I want to know why this table will go out of the form [duplicate]

Question

The top border of table has gone out of the form border (which is the border of blue background color)

form {
    margin-top: 100px;
    margin-left: 20%;
    width: 60%;
    background-color: #F0FFFF;
}

table {
    width: calc(100% - 20px);
    margin: 10px;
    text-align: center;
    border-collapse: collapse;
    border-style: none;
}

Answer 1

idk just replace table margin: 10px with form padding: 10px

and change table width: calc(100% - 20px); to table width: 100%;