#rbBox {
    max-width: 600px;
    margin: auto;
    padding: 20px;
    border: 1px solid #b51000;
    border-radius: 8px;
    font-family: Arial, sans-serif;
}
#rbBox h2 {
    color: #b51000;
    text-align: center;
}
#rbBox input {
    width: 95%;
    padding: 10px;
    font-size: 16px;
    border: 1px solid #b51000;
    border-radius: 5px;
}
#rbBox button {
    width: 100%;
    margin-top: 12px;
    padding: 10px;
    font-size: 16px;
    background: #b51000;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
}
#rbBox button:hover {
    background: #850c00;
}
#rbResult textarea {
    width: 95%;
    height: 220px;
    margin-top: 15px;
    font-size: 15px;
    border: 1px solid #b51000;
    border-radius: 5px;
    padding: 10px;
}
.copyBtn {
    margin-top: 10px;
    width: 100%;
    padding: 10px;
    background: #b51000;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
}
.copyBtn:hover {
    background: #850c00;
}