:root{
  --bg:#f5f4f0; --surface:#fbfbf9; --panel:#ffffff; --panel-soft:#f7f6f2;
  --ink:#1c1c1a; --ink-hover:#3a3935; --ink-2:#55534d; --sub:#7a776f; --muted:#8a877f;
  --line:#e3e1db; --line-2:#dcdad3; --line-3:#efeee9; --hover:#efeee9; --soft:#f3f2ee; --track:#ebe9e3;
  --accent:#5b4bdb;
  --c1:#7a6cf0; --c2:#f0a35b; --c3:#5bc0a0; --c4:#e0577a;
  --font:"IBM Plex Sans KR",sans-serif; --mono:"JetBrains Mono",monospace;
}
*{box-sizing:border-box}
[hidden]{display:none !important}
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--font);-webkit-font-smoothing:antialiased}
button{font:inherit;color:inherit}
.mono-label{font-family:var(--mono);font-size:11px;letter-spacing:.12em;color:var(--muted)}
.app{min-height:100vh;display:flex;flex-direction:column}
.topbar{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:16px 28px;border-bottom:1px solid var(--line);background:var(--surface);flex-wrap:wrap}
.brand{display:flex;align-items:baseline;gap:14px;min-width:0;flex-wrap:wrap}
.brand-title{font-size:17px;font-weight:700;letter-spacing:-.01em}
.actions{display:flex;gap:8px;flex-wrap:wrap}
.btn{height:36px;padding:0 14px;background:transparent;border:1px solid var(--line-2);border-radius:999px;font-size:13px;cursor:pointer;display:inline-flex;align-items:center;justify-content:center;gap:6px;white-space:nowrap;transition:background .15s,transform .1s}
.btn:hover{background:var(--hover)}
.btn:active{transform:scale(.97)}
.btn:disabled{opacity:.4;cursor:default}
.btn--solid{background:var(--ink);color:#fff;border:none;font-weight:500}
.btn--solid:hover{background:var(--ink-hover)}
.btn--accent{background:var(--accent);color:#fff;border:none;font-weight:500}
.btn--accent:hover{background:var(--accent);filter:brightness(1.08)}
.btn--icon{width:36px;padding:0}
:focus-visible{outline:2px solid var(--ink);outline-offset:2px}
.kbd{display:inline-block;font-family:var(--mono);font-size:11px;line-height:1.4;padding:1px 6px;margin-left:2px;border:1px solid var(--line-2);border-bottom-width:2px;border-radius:5px;background:var(--surface);color:var(--ink)}
.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}

/* ---------- 레이아웃 ---------- */
.game{flex:1;display:flex;flex-wrap:wrap;align-items:stretch;min-height:0}
.stage{position:relative;isolation:isolate;overflow:hidden;flex:999 1 460px;min-width:0;display:flex;flex-direction:column;align-items:center;gap:18px;padding:28px 28px 32px}
.glow{position:absolute;inset:-10%;z-index:-1;opacity:.28;filter:blur(70px);pointer-events:none;transition:background 1s;
  background:radial-gradient(60% 55% at 100% 0%,var(--c2),transparent 70%),radial-gradient(60% 55% at 0% 100%,var(--c3),transparent 70%),linear-gradient(135deg,var(--c1),var(--c4))}
.side{flex:1 1 280px;min-width:0;max-width:100%;border-left:1px solid var(--line);background:var(--panel);padding:28px 24px 40px;display:flex;flex-direction:column;gap:26px}
.group{display:flex;flex-direction:column;gap:12px}
.group + .group{border-top:1px solid var(--line-3);padding-top:22px}

/* HUD */
.hud{display:flex;gap:8px;flex-wrap:wrap;justify-content:center;width:100%;max-width:620px}
.hud-item{flex:1 1 0;min-width:68px;display:flex;flex-direction:column;align-items:flex-start;gap:2px;padding:10px 14px;background:rgba(255,255,255,.72);border:1px solid rgba(0,0,0,.06);border-radius:14px;backdrop-filter:blur(6px);-webkit-backdrop-filter:blur(6px)}
.hud-item strong{font-family:var(--mono);font-size:22px;font-weight:700;letter-spacing:-.03em;line-height:1.1}
.hud-level{flex:1.3 1 0}
.hud-level strong{color:var(--accent)}
.hud-size{font-family:var(--mono);font-size:11px;color:var(--sub)}
.hud-item strong.is-bump{animation:bump .3s ease}

