:root{
  --cell: 64px;
  --gap: 6px;
  --bg: #ffffff;
  --header: #e8ebf3;
  --panel: #f6f7f9;
  --text: #111111;
  --muted: #555555;
  --border: #ccc;
  --card-border: #ccc;
  --cell-bg: #ffffff;
  --cell-border: #ccc;
  --pill-bg: #ffffff;
  --pill-border: #ddd;
  --kbd-bg: #e2e6ee;
  --hint: #777;
  --ok: #22c55e;
  --bad: #ef4444;
  --focus: #2563eb;
  --shadow: 0 4px 12px rgba(0,0,0,.08);
  --radius: 14px;
  --group-blue: #1e3a8a;
  --pill-text: #333;
  --visit-bg: #f8f9fa;
  --visit-border: #ccc;
}
[data-theme="dark"]{
  --bg: #0f172a;
  --header: #1f2937;
  --panel: #111827;
  --text: #e5e7eb;
  --pill-text: #e5e7eb;
  --muted: #94a3b8;
  --border: #334155;
  --card-border: #1f2937;
  --cell-bg: #111827;
  --cell-border: #334155;
  --pill-bg: #0b1220;
  --pill-border: #1f2937;
  --kbd-bg: #1f2937;
  --hint: #cbd5e1;
  --shadow: 0 8px 20px rgba(0,0,0,.45);
  --ok: #22c55e;
  --bad: #f87171;
  --focus: #60a5fa;
  --visit-bg: #0b1220;
  --visit-border: #334155;
  --group-blue: #1e40af;
  --g-alkali: #4c1d95; --g-alkali-b: #7c3aed;
  --g-alkaline: #854d0e; --g-alkaline-b: #f59e0b;
  --g-transition: #0f5132; --g-transition-b: #198754;
  --g-transition-viii: #0b3a2a; --g-transition-viii-b: #147a50;
  --g-post: #0b6c99; --g-post-b: #1287c2;
  --g-metalloid: #0f766e; --g-metalloid-b: #14b8a6;
  --g-nonmetal: #7e22ce; --g-nonmetal-b: #a855f7;
  --g-halogen: #9d174d; --g-halogen-b: #e11d48;
  --g-noble: #1d4ed8; --g-noble-b: #3b82f6;
  --g-lanth: #166534; --g-lanth-b: #22c55e;
  --g-actin: #1e3a8a; --g-actin-b: #2563eb;
}
*{box-sizing:border-box}
html,body{height:100%;margin:0;background:var(--bg);color:var(--text);font-family:system-ui,Segoe UI,Roboto,Helvetica,Arial,sans-serif}
header{
  display:flex;align-items:center;justify-content:space-between;
  padding:14px 18px;background:var(--header);position:sticky;top:0;z-index:5;border-bottom:1px solid var(--border)
}
.header-left{display:flex;align-items:center}
header h1{font-size:18px;margin:0;font-weight:700;letter-spacing:.2px;color:var(--text)}
#logo{height:40px;margin-right:16px;}
.stats{display:flex;gap:14px;font-size:14px;color:var(--muted);align-items:center;}
.stats span{font-weight:600}.stats span b{color:var(--text);font-size:16px;font-weight:800}
.wrap{padding:18px;display:grid;grid-template-columns: 1fr 350px;gap:18px}
.sidebar{display:flex;flex-direction:column}
.board{background:var(--panel);border-radius:var(--radius);padding:16px;box-shadow:var(--shadow)}
.grid{
  display:grid;
  grid-template-columns: repeat(18, var(--cell));
  grid-auto-rows: var(--cell);
  gap: var(--gap);
  justify-content:center;
  margin:auto;
}
.cell{
  width:var(--cell);height:var(--cell);
  border-radius:10px;border:1px solid var(--cell-border);
  background:var(--cell-bg); display:flex;align-items:center;justify-content:center;
  position:relative; cursor:pointer; transition:.2s transform, background .2s;
  user-select:none;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
}
.cell:hover{outline:2px solid rgba(0,0,0,.05);transform:translateY(-2px)}
[data-theme="dark"] .cell:hover{outline:2px solid rgba(255,255,255,.05)}
.cell.empty{background:var(--panel)}
.cell.revealed{border-color:transparent;color:var(--text)}
.cell .mini{
  position:absolute;left:6px;top:4px;font-size:11px;
  color:var(--muted);font-weight:700;
}
.cell .sym{font-size:20px;font-weight:800;line-height:1;color:var(--text)}
.cell .name{
  position:absolute;bottom:4px;left:6px;right:6px;font-size:10px;
  color:var(--text);font-weight:600;
  white-space:nowrap;overflow:hidden;text-overflow:ellipsis;
}
.cell.bad{animation:shake .35s;border-color:var(--bad)!important;outline:2px solid rgba(255,0,0,.2)}
@keyframes shake{10%, 90%{transform:translateX(-1px)} 20%,80%{transform:translateX(2px)} 30%,50%,70%{transform:translateX(-4px)} 40%,60%{transform:translateX(4px)}}
.legend{background:var(--panel);border-radius:var(--radius);padding:14px;box-shadow:var(--shadow);height:fit-content}
.rowTitle{
  margin:12px 0 6px 0;
  color:var(--muted);
  font-weight:600;
  letter-spacing:.3px;
  font-size:12px;
  text-align:right;
  flex:0 0 96px; /* reserva ancho para evitar que la etiqueta desplace la fila */
}
.fgrid{display:grid;grid-template-columns: repeat(15, var(--cell));gap:var(--gap);justify-content:center}
.fgrid.f14{grid-template-columns: repeat(14, var(--cell))}
.pill{display:inline-flex;align-items:center;gap:8px;padding:8px 10px;border-radius:999px;background:var(--pill-bg);border:1px solid var(--pill-border);font-size:12px;color:var(--pill-text);margin:4px 6px 0 0}
.sw{width:14px;height:14px;border-radius:4px;border:1px solid #aaa}

