:root {
  --bg: #f6f3ec;
  --bg-panel: #ffffff;
  --bg-panel-2: #fbf9f4;
  --border: #ddd6c4;
  --text: #241f16;
  --text-muted: #6f6858;
  --accent: #cc5b3f;
  --accent-2: #a8452e;
  --success: #3f8c5f;
  --danger: #c23b3b;
  --warn: #b7862a;
  --tile-bg: #fffdf8;
  --tile-border: #e1d9c2;
  --tile-selected-bg: #241f16;
  --tile-selected-text: #fffdf8;
  --diff-yellow: #d9a520;
  --diff-yellow-bg: #fbeecb;
  --diff-green: #3f8c5f;
  --diff-green-bg: #dcf0e2;
  --diff-blue: #3a6fb0;
  --diff-blue-bg: #dbe7f7;
  --diff-purple: #7a4fb0;
  --diff-purple-bg: #e9def6;
  --radius: 12px;
  --radius-sm: 8px;
  --font-display: 'Source Serif 4', Georgia, 'Times New Roman', serif;
  --font-head: 'Inter', system-ui, -apple-system, 'Segoe UI', sans-serif;
  --font-body: 'Inter', system-ui, -apple-system, 'Segoe UI', sans-serif;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #17140f;
    --bg-panel: #221e17;
    --bg-panel-2: #2a251c;
    --border: #3c3527;
    --text: #f3ede0;
    --text-muted: #b3a993;
    --accent: #e8926f;
    --accent-2: #f0a988;
    --tile-bg: #2a251c;
    --tile-border: #423a29;
    --tile-selected-bg: #f3ede0;
    --tile-selected-text: #17140f;
    --diff-yellow-bg: #4a3c15;
    --diff-green-bg: #1e3c29;
    --diff-blue-bg: #1e3049;
    --diff-purple-bg: #372449;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #17140f;
  --bg-panel: #221e17;
  --bg-panel-2: #2a251c;
  --border: #3c3527;
  --text: #f3ede0;
  --text-muted: #b3a993;
  --accent: #e8926f;
  --accent-2: #f0a988;
  --tile-bg: #2a251c;
  --tile-border: #423a29;
  --tile-selected-bg: #f3ede0;
  --tile-selected-text: #17140f;
  --diff-yellow-bg: #4a3c15;
  --diff-green-bg: #1e3c29;
  --diff-blue-bg: #1e3049;
  --diff-purple-bg: #372449;
  color-scheme: dark;
}

* { box-sizing: border-box; }

/* El atributo `hidden` debe ganar siempre a cualquier `display` con más
   especificidad (ids, clases) declarado más abajo en esta hoja; si no,
   elementos como los modales o el panel de resultado quedarían visibles
   aunque JS les ponga `hidden`. */
[hidden] { display: none !important; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  min-height: 100%;
}

body {
  display: flex;
  flex-direction: column;
  min-height: 100dvh;
  padding-bottom: env(safe-area-inset-bottom, 0);
  touch-action: manipulation;
}

a { color: var(--accent-2); }

.card {
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 16px;
}

/* ---------- Header ---------- */
.site-header {
  text-align: center;
  padding: calc(env(safe-area-inset-top, 0) + 14px) 16px 4px;
}
.site-header h1 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.6rem, 6vw, 2.3rem);
  margin: 0 0 3px;
  letter-spacing: 0;
}
.site-header h1 .accent { color: var(--accent); font-style: italic; }
.tagline {
  margin: 0;
  color: var(--text-muted);
  font-size: 0.86rem;
}

main {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: 10px 12px 24px;
  max-width: 560px;
  width: 100%;
  margin: 0 auto;
}

/* ---------- Cómo jugar ---------- */
.howto {
  background: transparent;
  border: none;
  border-bottom: 1px solid var(--border);
  border-radius: 0;
  padding: 2px 2px 16px;
}
.howto h2 { font-family: var(--font-head); font-weight: 700; font-size: 0.95rem; margin: 0 0 6px; text-transform: uppercase; letter-spacing: 0.04em; }
.howto summary {
  cursor: pointer;
  color: var(--accent-2);
  font-weight: 600;
  padding: 4px 0;
  touch-action: manipulation;
}
.howto p, .howto li { font-size: 0.88rem; line-height: 1.45; color: var(--text-muted); }
.howto ul { margin: 8px 0 0; padding-left: 1.2em; }
.howto strong { color: var(--text); }

/* ---------- Game panel ---------- */
.game-panel { display: flex; flex-direction: column; gap: 10px; }

#puzzle-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  flex-wrap: wrap;
}
#puzzle-number {
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--text-muted);
}

#header-actions {
  display: flex;
  gap: 2px;
  flex-wrap: wrap;
}
.icon-btn {
  background: transparent;
  border: none;
  border-radius: var(--radius-sm);
  width: 38px;
  height: 38px;
  min-width: 38px;
  font-size: 1.02rem;
  color: var(--text);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  touch-action: manipulation;
}
.icon-btn:hover { background: var(--bg-panel-2); }
.icon-btn:active { transform: scale(0.92); background: var(--bg-panel-2); }

