:root {
  --bg: #0e1116;
  --panel: #171b22;
  --panel-2: #1e242d;
  --border: #2a323d;
  --text: #e6e9ef;
  --muted: #97a1b0;
  --accent: #7c5cff;
  --accent-2: #00c2a8;
  --shadow: 0 6px 24px rgba(0, 0, 0, 0.35);
  --w: #f5f5f5; --y: #ffd500; --r: #c41e3a; --o: #ff5800; --g: #009e60; --b: #0051ba;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: radial-gradient(1200px 600px at 70% -10%, #1a2030 0%, var(--bg) 55%);
  color: var(--text);
  min-height: 100vh;
}

.navbar {
  display: flex; align-items: center; justify-content: space-between;
  gap: 12px; padding: 7px 18px;
  border-bottom: 1px solid var(--border);
  background: rgba(20, 24, 32, 0.6);
}
.brand { display: flex; align-items: center; gap: 9px; }
.brand-cube { width: 36px; height: 36px; display: block; flex: none; }
.brand-cube canvas { display: block; }
.brand-name {
  font-size: 1.15rem; font-weight: 800; letter-spacing: 0.3px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.nav-help {
  appearance: none; background: var(--panel-2); color: var(--accent-2);
  border: 1px solid var(--border); border-radius: 999px;
  padding: 6px 14px; font-size: 0.82rem; font-weight: 700; cursor: pointer; transition: 0.15s;
}
.nav-help:hover { border-color: var(--accent-2); transform: translateY(-1px); }

.topbar { padding: 18px 24px 6px; text-align: center; }
.topbar h1 { margin: 0; font-size: 1.7rem; font-weight: 700; letter-spacing: 0.3px; }
.topbar .accent {
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.tagline { margin: 6px 0 0; color: var(--muted); font-size: 0.95rem; }

.layout {
  display: grid;
  grid-template-columns: 300px minmax(360px, 1fr) 360px;
  gap: 16px;
  padding: 18px 20px;
  max-width: 1400px;
  margin: 0 auto;
  align-items: start;
}
@media (max-width: 1080px) {
  .layout { grid-template-columns: 1fr; }
}

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 16px;
  box-shadow: var(--shadow);
}
.panel h2 { margin: 0 0 12px; font-size: 1.05rem; }
.size-field { margin-bottom: 12px; }
.size-field select { padding: 8px; border-radius: 8px; background: var(--panel-2); color: var(--text); border: 1px solid var(--border); font-weight: 600; }
.panel h3 { margin: 0; font-size: 0.95rem; }

/* Botones */
.btn {
  appearance: none; border: 1px solid var(--border);
  background: var(--panel-2); color: var(--text);
  padding: 9px 12px; border-radius: 10px; cursor: pointer;
  font-size: 0.9rem; font-weight: 600; transition: 0.15s;
}
.btn:hover { border-color: var(--accent); transform: translateY(-1px); }
.btn:active { transform: translateY(0); }
.btn:disabled { opacity: 0.45; cursor: not-allowed; transform: none; }
.btn-primary { background: linear-gradient(90deg, var(--accent), #6a4cff); border: none; }
.btn-ghost { background: transparent; }
.btn-wide { width: 100%; margin-top: 8px; }
.btn-row { display: flex; gap: 8px; }
.btn-row .btn { flex: 1; }

.playback { margin-top: 16px; border-top: 1px solid var(--border); padding-top: 14px; }
.speed { display: flex; flex-direction: column; gap: 4px; margin-top: 10px; font-size: 0.8rem; color: var(--muted); }
.speed input { width: 100%; }

/* Solución */
.solution { margin-top: 16px; border-top: 1px solid var(--border); padding-top: 14px; }
.solution-head { display: flex; justify-content: space-between; align-items: center; }
.pill { background: var(--panel-2); border: 1px solid var(--border); border-radius: 999px; padding: 2px 10px; font-size: 0.75rem; color: var(--muted); }
.solution-head-right { display: flex; align-items: center; gap: 8px; }
.btn-legend {
  appearance: none; background: var(--panel-2); color: var(--accent-2);
  border: 1px solid var(--border); border-radius: 999px;
  padding: 3px 10px; font-size: 0.74rem; font-weight: 700; cursor: pointer; transition: 0.15s;
}
.btn-legend:hover { border-color: var(--accent-2); transform: translateY(-1px); }

.status { font-size: 0.82rem; color: var(--muted); margin-top: 8px; min-height: 1.1em; }

