:root{color-scheme:dark;font:16px/1.6 system-ui,sans-serif;background:#0d1917;color:#eef3e8;--mint:#97dcc3;--dim:#aec2b9}*{box-sizing:border-box}body{max-width:1120px;margin:auto;padding:24px}a{color:var(--mint)}header{margin-bottom:32px}header .tag{display:block;margin-top:28px}.tag{font:12px/1.6 ui-monospace,monospace;letter-spacing:.13em;color:#e7bd79}h1{font:700 clamp(42px,8vw,76px)/1.1 Georgia,serif;margin:12px 0}h2{line-height:1.2}header p{margin:10px 0}.intro{max-width:72ch;color:var(--dim)}.layout{display:grid;grid-template-columns:minmax(0,1.05fr) minmax(0,1fr);gap:28px}.board-panel,.lesson-panel,.panel{background:#142621;border:1px solid #345047;border-radius:18px;padding:22px}.board-heading,.controls{display:flex;align-items:center;justify-content:space-between;gap:10px}.board-heading{margin-bottom:12px}#board{display:grid;grid-template-columns:repeat(8,minmax(0,1fr));grid-template-rows:repeat(8,minmax(0,1fr));width:100%;aspect-ratio:1;container-type:inline-size;border:2px solid #778f79}.square{min-width:0;min-height:0;overflow:hidden;position:relative;display:flex;align-items:center;justify-content:center;font-size:clamp(24px,5vw,48px);line-height:1;background:#dfd7bc;color:#141f1c}.square.dark{background:#769184}.square.moved{box-shadow:inset 0 0 0 4px #e9a449}.square.target{box-shadow:inset 0 0 0 4px #9b482e}.square small{position:absolute;font:10px system-ui;bottom:2px;left:3px;color:#15251e}.piece.white{color:#fffdf0;text-shadow:1px 1px 0 #253029,-1px -1px 0 #253029}.piece.black{color:#14211d;text-shadow:0 1px 0 #dce8d7}button{font:inherit;border:1px solid #708f7b;border-radius:9px;padding:10px 14px;background:#233e33;color:#fff;cursor:pointer}button:hover{background:#375b48}button:focus-visible,summary:focus-visible,a:focus-visible{outline:3px solid #e9bd74;outline-offset:3px}button:disabled{opacity:.4;cursor:default}.answers{display:grid;gap:12px;margin:24px 0}.answers button{text-align:left}#next{margin:16px 0;background:#b9e2ac;color:#112218}.panel{margin-top:26px}.skills{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}.skill{padding:14px;border:1px solid #4d6c5a;border-radius:12px}.skill strong{display:block}.muted,#positionLabel,#hintText{font-size:14px;color:var(--dim)}#feedback{border-left:3px solid var(--mint);padding-left:16px}#feedback:empty{display:none}#hintText:empty{display:none}.line{min-height:26px;color:#e7bd79}summary{cursor:pointer;color:var(--mint);padding:12px 0}pre{white-space:pre-wrap;overflow-wrap:anywhere;font-size:12px}.lesson-list{display:flex;flex-wrap:wrap;gap:8px;margin:12px 0}#storage{display:block;margin-top:12px}footer{padding:36px 0;color:var(--dim)}[hidden]{display:none!important}@media(max-width:720px){body{padding:14px}.layout{grid-template-columns:1fr;gap:16px}.board-panel,.lesson-panel,.panel{padding:16px}.skills{grid-template-columns:1fr}.square{font-size:clamp(26px,8vw,48px)}.controls button{font-size:13px}}

/* Piece size follows the board, including narrow two-column layouts. */
.piece{font-size:clamp(16px,9cqw,48px)}