:root{--bg-primary: #ffffff;--bg-secondary: #f0f4f8;--brand-primary: #3b6b91;--brand-secondary: #7499b9;--text-main: #34495e;--text-muted: #7f8c8d;--grid-line-thick: #3b6b91;--grid-line-thin: #bdc3c7;--cell-bg: #ffffff;--cell-highlight: #e3f2fd;--cell-selected: #bbdefb;--cell-same-num: #e1f5fe;--error-color: #e74c3c;--accent-blue: #5487b1}*{box-sizing:border-box}body{margin:0;padding:0;font-family:Pretendard,-apple-system,BlinkMacSystemFont,system-ui,Roboto,sans-serif;background-color:var(--bg-primary);color:var(--text-main);display:flex;justify-content:center;overflow-x:hidden}#root{width:100%;max-width:500px;padding:1rem}.sudoku-container{display:flex;flex-direction:column;gap:1.5rem;width:100%}.game-header{display:grid;grid-template-columns:1fr 1fr 1fr;align-items:center;padding:.5rem 0}.header-item{display:flex;flex-direction:column;align-items:center}.header-label{font-size:.75rem;color:var(--text-muted);margin-bottom:.2rem}.header-value{font-size:1.1rem;font-weight:600;color:var(--text-main)}.difficulty-select{border:none;background:transparent;font-size:1.1rem;font-weight:600;color:var(--text-main);cursor:pointer;padding:0;display:flex;align-items:center;gap:.25rem}.pause-btn{background:#eef2f7;border:none;border-radius:50%;width:36px;height:36px;display:flex;align-items:center;justify-content:center;cursor:pointer;color:var(--brand-primary)}.sudoku-board{display:grid;grid-template-columns:repeat(9,1fr);border:2px solid var(--brand-primary);background-color:var(--brand-primary);gap:1px;aspect-ratio:1}.sudoku-cell{background-color:var(--cell-bg);display:flex;justify-content:center;align-items:center;font-size:1.6rem;font-weight:400;cursor:pointer;-webkit-user-select:none;user-select:none;position:relative}.sudoku-cell.highlight{background-color:var(--cell-highlight)}.sudoku-cell.selected{background-color:var(--cell-selected)!important}.sudoku-cell.initial{color:#2c3e50;font-weight:500}.sudoku-cell.user.error{color:var(--error-color)}.sudoku-cell.user{color:var(--brand-primary)}.sudoku-cell.error{color:var(--error-color)}.level-badge{background:var(--brand-primary);color:#fff;padding:.2rem .6rem;border-radius:4px;font-size:.9rem;font-weight:600;margin-left:.5rem}.bonus-btn{display:flex;align-items:center;gap:.5rem;background:#27ae60!important;margin:0 auto}.bonus-btn:hover{background:#219150!important}.sudoku-cell:nth-child(3n){border-right:1px solid var(--brand-primary)}.sudoku-cell:nth-child(9n){border-right:none}.sudoku-cell:nth-child(n+19):nth-child(-n+27),.sudoku-cell:nth-child(n+46):nth-child(-n+54){border-bottom:1px solid var(--brand-primary)}.notes-grid{display:grid;grid-template-columns:repeat(3,1fr);width:100%;height:100%;padding:1px}.note-item{font-size:.65rem;color:var(--text-muted);display:flex;justify-content:center;align-items:center}.action-bar{display:flex;justify-content:space-around;padding:1rem 0}.icon-btn{background:transparent;border:none;cursor:pointer;color:var(--brand-primary);display:flex;flex-direction:column;align-items:center;gap:.25rem;position:relative}.icon-btn:disabled{color:#bdc3c7}.icon-badge{position:absolute;top:-8px;right:-8px;background-color:var(--brand-primary);color:#fff;font-size:.65rem;padding:2px 5px;border-radius:10px;font-weight:700;border:2px solid white}.note-toggle-badge{background:#eef2f7;padding:2px 8px;border-radius:10px;font-size:.65rem;font-weight:700;color:var(--brand-primary)}.note-toggle-badge.on{background:var(--brand-primary);color:#fff}.number-row{display:flex;justify-content:space-between;padding:.5rem 0}.number-btn{background:transparent;border:none;font-size:2.2rem;color:var(--brand-primary);cursor:pointer;flex:1;display:flex;justify-content:center;align-items:center;transition:transform .1s}.number-btn:active{transform:scale(.9)}.number-btn:disabled{color:#ecf0f1}.modal-overlay{position:fixed;top:0;left:0;right:0;bottom:0;background:#fffffff2;display:flex;justify-content:center;align-items:center;z-index:100;flex-direction:column;gap:1.5rem;text-align:center}.modal-content h2{font-size:2rem;color:var(--brand-primary)}.primary-btn{background:var(--brand-primary);color:#fff;border:none;padding:1rem 2rem;border-radius:8px;font-size:1.1rem;font-weight:600;cursor:pointer}.landing-page{display:flex;flex-direction:column;align-items:center;gap:2rem;padding-top:3rem;width:100%}.landing-header{text-align:center;margin-bottom:2rem}.landing-header