {
  display: flex;
  justify-content: safe center;
  align-items: flex-start;
  padding: 30px 20px;
  background-color: var(--surface-raised);
  background-image: radial-gradient(rgb(var(--accent-rgb) / 0.09) 1px, transparent 1px);
  background-size: 20px 20px;
  min-height: 720px;
  overflow: auto;
  transition: background-color 0.2s ease;
}

.preview-panel:fullscreen .preview-canvas {
  padding: 36px 24px;
  min-height: 0;
  height: 100%;
  display: flex;
  align-items: flex-start;
  justify-content: safe center;
  overflow: auto;
}

.device-frame {
  position: relative;
  margin: 0 auto;
  flex-shrink: 0;
  box-sizing: border-box;
  transition: width 0.35s cubic-bezier(0.16, 1, 0.3, 1),
              height 0.35s cubic-bezier(0.16, 1, 0.3, 1),
              border-radius 0.3s ease,
              box-shadow 0.3s ease;
}

.device-speaker-notch,
.device-browser-bar,
.device-home-indicator {
  display: none;
}

/* Modo fluido (ajustar al panel) */
.preview-canvas[data-device="fluid"] .device-frame {
  width: 100%;
  height: 100%;
  min-height: 600px;
  border-radius: 8px;
  border: 1px solid var(--line);
  background: #ffffff;
  overflow: hidden;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.06);
}

.preview-canvas[data-device="fluid"] #exercisePreview,
.preview-panel:fullscreen .preview-canvas[data-device="fluid"] #exercisePreview {
  width: 100% !important;
  height: 100% !important;
  min-height: 600px !important;
  border: 0;
  display: block;
  background: #ffffff;
}

/* ==============================================
   Dispositivo Móvil (375 × 667 px)
   ============================================== */
.preview-canvas[data-device="mobile"] .device-frame {
  width: 403px;
  height: 755px;
  min-height: 755px;
  max-height: 755px;
  flex: 0 0 auto;
  background: #0e1117;
  border: 3px solid #2d3340;
  border-radius: 46px;
  box-shadow:
    0 25px 65px -12px rgba(0, 0, 0, 0.65),
    0 0 0 1px rgba(255, 255, 255, 0.1),
    inset 0 0 0 2px #181c24;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding-top: 44px;
  padding-bottom: 38px;
  box-sizing: border-box;
}

/* Botones laterales del móvil */
.preview-canvas[data-device="mobile"] .device-frame::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 110px;
  width: 3px;
  height: 46px;
  background: #2d3340;
  border-radius: 3px 0 0 3px;
  box-shadow: 0 58px 0 #2d3340;
  pointer-events: none;
}

.preview-canvas[data-device="mobile"] .device-frame::after {
  content: "";
  position: absolute;
  right: -5px;
  top: 135px;
  width: 3px;
  height: 64px;
  background: #2d3340;
  border-radius: 0 3px 3px 0;
  pointer-events: none;
}

.preview-canvas[data-device="mobile"] .device-speaker-notch {
  display: flex;
  justify-content: center;
  align-items: center;
  position: absolute;
  top: 12px;
  left: 50%;
  transform: translateX(-50%);
  width: 106px;
  height: 22px;
  background: #000000;
  border-radius: 20px;
  z-index: 10;
  box-shadow: inset 0 1px 2px rgba(255, 255, 255, 0.18), 0 1px 4px rgba(0, 0, 0, 0.4);
  pointer-events: none;
}

.preview-canvas[data-device="mobile"] .device-speaker-notch::before {
  content: "";
  position: absolute;
  left: 20px;
  width: 36px;
  height: 3px;
  background: #222632;
  border-radius: 2px;
}

.preview-canvas[data-device="mobile"] .device-speaker-notch::after {
  content: "";
  position: absolute;
  right: 18px;
  width: 9px;
  height: 9px;
  background: radial-gradient(circle at 35% 35%, #253956 0%, #0c121d 65%, #040608 100%);
  border: 1.5px solid #283750;
  border-radius: 50%;
  box-shadow: inset 0 1px 1px rgba(255, 255, 255, 0.25);
}

