:root{color-scheme:light;--ink:#303c32;--muted:#88897d;--green:#3d5945;--paper:#f5f3ed}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font-family:-apple-system,BlinkMacSystemFont,'PingFang SC',sans-serif}button,a,select{-webkit-tap-highlight-color:transparent}button,select{font:inherit;color:inherit;cursor:pointer}button{border:0;background:transparent;padding:12px 14px;border-radius:8px}button:hover{background-color:#e8e9df}button:disabled{opacity:.35;cursor:default}button:focus-visible,a:focus-visible,select:focus-visible{outline:3px solid #8d9e7f;outline-offset:3px}header{max-width:1440px;margin:auto;padding:32px 5%;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid #dddcd3}.brand{text-decoration:none;color:var(--green);font:600 30px Georgia,serif;letter-spacing:-1px}.brand span{font:12px sans-serif;letter-spacing:3px;margin-left:16px}.edition{font-size:10px;letter-spacing:3px;color:var(--muted)}header button{font-size:12px}main{max-width:1380px;margin:0 auto;min-height:calc(100vh - 180px);padding:60px 5%;display:grid;grid-template-columns:270px 1fr;gap:70px;align-items:center}.eyebrow{font-size:11px;letter-spacing:4px;color:#788575}h1{font:400 43px/1.5 'Songti SC','Noto Serif CJK SC',serif;letter-spacing:2px;margin:24px 0}p{font-size:13px;line-height:2.1;color:#777e70}.art-label{border-left:2px solid #acb29a;padding-left:18px;margin:35px 0}.art-label span{font-size:11px;color:var(--muted)}h2{font:400 23px 'Songti SC',serif}.art-label h2{margin:9px 0}.difficulty label{display:block;font-size:12px;margin-bottom:12px}select{width:100%;padding:12px;border:1px solid #d8d9ce;background:transparent;border-radius:7px;font-size:13px}.small{font-size:11px;color:var(--muted)}.board-top{display:flex;justify-content:space-between;font-size:11px;color:#7c8476;padding-bottom:15px;letter-spacing:1px}.frame{position:relative;padding:10px;background:#e9e6dc;box-shadow:0 22px 45px -25px #474b3f55;border:1px solid #deddd2}#board{aspect-ratio:3400/2329;position:relative;background:#d4d5c5;touch-action:none;user-select:none;overflow:hidden}.tile{position:absolute;background-image:url(artwork.jpg);border-radius:0;padding:0;box-shadow:inset 0 0 0 1px #f5f3ed70;transition:box-shadow .22s ease,filter .22s ease;touch-action:none}.tile:hover{background-color:transparent;filter:brightness(1.04)}.tile.selected{z-index:3;box-shadow:inset 0 0 0 3px #f9f4d8}.tile.correct{box-shadow:inset 0 0 0 .5px #ffffff20}.tile.dragging{z-index:5;transition:box-shadow .18s ease,filter .18s ease;filter:brightness(1.04);box-shadow:0 8px 18px #0005;cursor:grabbing}.tile.target{box-shadow:inset 0 0 0 4px #faf5d1}#board.solved .tile{box-shadow:none}#reference{position:absolute;inset:10px;width:calc(100% - 20px);height:calc(100% - 20px);object-fit:fill;z-index:10}.progress{height:2px;background:#dddfd2;margin:22px 0 8px}.progress i{height:100%;background:#6c825e;display:block;transition:width .4s}.toolbar{display:flex;justify-content:center;gap:8px}.toolbar button{font-size:12px}.toolbar button[aria-pressed=true]{background:#dde2d3}.instruction{text-align:center;font-size:11px;margin:12px 0;color:#8a8d81}footer{max-width:1440px;margin:auto;padding:24px 5%;display:flex;justify-content:space-between;color:#9a9e91;font-size:9px;letter-spacing:1.5px}#complete{text-align:center}#complete h2{margin:20px 0 0}#complete p{margin:8px}dialog{border:1px solid #ddd9cc;border-radius:12px;background:var(--paper);color:var(--ink);max-width:540px;width:90%;padding:34px}dialog::backdrop{background:#27312680;backdrop-filter:blur(6px)}dialog img{width:100%}dialog a{font-size:12px;color:var(--green)}.close{float:right;font-size:25px;padding:0 