:root{--bg:#f5f3ed;--ink:#352d23;--muted:#908a83;--accent:#5c4831;--line:#dfdad5;--accent-soft:#e6cbac}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);font-family:'Noto Sans SC',system-ui,sans-serif}button,select{font:inherit;color:inherit}button{cursor:pointer;transition:background .18s,transform .18s}button:hover{filter:brightness(.96)}button:focus-visible,select:focus-visible,summary:focus-visible{outline:3px solid #b39855;outline-offset:3px}button:disabled{opacity:.45;cursor:default}header{height:92px;border-bottom:1px solid #e2ddd8;display:flex;align-items:center;justify-content:space-between;padding:0 6%}.brand{display:flex;align-items:center;gap:12px;text-decoration:none;color:var(--ink);font-size:22px;font-weight:700}.brand small{font-size:9px;letter-spacing:2px;font-weight:500;margin-left:13px}.logo{font-family:serif;font-size:35px}.local{font-size:11px;color:#7a736c;display:flex;align-items:center;gap:7px}.local i{width:6px;height:6px;border-radius:50%;background:#977b5a}main{max-width:1190px;margin:auto;padding:46px 38px 0}.intro{display:flex;align-items:end;justify-content:space-between;margin-bottom:33px}.eyebrow{font-size:10px;letter-spacing:2.5px;color:#81786e}h1{font-size:38px;letter-spacing:-1.2px;font-weight:500;margin:12px 0}h1 span{color:#a99175}.intro p{font-size:12px;color:#85807b;margin:0}.quiet{background:none;border:1px solid #dbd6d1;padding:10px 15px;border-radius:5px;font-size:12px}.layout{display:grid;grid-template-columns:minmax(0,630px) minmax(280px,340px);gap:38px;justify-content:space-between}.play{min-width:0}.player{display:flex;align-items:center;gap:12px;padding:0 0 17px}.player b{display:block;font-size:13px;font-weight:500}.player small{font-size:8px;letter-spacing:1.3px;color:#908a84;display:block;margin-top:4px}.avatar{width:38px;height:38px;border-radius:50%;display:grid;place-items:center;font-family:serif;font-size:28px}.dark{background:#4e4234;color:#f4f1e6}.light{background:#e9e3dc;color:#4e4234}.badge,#status{margin-left:auto;font-size:11px}.badge{padding:6px 10px;background:#eae3dc;border-radius:20px;color:#75614a}.board-shell{background:#4d4134;padding:13px;border-radius:6px;box-shadow:0 12px 25px #3b2e2014;margin-bottom:20px}#board{display:grid;grid-template-columns:repeat(8,1fr);aspect-ratio:1}.square{position:relative;aspect-ratio:1;border:0;padding:0;background:#e9ead7;display:flex;align-items:center;justify-content:center;touch-action:manipulation}.square.dark-square{background:#918679}.square.last{background:#d2b28d}.square.dark-square.last{background:#bc966b}.square.selected{background:#e5c86b}.piece{font-family:'DejaVu Sans','Segoe UI Symbol','Noto Sans Symbols 2',serif;font-size:clamp(25px,4.5vw,57px);line-height:1;z-index:1;pointer-events:none}.piece.white{color:#fffdf0;text-shadow:0 2px 0 #574f46,-1px 0 #574f46,1px 0 #574f46,0 -1px #574f46}.piece.black{color:#3c3023;text-shadow:0 1px 0 #f1f0d870}.coord{position:absolute;font-size:9px;font-weight:600;color:#5f5140;left:4px;top:2px}.file{left:auto;top:auto;right:4px;bottom:2px}.dark-square .coord{color:#f0f1db}.dot{position:absolute;width:24%;height:24%;background:#4c3b2840;border-radius:50%}.capture{position:absolute;inset:3%;border:5px solid #4a3b2960;border-radius:50%}.check{box-shadow:inset 0 0 0 4px #b95e4e}.hint{box-shadow:inset 0 0 0 4px #f4d866}.actions{display:flex;gap:10px;margin-top:5px}.actions button,dialog button{border:1px solid #d9d3cd;background:transparent;padding:12px 18px;border-radius:5px;font-size:12px}.actions .primary{margin-left:auto}.primary{background:var(--accent)!important;color:white;border-color:var(--accent)!important}aside{display:flex;flex-direction:column;gap:16px}.panel{background:#fbfaf6;border:1px solid #e4e0db;border-radius:7px;padding:22px}.panel-title{display:flex;justify-content:space-between;align-items:center;margin-bottom:18px}.panel h2{font-size:13px;font-weight:600;margin:0}.panel-title>span{font-size:8px;color:#a0988f;letter-spacing:1px}.modes{display:flex;flex-direction:column;gap:8px;margin-bottom:21px}.mode{display:flex;text-align:left;align-items:center;gap:12px;border:1px solid #e3ddd6;border-radius:5px;background:transparent;padding:13px}.mode>span{font-size:27px}.mode b{display:block;font-size:12px;font-weight:500}.mode small{font-size:9px;color:#938b81;display:block;margin-top:4px}.mode i{margin-left:auto;font-style:normal;color:#90806e}.mode.active{border-color:#887763;background:#f0e8df}.mode.active