How to prevent column break within an element?

Question

Consider the following HTML:

    

        
Number one
        
Number two
        &         


        
      

Answer 1

In 2019, having this works for me on Chrome, Firefox and Opera (after many other unsuccessful attempts):

.content {
    margin: 0;
    -webkit-column-break-inside: avoid;
    break-inside: avoid;
    break-inside: avoid-column;
}

li {
    -webkit-column-break-inside:avoid;
       -moz-column-break-inside:avoid;
            column-break-inside:avoid;
           break-inside: avoid-column;
             page-break-inside: avoid;
}