/* ব্যাকগ্রাউন্ড বৃত্ত */
        .area {
            position: absolute;
            width: 100%;
            height: 100%;
            overflow: hidden;
            top: 0;
            left: 0;
            z-index: -1;
        }

        .circles li {
            position: absolute;
            list-style: none;
            display: block;
            width: 20px;
            height: 20px;
            background: rgba(255, 255, 255, 0.2);
            animation: animate 25s linear infinite;
            bottom: -150px;
            border-radius: 50%;
        }

        .circles li:nth-child(1) { left: 25%; width: 80px; height: 80px; animation-delay: 0s; }
        .circles li:nth-child(2) { left: 10%; width: 20px; height: 20px; animation-delay: 2s; animation-duration: 12s; }
        .circles li:nth-child(3) { left: 70%; width: 20px; height: 20px; animation-delay: 4s; }
        .circles li:nth-child(4) { left: 40%; width: 60px; height: 60px; animation-delay: 0s; animation-duration: 18s; }
        .circles li:nth-child(5) { left: 65%; width: 20px; height: 20px; animation-delay: 0s; }
        .circles li:nth-child(6) { left: 75%; width: 110px; height: 110px; animation-delay: 3s; }
        .circles li:nth-child(7) { left: 35%; width: 150px; height: 150px; animation-delay: 7s; }
        .circles li:nth-child(8) { left: 50%; width: 25px; height: 25px; animation-delay: 15s; animation-duration: 45s; }
        .circles li:nth-child(9) { left: 20%; width: 15px; height: 15px; animation-delay: 2s; animation-duration: 35s; }
        .circles li:nth-child(10) { left: 85%; width: 150px; height: 150px; animation-delay: 0s; animation-duration: 11s; }

        @keyframes animate {
            0% { transform: translateY(0) rotate(0deg); opacity: 1; }
            100% { transform: translateY(-1000px) rotate(720deg); opacity: 0; }
        }