#boxMain {
    display: flex;
    flex-direction: column;
    justify-content: start;
    align-items: center;
}

#boxMain > div{
    display: flex;
    
    flex-direction: row;
    justify-content: center;
    align-items: center;
}

#txt1 {
    padding: 5px;
    font-size: larger;
}

form{
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: aliceblue;
    width: 100%;
    padding: 5px;
}

#btOk, #btCancel {
    width: 20%;
    margin-right: 5px;
}

#content {
    width: 600px;
    height: 500px;
    display: flex;
    justify-content: start;
    align-items: start;
    flex-wrap: wrap
}
.img {
    width:140px;
    padding: 2px;
    margin: 2px;
}
#btBefore, #btAfter {
    width:50px;
}