body {
    background-color: #1c1c1c; /* Primary dark color */
    color: #f9f9f9; /* White for clarity */
    font-family: 'Montserrat', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
}

.calculator-container {
    background-color: #2a2a2a; /* Slightly lighter dark for contrast */
    padding: 40px;
    border-radius: 8px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.4);
    width: 90%;
    max-width: 500px;
    text-align: center;
}

h1 {
    color: #b73239; /* Muted red accent */
    font-weight: 700;
    text-transform: uppercase;
}

p {
    color: #7a7a7a; /* Grey for supporting text */
    line-height: 1.6;
}

.input-group {
    margin-bottom: 20px;
    text-align: left;
}

label {
    display: block;
    margin-bottom: 8px;
    font-weight: 700;
    color: #f9f9f9;
}

input, select {
    width: 100%;
    padding: 12px;
    border: 1px solid #444;
    border-radius: 4px;
    background-color: #333;
    color: #f9f9f9;
    box-sizing: border-box;
    font-family: 'Montserrat', sans-serif;
    font-size: 16px;
}

select {
    appearance: none;
    background-image: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="%23f9f9f9"><path d="M7 10l5 5 5-5z"/></svg>');
    background-repeat: no-repeat;
    background-position: right 12px top 50%;
    background-size: 16px;
    cursor: pointer;
}

.calculate-btn {
    width: 100%;
    padding: 15px;
    background-color: #b73239;
    color: #fff;
    border: none;
    border-radius: 4px;
    font-size: 18px;
    font-weight: 700;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.calculate-btn:hover {
    background-color: #e2a53e; /* Gold accent on hover */
}

.result-container {
    margin-top: 25px;
    background-color: #333;
    padding: 20px;
    border-radius: 4px;
    text-align: center;
    min-height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
}

#result {
    font-size: 18px;
    font-weight: 700;
    color: #f9f9f9;
}

@media (max-width: 600px) {
    .calculator-container {
        padding: 20px;
    }
}