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HTML 

              
                <main>
  <section>
    <h1>Main title</h1>
    <p>Dragée powder bear claw tiramisu pudding gummi bears wafer. Macaroon chocolate cake cake marzipan icing carrot cake macaroon sweet. Lemon drops </p>
  </section>
  <section class="full-bleed-1">
    <h2>Full bleed (no margin)</h2>
    <p> cotton candy bear claw. Dessert danish pastry tootsie roll biscuit jujubes lollipop pastry tootsie roll.  </p>
  </section>
  <section class="full-bleed-2">
    <h2>Full bleed (margin on big screens)</h2>
    <p> cotton candy bear claw. Dessert danish pastry tootsie roll biscuit jujubes lollipop pastry tootsie roll.  </p>
  </section>
  <section class="full-bleed-3">
    <h2>Full bleed (margin on small screens)</h2>
    <p> cotton candy bear claw. Dessert danish pastry tootsie roll biscuit jujubes lollipop pastry tootsie roll.  </p>
  </section>
  <section class="full-bleed-4">
    <h2>Full bleed (always a margin)</h2>
    <p> cotton candy bear claw. Dessert danish pastry tootsie roll biscuit jujubes lollipop pastry tootsie roll.  </p>
  </section>
  <section>
    <h2>lemon drops candy</h2>
    <p>Dessert halvah sesame snaps jelly beans caramels marzipan. Cheesecake ice cream gummies lemon drops candy chocolate bar dessert pie. Tootsie roll gummi bears biscuit marshmallow sweet halvah fruitcake marzipan. Candy canes cake gummies marzipan marshmallow lollipop. Lemon drops apple pie tootsie roll pastry apple pie jelly-o. Biscuit lollipop biscuit muffin carrot cak</p>
  </section>
  <section>
    <h3>full bleed image</h3>
    <div class="full-bleed-2" >
      <img src="https://picsum.photos/id/115/1000/300">
    </div>
  </section>
  <section>
    <h3>Cake pie lollipop</h3>
    <p>Jelly chocolate biscuit sesame snaps dessert chocolate. Topping jelly-o jelly jujubes marzipan sugar plum. Cake pie lollipop halvah shortbread. Powder tiramisu tart wafer marshmallow gingerbread powder</p>
  </section>
</main>
!

CSS 

              
                html {
  container-type: inline-size;
}

main {
  --w: 600px; /* the max width*/
  --m: 1em;   /* minimum margin */
  
  margin-inline: max(   var(--m),(100cqw - var(--w))/2);
}
.full-bleed-1 {
  margin-inline: min(-1*var(--m),(var(--w) - 100cqw)/2);
}
.full-bleed-2 {
  margin-inline: min(-1*var(--m),(var(--w) - 100cqw)/2 + var(--m));
}
.full-bleed-3 {
  margin-inline: min(        0px,(var(--w) - 100cqw)/2);
}
.full-bleed-4 {
  margin-inline: min(        0px,(var(--w) - 100cqw)/2 + var(--m));
}



section[class*="full-bleed"] {
  padding-inline: var(--m);
  margin-block: var(--m);
  background: pink;
}
section {
  padding-block: .3em;
}

body {
  font-family: system-ui, sans-serif;
  background: #eee;
  margin: 0;
}
h1 {
  font-size: 3rem;
}
p {
  font-size: 1.5rem;
  text-align:justify;
}
img {
  width: 100%;
  height: 300px;
  object-fit: cover;
  display: block;
}
!

JS
!
999px

Console