CSS print and Flexbox

Hello I would like to create some page using css print.I looked around and the web I tried some stuff but saddly the alignment is not working.

The Layout I want to produce:

here is my html

<section class ="page_1"><p class="paragraph_1"> .... </p><p class="paragraph_2"> .... </p></section>

So I tried to make some css with the print media query

@page {   size: 8cm 13cm; /*custom size*/   } @media print {   section[class ^="page"] {     position: relative;     /*Same as the page size*/     width: 8cm;     height: 13cm;     display: flex;     justify-content: space-around;     flex-direction: column;     align-items: center;     page-break-after: always;     padding: 0.5cm 2cm;   }   p[class ^="paragraph"] {     /*NOTHING TO ADD FOR THE ALIGNEMENT*/   } }

It did not go as expected. (leave blank page and does not flex the elements)