/* Cubo paso a paso — modo oscuro.
   El cubo es lo único con color saturado; la interfaz se queda en tinta azulada
   y usa un lila (que no existe en el cubo) para marcar selección y movimiento. */

:root {
  --bg: #141821;
  --panel: #1a1f2a;
  --raised: #242b39;
  --line: #303849;
  --text: #e9ebf2;
  --muted: #9aa3b6;
  --accent: #b9a0ff;
  --accent-ink: #1b1436;
  --accent-wash: rgba(185, 160, 255, 0.14);
  --sans: 'Bricolage Grotesque', 'Segoe UI', system-ui, sans-serif;
  --mono: 'JetBrains Mono', ui-monospace, 'Cascadia Mono', Consolas, monospace;
  --radius: 10px;
}

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
  margin: 0;
}

body {
  background: var(--bg);
  color: var(--text);
  font: 400 15px/1.45 var(--sans);
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
}

h1,
h2,
h3,
p,
ol,
ul,
dl,
dd {
  margin: 0;
  padding: 0;
}

ol,
ul {
  list-style: none;
}

button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  cursor: pointer;
}

button:disabled {
  cursor: default;
  opacity: 0.35;
}

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

svg {
  display: block;
}

/* ---------------------------------------------------------------- Layout */

.app {
  display: grid;
  height: 100dvh;
  grid-template-columns: minmax(0, 1fr) clamp(300px, 27vw, 400px);
  grid-template-rows: auto minmax(0, 1fr) auto;
  grid-template-areas:
    'top top'
    'stage cases'
    'player cases';
}

/* ---------------------------------------------------------------- Barra superior */

.top {
  grid-area: top;
  display: flex;
  align-items: center;
  gap: 20px;
  padding: 14px 20px 6px;
  min-width: 0;
}

.social {
  flex: none;
  margin-right: -8px;
  border-radius: 4px;
  color: var(--muted);
  transition: color 0.15s;
}

.social:hover {
  color: var(--accent);
}

.social svg {
  width: 20px;
  height: 20px;
  fill: currentColor;
}

.brand {
  font-weight: 700;
  font-size: 17px;
  letter-spacing: -0.01em;
  white-space: nowrap;
}

.methods {
  display: flex;
  padding: 3px;
  border-radius: 999px;
  background: var(--panel);
  flex: none;
}

.methods button {
  padding: 5px 14px;
  border-radius: 999px;
  color: var(--muted);
  font-weight: 500;
}

.methods button[aria-pressed='true'] {
  background: var(--raised);
  color: var(--text);
}

.stages {
  flex: 1;
  min-width: 0;
  overflow-x: auto;
  scrollbar-width: none;
}

.stages ol {
  display: flex;
  align-items: center;
  width: max-content;
  padding: 2px;
}

/* Las etapas son una secuencia: el número y la línea que las une lo dicen. */
.stages li {
  display: flex;
  align-items: center;
}

.stages li + li::before {
  content: '';
  width: 10px;
  height: 1px;
  background: var(--line);
}

.stages button {
  display: flex;
  align-items: center;
  gap: 7px;
  padding: 5px 10px 5px 5px;
  border-radius: 999px;
  color: var(--muted);
  font-weight: 500;
  white-space: nowrap;
}

.stages .num {
  display: grid;
  place-items: center;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  border: 1px solid var(--line);
  font: 700 12px/1 var(--mono);
}

.stages button:hover {
  color: var(--text);
}

.stages button[aria-current] {
  background: var(--accent-wash);
  color: var(--text);
}

.stages button[aria-current] .num {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--accent-ink);
}

.ghost {
  flex: none;
  padding: 6px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--muted);
  white-space: nowrap;
}

.ghost:hover {
  color: var(--text);
  border-color: var(--muted);
}

/* Selector de cubo: botón con el cubo actual y menú con un dibujo de cada cubo. */
.puzzle-picker {
  position: relative;
  flex: none;
}

.puzzle-trigger {
  display: grid;
  place-items: center;
  width: 38px;
  height: 32px;
  padding: 0;
}

.cube-icon {
  width: 24px;
  height: 24px;
}

.puzzle-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  z-index: 30;
  display: flex;
  gap: 4px;
  padding: 5px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--panel);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.4);
}