i{color:#5c4831}label{font-size:11px;display:flex;align-items:center;justify-content:space-between;margin:13px 0}select{background:#f4f4ee;border:1px solid #e3ddd6;padding:7px 10px;border-radius:4px;font-size:11px;width:165px}.muted{font-size:9px;color:#9e9790;margin:15px 0 0;line-height:1.7}.stats{display:flex;justify-content:space-between}.stats b{display:block;font-size:23px;font-weight:500;font-variant-numeric:tabular-nums}.stats small{font-size:9px;color:#968f86}.insight{font-size:11px;line-height:1.8;border-top:1px solid #e7e2dc;padding-top:15px;margin:17px 0 0;color:#81766a}.text-btn{font-size:10px;background:none;border:0;padding:0;color:#897966}.history-head,.history-row{display:grid;grid-template-columns:32px 1fr 1fr;font-size:12px;padding:7px 10px}.history-head{background:#f1ece7;color:#948b81;font-size:9px}.history-row:nth-child(even){background:#f4f1ed}.history-row span:first-child{color:#a2998f}#history{max-height:145px;overflow:auto;min-height:70px}.empty{font-size:11px;text-align:center;color:#a69d93;padding:16px 0}.about{margin-top:35px;border-top:1px solid #e0dad4;padding:22px 0;font-size:11px;color:#8b8278;line-height:1.9}.about summary{cursor:pointer;color:#6b5e50;list-style:none}.about summary span{float:right}.about a{color:#6e5e4b}footer{border-top:1px solid #e0dad4;display:flex;justify-content:space-between;padding:23px 0;font-size:8px;letter-spacing:1.5px;color:#958b80}footer span{letter-spacing:1px}dialog{border:1px solid #dbd4cc;border-radius:12px;background:#f9f8f1;color:var(--ink);padding:30px;max-width:90vw}dialog::backdrop{background:#2c211466;backdrop-filter:blur(3px)}dialog h2{font-size:20px}dialog p{font-size:12px;color:#91887e;margin-bottom:24px}#promotionOptions{display:flex;gap:10px}#promotionOptions button{font-size:36px;padding:8px 14px} @media(max-width:850px){header{height:72px;padding:0 22px}.brand{font-size:18px}.brand small{display:none}.local{font-size:9px}main{padding:30px 20px 0}.layout{gap:25px;grid-template-columns:minmax(0,1.2fr) minmax(250px,1fr)}h1{font-size:29px}.panel{padding:17px}.board-shell{padding:8px}.piece{font-size:5vw}.intro p{font-size:11px}}@media(max-width:650px){.layout{display:flex;flex-direction:column;gap:28px}.piece{font-size:10vw}.intro{gap:8px;margin-bottom:28px}.intro h1{font-size:27px}.intro .quiet{font-size:10px;padding:8px;white-space:nowrap}.eyebrow{font-size:8px;letter-spacing:1.6px}.intro p{font-size:10px}.actions button{padding:11px 15px}.panel{padding:20px}.history-panel{min-height:180px}.stats{justify-content:space-around}.stats div{text-align:center}footer{font-size:7px;letter-spacing:1px}.board-shell{padding:9px}.local{display:none}}

/* Motion language: continuous shapes, restrained emphasis, quiet resting states. */
:root{--spring:cubic-bezier(.22,1,.36,1);--glass:rgba(255,255,251,.64)}
body{background:radial-gradient(ellipse at 85% 15%,#e6ded544,transparent 45%),radial-gradient(ellipse at 5% 70%,#e9dfbe33,transparent 45%),var(--bg)}
.header-tools{display:flex;align-items:center;gap:20px}.motion-toggle{font-size:10px;padding:8px 12px;border-radius:20px;background:#ffffff66}
.panel{background:var(--glass);backdrop-filter:blur(16px);border-color:#ffffffbb;box-shadow:0 0 0 1px #4d41340b,0 8px 30px #4d413405;transition:box-shadow .3s,border-color .3s;border-radius:14px}
.panel:hover{border-color:#ccc4ba;box-shadow:0 0 0 1px #4d413408,0 10px 30px #4d413409}
.island-stage{height:96px;display:flex;align-items:flex-start;justify-content:center;position:relative;z-index:8;padding-top:3px}
.island{width:238px;max-width:100%;border-radius:34px;background:linear-gradient(150deg,#3e3326f5,#2a2218f5);color:#f5efe8;border:1px solid #ffffff30;box-shadow:0 7px 20px #3b2e201a,inset 0 1px #ffffff16;backdrop-filter:blur(20px);overflow:hidden;transition:width .55s var(--spring),border-radius .5s var(--spring),background .4s,box-shadow .4s}
.island[data-state=thinking]{width:294px}.island[data-state=check]{width:268px;background:linear-gradient(130deg,#624c32,#422e25);box-shadow:0 7px 25px #aa6c3220}.island[data-state=ended]{width:294px}.island[data-state=hint]{width:258px}.island[data-state=notice]{width:248px}
.island.expanded{width:350px;border-radius:25px;box-shadow:0 16px 35px #3b2e2030}
#islandToggle{width:100%;display:flex;align-items:center;gap:12px;background:none;border:0;color:inherit;padding:15px 19px;text-align:left;min-height:66px;filter:none}