.preview-canvas[data-device="mobile"] #exercisePreview,
.preview-panel:fullscreen .preview-canvas[data-device="mobile"] #exercisePreview {
  width: 375px !important;
  height: 667px !important;
  min-height: 667px !important;
  max-height: 667px !important;
  flex: 0 0 667px !important;
  border: 0;
  border-radius: 20px;
  display: block;
  background: #ffffff;
  box-shadow: 0 0 0 1px rgba(0, 0, 0, 0.2);
}

.preview-canvas[data-device="mobile"] .device-home-indicator {
  display: block;
  position: absolute;
  bottom: 14px;
  left: 50%;
  transform: translateX(-50%);
  width: 126px;
  height: 4.5px;
  background: rgba(255, 255, 255, 0.45);
  border-radius: 4px;
  z-index: 10;
  pointer-events: none;
}

/* ==============================================
   Dispositivo Tablet (768 × 720 px)
   ============================================== */
.preview-canvas[data-device="tablet"] .device-frame {
  width: 808px;
  height: 784px;
  min-height: 784px;
  max-height: 784px;
  flex: 0 0 auto;
  background: #0e1117;
  border: 3px solid #2d3340;
  border-radius: 34px;
  box-shadow:
    0 25px 75px -15px rgba(0, 0, 0, 0.65),
    0 0 0 1px rgba(255, 255, 255, 0.1),
    inset 0 0 0 2px #181c24;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding-top: 29px;
  padding-bottom: 29px;
  box-sizing: border-box;
}

.preview-canvas[data-device="tablet"] .device-speaker-notch {
  display: block;
  position: absolute;
  top: 11px;
  left: 50%;
  transform: translateX(-50%);
  width: 8px;
  height: 8px;
  background: radial-gradient(circle at 35% 35%, #253956 0%, #0c121d 65%, #040608 100%);
  border: 1.5px solid #283750;
  border-radius: 50%;
  z-index: 10;
  pointer-events: none;
}

.preview-canvas[data-device="tablet"] #exercisePreview,
.preview-panel:fullscreen .preview-canvas[data-device="tablet"] #exercisePreview {
  width: 768px !important;
  height: 720px !important;
  min-height: 720px !important;
  max-height: 720px !important;
  flex: 0 0 720px !important;
  border: 0;
  border-radius: 12px;
  display: block;
  background: #ffffff;
  box-shadow: 0 0 0 1px rgba(0, 0, 0, 0.2);
}

.preview-canvas[data-device="tablet"] .device-home-indicator {
  display: block;
  position: absolute;
  bottom: 12px;
  left: 50%;
  transform: translateX(-50%);
  width: 140px;
  height: 4.5px;
  background: rgba(255, 255, 255, 0.45);
  border-radius: 4px;
  z-index: 10;
  pointer-events: none;
}

/* ==============================================
   Dispositivo Escritorio (1024 × 640 px)
   ============================================== */
.preview-canvas[data-device="desktop"] .device-frame {
  width: 1026px;
  height: 684px;
  min-height: 684px;
  max-height: 684px;
  flex: 0 0 auto;
  background: #ffffff;
  border: 1px solid var(--line);
  border-radius: 12px;
  box-shadow:
    0 25px 75px -12px rgba(0, 0, 0, 0.35),
    0 2px 10px rgba(0, 0, 0, 0.08);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  box-sizing: border-box;
}

.preview-canvas[data-device="desktop"] .device-browser-bar {
  display: flex;
  align-items: center;
  gap: 14px;
  height: 42px;
  min-height: 42px;
  padding: 0 16px;
  background: var(--surface-raised);
  border-bottom: 1px solid var(--line);
  box-sizing: border-box;
}

.preview-canvas[data-device="desktop"] .device-window-dots {
  display: inline-flex;
  gap: 7px;
  align-items: center;
}

.preview-canvas[data-device="desktop"] .device-window-dots i {
  display: block;
  width: 11px;
  height: 11px;
  border-radius: 50%;
}

.preview-canvas[data-device="desktop"] .device-window-dots i:nth-child(1) {
  background: #ff5f56;
  border: 1px solid #e0443e;
}