/* Colores de grupo adaptados para tema claro */
.g-alkali{background:#ffe2dc;border-color:#ffb8b0}
.g-alkaline{background:#fff0c2;border-color:#ffd84f}
.g-transition{background:#e6f4d8;border-color:#b8e994}
/* Realce sutil para VIIIB (grupos 8, 9 y 10) */
.cell.g-transition[data-col="8"],
.cell.g-transition[data-col="9"],
.cell.g-transition[data-col="10"]{
  background:#d2efb6;
  border-color:#9ddb6f;
}
.g-post{background:#d7e9f9;border-color:#a7d1f4}
.g-metalloid{background:#d6fff1;border-color:#9ef5da}
.g-nonmetal{background:#f2e0ff;border-color:#d4b5ff}
.g-halogen{background:#ffd6ee;border-color:#f7a8da}
.g-noble{background:#d7ecff;border-color:#a9d4ff}
.g-lanth{background:#d8ffd8;border-color:#aaffaa}
.g-actin{background:#d8f0ff;border-color:#aad7ff}

[data-theme="dark"] .g-alkali{background:var(--g-alkali);border-color:var(--g-alkali-b)}
[data-theme="dark"] .g-alkaline{background:var(--g-alkaline);border-color:var(--g-alkaline-b)}
[data-theme="dark"] .g-transition{background:var(--g-transition);border-color:var(--g-transition-b)}
[data-theme="dark"] .cell.g-transition[data-col="8"],
[data-theme="dark"] .cell.g-transition[data-col="9"],
[data-theme="dark"] .cell.g-transition[data-col="10"]{background:var(--g-transition-viii);border-color:var(--g-transition-viii-b)}
[data-theme="dark"] .g-post{background:var(--g-post);border-color:var(--g-post-b)}
[data-theme="dark"] .g-metalloid{background:var(--g-metalloid);border-color:var(--g-metalloid-b)}
[data-theme="dark"] .g-nonmetal{background:var(--g-nonmetal);border-color:var(--g-nonmetal-b)}
[data-theme="dark"] .g-halogen{background:var(--g-halogen);border-color:var(--g-halogen-b)}
[data-theme="dark"] .g-noble{background:var(--g-noble);border-color:var(--g-noble-b)}
[data-theme="dark"] .g-lanth{background:var(--g-lanth);border-color:var(--g-lanth-b)}
[data-theme="dark"] .g-actin{background:var(--g-actin);border-color:var(--g-actin-b)}

