:root{--primary-color: #2196F3;--primary-dark: #1976D2;--accent-color: #FFC107;--success-color: #4CAF50;--error-color: #F44336;--text-primary: #212121;--text-secondary: #757575;--bg-light: #FAFAFA;--bg-white: #FFFFFF;--border-color: #E0E0E0;--grid-border: #000000;--spacing-xs: 4px;--spacing-sm: 8px;--spacing-md: 16px;--spacing-lg: 24px;--spacing-xl: 32px;--font-family: "Inter", system-ui, -apple-system, sans-serif;--font-size-lg: 28px;--font-size-md: 20px;--font-size-sm: 16px}body{margin:0;font-family:var(--font-family);background-color:var(--bg-light);color:var(--text-primary);-webkit-font-smoothing:antialiased}#root{max-width:1200px;margin:0 auto;padding:var(--spacing-md);min-height:100vh;display:flex;flex-direction:column;align-items:center}.flex-center{display:flex;justify-content:center;align-items:center}.grid-container{display:grid;gap:0;border:2px solid var(--grid-border)}.grid-cell{background-color:var(--bg-white);width:100%;aspect-ratio:1;display:flex;justify-content:center;align-items:center;font-size:var(--font-size-lg);font-weight:700;position:relative;border:1px solid var(--grid-border);box-sizing:border-box}@media(max-width:600px){.grid-cell{font-size:var(--font-size-md)}}.grid-cell.header{background-color:var(--bg-white);color:#000}.grid-cell.active{border:3px solid var(--primary-color);z-index:1}.grid-cell.correct{color:var(--success-color)}.grid-cell.wrong{color:var(--error-color);animation:flash-red .3s ease}@keyframes flash-red{0%,to{background-color:var(--bg-white)}50%{background-color:#ffebee}}@keyframes pulse{0%{transform:scale(1)}50%{transform:scale(1.05)}to{transform:scale(1)}to{transform:scale(1)}}@keyframes hint-flash{0%{background-color:var(--bg-white)}50%{background-color:#e3f2fd;box-shadow:inset 0 0 10px #2196f34d}to{background-color:var(--bg-white)}}.hint-pulse-level{animation:hint-flash 1s ease-in-out 2}.hint-pulse-operator{animation:hint-flash 1s ease-in-out 2s 2 backwards}.material-symbols-outlined{font-variation-settings:"FILL" 0,"wght" 400,"GRAD" 0,"opsz" 24}