.preview-canvas[data-device="desktop"] .device-window-dots i:nth-child(2) {
  background: #ffbd2e;
  border: 1px solid #dea123;
}

.preview-canvas[data-device="desktop"] .device-window-dots i:nth-child(3) {
  background: #27c93f;
  border: 1px solid #1aab29;
}

.preview-canvas[data-device="desktop"] .device-browser-nav {
  display: inline-flex;
  gap: 6px;
  align-items: center;
  color: var(--muted);
  font-size: 14px;
  user-select: none;
}

.preview-canvas[data-device="desktop"] .device-browser-nav span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 20px;
  height: 20px;
  border-radius: 4px;
  opacity: 0.65;
}

.preview-canvas[data-device="desktop"] .device-url-pill {
  flex: 1;
  max-width: 480px;
  margin: 0 auto;
  text-align: center;
  font: 11px var(--mono);
  color: var(--muted);
  background: var(--surface);
  padding: 5px 14px;
  border-radius: 8px;
  border: 1px solid var(--line);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
}

.preview-canvas[data-device="desktop"] .device-url-lock {
  font-size: 10px;
  opacity: 0.8;
}

.preview-canvas[data-device="desktop"] #exercisePreview,
.preview-panel:fullscreen .preview-canvas[data-device="desktop"] #exercisePreview {
  width: 1024px !important;
  height: 640px !important;
  min-height: 640px !important;
  max-height: 640px !important;
  flex: 0 0 640px !important;
  border: 0;
  display: block;
  background: #ffffff;
}

html[data-theme="dark"] .preview-canvas[data-device="desktop"] .device-frame {
  background: var(--surface);
  border-color: var(--line);
}

.source-panel textarea {
  min-height: 280px;
  font-family: var(--mono);
  font-size: 13px;
  line-height: 1.65;
  tab-size: 2;
}

#cssDiagnostic {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 3px 9px;
  border-radius: 4px;
  font-size: 11px;
  font-weight: 600;
  background: rgb(var(--accent-rgb) / 0.12);
  color: var(--accent-ink);
}

#cssDiagnostic.has-warning {
  background: rgb(249 115 22 / 0.15);
  color: #ea580c;
}

.closing-line {
  padding-top: 42px;
  font-size: clamp(18px, 2.2vw, 25px);
  color: var(--text);
}

footer {
  color: var(--muted);
  padding: 28px 0 40px;
  border-top: 1px solid var(--line);
}

/* Documentación técnica "¿Cómo se hizo?" */
.explain-dialog {
  width: min(960px, calc(100% - 32px));
  max-height: 90vh;
  margin: auto;
  padding: 28px;
  overflow: auto;
  color: var(--text);
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface);
  box-shadow: 0 20px 50px rgb(0 0 0 / 0.25);
}

.explain-dialog::backdrop {
  background: rgb(15 23 42 / 0.6);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
}

.explain-dialog__header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
}

.explain-dialog h2 {
  margin: 6px 0 14px;
  font-size: 28px;
}

.dialog-close {
  width: 38px;
  height: 38px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--surface-raised);
  font-size: 24px;
  line-height: 1;
  color: var(--text);
  cursor: pointer;
  transition: all 0.18s ease;
}

.dialog-close:hover {
  background: var(--line);
  transform: scale(1.05);
}

.build-lead {
  max-width: 760px;
  margin-bottom: 20px;
  font-size: 14.5px;
  line-height: 1.65;
}

.build-flow {
  display: grid;
  grid-template-columns: repeat(3, minmax(130px, 1fr) auto) minmax(130px, 1fr);
  align-items: center;
  gap: 8px;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--bg);
}

.build-flow > div {
  min-width: 0;
  padding: 12px;
  border-radius: 6px;
  background: var(--surface);
  border: 1px solid var(--line);
}

.build-flow code,
.build-flow span {
  display: block;
}

.build-flow code {
  margin-bottom: 5px;
  color: var(--accent-ink);
  font-size: 13px;
  font-weight: 700;
}

.build-flow span {
  color: var(--muted);
  font-size: 11px;
  line-height: 1.4;
}