.puzzle-menu[hidden] {
  display: none;
}

.puzzle-option {
  display: grid;
  place-items: center;
  width: 52px;
  height: 52px;
  border-radius: 10px;
  color: var(--muted);
}

.puzzle-option .cube-icon {
  width: 34px;
  height: 34px;
}

.puzzle-option:hover {
  color: var(--text);
  background: var(--raised);
}

.puzzle-option[aria-pressed='true'] {
  color: var(--text);
  background: var(--accent-wash);
  box-shadow: inset 0 0 0 2px var(--accent);
}

/* Etapa de enlace (sin casos): solo se muestra la explicación y el botón. */
.enlace .transport,
.enlace .note {
  display: none;
}

.link-button {
  justify-self: start;
  border-color: var(--accent);
  color: var(--text);
}

/* ---------------------------------------------------------------- Cubo */

.stage {
  grid-area: stage;
  position: relative;
  min-height: 0;
  /* Halo circular detrás del cubo: se apaga en el color de la página antes de
     tocar el borde, así no se nota dónde acaba la zona del cubo. */
  background: radial-gradient(circle closest-side at 50% 50%, #343d54 0%, #232a3a 45%, var(--bg) 100%);
}

.viewport {
  position: absolute;
  inset: 0;
  cursor: grab;
  touch-action: none;
}

.viewport:active {
  cursor: grabbing;
}

.viewport:focus-visible {
  outline-offset: -4px;
}

.viewport canvas {
  width: 100%;
  height: 100%;
  display: block;
}

/* El movimiento actual, en grande, junto al cubo. */
.now {
  position: absolute;
  left: 22px;
  bottom: 12px;
  font: 700 clamp(44px, 7vw, 92px) / 1 var(--mono);
  letter-spacing: -0.04em;
  color: var(--text);
  opacity: 0.22;
  pointer-events: none;
  transition: opacity 0.15s, color 0.15s;
}

.now.moving {
  color: var(--accent);
  opacity: 0.95;
}

.view-tools {
  position: absolute;
  top: 12px;
  right: 12px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.hint {
  position: absolute;
  right: 16px;
  bottom: 14px;
  color: var(--muted);
  font-size: 13px;
  pointer-events: none;
}

.icon {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--raised);
  color: var(--text);
}

.icon svg {
  width: 20px;
  height: 20px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.icon:not(:disabled):hover {
  background: var(--line);
}

/* ---------------------------------------------------------------- Algoritmo */

.player {
  grid-area: player;
  display: grid;
  gap: 10px;
  padding: 8px 20px 18px;
  min-width: 0;
}

.case-head {
  display: flex;
  align-items: flex-start;
  gap: 12px;
}

.case-title {
  flex: 1;
  min-width: 0;
}

.case-title h1 {
  font-size: 22px;
  font-weight: 700;
  letter-spacing: -0.015em;
  line-height: 1.2;
}

.case-title p {
  margin-top: 3px;
  max-width: 78ch;
  color: var(--muted);
  display: -webkit-box;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
  line-clamp: 2;
  overflow: hidden;
}

.cases-open {
  display: none;
}

.variants {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}

.variants[hidden] {
  display: none;
}

.variants button {
  padding: 3px 11px;
  border-radius: 999px;
  border: 1px solid var(--line);
  color: var(--muted);
  font-size: 13px;
}

.variants button[aria-pressed='true'] {
  border-color: var(--accent);
  color: var(--text);
  background: var(--accent-wash);
}

.moves {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 14px;
  max-height: 96px;
  overflow-y: auto;
  padding: 2px;
}

.group {
  display: flex;
  flex-wrap: wrap; /* un algoritmo largo sin paréntesis es un solo grupo: debe poder partirse */
  min-width: 0;
  gap: 4px;
}

.move {
  min-width: 40px;
  height: 40px;
  padding: 0 8px;
  border-radius: 8px;
  background: var(--raised);
  font: 700 17px/1 var(--mono);
  transition: background 0.12s, color 0.12s, transform 0.12s;
}

.move:hover {
  background: var(--line);
}

.move.done {
  background: transparent;
  box-shadow: inset 0 0 0 1px var(--line);
  color: var(--muted);
}

