.input-group-addon {
    background-color: transparent;
    border: 0px solid #ccc;
    border-radius: 4px;
    color: #555;
    font-size: 14px;
    font-weight: 400;
    line-height: 1;
    padding: 6px 12px;
    text-align: center;
}
.input-group .form-control:last-child, .input-group-addon:last-child, .input-group-btn:first-child > .btn-group:not(:first-child) > .btn, .input-group-btn:first-child > .btn:not(:first-child), .input-group-btn:last-child > .btn, .input-group-btn:last-child > .btn-group > .btn, .input-group-btn:last-child > .dropdown-toggle {
    border-bottom-left-radius: 4px;
    border-top-left-radius: 4px;
}
.bao{margin-top: 15px;margin-bottom: 15px;}