/* Modal / pop-up */
.modal-overlay {
  position: fixed; inset: 0; z-index: 100;
  background: rgba(0, 0, 0, 0.6); backdrop-filter: blur(3px);
  display: flex; align-items: center; justify-content: center; padding: 20px;
}
.modal-overlay.hidden { display: none; }
.modal {
  position: relative; background: var(--panel); border: 1px solid var(--border);
  border-radius: 16px; box-shadow: var(--shadow); padding: 26px 26px 22px;
  max-width: 560px; width: 100%; max-height: 86vh; overflow-y: auto;
}
.modal h2 { margin: 0 0 12px; font-size: 1.25rem; }
.modal h3 { margin: 18px 0 6px; font-size: 0.95rem; color: var(--accent); }
.modal p { margin: 0 0 8px; font-size: 0.9rem; line-height: 1.5; color: var(--text); }
.modal .lead { color: var(--muted); }
.modal .hl { color: #fff; background: var(--accent); padding: 1px 6px; border-radius: 5px; font-weight: 700; }
.modal .hl2 { color: var(--accent-2); font-weight: 700; }
.modal .tip { margin-top: 16px; padding: 10px 12px; background: var(--panel-2); border-radius: 10px; border: 1px solid var(--border); color: var(--muted); }
.modal-close {
  position: absolute; top: 14px; right: 14px; width: 30px; height: 30px;
  border-radius: 8px; border: 1px solid var(--border); background: var(--panel-2);
  color: var(--text); cursor: pointer; font-size: 0.9rem; line-height: 1;
}
.modal-close:hover { border-color: var(--accent); }
.legend-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 8px 14px; margin: 8px 0; }
.legend-grid > div { font-size: 0.88rem; display: flex; align-items: center; gap: 8px; }
.legend-list { margin: 4px 0; padding-left: 4px; list-style: none; }
.legend-list li { font-size: 0.88rem; line-height: 1.7; }
.modal .muted { color: var(--muted); font-size: 0.8rem; }
.k {
  display: inline-block; min-width: 22px; text-align: center;
  font-family: ui-monospace, Menlo, monospace; font-size: 0.82rem; font-weight: 700;
  background: var(--panel-2); border: 1px solid var(--border); border-radius: 6px;
  padding: 2px 7px; color: var(--text);
}
.k.rot { color: var(--accent-2); border-color: var(--accent-2); font-style: italic; }
.status.err { color: #ff8a8a; }
.status.ok { color: var(--accent-2); }
.moves {
  margin-top: 10px; display: flex; flex-wrap: wrap; gap: 5px;
  max-height: 320px; overflow-y: auto; padding-right: 4px;
}
.move {
  font-family: ui-monospace, "SF Mono", Menlo, monospace;
  font-size: 0.8rem; background: var(--panel-2); border: 1px solid var(--border);
  padding: 3px 7px; border-radius: 6px; color: var(--text);
}
.phase-head {
  flex-basis: 100%;
  font-size: 0.72rem; font-weight: 700; letter-spacing: 0.5px;
  text-transform: uppercase; color: var(--accent-2);
  margin: 8px 0 2px; padding-top: 6px; border-top: 1px solid var(--border);
}
.phase-head:first-child { margin-top: 0; padding-top: 0; border-top: none; }
.move.done { opacity: 0.4; }
.move.current { background: var(--accent); border-color: var(--accent); color: #fff; font-weight: 700; }
.move.rot { border-color: var(--accent-2); color: var(--accent-2); font-style: italic; }
.move.rot.current { background: var(--accent-2); border-color: var(--accent-2); color: #04201c; }

/* Escenario 3D */
.stage { display: flex; flex-direction: column; align-items: center; padding: 8px; }
#cube-container { width: 100%; height: 560px; }
@media (max-width: 1080px) { #cube-container { height: 420px; } }
.hint { color: var(--muted); font-size: 0.8rem; margin: 4px 0 6px; }

/* Entrada */
.tabs { display: flex; gap: 6px; margin-bottom: 12px; }
.tab {
  flex: 1; padding: 8px; border-radius: 9px; cursor: pointer;
  background: transparent; border: 1px solid var(--border); color: var(--muted); font-weight: 600;
}
.tab.active { background: var(--panel-2); color: var(--text); border-color: var(--accent); }
.tab-body.hidden { display: none; }
.small { font-size: 0.8rem; color: var(--muted); margin: 0 0 10px; }
.field { display: flex; flex-direction: column; gap: 4px; font-size: 0.8rem; color: var(--muted); margin-bottom: 8px; }
.field select { padding: 7px; border-radius: 8px; background: var(--panel-2); color: var(--text); border: 1px solid var(--border); }
input[type=file] { width: 100%; font-size: 0.8rem; color: var(--muted); margin-bottom: 8px; }

/* Paleta */
.palette { display: flex; gap: 6px; margin-bottom: 12px; flex-wrap: wrap; }
.swatch { width: 30px; height: 30px; border-radius: 7px; cursor: pointer; border: 2px solid transparent; }
.swatch.sel { border-color: #fff; box-shadow: 0 0 0 2px var(--accent); }
.sw-W { background: var(--w); } .sw-Y { background: var(--y); } .sw-R { background: var(--r); }
.sw-O { background: var(--o); } .sw-G { background: var(--g); } .sw-B { background: var(--b); }

/* Net desplegado */
.net {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 4px;
  justify-items: center;
  margin-bottom: 12px;
  overflow-x: auto;
}
.face-grid {
  display: grid; grid-template-columns: repeat(5, 1fr); gap: 2px;
  background: #000; padding: 2px; border-radius: 5px;
}
.face-slot { display: flex; align-items: center; justify-content: center; }
.cell {
  width: 13px; height: 13px; border-radius: 3px; cursor: pointer; border: 1px solid rgba(0,0,0,0.35);
}
.cell.locked { cursor: default; box-shadow: inset 0 0 0 2px rgba(255,255,255,0.5); }
.face-label { font-size: 0.62rem; color: var(--muted); text-align: center; margin-bottom: 2px; }
.c-W { background: var(--w); } .c-Y { background: var(--y); } .c-R { background: var(--r); }
.c-O { background: var(--o); } .c-G { background: var(--g); } .c-B { background: var(--b); }
.c-\? { background: #333; }

/* Foto */
.photo-wrap { position: relative; width: 100%; margin-bottom: 8px; }
.photo-wrap canvas { width: 100%; border-radius: 8px; display: block; }
#photo-overlay { position: absolute; top: 0; left: 0; touch-action: none; }

.foot { text-align: center; color: var(--muted); font-size: 0.78rem; padding: 8px 0 24px; }
.dim { opacity: 0.7; }