.calc-container {
    max-width: 100%;
    margin: 30px auto;
    padding: 20px;
    background: #fff;
    border-radius: 10px;
    box-shadow: 0 0 15px rgba(0, 0, 0, 0.1);
}

.calc-header {
    text-align: center;
    margin-bottom: 30px;
    border-bottom: 2px solid #555;
    padding-bottom: 15px;
    color: #555;
}

.form-label {
    font-weight: 600;
    color: #555;
}

.result-box {
    background: #e9ecef;
    border: 1px solid #ced4da;
    padding: 15px;
    border-radius: 5px;
    text-align: center;
    font-size: 1.25rem;
    font-weight: bold;
    color: #333;
    margin-top: 10px;
}

.nav-tabs .nav-link.active {
    color: #fff;
    background-color: #555;
    border-color: #555;
}

.nav-tabs .nav-link {
    color: #495057;
    font-weight: 600;
}

.reference-table {
    margin-top: 50px;
    font-size: 0.9rem;
}

.reference-table th {
    background-color: #f8f9fa;
    text-align: center;
    vertical-align: middle;
}

.reference-table td {
    vertical-align: middle;
    text-align: center;
}

.input-group-text {
    min-width: 45px;
    justify-content: center;
}