/* style.css — Checkers */
:root{
  --bg:#13161d;
  --bg2:#1a1e27;
  --panel:#20242f;
  --panel2:#272c39;
  --border:#323a4d;
  --text:#e8ebf2;
  --muted:#8a92a6;
  --accent:#e0a458;
  --accent2:#f0b86c;
  --red:#e04848;
  --red-hi:#ff7a7a;
  --red-lo:#8a2222;
  --blk:#23262e;
  --blk-hi:#5b6273;
  --blk-lo:#0c0d11;
  --board-dark:#6b4226;
  --board-light:#e8c89a;
  --board-edge:#3a2415;
  --shadow:0 10px 30px rgba(0,0,0,.45);
  color-scheme:dark;
}
@media (prefers-color-scheme: light){
  :root{
    --bg:#f3efe6;
    --bg2:#ece6d8;
    --panel:#ffffff;
    --panel2:#f6f1e7;
    --border:#dcd3c0;
    --text:#2c2a24;
    --muted:#7a7565;
    --accent:#b87333;
    --accent2:#d4894a;
    --red:#cf3a3a;
    --red-hi:#e85d5d;
    --red-lo:#7e1e1e;
    --blk:#2a2a2e;
    --blk-hi:#5a5a64;
    --blk-lo:#111114;
    --board-dark:#9b6b3d;
    --board-light:#f1dcb4;
    --board-edge:#6e4a28;
    --shadow:0 8px 24px rgba(80,60,30,.18);
    color-scheme:light;
  }
}
html[data-theme="dark"]{
  --bg:#13161d;--bg2:#1a1e27;--panel:#20242f;--panel2:#272c39;--border:#323a4d;
  --text:#e8ebf2;--muted:#8a92a6;--accent:#e0a458;--accent2:#f0b86c;
  --red:#e04848;--red-hi:#ff7a7a;--red-lo:#8a2222;--blk:#23262e;--blk-hi:#5b6273;--blk-lo:#0c0d11;
  --board-dark:#6b4226;--board-light:#e8c89a;--board-edge:#3a2415;
  --shadow:0 10px 30px rgba(0,0,0,.45);color-scheme:dark;
}
html[data-theme="light"]{
  --bg:#f3efe6;--bg2:#ece6d8;--panel:#ffffff;--panel2:#f6f1e7;--border:#dcd3c0;
  --text:#2c2a24;--muted:#7a7565;--accent:#b87333;--accent2:#d4894a;
  --red:#cf3a3a;--red-hi:#e85d5d;--red-lo:#7e1e1e;--blk:#2a2a2e;--blk-hi:#5a5a64;--blk-lo:#111114;
  --board-dark:#9b6b3d;--board-light:#f1dcb4;--board-edge:#6e4a28;
  --shadow:0 8px 24px rgba(80,60,30,.18);color-scheme:light;
}

*{box-sizing:border-box}
html,body{margin:0;padding:0;height:100%}
body{
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  background:linear-gradient(180deg,var(--bg) 0%,var(--bg2) 100%);
  color:var(--text);
  overflow:hidden;
  touch-action:manipulation;
  -webkit-font-smoothing:antialiased;
}

.app{display:flex;flex-direction:column;height:100%;max-width:980px;margin:0 auto;padding:14px 14px 18px}

/* topbar */
.topbar{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-bottom:12px;flex-shrink:0}
.brand{display:flex;align-items:center;gap:10px}
.logo{font-size:22px;color:var(--accent);line-height:1}
.topbar h1{font-size:20px;font-weight:800;letter-spacing:.5px;margin:0}
.top-actions{display:flex;gap:8px}
.btn{font:inherit;font-weight:600;border-radius:10px;padding:9px 16px;cursor:pointer;border:1px solid var(--border);background:var(--panel2);color:var(--text);transition:transform .12s,background .15s,border-color .15s,box-shadow .15s}
.btn:hover{transform:translateY(-1px)}
.btn:active{transform:translateY(0)}
.btn.solid{background:linear-gradient(180deg,var(--accent2),var(--accent));color:#2a1a05;border-color:var(--accent);box-shadow:0 4px 14px rgba(224,164,88,.25)}
.btn.ghost{background:transparent}
.btn.ghost:hover{background:var(--panel2)}
.btn[disabled]{opacity:.4;cursor:not-allowed;transform:none}
.btn.lg{padding:12px 26px;font-size:15px}

/* layout */
.layout{flex:1;display:flex;gap:16px;min-height:0;align-items:stretch}
.board-area{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:center;min-width:0;gap:10px}
.panel{width:240px;flex-shrink:0;display:flex;flex-direction:column;gap:12px;overflow:auto}

