* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background: linear-gradient(135deg, #1e3c72 0%, #2a5298 100%);
            min-height: 100vh;
            padding: 20px;
            color: white;
        }

        .container {
            max-width: 800px;
            margin: 0 auto;
            background: rgba(255, 255, 255, 0.08);
            backdrop-filter: blur(20px);
            border-radius: 24px;
            padding: 32px;
            box-shadow: 0 24px 48px rgba(0, 0, 0, 0.2);
            border: 1px solid rgba(255, 255, 255, 0.15);
        }

        h1 {
            text-align: center;
            margin-bottom: 32px;
            font-size: 2.5rem;
            font-weight: 700;
            background: linear-gradient(135deg, #00d4ff, #00b4d8);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }

        .category-selector {
            display: flex;
            justify-content: center;
            gap: 15px;
            margin-bottom: 30px;
            flex-wrap: wrap;
        }

        .category-btn {
            padding: 14px 28px;
            border: none;
            border-radius: 30px;
            background: rgba(255, 255, 255, 0.12);
            color: white;
            cursor: pointer;
            transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
            font-size: 16px;
            font-weight: 500;
            backdrop-filter: blur(10px);
            border: 1px solid rgba(255, 255, 255, 0.1);
        }

        .category-btn:hover {
            background: rgba(255, 255, 255, 0.2);
            transform: translateY(-2px);
            border: 1px solid rgba(255, 255, 255, 0.2);
        }

        .category-btn.active {
            background: linear-gradient(135deg, #00d4ff, #00b4d8);
            transform: scale(1.05);
            box-shadow: 0 8px 24px rgba(0, 180, 216, 0.3);
            border: 1px solid transparent;
        }

        .converter-section {
            display: grid;
            grid-template-columns: 1fr auto 1fr;
            gap: 24px;
            align-items: center;
            margin-bottom: 32px;
        }

        .input-group {
            background: rgba(255, 255, 255, 0.08);
            border-radius: 16px;
            padding: 24px;
            backdrop-filter: blur(15px);
            border: 1px solid rgba(255, 255, 255, 0.12);
        }

        .input-group label {
            display: block;
            margin-bottom: 12px;
            font-weight: 600;
            font-size: 14px;
            text-transform: uppercase;
            letter-spacing: 0.5px;
            opacity: 0.9;
        }

        .input-wrapper {
            position: relative;
            margin-bottom: 16px;
        }

        input[type="number"] {
            width: 100%;
            padding: 16px 50px 16px 16px;
            border: none;
            border-radius: 12px;
            background: rgba(255, 255, 255, 0.95);
            color: #1a1a1a;
            font-size: 18px;
            font-weight: 500;
            outline: none;
            transition: all 0.3s ease;
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
        }

        input[type="number"]:focus {
            box-shadow: 0 4px 16px rgba(0, 212, 255, 0.2);
            background: rgba(255, 255, 255, 1);
        }

        .voice-btn {
            position: absolute;
            right: 12px;
            top: 50%;
            transform: translateY(-50%);
            background: linear-gradient(135deg, #00d4ff, #00b4d8);
            border: none;
            border-radius: 50%;
            width: 36px;
            height: 36px;
            cursor: pointer;
            color: white;
            font-size: 16px;
            transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
            box-shadow: 0 4px 12px rgba(0, 180, 216, 0.3);
        }

        .voice-btn:hover {
            transform: translateY(-50%) scale(1.1);
            box-shadow: 0 6px 16px rgba(0, 180, 216, 0.4);
        }

        .voice-btn.listening {
            animation: pulse 1s infinite;
        }

        @keyframes pulse {
            0% { transform: translateY(-50%) scale(1); box-shadow: 0 4px 12px rgba(0, 180, 216, 0.3); }
            50% { transform: translateY(-50%) scale(1.2); box-shadow: 0 8px 20px rgba(0, 180, 216, 0.5); }
            100% { transform: translateY(-50%) scale(1); box-shadow: 0 4px 12px rgba(0, 180, 216, 0.3); }
        }

        select {
            width: 100%;
            padding: 16px;
            border: none;
            border-radius: 12px;
            background: rgba(255, 255, 255, 0.95);
            color: #1a1a1a;
            font-size: 16px;
            font-weight: 500;
            outline: none;
            cursor: pointer;
            transition: all 0.3s ease;
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
        }

        select:focus {
            box-shadow: 0 4px 16px rgba(0, 212, 255, 0.2);
            background: rgba(255, 255, 255, 1);
        }

        .swap-btn {
            background: linear-gradient(135deg, #00d4ff, #00b4d8);
            border: none;
            border-radius: 50%;
            width: 64px;
            height: 64px;
            cursor: pointer;
            color: white;
            font-size: 24px;
            transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
            box-shadow: 0 8px 24px rgba(0, 180, 216, 0.3);
        }

        .swap-btn:hover {
            transform: rotate(180deg) scale(1.1);
            box-shadow: 0 12px 32px rgba(0, 180, 216, 0.4);
        }

        .visual-comparison {
            background: rgba(255, 255, 255, 0.08);
            border-radius: 16px;
            padding: 24px;
            backdrop-filter: blur(15px);
            border: 1px solid rgba(255, 255, 255, 0.12);
            text-align: center;
            min-height: 160px;
            display: flex;
            flex-direction: column;
            justify-content: center;
        }

        .comparison-icon {
            font-size: 52px;
            margin-bottom: 16px;
            animation: bounce 2s infinite;
        }

        @keyframes bounce {
            0%, 100% { transform: translateY(0); }
            50% { transform: translateY(-12px); }
        }

        .comparison-text {
            font-size: 18px;
            line-height: 1.6;
            font-weight: 500;
        }

        .error-message {
            color: #ff6b85;
            text-align: center;
            margin-top: 12px;
            font-weight: 500;
        }

        @media (max-width: 768px) {
            .converter-section {
                grid-template-columns: 1fr;
                gap: 15px;
            }
            
            .swap-btn {
                transform: rotate(90deg);
            }
            
            .swap-btn:hover {
                transform: rotate(270deg) scale(1.1);
            }
        }