:root{
  color-scheme: dark;
  --bg: #0e1116;
  --bg-2: #161b22;
  --panel: #1b2129;
  --panel-2: #20272f;
  --border: #2c343f;
  --border-strong: #3a4452;
  --text: #e6edf3;
  --muted: #8b97a6;
  --accent: #4ea1ff;
  --accent-2: #6cb6ff;
  --red: #e04848;
  --red-2: #ff6b6b;
  --red-dark: #8a2424;
  --black-piece: #2a2f3a;
  --black-piece-2: #3a4150;
  --square-light: #c8cdd4;
  --square-dark: #4a5260;
  --good: #3fb950;
  --bad: #f85149;
  --shadow: 0 10px 30px rgba(0,0,0,.5);
  --radius: 14px;
}

@media (prefers-color-scheme: light){
  :root{
    color-scheme: light;
    --bg: #eef1f5;
    --bg-2: #e3e8ef;
    --panel: #ffffff;
    --panel-2: #f4f6f9;
    --border: #d8dee7;
    --border-strong: #c0c8d2;
    --text: #1c2530;
    --muted: #5b6878;
    --accent: #2c7fd6;
    --accent-2: #1f6fc4;
    --red: #d63838;
    --red-2: #e85050;
    --red-dark: #6e1c1c;
    --black-piece: #2a2f3a;
    --black-piece-2: #4a5260;
    --square-light: #e8ecf1;
    --square-dark: #8a93a3;
    --shadow: 0 8px 24px rgba(20,30,50,.18);
  }
}

html[data-theme="dark"]{
  color-scheme: dark;
  --bg: #0e1116; --bg-2: #161b22; --panel: #1b2129; --panel-2: #20272f;
  --border: #2c343f; --border-strong: #3a4452; --text: #e6edf3; --muted: #8b97a6;
  --accent: #4ea1ff; --accent-2: #6cb6ff; --red: #e04848; --red-2: #ff6b6b;
  --red-dark: #8a2424; --black-piece: #2a2f3a; --black-piece-2: #3a4150;
  --square-light: #c8cdd4; --square-dark: #4a5260; --good: #3fb950; --bad: #f85149;
  --shadow: 0 10px 30px rgba(0,0,0,.5);
}
html[data-theme="light"]{
  color-scheme: light;
  --bg: #eef1f5; --bg-2: #e3e8ef; --panel: #ffffff; --panel-2: #f4f6f9;
  --border: #d8dee7; --border-strong: #c0c8d2; --text: #1c2530; --muted: #5b6878;
  --accent: #2c7fd6; --accent-2: #1f6fc4; --red: #d63838; --red-2: #e85050;
  --red-dark: #6e1c1c; --black-piece: #2a2f3a; --black-piece-2: #4a5260;
  --square-light: #e8ecf1; --square-dark: #8a93a3; --good: #2ea043; --bad: #d4423b;
  --shadow: 0 8px 24px rgba(20,30,50,.18);
}

*{ box-sizing: border-box; }
html, body{
  margin:0; padding:0; height:100%;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
  touch-action: manipulation;
}
body{ overflow: hidden; }

#app{
  height:100%;
  display:flex;
  flex-direction:column;
  background:
    radial-gradient(1200px 600px at 80% -10%, rgba(78,161,255,.08), transparent 60%),
    radial-gradient(900px 500px at -10% 110%, rgba(224,72,72,.06), transparent 60%),
    var(--bg);
}

#header{
  flex: 0 0 auto;
  padding: 14px 20px;
  display:flex; align-items:center; justify-content:space-between;
  gap: 12px;
  border-bottom: 1px solid var(--border);
  background: linear-gradient(180deg, var(--bg-2), var(--bg));
}
#header h1{
  margin:0; font-size: 20px; font-weight: 700; letter-spacing:.3px;
  display:flex; align-items:center; gap:10px;
}
#header h1::before{
  content:""; width:14px; height:14px; border-radius:50%;
  background: radial-gradient(circle at 35% 30%, var(--red-2), var(--red) 60%, var(--red-dark));
  box-shadow: 0 0 0 3px rgba(224,72,72,.15);
}
#status{
  font-size: 13px; font-weight: 600;
  padding: 6px 12px; border-radius: 999px;
  background: var(--panel); border: 1px solid var(--border);
  color: var(--muted);
}
#status.thinking{ color: var(--accent-2); border-color: rgba(78,161,255,.35); }
#status.win{ color: var(--good); border-color: rgba(63,185,80,.4); }
#status.lose{ color: var(--bad); border-color: rgba(248,81,73,.4); }

#main{
  flex: 1 1 auto;
  display:grid;
  grid-template-columns: 280px 1fr;
  gap: 16px;
  padding: 16px;
  min-height: 0;
}

