.catchy{display:block;margin-top:.7em;font-size:1.18rem;font-weight:700;color:#0078d7;letter-spacing:.01em;text-shadow:0 1px 8px rgba(0,120,215,.08)}.app-container.dark .catchy{color:gold;text-shadow:0 1px 8px rgba(255,215,0,.08)}.challenge-brain{display:flex;flex-direction:column;align-items:center;margin-top:.5em;margin-bottom:.5em;gap:.2em}.challenge{font-size:1.08rem;font-weight:600;color:#e4572e;letter-spacing:.01em;text-shadow:0 1px 6px rgba(228,87,46,.08)}.app-container.dark .challenge{color:#ffb347;text-shadow:0 1px 6px rgba(255,179,71,.08)}.brain{font-size:1.02rem;font-weight:500;color:#2e86ab;letter-spacing:.01em;text-shadow:0 1px 6px rgba(46,134,171,.08)}.app-container.dark .brain{color:#7fd1b9;text-shadow:0 1px 6px rgba(127,209,185,.08)}.coming-soon-header{margin-top:3.5rem;margin-bottom:1.5rem;text-align:center;animation:fadeIn 1.2s cubic-bezier(.4,0,.2,1)}.coming-soon-header h1{font-size:2.5rem;font-weight:800;letter-spacing:.03em;margin:0 0 .5rem;color:#0078d7;text-shadow:0 2px 12px rgba(0,120,215,.08)}.app-container.dark .coming-soon-header h1{color:gold;text-shadow:0 2px 12px rgba(255,215,0,.08)}.catchline{font-size:1.15rem;color:#444;font-weight:500;margin:0 auto;max-width:420px;line-height:1.5}.app-container.dark .catchline{color:#ffe}@keyframes fadeIn{0%{opacity:0;transform:translateY(-30px)}to{opacity:1;transform:translateY(0)}}.top-bar{width:100%;display:flex;justify-content:flex-end;align-items:center;position:absolute;top:0;left:0;padding:1rem 2rem 0 0;box-sizing:border-box;z-index:10}.switch{position:relative;display:inline-block;width:48px;height:24px}.slider{position:absolute;cursor:pointer;top:0;left:0;right:0;bottom:0;background-color:#ccc;transition:background .4s;border-radius:24px}input:checked+.slider{background-color:#0078d7}.slider-knob{position:absolute;top:3px;left:3px;width:18px;height:18px;background:#fff;border-radius:50%;transition:transform .4s;display:flex;align-items:center;justify-content:center;font-size:1.1rem;transition:background .3s;box-shadow:0 1px 4px #0000001f}input:checked+.slider .slider-knob{transform:translate(24px)}body{margin:0;font-family:Segoe UI,Tahoma,Geneva,Verdana,sans-serif}.app-container{min-height:100vh;background:#f5f5f5;color:#222;display:flex;flex-direction:column;align-items:center;justify-content:center;transition:background .3s,color .3s;position:relative}.app-container.dark{background:#181818;color:#f5f5f5}.header{margin-top:2.5rem;margin-bottom:1rem;display:flex;align-items:center;justify-content:center}.status{font-size:1.2rem;margin-bottom:1rem}.board{display:grid;grid-template-columns:repeat(3,70px);grid-template-rows:repeat(3,70px);gap:10px;margin-bottom:1rem}.cell{width:70px;height:70px;font-size:2rem;background:#fff;border:2px solid #888;border-radius:10px;cursor:pointer;transition:background .2s,color .2s}.app-container.dark .cell{background:#222;color:#f5f5f5;border:2px solid #444}.gameover-flash{animation:flashGameOver .9s cubic-bezier(.4,0,.2,1)}@keyframes flashGameOver{0%{box-shadow:0 0 #ffd70000,0 0 #0078d700}10%{box-shadow:0 0 40px 10px #ffd70040,0 0 40px 10px #0078d72e}50%{box-shadow:0 0 60px 20px #ffd7002e,0 0 60px 20px #0078d71f}to{box-shadow:0 0 #ffd70000,0 0 #0078d700}}.cell:focus{outline:none;border-color:#0078d7}.reset-btn{padding:.5rem 1.5rem;font-size:1rem;border:none;border-radius:5px;background:#0078d7;color:#fff;cursor:pointer;transition:background .2s}.reset-btn:hover{background:#005fa3}.switch{position:relative;display:inline-block;width:44px;height:24px;vertical-align:middle}.switch input{opacity:0;width:0;height:0}.slider{position:absolute;cursor:pointer;top:0;left:0;right:0;bottom:0;background:#e2e8f0;transition:background .3s;border-radius:999px;box-shadow:0 1px 4px #00000014;overflow:hidden}input:checked+.slider{background:#222e3a}.slider-knob{position:absolute;top:3px;left:3px;width:18px;height:18px;background:#fff;border-radius:50%;transition:transform .3s cubic-bezier(.4,0,.2,1);display:flex;align-items:center;justify-content:center;font-size:1.1rem;box-shadow:0 1px 4px #0000001f;z-index:2}input:checked+.slider .slider-knob{transform:translate(20px);background:#222e3a}.icon{transition:color .3s,opacity .3s;font-size:1.1rem;display:flex;align-items:center;justify-content:center;width:18px;height:18px;z-index:3}.sun{color:#fffbe6;opacity:1}.moon{color:#b8860b;opacity:1}@media (max-width: 600px){.board{grid-template-columns:repeat(3,50px);grid-template-rows:repeat(3,50px);gap:6px}.cell{width:50px;height:50px;font-size:1.3rem}}