.loading-overlay{position:fixed;top:0;right:0;bottom:0;left:0;background:#00000073;display:flex;align-items:center;justify-content:center;z-index:1000}.loading-box{background:#fff;border-radius:10px;padding:32px 40px;display:flex;flex-direction:column;align-items:center;gap:16px;font-size:1rem;color:#333;box-shadow:0 4px 24px #0003}.loading-spinner{width:40px;height:40px;border:4px solid #e0e0e0;border-top-color:#2196f3;border-radius:50%;animation:spin .8s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}:root{--cell-size: min(9vw, 60px);--border-color: #333;--black-cell: #222;--highlight-color: #e3f2fd;--error-color: #ffebee;--correct-color: #e3f2fd}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen,Ubuntu,sans-serif;display:flex;flex-direction:column;align-items:center;min-height:100vh;margin:0;padding:20px;background:#f5f5f5}h1{text-align:center;color:#333;margin-bottom:30px}.container{background:#fff;padding:20px;border-radius:10px;box-shadow:0 2px 10px #0000001a;max-width:800px;width:100%}.game-area{display:flex;justify-content:center;gap:20px;flex-wrap:wrap}.controls{display:flex;justify-content:space-between;align-items:center;gap:10px;margin-bottom:20px;flex-wrap:wrap}.controls-left,.controls-right{display:flex;align-items:center;gap:10px}.controls-left #primaryActionButton.solver-action-width{text-align:center}.controls-left{justify-content:flex-start}.controls-right{margin-left:auto}.mode-toggle{display:inline-flex;border:1px solid #2196f3;border-radius:999px;overflow:hidden}.mode-btn{border-radius:0;background:#e3f2fd;color:#1976d2;padding:7px 14px}.mode-btn:hover{background:#bbdefb}.mode-btn.active{background:#2196f3;color:#fff}.icon-control{width:36px;height:36px;padding:0;border-radius:8px;display:flex;align-items:center;justify-content:center;background:#e3f2fd;border:1px solid #2196f3;color:#333}.icon-control:hover{background:#bbdefb}#primaryActionButton:disabled{background:#bdbdbd;cursor:not-allowed}.difficulty-select{padding:8px 16px;border:1px solid #ccc;border-radius:4px;font-size:14px}.new-puzzle-group{display:inline-flex;align-items:stretch;gap:0;background:#2196f3;border-radius:4px;cursor:pointer;transition:background .2s;border:none}.new-puzzle-group:hover{background:#1976d2}.new-puzzle-group .difficulty-select{border:none;border-radius:0;background:transparent;color:#fff;font-size:14px;padding:0 4px;cursor:pointer;outline:none;align-self:center;text-align:center}.new-puzzle-group .difficulty-select option{background:#fff;color:#333}.sym-label{display:inline-flex;align-items:center;gap:4px;color:#fff;font-size:13px;padding:8px 10px;cursor:pointer;white-space:nowrap;border-left:1px solid rgba(255,255,255,.3)}.sym-label input[type=checkbox]{margin:0;cursor:pointer;accent-color:white;width:13px;height:13px}.new-puzzle-btn-label{color:#fff;font-size:14px;font-weight:500;padding:8px 8px 8px 12px;white-space:nowrap;-webkit-user-select:none;user-select:none;align-self:center;border-right:1px solid rgba(255,255,255,.3)}button{padding:8px 16px;border:none;border-radius:4px;background:#2196f3;color:#fff;cursor:pointer;font-size:14px;transition:background .2s}button:hover{background:#1976d2}.grid{display:grid;grid-template-columns:repeat(9,var(--cell-size));grid-template-rows:repeat(9,var(--cell-size));gap:1px;background:var(--border-color);border:2px solid var(--border-color)}.cell{background:#fff;display:flex;align-items:center;justify-content:center;font-size:calc(var(--cell-size) * .5);position:relative;-webkit-user-select:none;user-select:none}.cell.black{background:var(--black-cell);color:#fff}.cell.hint{font-weight:700;color:#333}.cell.selected{background:var(--highlight-color)}.cell.black.selected{background:var(--black-cell)}.cell.selected-strong{box-shadow:inset 0 0 0 2px #2196f3}.cell.black.selected-strong{box-shadow:inset 0 0 0 2px #90caf9}.cell.error{background:var(--error-color)}.cell.hint-affected{background:#fff7cc}.cell.correct{background:var(--correct-color)}.wrong-number{color:#ff4c4c}.notes{position:absolute;display:grid;grid-template-columns:repeat(3,1fr);grid-template-rows:repeat(3,1fr);font-size:calc(var(--cell-size) * .2);top:0;left:0;width:100%;height:100%;color:#666}.notes span{display:flex;align-items:center;justify-content:center;width:100%;height:100%}.notes