.island-icon{width:24px;flex-shrink:0;font-size:24px;text-align:center;color:#e9cdac;transition:color .3s}.island-copy{display:flex;flex-direction:column;gap:5px;min-width:0;white-space:nowrap}.island-copy b{font-size:12px;font-weight:500;letter-spacing:.5px}.island-copy small{font-size:9px;color:#c5bbb0;letter-spacing:.2px}.island-chevron{font-size:15px;color:#c0af9b;margin-left:auto;transition:transform .4s var(--spring)}.expanded .island-chevron{transform:rotate(180deg)}
#islandDetail{padding:0 20px 15px}#islandDetail p{border-top:1px solid #ffffff20;padding-top:12px;margin:0;color:#d2c8bc;font-size:10px;line-height:1.9}
.thinking-bars{display:none;align-items:center;gap:3px;height:18px;margin-left:auto}.thinking-bars i{width:3px;height:12px;border-radius:3px;background:#e6c7a3;animation:think-wave 1.1s ease-in-out infinite}.thinking-bars i:nth-child(2){animation-delay:.15s}.thinking-bars i:nth-child(3){animation-delay:.3s}.island[data-state=thinking] .thinking-bars{display:flex}.island[data-state=thinking] .island-chevron{display:none}
@keyframes think-wave{0%,100%{transform:scaleY(.4);opacity:.5}50%{transform:scaleY(1);opacity:1}}
aside{padding-top:96px}.board-shell{border-radius:12px;background:linear-gradient(145deg,#594b3c,#453a2e);box-shadow:0 16px 35px #3b2e2015,inset 0 1px #ffffff30}
#board{display:flex;flex-direction:column;isolation:isolate}.board-row{display:grid;grid-template-columns:repeat(8,minmax(0,1fr));flex:1;min-height:0}.square{transition:background-color .23s,box-shadow .25s;overflow:visible}.square:hover{filter:none}.square:hover::after{content:'';position:absolute;inset:0;background:#ffffff13;pointer-events:none}.piece{display:block;position:relative;will-change:transform}.piece-ghost{position:fixed!important;z-index:30!important;pointer-events:none;display:flex;align-items:center;justify-content:center}.dot{animation:dot-in .22s var(--spring)}.capture{animation:dot-in .25s var(--spring)}@keyframes dot-in{from{opacity:0;transform:scale(.6)}to{opacity:1;transform:scale(1)}}
.actions button,.quiet,dialog button{transition:background .2s,box-shadow .2s,transform .2s}.actions button:hover:not(:disabled),.quiet:hover{transform:translateY(-2px);box-shadow:0 5px 12px #3b2e2010}.actions button:active:not(:disabled),.quiet:active,dialog button:active{transform:scale(.96)}
.modes{position:relative;isolation:isolate;gap:8px}.mode{position:relative;min-height:76px;z-index:1;background:transparent;border-radius:9px;border-color:#e3ddd680;transition:border-color .3s,color .3s}.mode.active{background:transparent;border-color:transparent}.mode:hover{filter:none;border-color:#b6aa9c}.mode-track{position:absolute;z-index:0;inset:0 0 auto;height:76px;border:1px solid #9d856a;border-radius:9px;background:linear-gradient(120deg,#f2e8dc,#ede2d666);box-shadow:inset 0 1px #ffffffaa,0 3px 8px #4d413406;transform:translateY(0);transition:transform .48s var(--spring)}.modes[data-selected=mcts] .mode-track{transform:translateY(84px)}
.stats b{display:inline-block;min-width:1em}.stats div{overflow:hidden}.insight{min-height:55px}.history-row{border-radius:4px}.history-row:last-child{color:#5c4831}.about summary span{transition:transform .3s}.about[open] summary span{transform:rotate(45deg)}dialog{border-color:#ffffffbb;background:#faf6f1ee;backdrop-filter:blur(20px);box-shadow:0 24px 80px #2e221540}
.reduce-motion *, .reduce-motion *::before,.reduce-motion *::after{animation:none!important;transition:none!important;scroll-behavior:auto!important}.reduce-motion .actions button:hover,.reduce-motion .quiet:hover{transform:none}
@media(max-width:850px){main{padding-top:30px}.layout{grid-template-columns:minmax(0,1fr) 270px;gap:24px}.mode{padding:10px}.panel{padding:18px}.piece{font-size:4.6vw}}
@media(max-width:760px){.layout{display:flex;flex-direction:column;gap:28px}.play{width:100%;max-width:620px;margin:0 auto}aside{padding-top:0;width:100%;max-width:620px;margin:0 auto}.piece{font-size:min(10vw,57px)}.island-stage{height:91px}.panel{padding:22px}.mode{padding:13px}.header-tools .local{display:none}.intro h1{font-size:27px}.intro p{font-size:10px}.intro .quiet{font-size:10px;padding:8px}.eyebrow{font-size:8px;letter-spacing:1.5px}.intro{gap:10px}.island.expanded{max-width:100%}}
@media(max-width:390px){main{padding:25px 14px 0}header{padding:0 16px}.brand{font-size:16px}.intro h1{font-size:24px}.intro .quiet{font-size:9px}.motion-toggle{font-size:9px;padding:7px 9px}}
.island-stage{transition:height .42s var(--spring)}.island-stage.open{height:165px}
/* Chess.com Neo pieces: local PNGs keep the same silhouette on all devices. */
