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

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 20px;
        }

        .calculator {
            background: rgba(255, 255, 255, 0.1);
            backdrop-filter: blur(10px);
            border-radius: 20px;
            padding: 25px;
            box-shadow: 0 25px 45px rgba(0, 0, 0, 0.1);
            border: 1px solid rgba(255, 255, 255, 0.2);
            max-width: 400px;
            width: 100%;
        }

        .mode-selector {
            display: flex;
            margin-bottom: 20px;
            background: rgba(255, 255, 255, 0.1);
            border-radius: 15px;
            padding: 5px;
        }

        .mode-btn {
            flex: 1;
            padding: 10px 5px;
            border: none;
            background: transparent;
            color: white;
            cursor: pointer;
            border-radius: 10px;
            font-size: 12px;
            transition: all 0.3s ease;
        }

        .mode-btn.active {
            background: rgba(255, 255, 255, 0.2);
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
        }

        .display {
            background: rgba(0, 0, 0, 0.3);
            border-radius: 15px;
            padding: 20px;
            margin-bottom: 20px;
            min-height: 80px;
            display: flex;
            flex-direction: column;
            justify-content: center;
        }

        .display-text {
            color: white;
            font-size: 24px;
            text-align: right;
            word-wrap: break-word;
            min-height: 30px;
        }

        .expression {
            color: rgba(255, 255, 255, 0.7);
            font-size: 14px;
            text-align: right;
            margin-bottom: 5px;
        }

        .buttons {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 10px;
        }

        .btn {
            padding: 20px;
            border: none;
            border-radius: 15px;
            font-size: 18px;
            cursor: pointer;
            transition: all 0.3s ease;
            background: rgba(255, 255, 255, 0.1);
            color: white;
            backdrop-filter: blur(5px);
            border: 1px solid rgba(255, 255, 255, 0.1);
        }

        .btn:hover {
            background: rgba(255, 255, 255, 0.2);
            transform: translateY(-2px);
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
        }

        .btn:active {
            transform: translateY(0);
        }

        .btn-operator {
            background: rgba(255, 107, 107, 0.3);
        }

        .btn-operator:hover {
            background: rgba(255, 107, 107, 0.5);
        }

        .btn-equals {
            background: rgba(72, 187, 120, 0.3);
        }

        .btn-equals:hover {
            background: rgba(72, 187, 120, 0.5);
        }

        .btn-clear {
            background: rgba(245, 101, 101, 0.3);
        }

        .btn-clear:hover {
            background: rgba(245, 101, 101, 0.5);
        }

        .btn-wide {
            grid-column: span 2;
        }

        .conversion-panel {
            display: none;
            grid-template-columns: 1fr;
            gap: 10px;
            margin-top: 20px;
        }

        .conversion-panel.active {
            display: grid;
        }

        .conversion-row {
            display: flex;
            gap: 10px;
            align-items: center;
        }

        .conversion-input {
            flex: 1;
            padding: 10px;
            border: none;
            border-radius: 10px;
            background: rgba(255, 255, 255, 0.1);
            color: white;
            font-size: 16px;
        }

        .conversion-input::placeholder {
            color: rgba(255, 255, 255, 0.6);
        }

        .conversion-select {
            padding: 10px;
            border: none;
            border-radius: 10px;
            background: rgba(255, 255, 255, 0.1);
            color: white;
            font-size: 14px;
        }

        .conversion-select option {
            background: #333;
            color: white;
        }

        .metric-buttons {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 10px;
            margin-top: 15px;
        }

        .metric-btn {
            padding: 10px;
            border: none;
            border-radius: 10px;
            background: rgba(255, 255, 255, 0.1);
            color: white;
            font-size: 12px;
            cursor: pointer;
            transition: all 0.3s ease;
        }

        .metric-btn:hover {
            background: rgba(255, 255, 255, 0.2);
        }

        .currency-display {
            background: rgba(0, 0, 0, 0.2);
            border-radius: 10px;
            padding: 15px;
            margin-bottom: 15px;
            color: white;
            text-align: center;
        }

        .history {
            max-height: 100px;
            overflow-y: auto;
            margin-bottom: 10px;
        }

        .history-item {
            color: rgba(255, 255, 255, 0.7);
            font-size: 12px;
            padding: 2px 0;
        }

        @media (max-width: 480px) {
            .calculator {
                padding: 15px;
            }
            
            .btn {
                padding: 15px;
                font-size: 16px;
            }
            
            .display-text {
                font-size: 20px;
            }
        }