span.hint-removed{color:#d32f2f;font-weight:700}.hint-description{min-height:22px;margin-top:8px;margin-bottom:12px;text-align:center;color:#555;font-size:14px}.creator-panel{margin-top:8px;margin-bottom:12px}.creator-board-input{width:100%;height:36px;font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,Liberation Mono,Courier New,monospace;font-size:13px;border:1px solid #bbb;border-radius:6px;padding:8px;box-sizing:border-box}.creator-validation{margin-top:6px;min-height:20px;font-size:13px;color:#555}.creator-validation.valid{color:#2e7d32}.creator-validation.warn{color:#ef6c00}.creator-validation.error{color:#c62828}.solver-settings-options{text-align:left;display:flex;flex-direction:column;gap:8px;margin-top:12px}.solver-settings-options label{display:flex;gap:8px;align-items:flex-start}.numpad{display:grid;grid-template-columns:repeat(3,var(--cell-size));grid-template-rows:repeat(3,var(--cell-size));gap:5px}.numpad-btn{background:#e3f2fd;border:1px solid #2196f3;border-radius:4px;display:flex;align-items:center;justify-content:center;font-size:calc(var(--cell-size) * .5);cursor:pointer;transition:background .2s;width:var(--cell-size);height:var(--cell-size);padding:0;box-sizing:border-box}.numpad-btn:hover{background:#bbdefb}.numpad-controls{display:grid;grid-template-columns:repeat(3,1fr);gap:5px}.numpad-btn.control{background:#e3f2fd;border:1px solid #2196f3;border-radius:4px;color:#333}.numpad-btn.control:hover{background:#bbdefb}.numpad-btn.control.active{background:#2196f3;color:#fff}.numpad-btn.control.notes-active{background:#2196f3!important;color:#fff!important}.numpad-btn.control svg{width:20px;height:20px}.modal-overlay{display:none;position:fixed;top:0;left:0;right:0;bottom:0;background:#00000080;z-index:1000;align-items:center;justify-content:center}.modal{background:#fff;padding:20px;border-radius:8px;box-shadow:0 2px 10px #0000001a;max-width:400px;width:90%;text-align:center}.modal-buttons{display:flex;justify-content:center;gap:10px;margin-top:20px}.modal-buttons button{padding:8px 16px;border:none;border-radius:4px;cursor:pointer}.modal-buttons .confirm{background:#2196f3;color:#fff}.modal-buttons .cancel{background:#9e9e9e;color:#fff}.confetti{position:fixed;width:10px;height:10px;background-color:red;pointer-events:none;opacity:0;will-change:transform,opacity;animation:confettiFall 3s ease-in forwards}@keyframes confettiFall{0%{transform:translateY(-20vh) rotate(0);opacity:1}to{transform:translate(var(--drift-x, 0px),100vh) rotate(var(--spin, 720deg));opacity:0}}.info-sections{margin-top:30px;display:flex;flex-direction:column;gap:8px}.info-section{background:#f8f9fa;border-radius:8px;overflow:hidden}.info-section summary{padding:14px 18px;font-weight:600;font-size:1rem;color:#333;cursor:pointer;-webkit-user-select:none;user-select:none;list-style:none;display:flex;align-items:center;gap:8px}.info-section summary::-webkit-details-marker{display:none}.info-section summary:before{content:"▸";display:inline-block;font-size:.8rem;color:#666;transition:transform .2s ease;flex-shrink:0}.info-section[open] summary:before{transform:rotate(90deg)}.info-section summary:hover{background:#eef0f2}.info-section p{margin:0;padding:0 18px 14px;color:#555;font-size:.92rem;line-height:1.55}.info-section p+p{padding-top:6px}.footer{text-align:center;margin-top:20px;color:#666;display:flex;align-items:center;justify-content:center;gap:8px}.footer a{color:#2196f3;text-decoration:none}.footer a:hover{text-decoration:underline}.footer-github{color:#666;display:flex;align-items:center}.footer-github:hover{color:#333;text-decoration:none}@media(max-width:600px){.container{padding:10px}.controls{flex-direction:column;align-items:center;gap:8px}.controls-left,.controls-right{width:100%;justify-content:center}.controls-right{margin-left:0;order:-1}.mode-toggle{flex:1}.mode-btn{flex:1;padding:7px 8px}.new-puzzle-group{flex:1;justify-content:center}#clearButton,#primaryActionButton{flex:1}h1{font-size:24px}.numpad{grid-template-columns:repeat(6,minmax(50px,1fr));grid-template-rows:repeat(2,var(--cell-size))}.numpad-btn,.numpad-btn.control{width:100%;height:var(--cell-size)}.numpad-btn:nth-child(-n+6){grid-row:1}.numpad-btn:nth-child(n+7):nth-child(-n+9){grid-row:2}.numpad-controls{grid-row:2;grid-column:4 / span 3;margin:0}.numpad-controls .numpad-btn.control{width:100%}.info-sections{margin-top:48px}}