#board .piece{width:92%;height:92%;display:flex;align-items:center;justify-content:center;font-size:inherit;text-shadow:none;flex-shrink:0}
.piece img{width:100%;height:100%;object-fit:contain;display:block;user-select:none;pointer-events:none}
.piece-ghost{text-shadow:none!important;object-fit:contain}
#board .piece.piece-fallback{font-size:clamp(26px,6vw,57px)}
#board .piece-fallback.white{color:#fffdf0;text-shadow:0 1px #574f46,0 -1px #574f46,1px 0 #574f46,-1px 0 #574f46}
#promotionOptions button{padding:5px;border-radius:9px}#promotionOptions .piece{width:56px;height:56px;display:block;text-shadow:none}
.sound-toggle{font-size:10px;padding:8px 12px;border-radius:20px;background:#ffffff66;white-space:nowrap}
.header-tools{gap:10px}.asset-credit{font-size:10px;color:#908579}
@media(max-width:600px){.header-tools{gap:6px}.sound-toggle,.motion-toggle{font-size:9px;padding:7px 8px}header{padding:0 15px}.brand{gap:7px;font-size:17px}.brand .logo{font-size:28px}}
@media(max-width:360px){.brand{font-size:15px}.sound-toggle,.motion-toggle{padding:6px}.header-tools{gap:4px}}
/* Liquid glass: translucent depth, curved edge light and moving reflections. */
body{background:radial-gradient(ellipse at 12% 20%,#dacec0aa,transparent 45%),radial-gradient(ellipse at 85% 38%,#dedac6b0,transparent 42%),radial-gradient(ellipse at 45% 85%,#dfd8d080,transparent 40%),#f3f0ec;background-attachment:fixed}
header{background:#ffffff26;backdrop-filter:blur(22px) saturate(1.6);-webkit-backdrop-filter:blur(22px) saturate(1.6);border-bottom:1px solid #ffffffb0}
.liquid-glass{--light-x:20%;--light-y:0%;position:relative;isolation:isolate}
.panel{background:linear-gradient(135deg,#ffffff78,#fffffd28 55%,#efe8df45);border:1px solid #ffffffbb;backdrop-filter:blur(24px) saturate(1.65);-webkit-backdrop-filter:blur(24px) saturate(1.65);border-radius:22px;box-shadow:inset 1px 1px 1px #ffffffee,inset -1px -1px 2px #8b796420,0 12px 30px #5145370b,0 2px 4px #ffffff55}
.liquid-glass::before{content:'';position:absolute;inset:0;z-index:-1;border-radius:inherit;background:radial-gradient(ellipse at var(--light-x) var(--light-y),#ffffff66,transparent 65%);pointer-events:none}
.panel::after,.island::after,.board-shell::after{content:'';position:absolute;inset:0;border-radius:inherit;pointer-events:none;border:1px solid transparent;background:linear-gradient(140deg,#ffffffcf,#ffffff15 35%,#70625122 60%,#ffffff77) border-box;mask:linear-gradient(#fff 0 0) padding-box,linear-gradient(#fff 0 0);mask-composite:exclude;-webkit-mask:linear-gradient(#fff 0 0) padding-box,linear-gradient(#fff 0 0);-webkit-mask-composite:xor}
.island{background:linear-gradient(135deg,#4b3924de,#2f2315c9 70%,#4b3a27e8);backdrop-filter:blur(28px) saturate(1.8);-webkit-backdrop-filter:blur(28px) saturate(1.8);box-shadow:inset 1px 1px #ffffff60,inset -1px -1px 2px #241a0f77,0 12px 30px #4b392426}
.island::before{background:radial-gradient(ellipse at var(--light-x) var(--light-y),#ffedd82e,transparent 65%)}
.island[data-state=check]{background:linear-gradient(135deg,#785836e0,#443124dc)}
.board-shell{padding:15px;background:linear-gradient(135deg,#66564499,#493824c4);backdrop-filter:blur(24px) saturate(1.5);-webkit-backdrop-filter:blur(24px) saturate(1.5);border:1px solid #ffffff9c;border-radius:20px;box-shadow:inset 1px 1px #ffffffa0,inset -1px -1px #3b2d1c66,0 20px 42px #4c3f3124}
#board{border-radius:6px;overflow:clip}.board-row{overflow:visible}.piece{will-change:auto}
.quiet,.actions button,select{background:linear-gradient(135deg,#ffffff80,#ffffff30);backdrop-filter:blur(14px);-webkit-backdrop-filter:blur(14px);border-color:#ffffffb0;box-shadow:inset 0 1px #ffffffdd,0 3px 10px #51453708;border-radius:12px}
.actions .primary{background:linear-gradient(135deg,#6d5942e8,#4c3a25dc)!important;box-shadow:inset 0 1px #ffffff50,0 5px 12px #5c483120}
.mode-track{background:linear-gradient(135deg,#fff1e2b0,#e4d2bd55);border-color:#9a836899;box-shadow:inset 1px 1px #ffffffe8,inset -1px -1px #785f4215,0 4px 10px #51453708}
.mode small{color:#726659}.panel-title>span{color:#817465}.muted{color:#7e7162}.insight{color:#6c5d4c}.history-head{background:#e9dfd455}.history-row:nth-child(even){background:#ffffff35}
