/* ===== Root ===== */
.teaching-chess{
  --panel: rgba(255,255,255,0.0);
  --panelBorder: rgba(0,0,0,0.12);
  --muted: rgba(0,0,0,0.65);

  --sqLight:#f0d9b5;
  --sqDark:#b58863;
  --arrow: rgba(255,215,0,0.78);

  position: relative;
}

/* ===== Layout ===== */
.teaching-chess .tc-wrap{
  width:100%;
  max-width:100%;
  box-sizing:border-box;
  display:flex;
  flex-direction:column;
  gap:10px;
}

.teaching-chess .tc-topbar{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:10px;
  background:var(--panel);
  border:1px solid var(--panelBorder);
  border-radius:14px;
  padding:10px 12px;
}

.teaching-chess #status{
  font-size:14px;
  color:var(--muted);
  line-height:1.2;
  user-select:none;
}

.teaching-chess #newGameBtn{
  appearance:none;
  border:1px solid rgba(0,0,0,0.18);
  background:rgba(0,0,0,0.04);
  color:inherit;
  padding:8px 10px;
  border-radius:12px;
  cursor:pointer;
  font-weight:700;
  display:inline-flex; /* always visible */
}
.teaching-chess #newGameBtn:hover{filter:brightness(1.06)}

/* ===== Board ===== */
.teaching-chess #board{
  width:100%;
  max-width:100%;
  border-radius:0;
  overflow:hidden;
  position:relative;

  /* no page scroll / zoom while dragging */
  touch-action:none;
  -ms-touch-action:none;
  overscroll-behavior:contain;
  -webkit-user-select:none;
  user-select:none;
}

.teaching-chess #board *{
  touch-action:none;
  -webkit-user-select:none;
  user-select:none;
}

/* Board colors (override chessboard-js) */
.teaching-chess #board .white-1e1d7{background-color:var(--sqLight)!important}
.teaching-chess #board .black-3c85d{background-color:var(--sqDark)!important}

/* ===== AI Arrow ===== */
.teaching-chess .ai-arrow{
  position:absolute;
  inset:0;
  pointer-events:none;
  z-index:5;
  filter:drop-shadow(0 6px 10px rgba(0,0,0,.25));
}
.teaching-chess .ai-arrow .shaft,
.teaching-chess .ai-arrow .head,
.teaching-chess .ai-arrow .tailCap{
  fill:var(--arrow);
}

/* ===== Checkmated king highlight ===== */
.teaching-chess .cm-king{position:relative}
.teaching-chess .cm-king::after{
  content:"";
  position:absolute;
  inset:0;
  background:radial-gradient(circle at 50% 50%,
    rgba(255,60,60,.55) 0%,
    rgba(255,60,60,.30) 45%,
    rgba(255,60,60,0) 75%);
  filter:blur(6px);
  transform:scale(0.92);
  pointer-events:none;
}

/* ===== Promotion Overlay (CRITICAL) ===== */
.teaching-chess #promoOverlay{
  position:fixed;
  inset:0;
  display:none;                /* must be hidden by default */
  place-items:center;
  background:rgba(0,0,0,.35);
  backdrop-filter:blur(6px);
  z-index:999999;              /* always above board */
}

.teaching-chess .promoCard{
  width:min(92vw,420px);
  background:#fff;
  border:1px solid rgba(0,0,0,0.14);
  border-radius:16px;
  padding:14px;
  box-shadow:0 20px 70px rgba(0,0,0,.25);
}

.teaching-chess .promoTitle{
  font-weight:800;
  margin:0 0 10px;
  font-size:13px;
  color:rgba(0,0,0,.65);
  user-select:none;
}

.teaching-chess .promoBtns{
  display:grid;
  grid-template-columns:repeat(4,1fr);
  gap:10px;
}

.teaching-chess .promoBtn{
  border:1px solid rgba(0,0,0,0.18);
  background:rgba(0,0,0,0.04);
  border-radius:14px;
  padding:12px 10px;
  cursor:pointer;
  font-weight:900;
  display:flex;
  align-items:center;
  justify-content:center;
  user-select:none;
}

.teaching-chess .promoBtn:hover{filter:brightness(1.06)}