How can I justify text in a section rather than a whole page/website? I am currently using the miller template

I have had to put in a Markdown block and add in code to make two sections into white text & centered.(they are on two different pages)

The rest of my website had a css code put in to justify all the text which I was fine with until I realized it affected my headings which I had to code in as mentioend above.

How can I get my body text to remain justified but at the same time have my markdown block also respond to the css code to keep it centered...

Markdown CSS used:

    < html>
   < head>
   < style>
   div.a {
     text-align: center;
     color: #ffffff
     style="color:#fff;font-family:ltc-bodoni-175;"
     font-size:3em

   }

   div.b {
     text-align: center;
     color: #ffffff
     style="color:#fff;font-family:nunito;"
     font-size:1em
   }

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</ div>

</ body>
</ html>

Custom CSS:

p {
  text-align: justify !important;
}

url: https://love-petsphotography.squarespace.compw: LovePets#1

past this code in custom css box

p:last-child {
   text-align: justify;
}

thanks, but it is still affecting my headings and pulling it to the left (that heading is a markdown block with code - just like the other one

ok let me check