* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
        }
        body {
            background: radial-gradient(circle at 10% 30%, #13294e, #0b1a2f);
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 1.5rem;
        }
        .test-panel {
            background: rgba(18, 28, 40, 0.85);
            backdrop-filter: blur(14px);
            -webkit-backdrop-filter: blur(14px);
            border-radius: 2.5rem;
            box-shadow: 0 30px 50px -15px #00000080, 0 0 0 1px rgba(120, 180, 255, 0.2) inset;
            width: min(1000px, 100%);
            padding: 2.5rem 2.5rem 2.8rem;
            border: 1px solid #2f4b70;
        }
        h1 {
            font-size: 2.4rem;
            font-weight: 600;
            display: flex;
            align-items: center;
            gap: 0.8rem;
            color: #e5f0ff;
            letter-spacing: -0.02em;
            text-shadow: 0 2px 5px #00000040;
        }
        h1 i {
            background: linear-gradient(145deg, #5ca0ff, #2970cc);
            -webkit-background-clip: text;
            background-clip: text;
            color: transparent;
            font-size: 2.5rem;
        }
        .sub {
            color: #9bbae0;
            font-size: 1rem;
            margin-left: 4rem;
            margin-bottom: 2.5rem;
            border-left: 3px solid #3d8cff;
            padding-left: 1.2rem;
            font-weight: 350;
        }
        .url-input-area {
            display: flex;
            flex-wrap: wrap;
            gap: 1rem;
            margin-bottom: 2rem;
            align-items: center;
            background: rgba(0, 0, 0, 0.3);
            border-radius: 4rem;
            padding: 0.5rem 0.5rem 0.5rem 2rem;
            border: 1px solid #35648b;
        }
        .url-input-area i {
            color: #72b2ff;
            font-size: 1.3rem;
        }
        #urlInput {
            flex: 4 1 300px;
            background: transparent;
            border: none;
            padding: 1rem 0.5rem;
            font-size: 1.1rem;
            color: white;
            outline: none;
        }
        #urlInput::placeholder {
            color: #6d8eb0;
            font-weight: 300;
        }
        .test-btn {
            background: #1f5fcf;
            border: none;
            color: white;
            padding: 0.9rem 2.2rem;
            border-radius: 3rem;
            font-weight: 600;
            font-size: 1.1rem;
            display: inline-flex;
            align-items: center;
            gap: 0.7rem;
            cursor: pointer;
            box-shadow: 0 10px 18px -6px #0e2b50;
            transition: 0.15s;
            border: 1px solid #7ab0ff;
        }
        .test-btn i {
            color: white;
        }
        .test-btn:active {
            transform: translateY(2px);
            box-shadow: 0 5px 10px #00000060;
        }
        .test-btn:disabled {
            opacity: 0.45;
            pointer-events: none;
        }

        /* properties grid / cards */
        .speed-stats {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
            gap: 1.2rem;
            margin: 2.5rem 0 1.8rem;
        }
        .stat-card {
            background: #0f253bb3;
            border-radius: 2rem;
            padding: 1.5rem 1rem;
            text-align: center;
            border: 1px solid #315d88;
            backdrop-filter: blur(4px);
            box-shadow: 0 8px 0 #082135;
        }
        .stat-card i {
            font-size: 2rem;
            color: #65b0ff;
            margin-bottom: 0.6rem;
        }
        .stat-label {
            font-size: 0.9rem;
            text-transform: uppercase;
            letter-spacing: 0.06em;
            color: #a3c6ff;
        }
        .stat-value {
            font-size: 2.2rem;
            font-weight: 700;
            color: white;
            line-height: 1.3;
            text-shadow: 0 3px 5px black;
        }
        .stat-unit {
            font-size: 0.9rem;
            color: #7a9fd5;
            margin-left: 0.2rem;
        }
        .extra-properties {
            background: #0f1e2fb3;
            border-radius: 2rem;
            padding: 1.8rem 2rem;
            margin: 2rem 0 2rem;
            border: 1px solid #336699;
        }
        .props-grid {
            display: flex;
            flex-wrap: wrap;
            gap: 2rem 3rem;
            margin-top: 1rem;
            color: #d1e2fc;
        }
        .prop-item {
            display: flex;
            align-items: center;
            gap: 1rem;
            font-size: 1.1rem;
        }
        .prop-item i {
            width: 2rem;
            color: #70b2ff;
        }
        .prop-item span:first-of-type {
            font-weight: 300;
            color: #9ab9e6;
        }
        .prop-item .prop-val {
            font-weight: 600;
            color: white;
            background: #1f3f60;
            padding: 0.3rem 1rem;
            border-radius: 30px;
        }

        .action-row {
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            align-items: center;
            margin-top: 1.2rem;
        }
        .download-btn {
            background: #1f6f4c;
            border: none;
            color: white;
            padding: 1rem 2.4rem;
            border-radius: 3rem;
            font-weight: 600;
            font-size: 1.1rem;
            display: inline-flex;
            align-items: center;
            gap: 0.8rem;
            box-shadow: 0 8px 0 #0f3d2b;
            cursor: pointer;
            transition: 0.1s;
            border: 1px solid #72ca9a;
        }
        .download-btn:active {
            transform: translateY(4px);
            box-shadow: 0 4px 0 #0f3d2b;
        }
        .secure-badge {
            background: #1c3f5e;
            padding: 0.6rem 1.5rem;
            border-radius: 40px;
            color: #c5e0ff;
            font-weight: 500;
            font-size: 0.95rem;
            border: 1px solid #5c95cf;
        }
        .secure-badge i {
            color: #b1dc59;
        }
        .toast-info {
            color: #bbd6ff;
            margin: 1rem 0 0;
            font-size: 0.9rem;
            display: flex;
            align-items: center;
            gap: 0.5rem;
            background: #00000040;
            padding: 0.6rem 1.5rem;
            border-radius: 3rem;
            width: fit-content;
        }
        .footer-note {
            margin-top: 2rem;
            font-size: 0.85rem;
            color: #5679a1;
            display: flex;
            gap: 2rem;
            border-top: 1px solid #1f4560;
            padding-top: 1.5rem;
        }