/* turn bar */
.turn-bar{display:flex;align-items:center;gap:12px;background:var(--panel);border:1px solid var(--border);border-radius:14px;padding:10px 16px;width:min(100%, 560px);box-shadow:var(--shadow)}
.turn-piece{width:30px;height:30px;border-radius:50%;flex-shrink:0;box-shadow:inset 0 -3px 6px rgba(0,0,0,.4),0 2px 6px rgba(0,0,0,.4)}
.turn-piece.red{background:radial-gradient(circle at 35% 30%,var(--red-hi),var(--red) 60%,var(--red-lo))}
.turn-piece.blk{background:radial-gradient(circle at 35% 30%,var(--blk-hi),var(--blk) 60%,var(--blk-lo))}
.turn-text{line-height:1.25}
.turn-label{font-weight:800;font-size:16px}
.turn-sub{font-size:12.5px;color:var(--muted)}

/* board */
.board-wrap{position:relative;width:min(92vw, 70vh, 560px);padding:22px 22px 26px;background:linear-gradient(160deg,var(--board-edge),#2a1808);border-radius:16px;box-shadow:var(--shadow),inset 0 1px 0 rgba(255,255,255,.05)}
.coords{position:absolute;display:flex;color:rgba(232,200,154,.55);font-size:11px;font-weight:600;pointer-events:none;user-select:none}
.coords.rows{flex-direction:column;left:6px;top:22px;height:calc(100% - 48px);justify-content:space-around}
.coords.cols{flex-direction:row;left:22px;bottom:8px;width:calc(100% - 44px);justify-content:space-around}
.board{display:grid;grid-template-columns:repeat(8,1fr);grid-template-rows:repeat(8,1fr);aspect-ratio:1;width:100%;border-radius:6px;overflow:hidden;border:2px solid #1a0f06;position:relative}

.sq{position:relative;display:flex;align-items:center;justify-content:center}
.sq.light{background:var(--board-light)}
.sq.dark{background:var(--board-dark)}
.sq.from{box-shadow:inset 0 0 0 3px rgba(224,164,88,.5)}
.sq.to{box-shadow:inset 0 0 0 3px rgba(224,164,88,.85)}
.sq.selectable{cursor:pointer}
.sq.selectable::after{content:"";position:absolute;inset:4px;border-radius:6px;border:2px dashed rgba(255,255,255,.18);opacity:.7;pointer-events:none}
.sq.selected{box-shadow:inset 0 0 0 3px var(--accent)}
.sq.selected::after{display:none}

.dot{position:absolute;width:30%;height:30%;border-radius:50%;background:rgba(0,0,0,.32);box-shadow:0 0 0 2px rgba(255,255,255,.35);pointer-events:none;animation:pop .2s ease}
.dot.cap{background:rgba(224,72,72,.4);box-shadow:0 0 0 2px rgba(255,120,120,.6)}
@keyframes pop{from{transform:scale(.4);opacity:0}to{transform:scale(1);opacity:1}}

/* pieces */
.piece{
  position:absolute;width:78%;height:78%;border-radius:50%;
  display:flex;align-items:center;justify-content:center;
  transition:transform .15s;
  cursor:default;user-select:none;
  z-index:2;
}
.piece.red{
  background:radial-gradient(circle at 34% 28%,var(--red-hi) 0%,var(--red) 55%,var(--red-lo) 100%);
  box-shadow:0 3px 7px rgba(0,0,0,.45),inset 0 -4px 6px rgba(0,0,0,.35),inset 0 2px 3px rgba(255,255,255,.4);
}
.piece.blk{
  background:radial-gradient(circle at 34% 28%,var(--blk-hi) 0%,var(--blk) 55%,var(--blk-lo) 100%);
  box-shadow:0 3px 7px rgba(0,0,0,.5),inset 0 -4px 6px rgba(0,0,0,.55),inset 0 2px 3px rgba(255,255,255,.18);
}
.piece.king::before{
  content:"";position:absolute;inset:18%;border-radius:50%;
  border:2px solid rgba(255,255,255,.22);
  box-shadow:inset 0 0 0 2px rgba(0,0,0,.25);
}
.piece.red.king::before{border-color:rgba(255,220,180,.6)}
.piece.blk.king::before{border-color:rgba(255,235,200,.45)}
.crown{font-size:46%;line-height:1;color:var(--accent);text-shadow:0 1px 1px rgba(0,0,0,.5);z-index:1}
.sq.selectable .piece, .sq .piece{cursor:default}
.sq.selectable .piece{cursor:pointer}
.sq.selectable:hover .piece{transform:translateY(-2px) scale(1.03)}

/* capture flash */
.capture-flash{position:absolute;z-index:5;border-radius:50%;pointer-events:none;transform:translate(-50%,-50%);left:var(--lx);top:var(--ly)}
.capture-flash{animation:flash .5s ease-out forwards}
.capture-flash.red{background:radial-gradient(circle,rgba(255,120,120,.7),rgba(255,120,120,0) 70%)}
.capture-flash.blk{background:radial-gradient(circle,rgba(120,140,255,.6),rgba(120,140,255,0) 70%)}
@keyframes flash{0%{transform:scale(.3);opacity:.9}100%{transform:scale(1.4);opacity:0}}

