/*
 Theme Name:   Mountbliss Child
 Theme URI:    
 Description:  
 Author:       N/A
 Author URI:   
 Template:     xstore
 Version:      1.0
 Text Domain:  Mountbliss-child
*/

Here’s the CSS you can use to make all the text within this structure black:

 .bank-popup-content {
    background-color: #fefefe;
    margin: 48px auto;
    padding: 20px;
    border: 1px solid #888;
    width: 80%;
    max-width: 500px;
    border-radius: 8px;
    position: relative;
    font-size: 13px;
    text-align: center;
    transform: translateY(-20px);
    transition: transform 0.5s ease, opacity 0.5s ease;
    opacity: 0;
    color: #000; /* Text color set to black */
}

#bank-details-content {
    text-align: center;
    color: #000; /* Text color set to black */
}

#bank-details-content p {
    font-size: 13px;
    color: #000; /* Text color set to black */
}

.bank-details-note-indication {
    padding-top: 18px;
    color: #000; /* Text color set to black */
}

.bank-popup-content h3 {
    margin-top: 0 !important;
    font-size: 24px;
    color: #000; /* Text color set to black */
}

.bank-details-table td {
    padding: 8px;
    border-bottom: 1px solid #eee;
    font-size: 13px;
    color: #000; /* Text color set to black */
}

.bank-details-note {
    text-align: center;
    color: #000; /* Text color set to black */
}

.bank-details-note .orderReference,
.bank-details-note .orderPrice {
    font-weight: bold;
    font-size: 24px;
    color: #000; /* Text color set to black */
}

.upload-success p {
    margin-bottom: 15px;
    color: #000; /* Text color set to black */
}