.cbe-container {
    border: 2px solid #2c3e50;
    padding: 20px;
    max-width: 300px;
    background: #f9f9f9;
    border-radius: 10px;
    font-family: Arial, sans-serif;
}

.cbe-container h3 {
    text-align: center;
    color: #2c3e50;
}

.cbe-container label {
    display: block;
    margin-bottom: 10px;
}

.cbe-container input, 
.cbe-container select {
    width: 100%;
    padding: 5px;
    margin-top: 5px;
    margin-bottom: 15px;
}

#cbe-calc-btn {
    width: 100%;
    padding: 8px;
    background-color: #2c3e50;
    color: #fff;
    border: none;
    border-radius: 5px;
    cursor: pointer;
}

#cbe-calc-btn:hover {
    background-color: #34495e;
}

#cbe-result {
    margin-top: 15px;
    font-weight: bold;
    text-align: center;
    color: #e74c3c;
}

.cbe-error {
    color: #c0392b;
}