body {
            font-family: sans-serif;
            line-height: 1.6;
            max-width: 800px;
            margin: 0 auto;
            padding: 20px;
            color: #333;
        }

        header {
            border-bottom: 2px solid #333;
            margin-bottom: 20px;
        }

        nav a {
            margin-right: 15px;
            color: #000;
            display: block;
        }
        .converter-box {
            border: 2px dashed #ccc;
            padding: 40px;
            text-align: center;
            border-radius: 8px;
            background: #f9f9f9;
        }

        button {
            padding: 10px 20px;
            background: #000;
            color: #fff;
            border: none;
            cursor: pointer;
            border-radius: 4px;
        }

        section {
            margin-top: 40px;
        }

        .spinner {
            width: 16px;
            height: 16px;
            border: 2px solid #ffffff;
            border-bottom-color: transparent;
            border-radius: 50%;
            display: inline-block;
            animation: rotation 1s linear infinite;
            margin-left: 8px;
            vertical-align: middle;
        }

        @keyframes rotation {
            0% {
                transform: rotate(0deg);
            }

            100% {
                transform: rotate(360deg);
            }
        }

        #convertBtn:disabled {
            background-color: #555;
            cursor: not-allowed;
            opacity: 0.8;
        }