.footer{padding:12px 18px;color:var(--muted);font-size:12px}
.kbd{background:var(--kbd-bg);border:1px solid var(--border);padding:1px 6px;border-radius:6px}
.hint{font-size:12px;color:var(--hint);margin-top:8px}
.btn{
  padding:8px 10px;border-radius:10px;background:var(--panel);color:var(--text);border:1px solid var(--border);
  cursor:pointer;font-weight:600;font-size:14px;
}
.btn:hover{background:rgba(37,99,235,.08)}
.btn:active{transform:translateY(1px)}
.toolbar{display:flex;gap:10px;align-items:center}
.inputPop{
  position:fixed;inset:0;background:rgba(0,0,0,.25);backdrop-filter: blur(2px);
  display:none;z-index:20
}
.inputCard{
  background:var(--panel);border:1px solid var(--card-border);border-radius:16px;box-shadow:var(--shadow);
  width:min(420px, 92vw);padding:18px;color:var(--text);
}
.inputRow{display:flex;gap:8px}
.inputRow input{
  flex:1;font-size:18px;padding:10px 12px;border-radius:10px;border:1px solid var(--border);
  background:var(--cell-bg);color:var(--text);outline:2px solid transparent
}
.inputRow input:focus{outline-color:var(--focus)}
.inputRow input.error{border-color:var(--bad); outline-color: var(--bad); background:#fff6f6}
.small{font-size:12px;color:var(--muted)}
.complete{
  text-align:center;padding:16px;background:#eaffea;
  border:2px solid #22c55e;border-radius:12px;margin-top:12px;
  color:#166534;font-weight:600;font-size:14px;
}
.complete-summary{
  margin: 0 0 12px 0;
  font-size:14px;
  color:var(--text);
  text-align:center;
}
.complete-summary div{ margin-bottom:4px; }
.complete-positive{
  font-weight:700;
  color: var(--text);
  display:flex;
  align-items:center;
  justify-content:center;
  gap:8px;
  font-size:15px;
}
.complete-icon{ font-size:18px; line-height:1; }

/* Encabezados de grupos y periodos */
.gridWrapper {
  position: relative;
  display: inline-block;
}
.groupHeader, .periodHeader {
  font-weight:700;
  text-align:center;
  background:var(--group-blue);
  color:white;
  border-radius:8px;
  display:flex;
  align-items:center;
  justify-content:center;
}
.groupHeader{
  width:var(--cell);
  height:24px;
  font-size:12px;
}
.periodHeader{
  width:24px;
  height:var(--cell);
  font-size:14px;
}
.groupRow{
  display:grid;
  grid-template-columns: repeat(18, var(--cell));
  justify-content:center;
  gap:var(--gap);
  margin-bottom:6px;
  position: relative;
  left: calc((24px + var(--gap)) / 2);
}
.mainArea{display:flex;}
.periodCol{
  display:grid;
  grid-template-rows: repeat(7, var(--cell));
  gap:var(--gap);
  margin-right:6px;
}

/* Etiquetas Lantánidos y Actínidos */
.labelLanth, .labelAct {
  background:var(--group-blue);
  color:white;
  padding:6px 10px;
  border-radius:8px;
  width:fit-content;
  margin:12px 0 6px 0;
  font-weight:700;
  font-size:13px;
}
.labelLanth, .labelAct {
  display:flex;
  align-items:center;
  justify-content:center;
  min-width:90px;
  height:var(--cell);
  margin:0;
}

.legend{
  background:var(--panel);
  border-radius:var(--radius);
  padding:14px;
  box-shadow:var(--shadow);
  height:fit-content;
  display:flex;
  flex-direction:column;
  gap:6px;
}
.pill{
  display:flex;
  align-items:center;
  gap:8px;
  padding:6px 8px;
  border-radius:999px;
  background:var(--pill-bg);
  border:1px solid var(--pill-border);
  font-size:12px;
  color:var(--pill-text);
  margin:0;
}
.legend{max-width: 260px;}

/* Caja de créditos */
.credits{
  background:var(--panel);
  border-radius:var(--radius);
  padding:14px;
  box-shadow:var(--shadow);
  display:flex;
  flex-direction:column;
  gap:4px;
  font-size:12px;
  color:var(--muted);
  margin-top:auto;
}

