.calculator {
            background: white;
            border-radius: 20px;
            padding: 40px;
            box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
            max-width: 500px;
            margin: 0 auto;
        }

        .calculator h1 {
            color: #333;
            margin-bottom: 10px;
            font-size: 28px;
            text-align: center;
        }

        .calculator .subtitle {
            color: #666;
            text-align: center;
            margin-bottom: 30px;
            font-size: 14px;
        }

        .calculator .form-label {
            color: #555;
            font-weight: 600;
            font-size: 14px;
        }

        .calculator .form-control {
            padding: 15px;
            border: 2px solid #e0e0e0;
            border-radius: 10px;
            font-size: 16px;
            transition: all 0.3s;
        }

        .calculator .form-control:focus {
            border-color: #667eea;
            box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
        }

        .calculator .btn-calculate {
            width: 100%;
            padding: 15px;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            border: none;
            border-radius: 10px;
            font-size: 18px;
            font-weight: 600;
            transition: transform 0.2s, box-shadow 0.2s;
        }

        .calculator .btn-calculate:hover {
            transform: translateY(-2px);
            box-shadow: 0 10px 25px rgba(102, 126, 234, 0.3);
        }

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

        .calculator .result {
            margin-top: 30px;
            padding: 25px;
            background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
            border-radius: 15px;
            text-align: center;
            display: none;
        }

        .calculator .result.show {
            display: block;
            animation: slideIn 0.4s ease-out;
        }

        @keyframes slideIn {
            from {
                opacity: 0;
                transform: translateY(-10px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .calculator .result-label {
            color: #666;
            font-size: 14px;
            margin-bottom: 10px;
        }

        .calculator .result-value {
            font-size: 42px;
            font-weight: bold;
            color: #667eea;
        }

        .calculator .error-message {
            color: #e74c3c;
            font-size: 13px;
            margin-top: 5px;
            display: none;
        }

        .calculator .error-message.show {
            display: block;
        }