.analysis-panel{margin-top:22px}.analysis-panel[hidden]{display:none}.analysis-status{font-size:11px;color:#6b5a47;line-height:1.8;margin:0 0 14px}.analysis-note{font-size:10px;line-height:1.8;color:#7b6d5e;margin:15px 0 0}.candidate{width:100%;display:flex;gap:12px;align-items:center;text-align:left;border:1px solid #ffffffb0;border-radius:13px;padding:14px 12px;background:#ffffff33;margin-top:9px;transition:background .2s,border-color .2s}.candidate[aria-pressed=true]{background:linear-gradient(120deg,#f8ead999,#ffffff55);border-color:#a88c6b}.candidate-rank{font-size:11px;color:#93806b;font-variant-numeric:tabular-nums;align-self:flex-start;margin-top:3px}.candidate-body{min-width:0;flex:1}.candidate-body b{font-size:13px;font-weight:500;display:block}.candidate-body small{font-size:10px;color:#76695b;display:block;margin-top:8px;line-height:1.8;overflow-wrap:anywhere}.candidate-score{font-size:18px;font-weight:600;font-variant-numeric:tabular-nums;white-space:nowrap;color:#5c4831}.analysis-panel[aria-busy=true] .analysis-status{opacity:.8}
@media(max-width:760px){.board-shell{padding:10px;border-radius:16px}.analysis-panel{padding:18px}.candidate{gap:9px}.candidate-score{font-size:16px}.candidate-body b{font-size:12px}}
@supports not (backdrop-filter:blur(1px)){.panel{background:#f7f3eef5}.island{background:#453625f5}}
/* Performance pass: avoid stacked backdrop layers over an opaque chessboard. */
body{background-attachment:scroll}
header,.board-shell,.quiet,.actions button,select{backdrop-filter:none;-webkit-backdrop-filter:none}
.panel{backdrop-filter:blur(12px) saturate(1.25);-webkit-backdrop-filter:blur(12px) saturate(1.25);transition:border-color .2s}
.island{backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);transition:width .35s var(--spring),border-radius .3s var(--spring)}
.panel::after,.island::after,.board-shell::after{background:none;mask:none;-webkit-mask:none;border:1px solid #ffffff77;box-shadow:inset 0 1px #ffffff88}
.panel:hover{box-shadow:inset 1px 1px 1px #ffffffdd,0 8px 22px #5145370b}
.move-marker[hidden],.coord[hidden]{display:none!important}
.thinking-bars{contain:layout paint}.stats{contain:layout}.stats b{filter:none!important}
.island-stage{transition:height .3s var(--spring)}
html[data-effects=light] .panel{backdrop-filter:none;-webkit-backdrop-filter:none;background:linear-gradient(135deg,#fffffff0,#f4efe9d9);box-shadow:inset 1px 1px #ffffffdd,0 5px 16px #5145370a}
html[data-effects=light] .island{backdrop-filter:none;-webkit-backdrop-filter:none;background:linear-gradient(135deg,#53412cf5,#35291bf5)}
html[data-effects=light] .liquid-glass::before{background:linear-gradient(135deg,#ffffff20,transparent 65%)}
html[data-effects=light] .board-shell{box-shadow:inset 1px 1px #ffffff80,0 9px 20px #4c3f311c}
html[data-effects=light] dialog{backdrop-filter:none;-webkit-backdrop-filter:none;background:#f8f4effa}
html[data-effects=light] dialog::backdrop{backdrop-filter:none}
.engine-busy .liquid-glass::before{background:linear-gradient(135deg,#ffffff22,transparent 70%)}
@media(hover:none){button:hover{filter:none}.actions button:hover:not(:disabled),.quiet:hover{transform:none}}
/* One coordinated island morph, floating over a stationary chessboard. */
.island-stage,.island-stage.open{height:92px;padding-top:3px;transition:none;contain:layout style}
.island,.island.expanded{box-sizing:border-box;position:absolute;top:3px;left:50%;transform:translateX(-50%);max-width:calc(100% - 8px);margin:0;height:66px;transition:none;border:1px solid #f4e5d34d;box-shadow:inset 0 1px #ffffff25,0 7px 20px #36281824;overflow:hidden;will-change:auto}
.island.expanded{box-shadow:inset 0 1px #ffffff2b,0 16px 32px #36281830}
#islandToggle{height:64px;min-height:64px;padding:0 17px;gap:11px;touch-action:manipulation;outline-offset:-4px}
#islandToggle,.island-detail-actions button{-webkit-tap-highlight-color:transparent;user-select:none;-webkit-user-select:none;filter:none!important}
#islandToggle:active,.island-detail-actions button:active{background:transparent}
.island-icon{width:27px;flex:0 0 27px;line-height:1;display:grid;place-items:center;font-size:23px}
.island-copy{flex:1;min-width:0;gap:5px}.island-copy b,.island-copy small{display:block;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;line-height:1.4}
.island-copy b{font-size:12px;font-weight:500}.island-copy small{font-size:9px;color:#d0c5b9}
.island-chevron{display:block!important;flex:0 0 10px;margin-left:0;transition:transform .24s ease;color:#d2c6b8}
.thinking-bars{flex:0 0 15px;margin-left:0;gap:2px}.thinking-bars i{width:3px}
#islandDetail{padding:0 18px 16px;box-sizing:border-box}#islandDetail[hidden]{display:none}
#islandDescription{line-height:1.9;font-size:11px!important;border-top:1px solid #fff1e022!important;padding-top:12px!important;color:#dfd6cb!important}