.move.next {
  box-shadow: inset 0 0 0 2px var(--accent);
}

.move.active {
  background: var(--accent);
  color: var(--accent-ink);
  transform: translateY(-2px);
}

.note {
  min-height: 1.45em;
  color: var(--text);
  font-size: 14px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.transport {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px 22px;
}

.buttons {
  display: flex;
  align-items: center;
  gap: 8px;
}

.buttons .icon svg {
  fill: currentColor;
}

.icon.play {
  width: 52px;
  height: 52px;
  background: var(--accent);
  color: var(--accent-ink);
}

.icon.play:not(:disabled):hover {
  background: #cdbaff;
}

.icon.play svg {
  width: 24px;
  height: 24px;
}

.icon .i-pause {
  display: none;
}

.icon.play .i-pause {
  stroke-width: 3.2;
}

.icon.is-playing .i-pause {
  display: block;
}

.icon.is-playing .i-play {
  display: none;
}

.progress {
  min-width: 78px;
  color: var(--muted);
  font: 500 13px/1 var(--mono);
}

.speed,
.check {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--muted);
  font-size: 14px;
}

.speed input {
  width: 120px;
  accent-color: var(--accent);
}

.speed output {
  min-width: 42px;
  color: var(--text);
  font: 500 13px/1 var(--mono);
}

.check input {
  width: 16px;
  height: 16px;
  accent-color: var(--accent);
}

/* ---------------------------------------------------------------- Casos */

.cases {
  grid-area: cases;
  display: flex;
  flex-direction: column;
  min-height: 0;
}

.cases-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 16px 10px;
}

.cases-bar h2 {
  font-size: 16px;
  font-weight: 700;
}

.cases-close {
  display: none;
}

.cases-scroll {
  flex: 1;
  min-height: 0;
  overflow-y: auto;
  padding: 0 16px 20px;
  scrollbar-color: var(--line) transparent;
}

.stage-desc {
  color: var(--muted);
  font-size: 14px;
}

#case-list h3 {
  margin: 20px 0 8px;
  font-size: 13px;
  font-weight: 500;
  color: var(--muted);
}

#case-list ul {
  display: grid;
  gap: 6px;
}

#case-list.grid ul {
  grid-template-columns: repeat(auto-fill, minmax(82px, 1fr));
}

.case {
  width: 100%;
  border-radius: var(--radius);
  background: var(--panel);
  box-shadow: inset 0 0 0 1px transparent;
  text-align: left;
}

.case:hover {
  box-shadow: inset 0 0 0 1px var(--line);
}

.case[aria-pressed='true'] {
  background: var(--accent-wash);
  box-shadow: inset 0 0 0 2px var(--accent);
}

.case-text {
  display: block;
  min-width: 0;
}

.case-name {
  display: block;
  font-weight: 500;
}

.case-nick,
.case-alg {
  display: block;
  color: var(--muted);
  font-size: 12px;
}

.case-alg {
  font-family: var(--mono);
  overflow-wrap: anywhere;
}

/* Rejilla (etapas con muchos casos): miniatura arriba, número debajo. */
.grid .case {
  display: grid;
  gap: 6px;
  padding: 9px 8px 8px;
  text-align: center;
}

.grid .case svg {
  width: 100%;
  max-width: 68px;
  margin: 0 auto;
}

.grid .case-name {
  font: 700 14px/1.1 var(--mono);
}

.grid .case-nick {
  margin-top: 2px;
  line-height: 1.2;
}

/* Lista (etapas con pocos casos): miniatura a la izquierda, texto a la derecha. */
.rows .case {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 8px 10px;
}

.rows .case svg {
  flex: none;
  width: 58px;
}

.rows .case svg.layers {
  width: 104px;
}

.grid .case svg.layers {
  max-width: 100%;
}

.arrow {
  stroke: #14161d;
  stroke-width: 2.4;
  stroke-linecap: round;
}

.arrow-head {
  fill: #14161d;
}

.backdrop {
  display: none;
}

/* ---------------------------------------------------------------- Ayuda */

dialog {
  width: min(760px, calc(100vw - 32px));
  max-height: calc(100dvh - 32px);
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--panel);
  color: var(--text);
}

dialog::backdrop {
  background: rgba(8, 10, 15, 0.7);
}

.help-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  border-bottom: 1px solid var(--line);
}