#practice-banner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  flex-wrap: wrap;
  background: var(--bg-panel-2);
  border: none;
  border-left: 3px solid var(--diff-blue);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 8px 12px;
  font-size: 0.85rem;
}
#practice-banner button {
  background: transparent;
  color: var(--diff-blue);
  border: 1.5px solid var(--diff-blue);
  border-radius: var(--radius-sm);
  padding: 5px 11px;
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  touch-action: manipulation;
}

/* ---------- Grupos resueltos ---------- */
#solved-groups { display: flex; flex-direction: column; gap: 6px; }
.solved-group {
  border-radius: var(--radius-sm);
  padding: 10px 12px;
  text-align: center;
  animation: pop-in 0.28s ease;
}
.solved-group-name { font-weight: 700; font-size: 0.88rem; letter-spacing: 0.02em; }
.solved-group-words { font-size: 0.78rem; margin-top: 2px; opacity: 0.85; }
.solved-yellow { background: var(--diff-yellow-bg); color: #5c4813; }
.solved-green { background: var(--diff-green-bg); color: #1e4a2e; }
.solved-blue { background: var(--diff-blue-bg); color: #1c3a5e; }
.solved-purple { background: var(--diff-purple-bg); color: #3f235e; }

@keyframes pop-in {
  from { opacity: 0; transform: scale(0.92) translateY(-4px); }
  to { opacity: 1; transform: scale(1) translateY(0); }
}

/* ---------- Cuadrícula 4x4 ---------- */
#grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: clamp(6px, 2vw, 10px);
}
#grid.shake { animation: shake 0.4s ease; }
@keyframes shake {
  10%, 90% { transform: translateX(-2px); }
  20%, 80% { transform: translateX(4px); }
  30%, 50%, 70% { transform: translateX(-7px); }
  40%, 60% { transform: translateX(7px); }
}

.tile {
  aspect-ratio: 1 / 1;
  min-height: 64px;
  background: var(--tile-bg);
  border: 1.5px solid var(--tile-border);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-family: var(--font-body);
  font-weight: 700;
  font-size: clamp(0.62rem, 3.4vw, 0.86rem);
  line-height: 1.15;
  padding: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  text-transform: uppercase;
  cursor: pointer;
  touch-action: manipulation;
  user-select: none;
  -webkit-user-select: none;
  transition: background 0.12s ease, color 0.12s ease, transform 0.08s ease, border-color 0.12s ease;
  word-break: break-word;
  hyphens: auto;
}
.tile:active { transform: scale(0.96); }
.tile.selected {
  background: var(--tile-selected-bg);
  color: var(--tile-selected-text);
  border-color: var(--tile-selected-bg);
}
.tile:disabled { cursor: default; opacity: 0.55; }

/* ---------- Errores ---------- */
#mistakes-row {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--text-muted);
}
.mistake-dot {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  border: 2px solid var(--danger);
  display: inline-block;
}
.mistake-dot.used { background: var(--danger); }

#status-message {
  min-height: 1.3em;
  font-size: 0.88rem;
  font-weight: 600;
  text-align: center;
}
#status-message.ok { color: var(--success); }
#status-message.error { color: var(--danger); }
#status-message.warn { color: var(--warn); }

/* ---------- Controles ---------- */
#move-controls, #game-controls {
  display: flex;
  gap: 8px;
  justify-content: center;
}
#game-controls button {
  flex: 1;
  min-height: 46px;
  border-radius: var(--radius-sm);
  border: 1.5px solid var(--border);
  background: var(--bg-panel-2);
  color: var(--text);
  font-family: var(--font-body);
  font-weight: 700;
  font-size: 0.9rem;
  cursor: pointer;
  touch-action: manipulation;
}
#game-controls button:disabled { opacity: 0.45; cursor: default; }
#btn-submit {
  background: var(--accent) !important;
  border-color: var(--accent) !important;
  color: #fff !important;
}
#btn-submit:disabled { background: var(--bg-panel-2) !important; border-color: var(--border) !important; color: var(--text-muted) !important; }

/* ---------- Resultado ---------- */
#result-panel { display: flex; flex-direction: column; gap: 10px; margin-top: 4px; }
#result-title { font-family: var(--font-display); font-weight: 700; margin: 0; font-size: 1.3rem; text-align: center; }
.result-group { border-radius: var(--radius-sm); padding: 8px 12px; text-align: center; }
.result-group-name { font-weight: 700; font-size: 0.85rem; }
.result-group-words { font-size: 0.76rem; opacity: 0.85; margin-top: 2px; }
.result-yellow { background: var(--diff-yellow-bg); color: #5c4813; }
.result-green { background: var(--diff-green-bg); color: #1e4a2e; }
.result-blue { background: var(--diff-blue-bg); color: #1c3a5e; }
.result-purple { background: var(--diff-purple-bg); color: #3f235e; }