.island-detail-actions{display:flex;gap:8px;margin-top:13px;align-items:center}
.island-detail-actions button{font-size:10px;line-height:1.5;padding:8px 12px;border-radius:18px;border:1px solid #ffe9cf2e;color:#f7f0e9;background:#ffe9cf13;cursor:pointer;transition:background .15s;white-space:nowrap}
.island-detail-actions button:first-child{flex:1;background:#edd4b724;color:#f4e0c9}
.island-detail-actions button:hover:not(:disabled){background:#ffe9cf25}.island-detail-actions button:disabled{opacity:.45}
.island-dismiss{position:fixed;inset:0;z-index:7;width:100%;height:100%;border:0;background:#34291c0a;cursor:default;filter:none!important;-webkit-tap-highlight-color:transparent;animation:island-scrim .16s ease-out}
.island-dismiss[hidden]{display:none}
@keyframes island-scrim{from{opacity:0}to{opacity:1}}
.island::after{border-color:#fff3e51c;box-shadow:inset 0 1px #ffffff22}
@media(max-width:760px){.island-stage,.island-stage.open{height:88px}}
/* Compact controls expand inside a reserved area, clear of every board square. */
.island-stage,.island-stage.open{height:130px;min-height:130px}
#islandDetail{padding:0 16px 13px}
#islandDescription{display:none}
.island-detail-actions{margin-top:0;padding-top:3px}
.island-detail-actions button{padding:7px 12px}
.island-dismiss{display:none!important}
aside{padding-top:130px}
@media(max-width:760px){.island-stage,.island-stage.open{height:130px;min-height:130px}aside{padding-top:0}}
/* Brief, factual move reactions; no speech bubbles or idle movement. */
.coach-avatar{width:44px;height:44px;flex:0 0 44px;overflow:hidden;background:linear-gradient(135deg,#5c4a35,#433422);border:1px solid #ffffff70;box-shadow:inset 0 1px #ffffff30}
.coach-avatar[data-reaction=capture]{box-shadow:0 0 0 3px #c4a37d44,inset 0 1px #ffffff30}.coach-avatar[data-reaction=check],.coach-avatar[data-reaction=mate]{box-shadow:0 0 0 3px #c7a65355,inset 0 1px #ffffff30}
.coach-move{font-size:11px;font-variant-numeric:tabular-nums;color:#68533b;background:#ece0d34d;border:1px solid #ffffff99;padding:5px 9px;border-radius:15px;white-space:nowrap;margin-left:auto}.coach-move[hidden]{display:none}.coach-move:not([hidden])+.badge{margin-left:0}
.play-mode-label{margin:0 0 22px;padding-bottom:18px;border-bottom:1px solid #baab9930}.play-mode-label select{max-width:67%}#engineSettings[hidden],#sideSetting[hidden]{display:none!important}
/* Hints draw once and hold their final geometry; overlay never intercepts input. */
#board{position:relative}.hint-arrow-layer{position:absolute;inset:0;width:100%;height:100%;z-index:5;pointer-events:none;overflow:visible;opacity:.86}
.hint-arrow-line{stroke:#c69a31;stroke-width:12;stroke-linecap:round;fill:none;stroke-dasharray:1;stroke-dashoffset:0}.hint-arrow-head,.hint-arrow-tail{fill:#c69a31}.hint-arrow-tail{fill:#e3b94f}
.square.hint{box-shadow:none}.hint-halo{position:absolute;inset:3px;z-index:0;border:2px solid #eac259;background:#ead57a28;pointer-events:none;border-radius:5px;opacity:.75}.hint-to .hint-halo{background:#efd47840;border-color:#f6d46b}.square.hint-from{box-shadow:inset 0 0 0 2px #d4af4a}.square.hint-to{box-shadow:inset 0 0 0 2px #e5c45b}.hint-halo+.piece{z-index:1}
@media(max-width:600px){.coach-move{font-size:10px;padding:4px 7px}.player{gap:9px}.player b{font-size:12px}.coach-avatar{width:38px;height:38px;flex-basis:38px}}
.move-feedback{position:absolute;inset:3px;border:2px solid #f5db8c;border-radius:5px;pointer-events:none;z-index:2}

/* Dedicated promotion surface: no generic dialog layout or system-sized pieces. */
#promotion{width:min(520px,calc(100vw - 28px));max-width:520px;max-height:calc(100dvh - 28px);overflow:auto;padding:25px;border:1px solid #ffffffd9;border-radius:30px;background:radial-gradient(ellipse at 12% 0%,#f5e9dcbf,transparent 65%),linear-gradient(135deg,#ffffffed,#f7f3eee8);box-shadow:inset 0 1px 1px #fff,0 28px 90px #3f2c1740;backdrop-filter:blur(24px) saturate(130%);-webkit-backdrop-filter:blur(24px) saturate(130%)}
#promotion::backdrop{background:#3b2b184d;backdrop-filter:blur(5px);-webkit-backdrop-filter:blur(5px);animation:promotion-backdrop-in .24s ease-out}
.promotion-top{display:flex;justify-content:space-between;align-items:center;gap:16px}.promotion-eyebrow{font-size:9px;letter-spacing:2px;color:#8a7e70}
#promotion #promotionCancel{display:grid;place-items:center;width:32px;height:32px;padding:0;border:1px solid #ffffffd9;background:#ffffff70;border-radius:50%;font-size:13px;color:#766e64}
