body{margin:0;font-family:sans-serif;transition:background .3s,color .3s}body.light{background-color:#fff;color:#000}body.dark{background-color:#111827;color:#fff}button{margin:.5rem;padding:.5rem 1rem;font-size:1rem;border:none;border-radius:6px;cursor:pointer}.increment-btn{background-color:#2563eb;color:#fff}.reset-btn{background-color:#dc2626;color:#fff}.toggle-btn{background-color:#d1d5db}