8px}@media(max-width:900px){main{gap:32px;grid-template-columns:210px 1fr;padding:40px 4%}h1{font-size:32px}.toolbar{gap:0}.toolbar button{padding:12px 9px}}@media(max-width:650px){header{padding:20px 6%}.brand{font-size:25px}.edition{display:none}main{display:flex;flex-direction:column;gap:22px;padding:26px 5%}.intro{width:100%}.intro .eyebrow{font-size:10px}h1{font-size:28px;line-height:1.3;margin:14px 0}h1 br{display:none}.intro>p,.art-label{display:none}.difficulty{display:flex;justify-content:space-between;align-items:center;margin-top:20px}.difficulty label{font-size:11px;margin:0}select{width:155px;padding:10px}.play{width:100%}.frame{padding:6px}#reference{inset:6px;width:calc(100% - 12px);height:calc(100% - 12px)}footer{gap:12px;flex-direction:column;padding:24px 6%}.toolbar button{font-size:11px;padding:12px 9px}.instruction{font-size:10px}}@media(prefers-reduced-motion:reduce){*{transition:none!important}}
@media(min-width:901px){main{padding-top:30px;padding-bottom:30px}.play{width:100%;max-width:calc((100vh - 285px)*1.4598);justify-self:center}h1{font-size:38px;margin:18px 0}.art-label{margin:24px 0}}
.tile:disabled{opacity:1;cursor:default}

.tile{cursor:grab}.tile.selected{box-shadow:inset 0 0 0 3px #f9f4d8,0 5px 16px #26322525}.tile.correct.selected{box-shadow:inset 0 0 0 3px #f9f4d8}
/* Joined tiles retain only the outside contour; interior edges disappear. */
.tile::after{content:'';position:absolute;inset:0;pointer-events:none;border:1px solid #f5f3ed90;transition:border-color .25s}
.tile,.tile.correct{box-shadow:none}
.tile.join-left::after{border-left-color:transparent}.tile.join-right::after{border-right-color:transparent}.tile.join-top::after{border-top-color:transparent}.tile.join-bottom::after{border-bottom-color:transparent}
.tile.selected,.tile.correct.selected{box-shadow:none;filter:brightness(1.06)}
.tile.selected::after{border-color:#fff0bd}.tile.selected.join-left::after{border-left-color:transparent}.tile.selected.join-right::after{border-right-color:transparent}.tile.selected.join-top::after{border-top-color:transparent}.tile.selected.join-bottom::after{border-bottom-color:transparent}
.tile.dragging{box-shadow:none;filter:brightness(1.06)}.tile.dragging::after{border-color:#fff0bd80}.tile.dragging.join-left::after{border-left-color:transparent}.tile.dragging.join-right::after{border-right-color:transparent}.tile.dragging.join-top::after{border-top-color:transparent}.tile.dragging.join-bottom::after{border-bottom-color:transparent}
#board.solved .tile::after{border-color:transparent}
.tile.yielding{transition:transform .2s cubic-bezier(.22,.8,.25,1);z-index:1}
.tile.dragging{z-index:8;transition:filter .18s;will-change:transform}
/* Irregular groups can leave empty cells; keep tile size stable and scroll the expanded work surface. */
.frame{overflow:auto;max-height:68vh;overscroll-behavior:contain}
#board{min-width:100%;overflow:visible}
.tile.yielding{transition:transform .24s cubic-bezier(.22,.8,.25,1),filter .18s}
#reference{object-fit:contain}
/* Fixed board: a failed placement returns to its origin, never grows the canvas. */
.frame{overflow:hidden;max-height:none}#board{width:100%!important;overflow:hidden}

header{flex-wrap:wrap;gap:16px}.puzzle-nav{display:flex;gap:20px;align-items:center}.puzzle-nav a,footer a{color:inherit;text-decoration:none;font-size:12px}.puzzle-nav a:hover,footer a:hover{text-decoration:underline}header .brand{color:var(--ink)}@media(max-width:650px){header{gap:12px}.puzzle-nav{gap:14px}header #about{padding:8px 0}h1{letter-spacing:0}.toolbar{flex-wrap:wrap}}