#left-panel{
  display:flex; flex-direction:column; gap:14px;
  min-height: 0;
}

#score-card, #controls, #history-panel{
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px;
}
#score-card{ box-shadow: var(--shadow); }
.score-row{
  display:flex; align-items:center; gap:10px;
  padding: 6px 2px;
  font-size: 14px;
}
.score-row + .score-row{ border-top: 1px dashed var(--border); }
.score-row .name{ flex:1; font-weight:600; }
.score-row .captured{
  font-variant-numeric: tabular-nums;
  font-weight: 700; color: var(--muted);
  background: var(--panel-2); border:1px solid var(--border);
  min-width: 28px; text-align:center; padding: 2px 8px; border-radius: 8px;
}
.player-dot{
  width: 16px; height:16px; border-radius:50%;
  border: 1px solid rgba(0,0,0,.3);
  flex: 0 0 auto;
}
.player-dot.red{
  background: radial-gradient(circle at 35% 30%, var(--red-2), var(--red) 60%, var(--red-dark));
}
.player-dot.black{
  background: radial-gradient(circle at 35% 30%, var(--black-piece-2), var(--black-piece) 70%);
}

.ctrl-label{
  display:block;
  font-size: 11px; font-weight: 700; letter-spacing: .08em;
  text-transform: uppercase; color: var(--muted);
  margin-bottom: 8px;
}

#diff-btns{
  display:grid; grid-template-columns: repeat(4, 1fr); gap:6px;
  margin-bottom: 12px;
}
#diff-btns button{
  font-size: 11px; font-weight: 600;
  padding: 7px 4px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--panel-2);
  color: var(--muted);
  cursor: pointer;
  transition: all .15s ease;
}
#diff-btns button:hover{ color: var(--text); border-color: var(--border-strong); }
#diff-btns button.active{
  background: var(--accent); color: #fff;
  border-color: var(--accent);
  box-shadow: 0 4px 12px rgba(78,161,255,.3);
}

.btn-row{ display:flex; gap:8px; }
.btn-row button{
  flex:1;
  font-size: 13px; font-weight: 600;
  padding: 9px 8px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--panel-2);
  color: var(--text);
  cursor: pointer;
  transition: all .15s ease;
}
.btn-row button:hover{ border-color: var(--accent); color: var(--accent-2); transform: translateY(-1px); }
.btn-row button:active{ transform: translateY(0); }
.btn-row button:disabled{ opacity:.4; cursor:not-allowed; transform:none; }
#new-btn{ background: var(--accent); color:#fff; border-color: var(--accent); }
#new-btn:hover{ filter: brightness(1.08); color:#fff; }

#history-panel{ flex:1 1 auto; display:flex; flex-direction:column; min-height:0; }
#move-list{
  flex:1 1 auto;
  overflow:auto;
  margin-top: 6px;
  font-size: 13px;
  font-family: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
}
#move-list::-webkit-scrollbar{ width:8px; }
#move-list::-webkit-scrollbar-thumb{ background: var(--border-strong); border-radius:4px; }
#move-list::-webkit-scrollbar-track{ background: transparent; }

.move-pair{
  display:flex; align-items:center; gap:8px;
  padding: 4px 4px;
  border-bottom: 1px solid transparent;
}
.move-pair:nth-child(odd){ background: rgba(255,255,255,.02); }
html[data-theme="light"] .move-pair:nth-child(odd){ background: rgba(0,0,0,.025); }
.mv-num{ color: var(--muted); width: 26px; flex:0 0 auto; }
.mv{ flex:1 1 0; }
.mv.red{ color: var(--red-2); }
.mv.black{ color: var(--muted); }

#board-wrap{
  display:flex; align-items:center; justify-content:center;
  min-height: 0; min-width: 0;
  padding: 4px;
}
#board{
  position: relative;
  width: min(100%, calc(100vh - 140px));
  aspect-ratio: 1 / 1;
  max-width: 640px;
  border-radius: 16px;
  overflow: hidden;
  box-shadow: var(--shadow), 0 0 0 1px var(--border-strong);
  background: var(--square-dark);
}
#squares-layer, #pieces-layer, #highlights-layer{
  position:absolute; inset:0;
  display:grid;
  grid-template-columns: repeat(8, 1fr);
  grid-template-rows: repeat(8, 1fr);
}
#pieces-layer, #highlights-layer{ pointer-events: none; }

.square{
  position: relative;
}
.square.light{ background: var(--square-light); }
.square.dark{
  background: var(--square-dark);
  background-image: linear-gradient(135deg, rgba(255,255,255,.04), rgba(0,0,0,.08));
}
.square.dark::after{
  content:""; position:absolute; inset:0;
  box-shadow: inset 0 0 0 1px rgba(0,0,0,.12);
  pointer-events:none;
}