.help-head h2 {
  font-size: 19px;
}

.help-body {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px 32px;
  padding: 20px;
}

.help-body h3 {
  margin-bottom: 8px;
  font-size: 15px;
}

.help-body p {
  color: var(--muted);
  font-size: 14px;
}

.legend {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 8px 14px;
  margin: 14px 0;
  font-size: 14px;
}

.legend dt {
  font: 700 14px/1.45 var(--mono);
  white-space: nowrap;
}

.legend.keys dt {
  font-family: var(--sans);
  font-weight: 400;
}

kbd {
  display: inline-block;
  min-width: 24px;
  padding: 1px 6px;
  border: 1px solid var(--line);
  border-bottom-width: 2px;
  border-radius: 6px;
  background: var(--raised);
  font: 500 12px/1.5 var(--mono);
  text-align: center;
}

.fatal {
  position: fixed;
  inset: auto 16px 16px 16px;
  padding: 14px 16px;
  border-radius: var(--radius);
  background: #5a1d24;
  color: #fff;
}

/* Con más etapas de las que caben a cualquier ancho, solo la actual muestra su nombre. */
.stages .crowded button:not([aria-current]) span:last-child {
  display: none;
}

.stages .crowded button:not([aria-current]) {
  padding: 5px;
}

/* Con muchas etapas y poco ancho, solo la etapa actual muestra su nombre. */
@media (max-width: 1340px) {
  .stages .many button:not([aria-current]) span:last-child {
    display: none;
  }

  .stages .many button:not([aria-current]) {
    padding: 5px;
  }
}

/* ---------------------------------------------------------------- Pantallas bajas */

@media (max-height: 760px) and (min-width: 861px) {
  .player {
    gap: 8px;
    padding: 10px 18px 12px;
  }

  .case-title p {
    -webkit-line-clamp: 1;
    line-clamp: 1;
  }

  .moves {
    max-height: 48px;
  }
}

/* ---------------------------------------------------------------- Móvil */

@media (max-width: 860px) {
  .app {
    grid-template-columns: minmax(0, 1fr);
    grid-template-areas:
      'top'
      'stage'
      'player';
  }

  .top {
    flex-wrap: wrap;
    gap: 8px 10px;
    padding: 8px 12px;
  }

  .social {
    margin-right: 0;
  }

  .brand {
    flex: 1;
    font-size: 15px;
  }

  .methods button {
    padding: 4px 10px;
    font-size: 14px;
  }

  .stages {
    order: 3;
    flex: 1 1 60%;
  }

  .top .ghost,
  .puzzle-picker {
    order: 4;
  }

  .top .ghost {
    padding: 4px 10px;
    font-size: 13px;
  }

  .hint,
  .view-tools {
    display: none;
  }

  .now {
    left: 12px;
    bottom: 6px;
  }

  .player {
    gap: 8px;
    padding: 10px 12px calc(12px + env(safe-area-inset-bottom));
  }

  .case-title h1 {
    font-size: 18px;
  }

  .cases-open {
    display: block;
    border-color: var(--accent);
    color: var(--text);
  }

  .moves {
    flex-wrap: nowrap;
    overflow-x: auto;
    overflow-y: hidden;
    max-height: none;
    scrollbar-width: none;
  }

  .transport {
    gap: 8px 14px;
  }

  .speed input {
    width: 90px;
  }

  /* El panel de casos pasa a ser un cajón inferior. */
  .cases {
    position: fixed;
    inset: 14dvh 0 0 0;
    z-index: 20;
    background: var(--panel);
    border-radius: 16px 16px 0 0;
    box-shadow: 0 -12px 40px rgba(0, 0, 0, 0.45);
    transform: translateY(100%);
    visibility: hidden;
    transition: transform 0.25s ease, visibility 0.25s;
  }

  .cases .case:not([aria-pressed='true']) {
    background: var(--bg);
  }

  .cases-open .cases {
    transform: none;
    visibility: visible;
  }

  .cases-close {
    display: grid;
  }

  .backdrop:not([hidden]) {
    display: block;
    position: fixed;
    inset: 0;
    z-index: 10;
    background: rgba(8, 10, 15, 0.6);
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    transition: none !important;
  }
}