@keyframes snowfall{0%{background-position:0 0,25px 25px}to{background-position:50px 50px,75px 75px}}@keyframes float{0%,to{transform:translateY(0)}50%{transform:translateY(-10px)}}@keyframes sparkle{0%,to{opacity:1}50%{opacity:.5}}@keyframes fadeSlideIn{0%{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}.fade-slide-in{animation:fadeSlideIn .6s ease-out forwards}.frost-effect{position:relative;overflow:hidden}.frost-effect:before{content:"";position:absolute;top:0;left:0;right:0;bottom:0;background:linear-gradient(120deg,#ffffff4d,#ffffff1a);-webkit-backdrop-filter:blur(4px);backdrop-filter:blur(4px);border-radius:inherit;opacity:0;transition:opacity .3s ease}.frost-effect:hover:before{opacity:1}.snowflake{position:fixed;pointer-events:none;animation:float 6s ease-in-out infinite;color:#fff;text-shadow:0 0 5px rgba(255,255,255,.8);opacity:.6}.sparkle{position:absolute;width:4px;height:4px;background:#fff;border-radius:50%;animation:sparkle 1.5s ease-in-out infinite}body{margin:0;font-family:Inter,-apple-system,BlinkMacSystemFont,sans-serif;min-height:100vh;background:linear-gradient(#ffffffd9,#ffffffd9),url(https://images.unsplash.com/photo-1482597869166-609e91429f40?auto=format&fit=crop&q=80&w=1920) center/cover fixed;color:#2d3748;position:relative}.container{max-width:800px;margin:3rem auto;padding:2.5rem;background:#ffffffeb;border-radius:16px;box-shadow:0 4px 20px #00000014,0 0 50px #94bee933 inset;-webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px);animation:fadeSlideIn .8s ease-out}h1{text-align:center;margin-bottom:1rem;font-size:2.5rem;font-weight:800;letter-spacing:-.025em;background:linear-gradient(45deg,#1a365d,#2b6cb0,#90cdf4);-webkit-background-clip:text;-webkit-text-fill-color:transparent;animation:float 6s ease-in-out infinite}.todo-section{background:#fffc;padding:2rem;border-radius:12px;border:1px solid rgba(226,232,240,.8);transition:transform .3s ease,box-shadow .3s ease}.todo-section:hover{transform:translateY(-2px);box-shadow:0 8px 30px #0000001a,0 0 20px #94bee94d}.task{display:flex;align-items:center;gap:.75rem;padding:.75rem;background:#fff;border-radius:8px;border:1px solid #e2e8f0;transition:all .3s ease;animation:fadeSlideIn .5s ease-out;position:relative;overflow:hidden}.task:hover{transform:translate(4px);background:linear-gradient(45deg,#fffffff2,#edf2f7f2);border-color:#90cdf4}.add-task button{padding:.75rem 1.5rem;background:linear-gradient(45deg,#2b6cb0,#4299e1);color:#fff;border:none;border-radius:8px;cursor:pointer;font-weight:600;transition:all .3s ease;position:relative;overflow:hidden}.add-task button:hover{transform:translateY(-2px);box-shadow:0 4px 12px #4299e140,0 0 0 2px #4299e11a}.add-task button:after{content:"";position:absolute;top:-50%;left:-50%;width:200%;height:200%;background:linear-gradient(transparent,rgba(255,255,255,.2),transparent);transform:rotate(45deg);transition:.5s}.add-task button:hover:after{left:100%}.completion-message{text-align:center;margin-top:3rem;padding:2rem;background:linear-gradient(135deg,#ebf8ff,#e6fffa);border-radius:12px;animation:float 6s ease-in-out infinite;position:relative}.task.frost-effect:hover:before{opacity:.5}.task input[type=checkbox]{width:1.25rem;height:1.25rem;border:2px solid #4299e1;border-radius:4px;cursor:pointer;transition:all .3s ease;position:relative}.task input[type=checkbox]:checked{background:#4299e1;border-color:#2b6cb0;animation:sparkle .5s ease-out}