.build-flow > b {
  color: var(--accent-ink);
  font-weight: 700;
  font-size: 16px;
}

.build-section {
  margin-top: 26px;
  padding-top: 22px;
  border-top: 1px solid var(--line);
}

.build-section h3 {
  margin: 6px 0 16px;
  font-size: 21px;
}

.file-map {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
}

.file-map article {
  display: grid;
  grid-template-columns: minmax(120px, 0.38fr) minmax(0, 1fr);
  gap: 12px;
  min-width: 0;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--bg);
}

.file-map code {
  color: var(--accent-ink);
  font-size: 11.5px;
  font-weight: 700;
  overflow-wrap: anywhere;
}

.file-map span {
  color: var(--muted);
  font-size: 11.5px;
  line-height: 1.45;
}

.build-steps {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.build-steps li {
  min-width: 0;
  padding: 14px;
  border: 1px solid var(--line);
  border-top: 3px solid var(--accent);
  background: var(--bg);
  border-radius: 0 0 6px 6px;
}

.build-steps b {
  display: grid;
  width: 26px;
  height: 26px;
  margin-bottom: 9px;
  place-items: center;
  border-radius: 50%;
  background: var(--accent);
  color: #ffffff;
  font: 11px var(--mono);
  font-weight: 700;
}

.build-steps span {
  color: var(--muted);
  font-size: 12px;
  line-height: 1.5;
}

.build-details {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
}

.build-details details {
  min-width: 0;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--bg);
}

.build-details summary {
  padding: 13px;
  color: var(--text);
  font-size: 12px;
  font-weight: 650;
  cursor: pointer;
}

.build-details details[open] summary {
  border-bottom: 1px solid var(--line);
}

.build-details p {
  margin: 12px 13px 0;
  font-size: 11.5px;
  color: var(--muted);
}

.build-details pre {
  margin: 11px 13px 13px;
  padding: 11px;
  font-size: 9.5px;
  line-height: 1.55;
  border-radius: 6px;
}

.build-decisions ul {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px 22px;
  margin: 0;
  padding-left: 20px;
}

.build-decisions li {
  color: var(--muted);
  font-size: 12px;
  line-height: 1.55;
}

/* Playground inmediato */
.quick-playground {
  position: relative;
  margin-top: 26px;
  padding: 54px 0;
}

.quick-playground::before {
  content: "";
  position: absolute;
  z-index: -1;
  inset: 0 -42px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px),
    var(--surface);
  background-size: 28px 28px;
  opacity: 0.62;
}

.quick-play-layout {
  display: grid;
  grid-template-columns: minmax(230px, 0.72fr) minmax(0, 1.28fr);
  gap: 14px;
  align-items: stretch;
}

.quick-play-controls,
.quick-play-result {
  min-width: 0;
  border: 1px solid var(--line);
  border-radius: 9px;
  background: var(--bg);
}

.quick-play-controls {
  display: grid;
  align-content: start;
  gap: 18px;
  padding: 22px;
}

.quick-play-controls > label:not(.check-control) {
  display: grid;
  gap: 8px;
}

.quick-play-controls label > span {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: center;
  color: var(--muted);
  font-size: 11px;
}

.quick-play-controls label b {
  color: var(--text);
  font-weight: 650;
}

.quick-play-controls output {
  color: var(--accent-ink);
  font: 10px var(--mono);
  font-weight: 700;
}

.quick-play-controls input[type="range"] {
  width: 100%;
  accent-color: var(--accent);
}

.quick-color-control input {
  width: 100%;
  height: 42px;
  padding: 4px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--surface);
  cursor: pointer;
}

.quick-preset-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 6px;
}

.quick-preset-list button {
  min-height: 38px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--surface);
  color: var(--muted);
  font-size: 11px;
  cursor: pointer;
}

.quick-preset-list button:hover,
.quick-preset-list button.active {
  border-color: var(--accent);
  background: var(--accent-soft);
  color: var(--accent-ink);
}