/* Ventana de entrada */
.inputCard {
  position: absolute;
  background: var(--panel);
  border: 1px solid var(--card-border);
  border-radius: 14px;
  box-shadow: var(--shadow);
  padding: 20px;
  color: var(--text);
  min-width: 280px;
}
.inputCard h3 { margin-top: 0; font-size: 18px; font-weight: 700; }
.inputRow { display: flex; gap: 8px; margin-top: 8px; }
.inputRow input {
  flex: 1;
  font-size: 18px;
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--cell-bg);
  color: var(--text);
  outline: 2px solid transparent;
}
.inputRow input:focus { outline-color: var(--focus); }
.inputButtons {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  margin-top: 16px;
}
.btn { padding: 8px 12px; border-radius: 10px; background: var(--panel); color:var(--text); border:1px solid var(--border); cursor:pointer; font-weight:600; font-size:14px; min-width: 100px; }
.btn:hover { background:rgba(37,99,235,.08); }
.btn:active { transform: translateY(1px); }
.btn-secondary { background:var(--panel); border-color:var(--border); }
.btn-danger { background:#fee2e2; border-color:#fca5a5; color:#991b1b; }
.btn-danger:hover { background:#fecaca; }
.btnGroupRight{ display:flex; gap:10px; }

/* Contenedor popup anclado */
.inputPop {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,.25);
  backdrop-filter: blur(2px);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 20;
}
.inputPop.open { display: flex; }

/* Resaltado de la celda activa */
.cell.active {
  position: relative;
  z-index: 5;
  outline: 3px solid var(--focus);
  box-shadow: 0 0 12px rgba(37,99,235,.4);
}
.cell.cursor {
  outline: 2px solid var(--focus);
  box-shadow: 0 0 8px rgba(37,99,235,.35);
}

/* Marca de relleno automático */
.cell.auto::after{
  content:"*";
  position:absolute;
  top:3px; right:5px;
  font-size:20px; font-weight:900;
  color: var(--bad);
  text-shadow: 0 1px 0 rgba(255,255,255,.6);
  pointer-events:none;
  animation: blinkMark 0.6s ease-in-out 0s 2;
}
/* Marca de error previo */
.cell.had-error::after{
  content:"*";
  position:absolute;
  top:3px; right:5px;
  font-size:20px; font-weight:900;
  color: var(--focus);
  text-shadow: 0 1px 0 rgba(255,255,255,.6);
  pointer-events:none;
}
@keyframes blinkMark { 0%, 100% { opacity: 1; } 50% { opacity: .15; } }

/* Botón de sonido */
.sound-toggle-btn {
  font-size: 1.2rem;
  line-height: 1;
  padding: 6px 8px;
  margin-right: 12px;
  cursor: pointer;
  background: transparent;
  border: 1px solid transparent;
  border-radius: 6px;
}
.sound-toggle-btn:hover,
.sound-toggle-btn:focus {
  border-color: var(--border);
  outline: none;
}

/* Botón de tema */
.theme-toggle-btn {
  font-size: 1.2rem;
  line-height: 1;
  padding: 6px 8px;
  margin-right: 8px;
  cursor: pointer;
  background: transparent;
  border: 1px solid transparent;
  border-radius: 6px;
}
.theme-toggle-btn:hover,
.theme-toggle-btn:focus {
  border-color: var(--border);
  outline: none;
}