/* panel cards */
.panel-card{background:var(--panel);border:1px solid var(--border);border-radius:14px;padding:14px;box-shadow:var(--shadow)}
.card-title{font-size:11px;font-weight:700;letter-spacing:.8px;text-transform:uppercase;color:var(--muted);margin:0 0 8px}
.card-title:not(:first-child){margin-top:14px}

.scores{display:grid;grid-template-columns:1fr auto 1fr;align-items:center;gap:6px}
.score{text-align:center}
.score-head{font-size:12px;color:var(--muted);display:flex;align-items:center;justify-content:center;gap:6px;margin-bottom:2px}
.dot{width:11px;height:11px;border-radius:50%;display:inline-block}
.dot.red{background:var(--red);box-shadow:0 0 0 2px rgba(224,72,72,.25)}
.dot.blk{background:var(--blk);box-shadow:0 0 0 2px rgba(120,130,150,.25);border:1px solid var(--border)}
.score-val{font-size:28px;font-weight:800}
.vs{color:var(--muted);font-size:11px;font-weight:700}
.captured{display:flex;flex-wrap:wrap;gap:3px;justify-content:center;margin-top:6px;min-height:14px}
.mini{width:9px;height:9px;border-radius:50%;display:inline-block}
.mini.red{background:var(--red)}
.mini.blk{background:var(--blk);border:1px solid var(--border)}

.seg{display:flex;gap:4px;background:var(--bg2);padding:4px;border-radius:10px;border:1px solid var(--border)}
.seg-btn{flex:1;font:inherit;font-size:12.5px;font-weight:600;border:0;background:transparent;color:var(--muted);padding:7px 6px;border-radius:7px;cursor:pointer;transition:background .15s,color .15s}
.seg-btn:hover{color:var(--text)}
.seg-btn.active{background:var(--panel2);color:var(--text);box-shadow:0 1px 3px rgba(0,0,0,.25)}

.history-card{flex:1;min-height:120px;display:flex;flex-direction:column}
.history{list-style:none;margin:0;padding:0;overflow:auto;flex:1;display:flex;flex-direction:column;gap:2px;max-height:240px}
.history li{display:grid;grid-template-columns:26px 1fr 1fr;gap:6px;font-size:13px;padding:3px 4px;border-radius:6px;align-items:center}
.history li:nth-child(odd){background:var(--bg2)}
.hnum{color:var(--muted);font-weight:700;font-size:11px}
.hmove{font-variant-numeric:tabular-nums;font-weight:600}
.hmove.red{color:var(--red-hi)}
.hmove.blk{color:var(--text)}

/* overlay */
.overlay{position:fixed;inset:0;background:rgba(8,10,14,.7);backdrop-filter:blur(6px);display:flex;align-items:center;justify-content:center;z-index:50;animation:fade .25s ease}
.overlay[hidden]{display:none}
@keyframes fade{from{opacity:0}to{opacity:1}}
.overlay-card{background:var(--panel);border:1px solid var(--border);border-radius:18px;padding:28px 34px;text-align:center;box-shadow:var(--shadow);max-width:320px;animation:rise .3s cubic-bezier(.2,.8,.2,1)}
@keyframes rise{from{transform:translateY(20px) scale(.96);opacity:0}to{transform:none;opacity:1}}
.overlay-piece{width:64px;height:64px;border-radius:50%;margin:0 auto 14px;box-shadow:0 6px 18px rgba(0,0,0,.5),inset 0 -5px 8px rgba(0,0,0,.4),inset 0 3px 4px rgba(255,255,255,.3)}
.overlay-piece.red{background:radial-gradient(circle at 34% 28%,var(--red-hi),var(--red) 55%,var(--red-lo))}
.overlay-piece.blk{background:radial-gradient(circle at 34% 28%,var(--blk-hi),var(--blk) 55%,var(--blk-lo))}
.overlay-piece.king::after{content:"♛";display:block;color:var(--accent);font-size:28px;line-height:64px}
.overlay-title{font-size:24px;font-weight:800;margin-bottom:4px}
.overlay-sub{font-size:13.5px;color:var(--muted);margin-bottom:18px}

/* responsive */
@media (max-width:760px){
  .layout{flex-direction:column;align-items:center;gap:10px}
  .panel{width:100%;max-width:560px;flex-direction:row;flex-wrap:wrap;overflow:visible}
  .panel-card{flex:1 1 240px}
  .history-card{flex:1 1 100%}
  .history{max-height:120px}
  .board-wrap{width:min(94vw, 60vh, 480px)}
}
@media (max-width:420px){
  .app{padding:8px 8px 12px}
  .topbar h1{font-size:17px}
  .panel{flex-direction:column}
  .board-wrap{padding:16px 16px 22px}
}
@media (max-height:560px) and (orientation:landscape){
  .board-wrap{width:min(78vw, 56vh, 420px)}
}