.quick-motion-control {
  margin-top: 2px;
}

.quick-play-result {
  overflow: hidden;
}

.quick-play-result .editor-panel-bar {
  min-height: 42px;
}

.quick-play-stage {
  min-height: 360px;
  display: grid;
  place-items: center;
  padding: clamp(22px, 5vw, 54px);
  overflow: hidden;
  background:
    radial-gradient(circle at 20% 20%, color-mix(in srgb, var(--accent) 22%, transparent), transparent 36%),
    repeating-linear-gradient(135deg, transparent 0 14px, color-mix(in srgb, var(--line) 48%, transparent) 14px 15px),
    var(--surface);
}

.quick-play-card {
  --quick-color: #c5f568;
  --quick-ink: #24341b;
  --quick-radius: 24px;
  --quick-shadow: 10px;
  width: min(100%, 360px);
  padding: clamp(22px, 5vw, 36px);
  border: 2px solid var(--quick-ink);
  border-radius: var(--quick-radius);
  background: var(--quick-color);
  color: var(--quick-ink);
  box-shadow: var(--quick-shadow) var(--quick-shadow) 0 var(--quick-ink);
  transition: transform 240ms ease, box-shadow 240ms ease, border-radius 240ms ease;
}

.quick-play-card.motion-on:hover {
  transform: translateY(-9px) rotate(-1deg);
  box-shadow: calc(var(--quick-shadow) + 4px) calc(var(--quick-shadow) + 7px) 0 var(--quick-ink);
}

.quick-play-card > span {
  font: 9px var(--mono);
  font-weight: 800;
  letter-spacing: 0.13em;
}

.quick-play-card > div {
  margin: 10px 0 2px;
  font: clamp(46px, 8vw, 76px) var(--mono);
  font-weight: 800;
  line-height: 1;
}

.quick-play-card h3 {
  margin: 8px 0;
  font-size: clamp(24px, 4vw, 38px);
  line-height: 0.98;
  letter-spacing: -0.04em;
}

.quick-play-card p {
  margin: 0 0 18px;
  font-size: 12px;
}

.quick-play-card button {
  min-height: 39px;
  padding: 8px 13px;
  border: 1px solid var(--quick-ink);
  border-radius: calc(var(--quick-radius) * 0.35);
  background: var(--quick-ink);
  color: var(--quick-color);
  font-size: 11px;
  font-weight: 700;
}

.quick-code-bar {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 12px;
  align-items: center;
  padding: 13px;
  background: #111a14;
}

.quick-code-bar pre {
  max-height: 142px;
  overflow: auto;
  padding: 0;
  border: 0;
  background: transparent;
  color: #c5f568;
  font-size: 10px;
}

.quick-code-bar .small-button {
  border-color: #536146;
  color: #f0f1e9;
  background: #1c251e;
}

.quick-play-next {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  align-items: center;
  margin-top: 12px;
  padding: 13px 16px;
  border: 1px dashed var(--line-strong);
  border-radius: 8px;
  background: var(--bg);
  color: var(--muted);
  font-size: 12px;
}

.quick-play-next .button {
  min-height: 38px;
  padding-block: 7px;
}

/* Historia de CSS */
.css-history {
  padding-top: 86px;
}

.history-workbench {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--bg);
}

.history-tabs {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  border-bottom: 1px solid var(--line);
  background: var(--surface);
}

.history-tabs button {
  min-height: 72px;
  display: grid;
  place-content: center;
  gap: 2px;
  border: 0;
  border-right: 1px solid var(--line);
  background: transparent;
  color: var(--muted);
  cursor: pointer;
}

.history-tabs button:last-child {
  border-right: 0;
}

.history-tabs button b {
  color: var(--accent-ink);
  font: 12px var(--mono);
}

.history-tabs button span {
  font-size: 10px;
}

.history-tabs button:hover,
.history-tabs button[aria-selected="true"] {
  background: var(--accent);
  color: var(--accent-contrast);
}

.history-tabs button[aria-selected="true"] b,
.history-tabs button:hover b {
  color: inherit;
}

.history-panel {
  min-height: 315px;
  display: grid;
  grid-template-columns: 170px minmax(0, 1fr);
  gap: 30px;
  align-items: start;
  padding: clamp(28px, 6vw, 62px);
  outline: 0;
}