.piece{
  position:absolute;
  top:0; left:0;
  width: 12.5%; height: 12.5%;
  display:flex; align-items:center; justify-content:center;
  transition: transform .28s cubic-bezier(.4,.0,.2,1), opacity .26s ease;
  pointer-events: none;
  z-index: 2;
}
.piece-face{
  width: 74%; height: 74%;
  border-radius: 50%;
  display:flex; align-items:center; justify-content:center;
  box-shadow:
    inset 0 -3px 6px rgba(0,0,0,.35),
    inset 0 3px 5px rgba(255,255,255,.18),
    0 4px 8px rgba(0,0,0,.45);
  transition: transform .15s ease;
}
.piece.red .piece-face{
  background: radial-gradient(circle at 35% 30%, var(--red-2), var(--red) 55%, var(--red-dark) 100%);
  border: 2px solid rgba(0,0,0,.25);
}
.piece.black .piece-face{
  background: radial-gradient(circle at 35% 30%, var(--black-piece-2), var(--black-piece) 70%);
  border: 2px solid rgba(0,0,0,.4);
}
.piece.selected .piece-face{
  transform: scale(1.08);
  box-shadow:
    inset 0 -3px 6px rgba(0,0,0,.35),
    inset 0 3px 5px rgba(255,255,255,.25),
    0 0 0 3px var(--accent),
    0 0 18px rgba(78,161,255,.6);
}
.piece .crown{
  position:absolute;
  font-size: 0;
  opacity: 0;
  color: #ffd76b;
  text-shadow: 0 1px 2px rgba(0,0,0,.6);
  transition: opacity .2s ease, font-size .2s ease;
  pointer-events:none;
}
.piece.king .crown{
  opacity: 1;
  font-size: calc(min(100vw, 100vh) * 0.03);
  line-height: 1;
}
.piece.captured{
  opacity: 0;
  transform: scale(.4);
  z-index: 1;
}

.move-dot{
  position:absolute;
  top:0; left:0;
  width: 12.5%; height: 12.5%;
  display:flex; align-items:center; justify-content:center;
  pointer-events: auto;
  cursor: pointer;
  z-index: 3;
}
.move-dot::after{
  content:"";
  width: 28%; height: 28%;
  border-radius: 50%;
  background: var(--accent);
  opacity: .55;
  box-shadow: 0 0 10px rgba(78,161,255,.5);
  transition: transform .15s ease, opacity .15s ease;
}
.move-dot.capture::after{
  width: 70%; height: 70%;
  background: transparent;
  border: 3px solid var(--accent-2);
  opacity: .8;
  box-shadow: 0 0 14px rgba(108,182,255,.55);
}
.move-dot:hover::after{
  transform: scale(1.15);
  opacity: .9;
}

#overlay{
  position: fixed; inset:0;
  display:flex; align-items:center; justify-content:center;
  background: rgba(0,0,0,.55);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  z-index: 50;
  transition: opacity .25s ease;
}
#overlay.hidden{
  opacity:0; pointer-events:none;
}
#overlay-box{
  background: var(--panel);
  border: 1px solid var(--border-strong);
  border-radius: 18px;
  padding: 28px 32px;
  text-align:center;
  box-shadow: var(--shadow);
  max-width: 340px;
  animation: pop .3s cubic-bezier(.2,.9,.3,1.2);
}
@keyframes pop{
  from{ transform: scale(.85); opacity:0; }
  to{ transform: scale(1); opacity:1; }
}
#overlay-box h2{
  margin:0 0 8px; font-size: 26px; font-weight: 800;
}
#overlay-box p{
  margin: 0 0 18px; color: var(--muted); font-size: 14px;
}
#overlay-btn{
  font-size: 15px; font-weight: 700;
  padding: 11px 22px;
  border-radius: 12px;
  border: none;
  background: var(--accent);
  color: #fff;
  cursor: pointer;
  transition: transform .12s ease, filter .15s ease;
}
#overlay-btn:hover{ filter: brightness(1.1); transform: translateY(-1px); }
#overlay-btn:active{ transform: translateY(0); }

@media (max-width: 760px){
  #main{
    grid-template-columns: 1fr;
    grid-template-rows: auto 1fr;
    gap: 12px;
    padding: 12px;
  }
  #left-panel{
    flex-direction: row;
    gap: 10px;
    overflow-x: auto;
  }
  #score-card, #controls{ flex: 0 0 auto; }
  #history-panel{ flex: 1 1 0; min-width: 180px; }
  #header{ padding: 10px 14px; }
  #header h1{ font-size: 17px; }
  #board{
    width: min(100%, calc(100vh - 220px));
    max-width: 100%;
  }
}

@media (max-width: 480px){
  #left-panel{ flex-direction: column; overflow: visible; }
  #history-panel{ min-width: 0; max-height: 120px; }
  #diff-btns button{ font-size: 10px; padding: 6px 2px; }
}