:root{--color-bg: #121212;--color-text: #ffffff;--color-primary: #4361ee;--color-secondary: #7209b7;--color-accent: #f72585;--color-surface: #1f1f1f;--color-surface-hover: #2d2d2d;--color-border: #404040;--color-success: #4cc9f0;--color-error: #f72585;--font-main: "Inter", system-ui, -apple-system, sans-serif;--spacing-xs: 4px;--spacing-sm: 8px;--spacing-md: 16px;--spacing-lg: 24px;--spacing-xl: 32px;--radius-sm: 4px;--radius-md: 8px;--radius-lg: 16px}@keyframes shake{0%,to{transform:translate(0)}25%{transform:translate(-5px)}75%{transform:translate(5px)}}@keyframes pulse-green{0%{transform:scale(1);box-shadow:0 0 #4cc9f0b3}70%{transform:scale(1.02);box-shadow:0 0 0 10px #4cc9f000}to{transform:scale(1);box-shadow:0 0 #4cc9f000}}@keyframes fade-in{0%{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}body{margin:0;padding:0;font-family:var(--font-main);background-color:var(--color-bg);color:var(--color-text);-webkit-font-smoothing:antialiased}*{box-sizing:border-box}button{cursor:pointer;border:none;font-family:inherit}.app-container{max-width:600px;margin:0 auto;padding:20px;display:flex;flex-direction:column;align-items:center;min-height:100vh}@media(max-width:450px){.app-container{padding:10px 5px}}.app-header{text-align:center;margin-bottom:2rem}.app-header h1{margin:0;color:var(--color-primary);font-size:2.5rem}.start-screen{text-align:center;margin-top:50px}.start-btn{background:var(--color-secondary);color:var(--color-bg);font-size:1.5rem;padding:15px 40px;border-radius:50px;font-weight:700;margin-top:30px;transition:transform .2s,background-color .2s;display:block;width:100%;max-width:300px;margin-left:auto;margin-right:auto}.mode-selection{display:flex;flex-direction:column;gap:15px;margin-top:30px}.btn-secondary{background:transparent;border:2px solid var(--color-secondary);color:var(--color-secondary)}.btn-secondary:hover{background:#7209b71a}.start-btn:hover{transform:scale(1.05)}.game-area{width:100%;display:flex;flex-direction:column;align-items:center}.game-info{width:100%;display:flex;justify-content:center;margin-bottom:20px}.game-board-container{display:flex;flex-direction:column;align-items:center;-webkit-user-select:none;user-select:none;touch-action:none;width:100%}.grid{display:grid;grid-template-columns:repeat(4,1fr);gap:var(--spacing-sm);padding:var(--spacing-sm);background:var(--color-surface);border-radius:var(--radius-md);box-shadow:0 4px 6px #0000001a;width:100%;max-width:500px;margin:0 auto}@media(max-width:450px){.grid{gap:4px;padding:4px}}.cell{width:auto;aspect-ratio:1;background:var(--color-bg);border-radius:var(--radius-sm);display:flex;align-items:center;justify-content:center;font-size:clamp(1.5rem,5vw,2.5rem);font-weight:700;cursor:pointer;transition:all .1s ease;border:2px solid var(--color-border)}.cell.selected{background:var(--color-primary);color:#fff;border-color:var(--color-primary);transform:scale(.95)}.shake{animation:shake .5s cubic-bezier(.36,.07,.19,.97) both}.valid-pulse{animation:pulse-green .5s ease-out}