#promotion h2{margin:4px 0 8px;font-size:26px;font-weight:500;letter-spacing:-.5px}#promotion h2 span{color:#b89c7c}#promotion #promotionRoute{margin:0;font-size:12px;color:#7d7265;font-variant-numeric:tabular-nums}
.promotion-transformation{display:flex;align-items:center;justify-content:center;gap:22px;height:130px;margin:4px 0 12px}.promotion-transformation .piece{display:block;width:68px;height:68px;font-size:55px}.promotion-transformation .piece img{width:100%;height:100%;object-fit:contain}.promotion-flow{font-size:28px;font-weight:300;color:#b4a18b}#promotionPawn{opacity:.45;transform:scale(.85)}.promotion-preview-wrap{position:relative;width:88px;height:88px;display:grid;place-items:center;border:1px solid #ffffffd9;border-radius:26px;background:linear-gradient(145deg,#ffffffd9,#e8dcce77);box-shadow:0 8px 20px #5c483110,inset 0 1px 2px #fff}#promotionPreviewName{position:absolute;bottom:-19px;font-size:10px;color:#857665}
#promotion #promotionOptions{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:9px}
#promotion #promotionOptions .promotion-choice{position:relative;display:flex;flex-direction:column;align-items:center;gap:3px;min-width:0;padding:15px 8px 13px;border:1px solid #ffffffed;border-radius:18px;background:#ffffff75;box-shadow:inset 0 1px 1px #fff,0 4px 12px #5c483105;transition:background .18s,border-color .18s,box-shadow .18s,transform .18s}
#promotion #promotionOptions .piece{width:58px;height:58px;display:block;font-size:48px}#promotionOptions .piece img{width:100%;height:100%;object-fit:contain}#promotionOptions b{font-size:14px;font-weight:500;margin-top:5px}#promotionOptions small{font-size:7px;letter-spacing:1.2px;color:#91867a}#promotionOptions kbd{position:absolute;top:6px;right:8px;font:8px system-ui;color:#ada296}
#promotion #promotionOptions .previewed{border-color:#b59c80;background:#f5ede4bb;box-shadow:inset 0 1px 2px #fff,0 5px 15px #5c483110}#promotion #promotionOptions button:hover{filter:none;transform:translateY(-3px)}#promotion #promotionOptions button:focus-visible{outline:2px solid #9e8263;outline-offset:3px}#promotion[data-choosing] #promotionOptions button{opacity:.35;transform:none}#promotion[data-choosing=q] #promotionOptions [data-type=q],#promotion[data-choosing=r] #promotionOptions [data-type=r],#promotion[data-choosing=b] #promotionOptions [data-type=b],#promotion[data-choosing=n] #promotionOptions [data-type=n]{opacity:1;background:#ecdcc9;border-color:#aa8d6b;box-shadow:0 0 0 3px #c4a98b22}
#promotion #promotionHelp{margin:20px 0 0;text-align:center;font-size:11px;line-height:1.7;color:#837668}#promotionHelp span{display:block;margin-top:4px;font-size:9px;color:#a2978b}
html[data-effects=light] #promotion{backdrop-filter:none;-webkit-backdrop-filter:none;background:linear-gradient(135deg,#fcf9f5,#f5efe8)}html[data-effects=light] #promotion::backdrop{backdrop-filter:none;-webkit-backdrop-filter:none}
@keyframes promotion-backdrop-in{from{background:#3b2b1800}to{background:#3b2b184d}}
@media(max-width:420px){#promotion{padding:21px;border-radius:26px}#promotion h2{font-size:24px}#promotion #promotionOptions{gap:7px}#promotion #promotionOptions .promotion-choice{padding:14px 4px 12px;border-radius:15px}#promotion #promotionOptions .piece{width:48px;height:48px}#promotionOptions small{font-size:6px;letter-spacing:.8px}.promotion-transformation{height:115px}}
@media(prefers-reduced-motion:reduce){#promotion::backdrop{animation:none}}.reduce-motion #promotion::backdrop{animation:none}.reduce-motion #promotionOptions button{transition:none!important}

/* A selected piece stays lightly lifted until it is placed. */
#board .piece{transition:transform .18s cubic-bezier(.2,.8,.2,1),filter .18s ease;transform-origin:50% 75%}
#board .square.selected{z-index:2;background:#dfc6aa;box-shadow:inset 0 0 0 2px #c4a887}
#board .square.selected .piece{transform:translateY(-4px) scale(1.055);filter:drop-shadow(0 5px 2px #45352338);z-index:3}
#board .square:active{filter:none}.move-marker{pointer-events:none}
/* Noninteractive turn display; chess rules still determine who moves next. */