/* 보드 */
.board-wrap{width:100%;display:flex;justify-content:center}
.board{
  --cols:4;--rows:5;--gap:2px;--rad:6px;
  position:relative;width:min(100%,620px,calc((100vh - 260px) * var(--cols) / var(--rows)));min-width:min(100%,260px);
  aspect-ratio:var(--cols)/var(--rows);border-radius:14px;outline:none;
  user-select:none;-webkit-user-select:none;-webkit-touch-callout:none;
}
.board:focus-visible{box-shadow:0 0 0 3px var(--panel),0 0 0 5px var(--ink)}
.tile{
  position:absolute;left:0;top:0;width:calc(100% / var(--cols));height:calc(100% / var(--rows));
  transform:translate(calc(var(--x) * 100% + var(--dx,0px)),calc(var(--y) * 100% + var(--dy,0px)));
  transition:transform .3s cubic-bezier(.2,.9,.25,1);z-index:1;touch-action:none;cursor:grab;
}
.tile i{position:absolute;inset:var(--gap);border-radius:var(--rad);background:var(--c);transition:inset .5s ease,border-radius .5s ease,transform .18s ease,box-shadow .18s ease}
.tile.is-fixed{cursor:default;touch-action:auto}
.tile.is-fixed i::after{content:"";position:absolute;left:50%;top:50%;width:clamp(4px,18%,8px);aspect-ratio:1;border-radius:50%;transform:translate(-50%,-50%);background:var(--dot,#fff);opacity:.85}
.tile.is-drag{transition:none;z-index:20;cursor:grabbing}
.tile.is-drag i{transform:scale(1.18);box-shadow:0 14px 28px -8px rgba(0,0,0,.45),0 0 0 2px #fff;border-radius:calc(var(--rad) + 2px)}
.tile.is-target i{transform:scale(.84);box-shadow:0 0 0 2px #fff,0 0 0 4px var(--ink)}
.tile.is-picked{z-index:5}
.tile.is-picked i{transform:scale(.86);box-shadow:0 0 0 2px #fff,0 0 0 4px var(--ink);animation:pick 1s ease-in-out infinite}
.tile.is-cursor i{box-shadow:inset 0 0 0 2px #fff,0 0 0 2px var(--ink)}
.tile.is-swapped{z-index:4}
.tile.is-fly{transition:transform .55s cubic-bezier(.5,0,.2,1)}
.board.is-locked .tile{cursor:default}
.board.is-peek .tile{transform:translate(calc(var(--hx) * 100%),calc(var(--hy) * 100%));transition:transform .22s ease}
.board.is-solved .tile i{inset:0;border-radius:0}
.board.is-solved .tile.is-fixed i::after{opacity:0;transition:opacity .4s}
.board.is-solved .tile i{animation:wave .7s cubic-bezier(.3,.7,.3,1) var(--wd,0ms) both}
.board.is-solved{box-shadow:0 22px 50px -24px rgba(0,0,0,.45);transition:box-shadow .6s}

.memo{position:absolute;left:50%;top:10px;z-index:30;transform:translateX(-50%);display:flex;flex-direction:column;align-items:center;gap:6px;padding:8px 14px 9px;border-radius:999px;background:var(--ink);color:#fff;font-size:12.5px;white-space:nowrap;pointer-events:none;box-shadow:0 8px 20px -8px rgba(0,0,0,.5)}
.memo small{opacity:.65;font-size:11px}
.memo i{display:block;width:100%;height:3px;border-radius:3px;background:rgba(255,255,255,.9);transform-origin:left;animation:memo var(--memo,3s) linear forwards}

.under{display:flex;align-items:center;gap:10px;flex-wrap:wrap;justify-content:center}
.btn--peek{background:rgba(255,255,255,.75);touch-action:none;-webkit-user-select:none;user-select:none}
.btn--peek.is-on{background:var(--ink);color:#fff;border-color:var(--ink)}
.peek-help{font-size:12px;color:var(--sub)}

