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/* Challenge v2: stronger hierarchy, meaningful difficulty accents and responsive puzzle surfaces */
.hero { border-bottom: 1px solid #273951; margin-bottom: 24px; }
.hero-copy > p { max-width: 650px; }
.game-panel { background: linear-gradient(148deg,#1b2a40,#111b2b 65%); border-color:#37516b; }
.challenge-meta { display:flex;justify-content:space-between;align-items:center;gap:12px;margin-top:21px;flex-wrap:wrap; }
.difficulty-pill { display:inline-flex;align-items:center;border:1px solid #356b68;border-radius:100px;background:#153d3a;color:#9af6db;font-size:11px;font-weight:800;letter-spacing:.05em;padding:8px 14px; }
.precision-note { font-size:10px;font-weight:800;letter-spacing:1.25px;color:#819bb2; }
.board-wrap { background:radial-gradient(ellipse at 50% 30%,#23334c,#0b1527 73%);border-color:#39506c; }
.puzzle-grid { width:min(100%,485px); }
.tile { background:linear-gradient(145deg,#243851,#1b2940);border:1px solid #47637d;position:relative;box-shadow:inset 0 1px #ffffff0c; }
.tile svg { width:82%;height:82%; }
.tile:not(:disabled):hover {background:#36536a;border-color:#8fe5d8;}
.puzzle-grid[data-palette="0"] .tile {color:#72e6d1}
.puzzle-grid[data-palette="1"] .tile {color:#ffca92}
.puzzle-grid[data-palette="2"] .tile {color:#c2a9ff}
.puzzle-grid[data-palette="3"] .tile {color:#9ccafb}
.tile.hinted { outline:2px solid #fbc38a;outline-offset:-2px;background:#3b3640; }
.tile.correct {background:#19594f;border-color:#6defcd;box-shadow:0 0 0 2px #65eac955}
.tile.wrong {background:#623642;border-color:#fd7f9d;}
.difficulty-controls select {color:#d5faf0;border-color:#446677;}
.point-summary {padding:15px 0;margin-top:12px;border-bottom:1px solid #304056;display:flex;justify-content:space-between;align-items:center;gap:7px;}
.point-summary span {font-size:10px;font-weight:800;letter-spacing:1px;color:#a6bbd2;}
.point-summary strong {font-size:27px;font-weight:850;color:#92f4d6;font-variant-numeric:tabular-nums;}
.stats-divider {margin:18px 0 15px;}
.feedback {line-height:1.6;font-weight:500;}
@media(max-width:450px){.tile{border-radius:6px;padding:3px}.puzzle-grid{gap:4px}.game-status{gap:9px}.precision-note{font-size:9px}.game-panel{padding:18px 12px}.board-wrap{padding:8px}.difficulty-pill{font-size:10px}}