.layout{display:flex;min-height:100vh}.sidebar{width:220px;background:var(--sidebar-bg);border-right:1px solid var(--sidebar-border);display:flex;flex-direction:column}.sidebar-header{padding:20px;border-bottom:1px solid var(--sidebar-border)}.sidebar-header h2{margin:0;font-size:1.1rem;font-weight:600;color:var(--text)}.sidebar-nav{padding:8px;display:flex;flex-direction:column;gap:2px}.nav-item{display:flex;align-items:center;gap:12px;padding:10px 14px;background:transparent;border:none;border-radius:6px;color:var(--sidebar-text);cursor:pointer;font-size:.95rem;text-align:left;transition:background .15s,color .15s}.nav-item:hover{background:var(--sidebar-hover)}.nav-item.active{background:var(--accent);color:#fff}.nav-icon{font-size:1.1rem}.nav-name{flex:1}.main-content{flex:1;padding:20px}.home-main{text-align:center;max-width:600px;margin:0 auto}.home-text{font-size:1.1rem;line-height:1.8;color:var(--text-muted)}.home-text+.home-text{margin-top:1.5rem}.subtitle{margin:0;color:var(--text-muted);font-size:.95rem}.app-main{display:flex;flex-direction:column;align-items:center;gap:1.25rem}.sudoku-grid{display:flex;flex-direction:column;position:relative;background:var(--grid-bg);padding:0;border:3px solid var(--grid-line);border-radius:2px;box-shadow:var(--shadow-md)}.path-overlay-svg{position:absolute;top:0;left:0;width:100%;height:100%;pointer-events:none;z-index:1}.sudoku-row{display:flex}.sudoku-cell-wrap{padding:1px;position:relative}.sudoku-cell-wrap.border-right{padding-right:2px}.sudoku-cell-wrap.border-bottom{padding-bottom:2px}.sudoku-cell{width:2.25rem;height:2.25rem;text-align:center;font-size:1.25rem;font-weight:500;border:none;border-radius:0;background:transparent;color:var(--cell-text);box-sizing:border-box;position:relative;z-index:2}.sudoku-cell.solved{color:var(--cell-readonly-text)}.sudoku-cell:focus{outline:none;box-shadow:inset 0 0 0 2px var(--focus-ring)}.sudoku-cell::placeholder{color:var(--placeholder)}.actions{display:flex;gap:.75rem;flex-wrap:wrap;justify-content:center}.actions button{padding:.5rem 1.25rem;font-size:.95rem;border-radius:6px;border:1px solid var(--btn-border);background:var(--btn-bg);color:var(--btn-text);cursor:pointer;transition:background .15s,border-color .15s,box-shadow .15s;box-shadow:var(--shadow-sm)}.actions button:hover:not(:disabled){background:var(--btn-hover-bg);border-color:var(--btn-hover-border)}.actions button:disabled{opacity:.5;cursor:not-allowed}.message{padding:.75rem 1rem;border-radius:6px;max-width:28rem;text-align:center;font-size:.95rem}.message-success{background:var(--success-bg);color:var(--success);border:1px solid var(--success-border)}.message-error{background:var(--error-bg);color:var(--error);border:1px solid var(--error-border)}.modal-backdrop{position:fixed;top:0;left:0;width:100vw;height:100vh;background:#0f172a66;display:flex;align-items:center;justify-content:center;z-index:1000}.modal{background:var(--surface);padding:1.5rem;border-radius:10px;width:90vw;max-width:28rem;box-shadow:var(--shadow-lg);color:var(--text)}.modal h2{margin-top:0;font-size:1.15rem}.modal-row{display:flex;align-items:center;margin:.75rem 0}.modal-row label{flex:0 0 4.5rem;font-size:.9rem;color:var(--text)}.modal-row input,.modal-row select{flex:1;padding:.45rem .6rem;border:1px solid var(--border);border-radius:6px;background:var(--surface);color:var(--text);font-size:.9rem}.modal-row input:focus,.modal-row select:focus{outline:none;border-color:var(--focus-ring);box-shadow:0 0 0 3px #3b82f626}.modal-actions{display:flex;justify-content:flex-end;gap:.75rem;margin-top:1.25rem}.modal-actions button{padding:.5rem 1rem;border-radius:6px;border:1px solid var(--btn-border);background:var(--btn-bg);color:var(--btn-text);cursor:pointer;font-size:.9rem}.modal-actions button:hover{background:var(--btn-hover-bg)}.modal-actions button:disabled{opacity:.5;cursor:not-allowed}.cell-overlay{position:absolute;top:0;right:0;bottom:0;left:0;background:var(--constraint-color);opacity:.4;pointer-events:none;z-index:0}.sudoku-cell-inner{position:relative;background:var(--cell-bg)}.sudoku-cell-inner.constraint-selected .cell-overlay{opacity:.55;box-shadow:inset 0 0 0 2px var(--accent)}.sudoku-cell-inner.preview .cell-overlay{opacity:.25}.sudoku-grid.selecting,.sudoku-grid.selecting *{cursor:crosshair;user-select:none;-webkit-user-select:none}.path-index{position:absolute;top:1px;left:3px;font-size:.55rem;color:var(--cell-text);z-index:1;pointer-events:none;font-weight:700}.constraint-toolbar{display:flex;gap:.4rem;flex-wrap:wrap;justify-content:center;align-items:center}.constraint-toolbar button{padding:.35rem .75rem;font-size:.85rem;border-radius:6px;border:1px solid var(--btn-border);background:var(--btn-bg);color:var(--btn-text);cursor:pointer;transition:background .15s,border-color .15s}.constraint-toolbar button:hover:not(:disabled){background:var(--btn-hover-bg);border-color:var(--btn-hover-border)}.constraint-toolbar button.active{background:var(--btn-active-bg);border-color:var(--btn-active-bg);color:var(--btn-active-text)}.constraint-toolbar button:disabled{opacity:.5;cursor:not-allowed}.toolbar-sep{color:var(--text-subtle);margin:0 .15rem}.constraint-sidebar{position:fixed;top:0;right:0;width:280px;height:100vh;background:var(--sidebar-bg);border-left:1px solid var(--sidebar-border);display:flex;flex-direction:column;z-index:500;overflow-y:auto;color:var(--sidebar-text);box-shadow:var(--shadow-lg)}.constraint-sidebar-header{display:flex;justify-content:space-between;align-items:center;padding:.75rem 1rem;border-bottom:1px solid var(--sidebar-border);font-weight:600;font-size:.95rem}.constraint-sidebar-header button{background:none;border:none;color:var(--sidebar-text);font-size:1.2rem;cursor:pointer;padding:0 .25rem}.constraint-list{flex:1;overflow-y:auto;padding:.5rem}.constraint-list-empty{padding:1.5rem 1rem;text-align:center;color:var(--text-muted);font-size:.85rem}.constraint-item{display:flex;align-items:flex-start;gap:.5rem;padding:.5rem;border-radius:6px;cursor:pointer;margin-bottom:.15rem;transition:background .1s}.constraint-item:hover{background:var(--sidebar-hover)}.constraint-item.active{background:var(--sidebar-active)}.constraint-item-color{width:12px;height:12px;border-radius:50%;flex-shrink:0;margin-top:3px}.constraint-item-info{flex:1;min-width:0}.constraint-item-name{font-size:.85rem;font-weight:500}.constraint-item-summary{font-size:.75rem;color:var(--text-muted);margin-top:1px}.constraint-item-delete{background:none;border:none;color:var(--text-muted);cursor:pointer;font-size:.85rem;padding:2px 4px;border-radius:4px;visibility:hidden}.constraint-item:hover .constraint-item-delete{visibility:visible}.constraint-item-delete:hover{color:var(--error);background:var(--error-bg)}.constraint-editor{border-top:1px solid var(--sidebar-border);padding:.75rem 1rem}.constraint-editor h3{margin:0 0 .5rem;font-size:.9rem}.editor-field{margin-bottom:.6rem}.editor-field label{display:block;font-size:.8rem;color:var(--text-muted);margin-bottom:.2rem}.editor-field input,.editor-field select{width:100%;padding:.35rem .5rem;border:1px solid var(--sidebar-border);border-radius:6px;background:var(--surface);color:var(--text);font-size:.85rem;box-sizing:border-box}.editor-field input:focus,.editor-field select:focus{outline:none;border-color:var(--focus-ring);box-shadow:0 0 0 2px #3b82f626}.color-palette{display:flex;gap:.35rem;flex-wrap:wrap}.color-swatch{width:22px;height:22px;border-radius:50%;cursor:pointer;border:2px solid transparent;transition:border-color .15s,transform .1s}.color-swatch:hover{border-color:var(--text-muted);transform:scale(1.15)}.color-swatch.selected{border-color:var(--text);box-shadow:0 0 0 2px var(--surface),0 0 0 3px var(--text)}.editor-actions{display:flex;gap:.4rem;margin-top:.75rem}.editor-actions button{flex:1;padding:.35rem .5rem;font-size:.8rem;border-radius:6px;border:1px solid var(--sidebar-border);background:var(--surface);color:var(--sidebar-text);cursor:pointer}.editor-actions button:hover{background:var(--sidebar-hover)}.editor-actions button.danger{color:var(--error)}.editor-actions button.danger:hover{background:var(--error-bg)}*,*:before,*:after{box-sizing:border-box}:root{--bg: #f1f5f9;--surface: #ffffff;--border: #e2e8f0;--border-heavy: #cbd5e1;--text: #0f172a;--text-muted: #64748b;--text-subtle: #94a3b8;--accent: #3b82f6;--accent-hover: #2563eb;--accent-light: #eff6ff;--success: #059669;--success-bg: #ecfdf5;--success-border: #a7f3d0;--error: #dc2626;--error-bg: #fef2f2;--error-border: #fecaca;--grid-bg: #000000;--grid-line: #000000;--cell-bg: #ffffff;--cell-text: #0f172a;--cell-readonly-bg: #f8fafc;--cell-readonly-text: #3b82f6;--placeholder: #94a3b8;--focus-ring: #3b82f6;--btn-bg: #ffffff;--btn-border: #cbd5e1;--btn-text: #334155;--btn-hover-bg: #f1f5f9;--btn-hover-border: #94a3b8;--btn-active-bg: #3b82f6;--btn-active-text: #ffffff;--sidebar-bg: #ffffff;--sidebar-border: #e2e8f0;--sidebar-text: #334155;--sidebar-hover: #f1f5f9;--sidebar-active: #eff6ff;--shadow-sm: 0 1px 2px rgba(0, 0, 0, .05);--shadow-md: 0 4px 12px rgba(0, 0, 0, .08);--shadow-lg: 0 8px 24px rgba(0, 0, 0, .12)}body{margin:0;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,sans-serif;background:var(--bg);color:var(--text);line-height:1.5;-webkit-font-smoothing:antialiased}#root{min-height:100vh}.app{min-height:100vh;padding:2rem}.app-header{text-align:center;margin-bottom:2rem}.app-header h1{margin:0 0 .5rem;font-size:1.75rem;font-weight:600;color:var(--text)}