body{margin:0;min-height:100vh;transition:all .3s ease}.app-container{min-height:100vh;padding:2rem}.theme-toggle{position:fixed;top:20px;right:20px;padding:8px 16px;border-radius:20px;border:none;cursor:pointer;display:flex;align-items:center;gap:8px;font-weight:700;transition:all .3s ease;z-index:1000}.theme-toggle:hover{transform:scale(1.05)}