/* Selector de idioma */
.lang-select {
  margin-right: 8px;
  padding: 4px 6px;
  font-size: 14px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--cell-bg);
  color: var(--text);
  min-width: 120px;
  height: 30px;
  line-height: 30px;
  appearance: auto;
  background-repeat: no-repeat;
  background-position: 8px 50%;
  background-size: 18px 12px;
  padding-left: 34px;
}
.lang-select[data-flag="es"]{
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='18' height='12' viewBox='0 0 18 12'><rect width='18' height='12' fill='%23AA151B'/><rect y='3' width='18' height='6' fill='%23F1BF00'/></svg>");
}
.lang-select[data-flag="en"]{
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='18' height='12' viewBox='0 0 18 12'><rect width='18' height='12' fill='%23012E6E'/><path d='M0 0l18 12M18 0L0 12' stroke='%23fff' stroke-width='3'/><path d='M0 0l18 12M18 0L0 12' stroke='%23C8102E' stroke-width='1.5'/><rect x='7' width='4' height='12' fill='%23fff'/><rect y='4' width='18' height='4' fill='%23fff'/><rect x='8' width='2' height='12' fill='%23C8102E'/><rect y='5' width='18' height='2' fill='%23C8102E'/></svg>");
}
.lang-select[data-flag="ca"]{
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='18' height='12' viewBox='0 0 18 12'><rect width='18' height='12' fill='%23FCDD09'/><g fill='%23DA121A'><rect y='1' width='18' height='1'/><rect y='3' width='18' height='1'/><rect y='5' width='18' height='1'/><rect y='7' width='18' height='1'/><rect y='9' width='18' height='1'/></g></svg>");
}

/* Tooltip */
.tp-tooltip {
  position: fixed;
  z-index: 1000;
  background: #1e3a8a;
  color: #ffea00;
  border: none;
  border-radius: 7px;
  padding: 3px 6px;
  font-size: 12px;
  box-shadow: 0 10px 20px rgba(0,0,0,.25);
  white-space: nowrap;
  pointer-events: none;
  font-weight: 600;
}
.tp-tooltip.in-cell {
  position: absolute;
  top: 4px;
  right: 4px;
  max-width: calc(100% - 8px);
  z-index: 3;
}
.tp-tooltip.tail-down::after,
.tp-tooltip.tail-up::after {
  content: "";
  position: absolute;
}
.tp-tooltip.tail-down::after {
  bottom: -1px; left: var(--tp-arrow-x, 62%);
  transform: translateX(-50%);
  border-left: 5px solid transparent;
  border-right: 5px solid transparent;
  border-top: 14px solid #1e3a8a;
}
.tp-tooltip.tail-up::after {
  top: -1px; left: var(--tp-arrow-x, 62%);
  transform: translateX(-50%);
  border-left: 5px solid transparent;
  border-right: 5px solid transparent;
  border-bottom: 14px solid #1e3a8a;
}

.dont-know-asterisk,
.had-error-asterisk {
  font-size: 20px;
  font-weight: 900;
  line-height: 1;
}
.dont-know-asterisk { color: var(--bad); }
.had-error-asterisk { color: var(--focus); }

/* Contador de visitas */
.visit-counter {
  display: flex;
  gap: 1px;
  background-color: var(--header);
  border: 1px solid var(--visit-border);
  border-radius: 5px;
  padding: 1px;
}
.visit-counter span {
  display: inline-block;
  font-family: system-ui, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
  font-weight: 700;
  font-size: 18px;
  color: var(--text);
  background-color: var(--visit-bg);
  padding: 2px 5px;
  border-radius: 3px;
  line-height: 1;
  min-width: 1.2em;
  text-align: center;
}

/* Ajustes responsivos */
@media (max-width: 1200px){
  :root{
    --cell: 56px;
    --gap: 6px;
  }
}
@media (max-width: 900px){
  :root{
    --cell: 42px;
    --gap: 3px;
  }
  .wrap{
    grid-template-columns: 1fr;
  }
  .mainArea{
    display: grid;
    grid-template-columns: auto auto;
    align-items: start;
    column-gap: var(--gap);
  }
  .board{
    overflow-x: auto;
  }
  .gridWrapper{
    min-width: max-content;
    margin: 0 auto;
  }
  .groupRow,
  .grid,
  .fgrid{
    min-width: max-content;
    justify-content: flex-start;
  }
  .grid{
    justify-content: flex-start;
  }
  .groupRow{
    left: 0;
    margin-left: calc(24px + var(--gap));
  }
  .periodCol{
    margin: 0;
  }
  .legend{
    width: 100%;
    max-width: 520px;
  }
  .sidebar{
    flex-direction: column;
    gap: 14px;
  }
  .credits{
    margin-top: 0;
  }
}
@media (max-width: 640px){
  :root{
    --cell: 40px;
    --gap: 3px;
  }
  header{
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }
  .toolbar{
    flex-wrap: wrap;
  }
  .wrap{
    padding: 12px;
  }
}