.history-year {
  color: color-mix(in srgb, var(--accent) 36%, transparent);
  font: clamp(44px, 7vw, 86px) var(--mono);
  font-weight: 800;
  letter-spacing: -0.08em;
  line-height: 0.9;
}

.history-panel h3 {
  margin: 7px 0 10px;
  font-size: clamp(25px, 4vw, 42px);
  line-height: 1;
  letter-spacing: -0.04em;
}

.history-panel p {
  max-width: 68ch;
  margin: 0;
  color: var(--muted);
  font-size: 13px;
}

.history-panel pre {
  max-width: 650px;
  margin-top: 20px;
  padding: 16px;
  border-radius: 7px;
  color: #c5f568;
  background: #111a14;
  font-size: 11px;
}

.history-reason-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
  gap: 12px;
  align-items: stretch;
  margin-top: 14px;
}

.history-reason-grid article {
  min-width: 0;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.history-reason-grid article > span {
  color: var(--accent-ink);
  font: 9px var(--mono);
  font-weight: 800;
}

.history-reason-grid h3 {
  margin: 7px 0 13px;
  font-size: 18px;
  line-height: 1.15;
}

.history-reason-grid pre {
  min-height: 105px;
  padding: 14px;
  border-radius: 6px;
  font-size: 10px;
}

.history-reason-grid p {
  margin: 12px 0 0;
  color: var(--muted);
  font-size: 11.5px;
}

.history-arrow {
  display: grid;
  place-items: center;
  color: var(--accent-ink);
  font-size: 30px;
}

.history-clarification {
  display: grid;
  grid-template-columns: 210px minmax(0, 1fr);
  gap: 22px;
  margin-top: 14px;
  padding: 19px 22px;
  border-left: 4px solid var(--accent);
  background: var(--accent-soft);
}

.history-clarification strong {
  font-size: 13px;
}

.history-clarification p {
  margin: 0;
  color: var(--muted);
  font-size: 12px;
}

.history-sources {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  margin-top: 14px;
  color: var(--muted);
  font-size: 10px;
}

.history-sources a {
  color: var(--accent-ink);
  font-weight: 700;
}

.playground-dock {
  position: fixed;
  z-index: 60;
  right: 22px;
  bottom: 20px;
  display: grid;
  grid-template-columns: auto auto;
  gap: 0 9px;
  align-items: center;
  padding: 10px 14px;
  border: 1px solid color-mix(in srgb, var(--accent) 72%, #000);
  border-radius: 9px;
  background: var(--accent);
  color: var(--accent-contrast);
  box-shadow: 0 12px 30px rgb(0 0 0 / 0.2);
  text-decoration: none;
  transition: transform 180ms ease, box-shadow 180ms ease;
}

.playground-dock:hover,
.playground-dock:focus-visible {
  transform: translateY(-4px);
  box-shadow: 0 16px 36px rgb(0 0 0 / 0.28);
}

.playground-dock > span {
  grid-row: 1 / 3;
  font: 16px var(--mono);
  font-weight: 800;
}

.playground-dock b {
  font-size: 11px;
  line-height: 1.1;
}

.playground-dock small {
  font: 8px var(--mono);
  opacity: 0.76;
}

/* Adaptación responsive */
@media (max-width: 1000px) {
  .sidebar {
    padding-inline: 24px;
  }

  .topbar {
    padding-inline: 24px;
  }

  main {
    padding-inline: 24px;
  }

  .hero {
    gap: 28px;
  }

  .hero h1 {
    font-size: 52px;
  }
}

@media (max-width: 820px) {
  .sidebar {
    display: none;
  }

  .topbar {
    padding: 9px 20px;
  }

  .mobile-index {
    border: 1px solid var(--line);
    background: var(--surface);
    border-radius: 8px;
    margin-bottom: 16px;
  }

  .hero {
    grid-template-columns: 1fr 0.8fr;
  }

  .hero h1 {
    font-size: clamp(44px, 8vw, 60px);
  }

  .build-flow {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .build-flow > b {
    display: none;
  }

