:root {
  --sq: min(11vmin, 76px);
  --light: #f0d9b5;
  --dark: #b58863;
  --sel: rgba(20, 85, 30, .5);
  --last: rgba(155, 199, 0, .41);
  --check: rgba(220, 40, 40, .55);
  --bg: #262421;
  --panel: #302e2c;
  --text: #e8e6e3;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 15px/1.45 -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  min-height: 100vh;
  display: grid;
  place-items: center;
}

main { display: flex; gap: 28px; padding: 24px; flex-wrap: wrap; justify-content: center; }

#play { display: flex; gap: 10px; align-items: flex-start; }
#boardwrap { position: relative; }

#evalbar {
  width: 16px; height: calc(var(--sq) * 8);
  background: #3a3735; border-radius: 3px; overflow: hidden;
  position: relative; box-shadow: inset 0 0 0 1px rgba(0,0,0,.3);
}
#evalbar-fill {
  position: absolute; left: 0; right: 0; bottom: 0;
  height: 50%; background: #f4f4f2;
  transition: height .35s ease;
}
#evalbar.flipped #evalbar-fill { bottom: auto; top: 0; }

#board {
  display: grid;
  grid-template-columns: repeat(8, var(--sq));
  grid-template-rows: repeat(8, var(--sq));
  border-radius: 4px;
  overflow: hidden;
  box-shadow: 0 8px 30px rgba(0,0,0,.5);
  user-select: none;
}

.sq {
  width: var(--sq); height: var(--sq);
  display: grid; place-items: center;
  font-size: calc(var(--sq) * .74);
  cursor: pointer;
  position: relative;
  line-height: 1;
}
.sq.light { background: var(--light); }
.sq.dark  { background: var(--dark); }
.sq.last::before, .sq.sel::before, .sq.check::before {
  content: ""; position: absolute; inset: 0;
}
.sq.last::before  { background: var(--last); }
.sq.sel::before   { background: var(--sel); }
.sq.check::before { background: radial-gradient(circle, var(--check) 0%, transparent 70%); }
.sq .glyph { position: relative; z-index: 1; }
.sq .glyph.white { color: #fff; text-shadow: 0 1px 2px rgba(0,0,0,.75); }
.sq .glyph.black { color: #111; text-shadow: 0 1px 2px rgba(255,255,255,.25); }

.sq.target::after {
  content: ""; position: absolute; z-index: 2;
  width: 30%; height: 30%; border-radius: 50%;
  background: rgba(20, 85, 30, .35);
}
.sq.target.capture::after {
  width: 92%; height: 92%; background: none;
  border: calc(var(--sq) * .07) solid rgba(20, 85, 30, .35);
}

.coord {
  position: absolute; z-index: 1; font-size: calc(var(--sq) * .16);
  font-weight: 600; opacity: .8; pointer-events: none;
}
.coord.file { right: 4px; bottom: 2px; }
.coord.rank { left: 4px; top: 2px; }

#promo {
  position: absolute; inset: 0; z-index: 10;
  background: rgba(0,0,0,.55);
  display: grid; place-items: center;
}
#promo.hidden { display: none; }
#promo-choices {
  display: flex; gap: 10px; background: var(--panel);
  padding: 16px; border-radius: 10px;
}
#promo-choices button {
  font-size: calc(var(--sq) * .8);
  width: var(--sq); height: var(--sq);
  border: 0; border-radius: 8px; cursor: pointer;
  background: var(--light);
}
#promo-choices button:hover { background: #fff; }

#panel {
  width: 300px; background: var(--panel);
  border-radius: 10px; padding: 18px 20px;
  display: flex; flex-direction: column; gap: 12px;
  align-self: stretch;
}
#panel h1 { margin: 0; font-size: 26px; }
.sub { margin: 0; opacity: .75; font-size: 13px; }
.sub b { color: #ffd479; }

#status { font-size: 17px; font-weight: 600; min-height: 24px; }

.row { display: flex; gap: 8px; align-items: center; }
button, select {
  font: inherit; padding: 7px 12px; border-radius: 7px; border: 0;
  background: #4a4744; color: var(--text); cursor: pointer;
}
button:hover { background: #5a5754; }
select { flex: 1; }

#pad-wrap { display: flex; flex-direction: column; gap: 6px; }
#pad {
  position: relative; width: 100%; height: 120px;
  border-radius: 8px; cursor: crosshair; touch-action: none;
  background:
    linear-gradient(to top, rgba(90,150,90,.10), rgba(200,80,80,.22)),
    #201f1d;
  box-shadow: inset 0 0 0 1px rgba(255,255,255,.08);
  outline: none;
}
#pad:focus { box-shadow: inset 0 0 0 2px #ffd479; }
.pad-axis {
  position: absolute; font-size: 10px; opacity: .5; pointer-events: none;
  user-select: none;
}
.pad-x { left: 6px; bottom: 4px; }
.pad-y { left: 6px; top: 4px; }
#pad-dot {
  position: absolute; width: 16px; height: 16px; border-radius: 50%;
  background: #ffd479; border: 2px solid #201f1d;
  transform: translate(-50%, -50%); pointer-events: none;
  box-shadow: 0 1px 4px rgba(0,0,0,.5);
}
#pad-label {
  font-family: ui-monospace, Menlo, monospace; font-size: 12.5px;
  opacity: .85; text-align: center;
}

#readout { font-family: ui-monospace, Menlo, monospace; font-size: 13px; }
#evaltext { font-size: 16px; font-weight: 700; }
#pv { opacity: .7; word-wrap: break-word; min-height: 34px; }

#moves {
  font-family: ui-monospace, Menlo, monospace; font-size: 12.5px;
  opacity: .8; overflow-y: auto; max-height: 180px; word-wrap: break-word;
}