.turn-rail{display:flex;align-items:center;justify-content:space-between;gap:14px;margin:-2px 0 14px;padding:0 2px}.turn-rail[hidden]{display:none}.turn-caption{font-size:10px;color:#8f8376;letter-spacing:.5px}.turn-track{position:relative;display:flex;padding:4px;width:164px;height:37px;border:1px solid #ffffffb3;border-radius:24px;background:#e5dbcf60;box-shadow:inset 0 1px 4px #5b4a3610}.turn-slider{position:absolute;left:4px;top:4px;width:calc((100% - 8px)/2);height:27px;border:1px solid #ffffffd9;border-radius:19px;background:#ffffffc7;box-shadow:0 2px 7px #5c483117;transition:transform .36s cubic-bezier(.22,.85,.24,1),background .28s,border-color .28s}.turn-track[data-turn=b] .turn-slider{transform:translateX(100%);background:#584836;border-color:#736759}.turn-side{position:relative;display:flex;align-items:center;justify-content:center;gap:7px;flex:1;font-size:11px;color:#978e83;transition:color .28s}.turn-side[aria-current=true]{color:#4f4130}.turn-track[data-turn=b] #turnBlack{color:#f5efe9}.turn-dot{width:8px;height:8px;border-radius:50%;border:1px solid #9c8e7f}.white-dot{background:#fdfef2}.black-dot{background:#534534}.turn-track[data-turn=b] .black-dot{background:#eadccb;border-color:#eee3d7}
@media(max-width:600px){#board .square.selected .piece{transform:translateY(-3px) scale(1.055)}.turn-track{width:150px}.turn-rail{margin-bottom:12px}}
@media(prefers-reduced-motion:reduce){#board .piece,.turn-slider,.turn-side{transition:none!important}#board .square.selected .piece{transform:none!important}}
.reduce-motion #board .piece,.reduce-motion .turn-slider,.reduce-motion .turn-side{transition:none!important}.reduce-motion #board .square.selected .piece{transform:none!important}

.island-copy small.book-caption{text-overflow:clip;overflow:hidden;white-space:nowrap}
.book-caption>span{display:inline-block;white-space:nowrap}
.reduce-motion .island-copy small.book-caption{white-space:normal;font-size:9px;line-height:1.15;max-height:2.3em}
.reduce-motion .book-caption>span{white-space:normal}
@media(prefers-reduced-motion:reduce){.island-copy small.book-caption{white-space:normal;font-size:9px;line-height:1.15;max-height:2.3em}.book-caption>span{white-space:normal}}

/* Only the analysis workspace owns a move-quality piece badge. */
.analysis-workspace .analysis-piece-badge{position:absolute;top:2%;right:2%;width:34%;max-width:none;min-width:0;aspect-ratio:1;z-index:18;display:block;pointer-events:none;filter:drop-shadow(0 1px 2px #3c2d3260);transform-origin:75% 25%}
.analysis-workspace .analysis-piece-badge img{display:block;width:100%;height:100%;object-fit:contain;border-radius:50%;pointer-events:none}

/* Badge-only reference motion: recoil, soft color glow, and two impact rings. */
.analysis-workspace .analysis-piece-badge{--badge-accent:#91b75c;transform-origin:center;isolation:isolate;overflow:visible;filter:drop-shadow(0 0 2px var(--badge-accent)) drop-shadow(0 1px 1px #3c2d3240)}
.analysis-workspace .analysis-piece-badge[data-kind=book]{--badge-accent:#e6a15c}.analysis-workspace .analysis-piece-badge[data-kind=brilliant]{--badge-accent:#26d9be}.analysis-workspace .analysis-piece-badge[data-kind=great]{--badge-accent:#55bce4}.analysis-workspace .analysis-piece-badge[data-kind=interesting]{--badge-accent:#b68cdd}.analysis-workspace .analysis-piece-badge[data-kind=inaccuracy]{--badge-accent:#e6bb4b}.analysis-workspace .analysis-piece-badge[data-kind=mistake]{--badge-accent:#ed9851}.analysis-workspace .analysis-piece-badge[data-kind=blunder],.analysis-workspace .analysis-piece-badge[data-kind=miss]{--badge-accent:#ed6462}.analysis-workspace .analysis-piece-badge[data-kind=forced]{--badge-accent:#a5adb8}
.analysis-workspace .analysis-piece-badge>img{position:relative;z-index:2}
.analysis-workspace .piece-badge-halo,.analysis-workspace .piece-badge-ring{position:absolute;display:block;border-radius:50%;pointer-events:none;opacity:0;z-index:0}
.analysis-workspace .piece-badge-halo{inset:-24%;background:radial-gradient(circle,var(--badge-accent),transparent 69%)}
.analysis-workspace .piece-badge-ring{inset:-10%;border:1px solid var(--badge-accent)}
.reduce-motion .analysis-piece-badge .piece-badge-halo,.reduce-motion .analysis-piece-badge .piece-badge-ring{display:none}
@media(prefers-reduced-motion:reduce){.analysis-piece-badge .piece-badge-halo,.analysis-piece-badge .piece-badge-ring{display:none}}

/* All badge geometry follows its square, including the impact decoration. */
@supports(container-type:inline-size){
 .analysis-workspace .analysis-piece-badge{container-type:inline-size;filter:none}
 .analysis-workspace .analysis-piece-badge>img{filter:drop-shadow(0 0 7.4cqw var(--badge-accent)) drop-shadow(0 3.7cqw 3.7cqw #3c2d3240)}
 .analysis-workspace .analysis-piece-badge .piece-badge-ring{border-width:0;box-shadow:inset 0 0 0 3.7cqw var(--badge-accent)}
}