* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
        }

        body {
            background: linear-gradient(145deg, #0b0e14 0%, #1a1f2a 100%);
            min-height: 100vh;
            display: flex;
            justify-content: center;
            align-items: center;
            padding: 1.5rem;
        }

        .tool-container {
            max-width: 800px;
            width: 100%;
            background: rgba(20, 25, 35, 0.75);
            backdrop-filter: blur(16px);
            -webkit-backdrop-filter: blur(16px);
            border-radius: 40px;
            border: 1px solid rgba(255, 255, 255, 0.08);
            box-shadow: 0 25px 40px -10px rgba(0,0,0,0.5);
            padding: 2.5rem 2rem;
            color: #edf2fb;
            transition: all 0.2s;
        }

        h1 {
            font-size: 1.9rem;
            font-weight: 600;
            letter-spacing: -0.01em;
            display: flex;
            align-items: center;
            gap: 0.5rem;
            margin-bottom: 0.25rem;
        }

        h1 span {
            background: #3b82f6;
            padding: 0.2rem 0.7rem;
            font-size: 0.85rem;
            font-weight: 500;
            border-radius: 100px;
            color: white;
            text-transform: uppercase;
            letter-spacing: 0.04em;
        }

        .subhead {
            font-size: 0.95rem;
            color: #a6b3cf;
            margin-bottom: 2rem;
            border-left: 4px solid #3b82f6;
            padding-left: 1rem;
            background: rgba(59,130,246,0.08);
            border-radius: 0 12px 12px 0;
            line-height: 1.5;
        }

        /* drop zone */
        .drop-zone {
            background: rgba(12, 18, 28, 0.6);
            border: 2px dashed rgba(59,130,246,0.4);
            border-radius: 28px;
            padding: 2.5rem 1.5rem;
            text-align: center;
            transition: all 0.2s ease;
            cursor: pointer;
            margin-bottom: 1.5rem;
            position: relative;
        }

        .drop-zone:hover {
            border-color: #3b82f6;
            background: rgba(59,130,246,0.08);
        }

        .drop-zone.dragover {
            border-color: #3b82f6;
            background: rgba(59,130,246,0.15);
            transform: scale(1.01);
        }

        .upload-icon {
            font-size: 3.2rem;
            line-height: 1;
            margin-bottom: 0.7rem;
            filter: drop-shadow(0 8px 6px rgba(0,0,0,0.3));
        }

        .drop-zone p {
            font-size: 1.2rem;
            font-weight: 450;
            color: #d6e2ff;
        }

        .drop-zone small {
            display: block;
            margin-top: 0.8rem;
            color: #8f9eb5;
            font-size: 0.85rem;
        }

        .file-info {
            background: rgba(0, 0, 0, 0.3);
            border-radius: 20px;
            padding: 1.4rem 1.8rem;
            margin-bottom: 1.8rem;
            border: 1px solid rgba(255,255,255,0.05);
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            align-items: center;
        }

        .file-details {
            display: flex;
            flex-direction: column;
            gap: 0.3rem;
        }

        .file-name {
            font-weight: 600;
            font-size: 1.1rem;
            color: white;
            word-break: break-word;
        }

        .file-meta {
            font-size: 0.85rem;
            color: #a0afc5;
            display: flex;
            gap: 1rem;
            flex-wrap: wrap;
        }

        .file-meta span {
            background: #2a323f;
            padding: 0.25rem 0.9rem;
            border-radius: 30px;
            display: inline-block;
        }

        .action-group {
            display: flex;
            flex-wrap: wrap;
            gap: 1rem;
            align-items: center;
            justify-content: space-between;
            margin-top: 0.5rem;
        }

        .btn {
            background: rgba(255,255,255,0.05);
            border: 1px solid rgba(255,255,255,0.1);
            padding: 0.8rem 1.8rem;
            border-radius: 50px;
            font-weight: 550;
            font-size: 0.98rem;
            color: #edf2fb;
            cursor: pointer;
            transition: 0.2s;
            display: inline-flex;
            align-items: center;
            gap: 0.6rem;
            backdrop-filter: blur(4px);
        }

        .btn-primary {
            background: #3b82f6;
            border: none;
            color: white;
            box-shadow: 0 8px 18px rgba(59,130,246,0.25);
        }

        .btn-primary:hover {
            background: #2563eb;
            transform: translateY(-2px);
            box-shadow: 0 14px 22px rgba(37,99,235,0.3);
        }

        .btn:disabled {
            opacity: 0.4;
            pointer-events: none;
            filter: grayscale(0.6);
        }

        .btn-download {
            background: #1e293b;
            border-color: #4b5563;
        }

        .btn-download:hover {
            background: #2d3a4f;
            border-color: #6b7b8f;
        }

        .progress-section {
            margin: 1.2rem 0 1.5rem;
        }

        .progress-bar-bg {
            width: 100%;
            height: 10px;
            background: #232a33;
            border-radius: 100px;
            overflow: hidden;
        }

        .progress-fill {
            height: 10px;
            width: 0%;
            background: linear-gradient(90deg, #3b82f6, #a855f7);
            border-radius: 100px;
            transition: width 0.1s linear;
            box-shadow: 0 0 10px #3b82f6;
        }

        .status-msg {
            font-size: 0.95rem;
            color: #b9c7dd;
            margin-top: 0.5rem;
            min-height: 1.8rem;
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }

        .badge {
            background: #0f172a;
            padding: 0.2rem 0.8rem;
            border-radius: 30px;
            font-size: 0.75rem;
            font-weight: 600;
            color: #94a3b8;
            border: 1px solid #334155;
        }

        .footer-note {
            margin-top: 2rem;
            font-size: 0.78rem;
            color: #6f7d94;
            text-align: center;
            border-top: 1px solid rgba(255,255,255,0.06);
            padding-top: 1.5rem;
        }

        .error-msg {
            color: #f87171;
            background: rgba(220,38,38,0.15);
            padding: 0.5rem 1rem;
            border-radius: 40px;
            border-left: 3px solid #ef4444;
        }

        .flex-spacer {
            flex: 1;
        }

        @media (max-width: 550px) {
            .tool-container { padding: 1.8rem 1.2rem; }
            .file-info { flex-direction: column; align-items: flex-start; gap: 1rem; }
        }