h1{font-size:2.5rem;color:var(--brand-primary);margin:.5rem 0}.landing-header p{color:var(--text-muted);font-size:1.1rem}.game-grid{display:grid;grid-template-columns:1fr;gap:1.5rem;width:100%}.game-card{background:#fff;border:1px solid #e1e8ed;border-radius:16px;padding:1.5rem;display:flex;gap:1.5rem;align-items:center;cursor:pointer;transition:all .2s ease;box-shadow:0 4px 6px #0000000d}.game-card:hover{transform:translateY(-4px);box-shadow:0 12px 20px #0000001a;border-color:var(--brand-primary)}.game-card.coming-soon{opacity:.7;cursor:default;background:var(--bg-secondary)}.game-card.coming-soon:hover{transform:none;box-shadow:0 4px 6px #0000000d}.game-card-icon{background:var(--bg-secondary);color:var(--brand-primary);width:80px;height:80px;border-radius:12px;display:flex;align-items:center;justify-content:center;flex-shrink:0}.game-card-content h3{margin:0 0 .5rem;font-size:1.3rem;color:var(--text-main)}.game-card-content p{margin:0;color:var(--text-muted);font-size:.95rem;line-height:1.4}.game-card-footer{margin-top:1rem}.play-now{color:var(--brand-primary);font-weight:600;display:flex;align-items:center;gap:.4rem;font-size:.9rem}.landing-footer{margin-top:3rem;color:var(--text-muted);font-size:.9rem}.back-btn{background:transparent;border:none;color:var(--text-muted);cursor:pointer;padding:0;margin-right:.5rem;display:flex;align-items:center;justify-content:center;transition:color .2s}.back-btn:hover{color:var(--brand-primary)}.mode-select-page{min-height:100vh;padding:2rem 1rem;max-width:800px;margin:0 auto}.mode-header{display:flex;align-items:center;gap:1rem;margin-bottom:3rem}.mode-header h1{font-size:2rem;font-weight:700;margin:0}.mode-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:2rem}.stage-mode-card{opacity:.8}.coming-soon-label{background:var(--bg-secondary);padding:.25rem .75rem;border-radius:1rem;font-size:.875rem;color:var(--text-secondary)}@keyframes board-entrance{0%{opacity:0;transform:scale(.5) translateY(10px)}to{opacity:1;transform:scale(1) translateY(0)}}.sudoku-board.is-entering .animate-entrance{animation:board-entrance .5s cubic-bezier(.16,1,.3,1) both;animation-delay:calc((var(--row) + var(--col)) * .05s)}@keyframes mistake-flash{0%{background-color:#e74c3ccc;box-shadow:inset 0 0 25px #e74c3c66,0 0 15px #e74c3c4d;z-index:10}to{background-color:transparent;box-shadow:none;z-index:1}}.animate-mistake{animation:mistake-flash .6s cubic-bezier(.25,1,.5,1) forwards}@keyframes premium-sweep{0%{filter:brightness(1);transform:scale(1);box-shadow:none}30%{filter:brightness(1.6);transform:scale(1.1);z-index:100;box-shadow:0 0 30px 5px rgba(var(--brand-primary-rgb),.6)}to{filter:brightness(1);transform:scale(1);box-shadow:none}}.animate-sweep-row{animation:premium-sweep .7s cubic-bezier(.16,1,.3,1) both;animation-delay:calc(var(--col-idx) * .04s)}.animate-sweep-col{animation:premium-sweep .7s cubic-bezier(.16,1,.3,1) both;animation-delay:calc(var(--row-idx) * .04s)}.animate-sweep-sector{animation:premium-sweep .7s cubic-bezier(.16,1,.3,1) both;animation-delay:calc((var(--inner-row) * 3 + var(--inner-col)) * .04s)}:root{--brand-primary-rgb: 52, 152, 219}.difficulty-select-page{min-height:100vh;padding:2rem 1rem;max-width:500px;margin:0 auto;display:flex;flex-direction:column;gap:2rem}.game-card[data-difficulty=Easy] .game-card-icon{background-color:#e8f5e9;color:#2ecc71}.game-card[data-difficulty=Medium] .game-card-icon{background-color:#e3f2fd;color:#3498db}.game-card[data-difficulty=Hard] .game-card-icon{background-color:#fffde7;color:#f1c40f}.game-card[data-difficulty=Expert] .game-card-icon{background-color:#fff3e0;color:#e67e22}.game-card[data-difficulty=Master] .game-card-icon{background-color:#ffebee;color:#e74c3c}.game-card .game-card-footer{background:var(--bg-secondary);padding:.5rem .8rem;border-radius:8px;display:inline-block;margin-top:1rem}.game-card .play-now{color:var(--brand-primary);font-weight:600;display:flex;align-items:center;gap:.4rem;font-size:.9rem}.best-time{display:flex;align-items:center;gap:.5rem;font-size:.9rem;color:var(--text-muted);font-weight:500}.best-time svg{color:#f1c40f}@keyframes fade-in-up{0%{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}.animate-fade-in{animation:fade-in-up .5s ease-out both;animation-delay:var(--delay, 0s)}