:root{--bg: #050505;--surface: #0d0d0d;--border: #1a1a1a;--text: #e8e8e8;--text-dim: #666;--accent-x: #ff3b3b;--accent-o: #3b8bff;--accent-win: #ffd700;--radius: 4px}*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}body{font-family:JetBrains Mono,SF Mono,Fira Code,monospace;background:var(--bg);color:var(--text);min-height:100dvh;display:flex;justify-content:center;align-items:center}#root{width:100%;max-width:420px;padding:1.5rem}.app{display:flex;flex-direction:column;align-items:center;gap:1.5rem}.app__header{text-align:center}.app__title{font-size:3rem;font-weight:800;letter-spacing:.15em;line-height:1}.app__title-x{color:var(--accent-x)}.app__title-sep{color:var(--text-dim);font-weight:300}.app__title-o{color:var(--accent-o)}.app__subtitle{color:var(--text-dim);font-size:.75rem;text-transform:uppercase;letter-spacing:.2em;margin-top:.5rem}.mode-selector{display:flex;gap:.5rem}.mode-selector__btn{font-family:inherit;font-size:.7rem;text-transform:uppercase;letter-spacing:.1em;padding:.5rem .75rem;border:1px solid var(--border);border-radius:var(--radius);background:transparent;color:var(--text-dim);cursor:pointer;transition:all .15s ease}.mode-selector__btn:hover{border-color:var(--text-dim);color:var(--text)}.mode-selector__btn--active{border-color:var(--text);color:var(--text);background:var(--surface)}.game-status{text-align:center;min-height:2.5rem;display:flex;flex-direction:column;align-items:center;justify-content:center}.game-status__text{font-size:.85rem;color:var(--text-dim);transition:color .2s ease}.game-status__text--final{color:var(--text);font-weight:600}.game-status__error{font-size:.65rem;color:#ff6b35;margin-top:.25rem}.board{display:grid;grid-template-columns:repeat(3,1fr);gap:3px;width:100%;max-width:300px;aspect-ratio:1;background:var(--border);border-radius:var(--radius);overflow:hidden}.cell{background:var(--surface);border:none;cursor:pointer;display:flex;align-items:center;justify-content:center;font-family:inherit;transition:background .1s ease}.cell:hover:not(:disabled){background:#141414}.cell:disabled{cursor:default}.cell__mark{font-size:2.5rem;font-weight:800;line-height:1;animation:mark-appear .15s ease-out}.cell--x .cell__mark{color:var(--accent-x)}.cell--o .cell__mark{color:var(--accent-o)}.cell--winning{background:#1a1500}.cell--winning .cell__mark{color:var(--accent-win);animation:mark-pulse .6s ease-in-out}.app__play-again{font-family:inherit;font-size:.75rem;text-transform:uppercase;letter-spacing:.15em;padding:.6rem 1.5rem;border:1px solid var(--text-dim);border-radius:var(--radius);background:transparent;color:var(--text);cursor:pointer;transition:all .15s ease}.app__play-again:hover{background:var(--text);color:var(--bg)}.app__footer{font-size:.6rem;color:var(--text-dim)}.app__footer a{color:var(--text-dim);text-decoration:none;border-bottom:1px solid transparent;transition:border-color .15s ease}.app__footer a:hover{border-color:var(--text-dim)}@keyframes mark-appear{0%{opacity:0;transform:scale(.5)}to{opacity:1;transform:scale(1)}}@keyframes mark-pulse{0%,to{transform:scale(1)}50%{transform:scale(1.15)}}@media(max-width:360px){#root{padding:1rem}.app__title{font-size:2.5rem}.cell__mark{font-size:2rem}}