  .file-map,
  .build-details {
    grid-template-columns: minmax(0, 1fr);
  }

  .build-steps {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .selector-definition,
  .selector-result {
    grid-template-columns: minmax(0, 1fr);
  }

  .selector-relations-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .selector-first-example {
    grid-template-columns: minmax(0, 1fr);
  }

  .selector-first-example pre {
    min-height: 0;
  }

  .selector-button-grid.advanced {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .quick-play-layout {
    grid-template-columns: minmax(0, 1fr);
  }

  .history-panel {
    grid-template-columns: 125px minmax(0, 1fr);
  }
}

@media (max-width: 600px) {
  html {
    scroll-padding-top: 138px;
  }

  .topbar {
    min-height: 106px;
  }

  .topbar .mobile-brand {
    flex-basis: 100%;
    font-weight: 700;
  }

  .toolbar {
    display: grid;
    grid-template-columns: minmax(0, 1fr) repeat(3, 44px);
    gap: 8px;
    width: 100%;
  }

  .appearance-control {
    width: 100%;
    min-width: 0;
    padding-left: 10px;
  }

  .appearance-control select {
    width: 100%;
    font-size: 16px;
  }

  .icon-button,
  .theme-button,
  .explain-button {
    width: 44px;
    min-height: 42px;
    padding: 0;
  }

  .explain-button span,
  .theme-button > span:first-of-type,
  .icon-button span {
    display: none;
  }

  main {
    padding-inline: 18px;
  }

  .hero {
    grid-template-columns: 1fr;
    padding: 38px 0 32px;
  }

  .hero h1 {
    font-size: clamp(43px, 13vw, 58px);
  }

  .hero-art {
    min-height: 245px;
  }

  .css-sculpture {
    width: 210px;
    height: 125px;
  }

  .sculpture-front {
    font-size: 66px;
  }

  .section-title {
    align-items: flex-start;
  }

  .section-badge {
    display: none;
  }

  .selector-steps,
  .selector-relations-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  #selectorControls,
  .selector-stage {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .selector-basic-grid,
  .selector-button-grid.basic {
    grid-template-columns: minmax(0, 1fr);
  }

  .selector-definition,
  .selector-relations {
    padding: 16px;
  }

  .lab-section {
    padding: 42px 0;
  }

  .closing-line,
  footer {
    align-items: flex-start;
    flex-direction: column;
  }

  .explain-dialog {
    padding: 18px;
  }

  .build-flow,
  .build-steps,
  .build-decisions ul {
    grid-template-columns: minmax(0, 1fr);
  }

  .file-map article {
    grid-template-columns: minmax(0, 1fr);
    gap: 4px;
  }

  .quick-playground::before {
    inset-inline: -12px;
  }

  .quick-play-controls {
    padding: 17px;
  }

  .quick-play-stage {
    min-height: 310px;
    padding: 28px 20px;
  }

  .quick-code-bar {
    grid-template-columns: minmax(0, 1fr);
  }

  .quick-code-bar .small-button {
    justify-self: start;
  }

  .quick-play-next {
    align-items: stretch;
    flex-direction: column;
  }

  .history-tabs {
    grid-template-columns: repeat(5, minmax(56px, 1fr));
    overflow-x: auto;
  }

  .history-tabs button {
    min-height: 62px;
    padding: 7px 4px;
  }

  .history-tabs button span {
    display: none;
  }

  .history-panel {
    min-height: 440px;
    grid-template-columns: minmax(0, 1fr);
    gap: 12px;
    padding: 24px 19px;
  }

  .history-year {
    font-size: 50px;
  }

  .history-reason-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .history-arrow {
    transform: rotate(90deg);
  }

  .history-clarification {
    grid-template-columns: minmax(0, 1fr);
    gap: 6px;
  }

  .playground-dock {
    right: 12px;
    bottom: 12px;
    grid-template-columns: auto;
    width: 46px;
    height: 46px;
    place-items: center;
    padding: 0;
    border-radius: 50%;
  }

  .playground-dock > span {
    grid-row: auto;
  }

  .playground-dock b,
  .playground-dock small {
    display: none;
  }
}

@media print {
  .explain-button,
  .explain-dialog {
    display: none;
  }
}