/* 사이드 */
.rules{margin:0;padding:0;list-style:none;display:flex;flex-direction:column;gap:9px;font-size:13px;color:var(--ink-2);line-height:1.6;counter-reset:rule}
.rules li{display:flex;gap:10px;align-items:baseline}
.rules li::before{counter-increment:rule;content:counter(rule,decimal-leading-zero);font-family:var(--mono);font-size:11px;color:var(--accent);flex-shrink:0}
.dot-sample{display:inline-block;width:14px;height:14px;border-radius:4px;background:var(--accent);position:relative;vertical-align:-2px;flex-shrink:0}
.dot-sample::after{content:"";position:absolute;left:50%;top:50%;width:5px;height:5px;margin:-2.5px;border-radius:50%;background:#fff}
.best-card{display:flex;align-items:baseline;justify-content:space-between;gap:12px;padding:14px 16px;border-radius:12px;background:var(--panel-soft);font-family:var(--mono);font-size:14px}
.best-stars{color:#e8a317;letter-spacing:2px}
.progress{display:flex;flex-direction:column;gap:6px}
.progress-bar{height:6px;border-radius:6px;background:var(--track);overflow:hidden}
.progress-bar i{display:block;height:100%;width:0;border-radius:6px;background:linear-gradient(90deg,var(--c1),var(--c2),var(--c3),var(--c4));transition:width .6s}
.keys{font-size:12px;color:var(--ink-2)}
.keys div{display:flex;justify-content:space-between;align-items:center;gap:12px;flex-wrap:wrap}

/* 모달 */
.modal{position:fixed;inset:0;z-index:100;display:flex;align-items:center;justify-content:center;padding:16px;background:rgba(28,28,26,.5);backdrop-filter:blur(3px);-webkit-backdrop-filter:blur(3px);animation:fade .2s ease}
.modal-card{width:100%;max-width:440px;max-height:calc(100vh - 32px);overflow:auto;background:var(--panel);border-radius:22px;padding:22px;box-shadow:0 30px 80px rgba(0,0,0,.3);animation:rise .35s cubic-bezier(.2,1.2,.4,1)}
.modal-card--wide{max-width:780px}
.modal-head{display:flex;justify-content:space-between;align-items:flex-start;gap:12px;margin-bottom:16px}
.modal-title{margin:2px 0 0;font-size:20px;letter-spacing:-.02em}
.level-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(96px,1fr));gap:10px}
.lv{display:flex;flex-direction:column;gap:6px;padding:8px 8px 10px;background:var(--surface);border:1px solid var(--line);border-radius:14px;cursor:pointer;text-align:left;transition:transform .12s,border-color .15s}
.lv:hover{border-color:var(--ink);transform:translateY(-2px)}
.lv canvas{display:block;width:100%;aspect-ratio:1/1;object-fit:contain;image-rendering:pixelated}
.lv-top{display:flex;justify-content:space-between;align-items:baseline;gap:4px}
.lv-no{font-family:var(--mono);font-size:12px;font-weight:700}
.lv-size{font-family:var(--mono);font-size:10px;color:var(--muted)}
.lv-stars{font-size:12px;letter-spacing:1px;color:#e8a317}
.lv-stars .off{color:var(--line-2)}
.lv.is-current{border-color:var(--accent);box-shadow:0 0 0 2px color-mix(in srgb,var(--accent) 25%,transparent)}
.lv:disabled{cursor:default;opacity:.5}
.lv:disabled .lv-stars{color:var(--muted)}
.lv:disabled:hover{transform:none;border-color:var(--line)}

.result{padding:16px}
.result-card{display:flex;gap:18px;align-items:center;padding:18px;border-radius:16px;background:var(--panel-soft);position:relative;overflow:hidden}
.result-art{width:120px;height:auto;border-radius:10px;box-shadow:0 14px 30px -14px rgba(0,0,0,.5);flex-shrink:0}
.result-body{display:flex;flex-direction:column;gap:6px;min-width:0}
.result-title{margin:0;font-size:24px;letter-spacing:-.02em}
.result-stars{font-size:26px;letter-spacing:3px;color:#e8a317;line-height:1}
.result-stars .off{color:#d8d5cc}
.result-stars span{display:inline-block;animation:star .5s cubic-bezier(.3,1.6,.5,1) backwards}
.result-stars span:nth-child(2){animation-delay:.12s}
.result-stars span:nth-child(3){animation-delay:.24s}
.result-stats{display:flex;gap:18px;margin:4px 0 0}
.result-stats div{display:flex;flex-direction:column}
.result-stats dt{font-size:11px;color:var(--sub)}
.result-stats dd{margin:0;font-family:var(--mono);font-size:18px;font-weight:700;letter-spacing:-.03em}
.result-note{margin:0;font-size:12.5px;color:var(--ink-2)}
.result-actions{display:flex;flex-wrap:wrap;gap:8px;justify-content:center;margin-top:14px}

