A grid for content

style.css

.content-grid {
  --padding: 1rem;
  --content-max-width: 700px;
  --breakout-max-width: 900px;
  justify-items: center;
  display: grid;
  grid-auto-flow: row;
}
.content-grid > * {
  box-sizing: border-box;
}
.content-grid > :not(img) {
  width: 100%;
}
.content-grid > :not(.breakout, .full-width) {
  max-width: min(var(--content-max-width), 100%);
  padding-inline: var(--padding);
  background: yellow;
}
.content-grid > .breakout {
  max-width: min(var(--breakout-max-width), 100%);
  padding-inline: var(--padding);
  background: blue;
}
.content-grid > .full-width {
  width: 100%;
  background: red;
}