#share-row { display: flex; align-items: center; gap: 10px; justify-content: center; flex-wrap: wrap; }
#btn-share {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: var(--radius-sm);
  padding: 10px 18px;
  font-weight: 700;
  font-size: 0.9rem;
  cursor: pointer;
  touch-action: manipulation;
}
#share-feedback { font-size: 0.82rem; color: var(--success); font-weight: 600; }
#next-puzzle-countdown { text-align: center; font-size: 0.82rem; color: var(--text-muted); }

/* ---------- Modales ---------- */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(20, 16, 8, 0.55);
  display: flex;
  align-items: flex-end;
  justify-content: center;
  z-index: 50;
  padding: 0;
}
@media (min-width: 520px) {
  .modal-backdrop { align-items: center; padding: 20px; }
}
.modal {
  width: 100%;
  max-width: 480px;
  max-height: 88vh;
  overflow-y: auto;
  border-radius: var(--radius) var(--radius) 0 0;
  padding: 20px 18px calc(20px + env(safe-area-inset-bottom, 0));
}
@media (min-width: 520px) {
  .modal { border-radius: var(--radius); }
}
.modal h2 { font-family: var(--font-head); font-weight: 700; margin: 0 0 10px; font-size: 1.1rem; }
#modal-welcome h2 { font-family: var(--font-display); font-size: 1.3rem; }
.modal h3 { font-size: 0.95rem; margin: 14px 0 8px; }
.modal p, .modal li { font-size: 0.9rem; line-height: 1.5; color: var(--text-muted); }
.modal ul { padding-left: 1.2em; margin: 8px 0; }
.modal strong { color: var(--text); }
.modal button.primary, .modal > button {
  margin-top: 14px;
  width: 100%;
  min-height: 46px;
  border-radius: var(--radius-sm);
  border: none;
  background: var(--accent);
  color: #fff;
  font-weight: 700;
  font-size: 0.95rem;
  cursor: pointer;
  touch-action: manipulation;
}

#faq {
  background: transparent;
  border: none;
  border-radius: 0;
  border-top: 1px solid var(--border);
  padding: 18px 2px 4px;
}
#faq h2 { font-family: var(--font-head); font-weight: 700; font-size: 0.95rem; margin: 0 0 14px; text-transform: uppercase; letter-spacing: 0.04em; }
.faq-item { margin-bottom: 14px; padding-bottom: 14px; border-bottom: 1px solid var(--border); }
.faq-item:last-child { margin-bottom: 0; padding-bottom: 0; border-bottom: none; }
.faq-item h3 { margin: 0 0 4px; font-size: 0.9rem; color: var(--text); font-weight: 600; }
.faq-item p { margin: 0; }

/* ---------- Estadísticas ---------- */
.stats-summary {
  display: flex;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  overflow: hidden;
}
.stat-tile { flex: 1; text-align: center; padding: 10px 4px; border-right: 1px solid var(--border); }
.stat-tile:last-child { border-right: none; }
.stat-num { display: block; font-family: var(--font-head); font-size: 1.3rem; font-weight: 700; }
.stat-label { font-size: 0.64rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.03em; }
.stats-distribution { display: flex; flex-direction: column; gap: 6px; margin-top: 4px; }
.dist-row { display: flex; align-items: center; gap: 8px; font-size: 0.78rem; }
.dist-label { width: 78px; flex-shrink: 0; color: var(--text-muted); }
.dist-bar-track { flex: 1; background: var(--bg-panel-2); border-radius: 6px; height: 16px; overflow: hidden; }
.dist-bar-fill { height: 100%; background: var(--accent); border-radius: 6px; min-width: 2px; }
.dist-count { width: 22px; text-align: right; font-weight: 700; }
.stats-note { font-size: 0.76rem; margin-top: 10px; }

/* ---------- Archivo ---------- */
.archive-hint { font-size: 0.85rem; }
#archive-list { display: flex; flex-direction: column; gap: 8px; max-height: 50vh; overflow-y: auto; }
.archive-item {
  text-align: left;
  background: var(--bg-panel-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 10px 12px;
  cursor: pointer;
  touch-action: manipulation;
}
.archive-item h3 { margin: 0 0 3px; font-size: 0.9rem; font-family: var(--font-head); color: var(--text); }
.archive-teaser { margin: 0; font-size: 0.76rem; color: var(--text-muted); }

/* ---------- Footer ---------- */
.site-footer {
  text-align: center;
  padding: 10px 16px calc(16px + env(safe-area-inset-bottom, 0));
  font-size: 0.76rem;
  color: var(--text-muted);
}
.site-footer a { color: var(--text-muted); }

/* ---------- Utilidades ---------- */
.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}