.toast{position:fixed;left:50%;bottom:28px;z-index:200;transform:translate(-50%,20px);opacity:0;pointer-events:none;max-width:calc(100% - 32px);padding:10px 16px;border-radius:999px;background:var(--ink);color:#fff;font-size:13px;box-shadow:0 10px 30px rgba(0,0,0,.25);transition:opacity .2s,transform .25s cubic-bezier(.2,1.2,.4,1);text-align:center}
.toast.is-on{opacity:1;transform:translate(-50%,0)}

@keyframes wave{0%{transform:scale(1);filter:brightness(1)}35%{transform:scale(.55);filter:brightness(1.25)}70%{transform:scale(1.06)}100%{transform:scale(1);filter:brightness(1)}}
@keyframes pick{0%,100%{transform:scale(.86)}50%{transform:scale(.8)}}
@keyframes memo{from{transform:scaleX(1)}to{transform:scaleX(0)}}
@keyframes bump{0%{transform:scale(1)}40%{transform:scale(1.2)}100%{transform:scale(1)}}
@keyframes fade{from{opacity:0}to{opacity:1}}
@keyframes rise{from{opacity:0;transform:translateY(16px) scale(.96)}to{opacity:1;transform:none}}
@keyframes star{from{opacity:0;transform:scale(.2) rotate(-40deg)}to{opacity:1;transform:none}}

@media (max-width:640px){
  .topbar{padding:14px 16px}
  .stage{padding:16px 16px 24px;gap:14px}
  .hud{gap:6px}
  .hud-item{min-width:0;padding:8px 10px;border-radius:12px}
  .hud-item strong{font-size:18px}
  .board{width:min(100%,calc((100vh - 230px) * var(--cols) / var(--rows)))}
  .side{border-left:none;border-top:1px solid var(--line);padding:24px 16px 40px}
  .result-card{flex-direction:column;text-align:center}
  .result-body{align-items:center}
  .peek-help{display:none}
}
@media (hover:none){ .keys{display:none} }
@media (prefers-reduced-motion:reduce){
  *,*::before,*::after{animation-duration:.01ms !important;animation-iteration-count:1 !important;transition-duration:.01ms !important}
}

/* 다크 모드 (인쇄는 라이트 그대로) — 타일 색(판단 대상)과 완성 그림은 그대로 */
@media screen{
  :root[data-theme="dark"]{
    color-scheme:dark;
    --bg:#141318; --surface:#1a1920; --panel:#1f1e26; --panel-soft:#24232c;
    --ink:#ecebf0; --ink-hover:#ffffff; --ink-2:#c9c7d1; --sub:#a09eab; --muted:#8a8895;
    --line:#2e2d36; --line-2:#393843; --line-3:#26252d; --hover:#2a2932; --soft:#26252d; --track:#34333d;
    --accent:#9b8eff; --lock-fill:#2c2b33;
  }
  :root[data-theme="dark"] .btn--solid,:root[data-theme="dark"] .btn--accent,:root[data-theme="dark"] .toast,
  :root[data-theme="dark"] .memo,:root[data-theme="dark"] .btn--peek.is-on{color:var(--bg)}
  :root[data-theme="dark"] .glow{opacity:.2}
  :root[data-theme="dark"] .hud-item{background:rgba(31,30,38,.72);border-color:rgba(255,255,255,.07)}
  :root[data-theme="dark"] .btn--peek{background:rgba(31,30,38,.75)}
  :root[data-theme="dark"] .btn--peek.is-on{background:var(--ink)}
  :root[data-theme="dark"] .tile.is-drag i{box-shadow:0 14px 28px -8px rgba(0,0,0,.7),0 0 0 2px var(--ink)}
  :root[data-theme="dark"] .tile.is-target i,:root[data-theme="dark"] .tile.is-picked i{box-shadow:0 0 0 2px var(--bg),0 0 0 4px var(--ink)}
  :root[data-theme="dark"] .tile.is-cursor i{box-shadow:inset 0 0 0 2px var(--bg),0 0 0 2px var(--ink)}
  :root[data-theme="dark"] .board.is-solved{box-shadow:0 22px 50px -24px rgba(0,0,0,.8)}
  :root[data-theme="dark"] .memo i{background:rgba(20,19,24,.85)}
  :root[data-theme="dark"] .lv-stars .off,:root[data-theme="dark"] .result-stars .off{color:#6c6a77}
  :root[data-theme="dark"] .modal{background:rgba(0,0,0,.6)}
  :root[data-theme="dark"] .modal-card{box-shadow:0 30px 80px rgba(0,0,0,.6),0 0 0 1px var(--line-2)}
}