cssgridgenerator
Page shells

CSS Three Column Layout Generator

Two rails and a fluid middle, folding down to one column in a sensible order.

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1204px

Drag across the grid to draw an area. Arrow keys nudge, Shift + arrows resize.

space to pan · ⌘scroll to zoom
1200px2minmax(0, 1fr)3240px4
11fr2
main1 / 2 / 2 / 3
left1 / 1 / 2 / 2
right1 / 3 / 2 / 4

Reading orderAt Desktop, left is the first thing seen but main is the first thing focused. Placement has moved the layout out of document order, so keyboard and screen reader users get a different sequence from everyone else.

Seenleft → main → right

Focusedmain → left → right

Usually the fix is in the markup, not in CSS: reorder the children so the HTML reads the way the page does, then place them back where you want them. Reaching for order or row-reverse instead moves the picture without moving the focus, which is the bug rather than the cure.

It is not always wrong. A full-height sidebar beside a topbar diverges by construction, and the accepted answer there is a skip link to the main content rather than a reordered document. WCAG 2.2 SC 1.3.2 asks that the sequence be meaningful — not that it be identical.

Also out of order at Tablet.

Named areas. The CSS is a picture of the layout, and only the properties that actually change get repeated inside each media query.

.three-col {
  display: grid;
  grid-template-columns: 1fr;
  grid-template-rows: auto auto auto;
  gap: 16px;
  grid-template-areas:
    "main"
    "left"
    "right";
}

.three-col > .main { grid-area: main; }
.three-col > .left { grid-area: left; }
.three-col > .right { grid-area: right; }

@media (min-width: 700px) {
  .three-col {
    grid-template-columns: minmax(0, 1fr) 220px;
    grid-template-rows: auto auto;
    gap: 20px;
    grid-template-areas:
      "main right"
      "left right";
  }
}

@media (min-width: 1024px) {
  .three-col {
    grid-template-columns: 200px minmax(0, 1fr) 240px;
    grid-template-rows: 1fr;
    gap: 24px;
    grid-template-areas:
      "left main right";
  }
}

How this layout works

The middle column carries 1fr and the rails are fixed or ranged. That is the difference between a three-column layout that survives a 320px phone and one that overflows: only one track is allowed to be greedy.

The interesting decision is the intermediate step. At tablet the left rail moves under the content and the right rail sits beside it, so you get two columns before you get three — a jump straight from one to three wastes the middle range of screen sizes.

Placement changes, source order does not. Keep the DOM in reading order and let the grid move things; a rail that is visually last but first in the HTML is the first thing a keyboard user tabs into.

Every property used here is listed in the CSS Grid cheat sheet, with the reason to reach for it.

Frequently asked questions

How do I build a three column layout that works on mobile?
Go one column, then two, then three. The useful middle step puts one rail below the content and the other beside it — jumping straight from one column to three wastes every screen size between a phone and a laptop.
Should the side columns be fixed width or fractional?
Fixed or ranged, with the middle column taking 1fr. Only one track should be allowed to absorb the leftover space; three fractional columns means the content column shrinks in step with the rails at exactly the width where it can least afford to.
How do I center a grid in CSS?
Use justify-content: center on the grid container to centre the whole grid inside it, and margin-inline: auto with a max-width to centre the container in the page. These are different jobs: the first moves the tracks within the container, the second moves the container itself.
How do I center items inside a CSS grid?
Set place-items: center on the container. That is shorthand for align-items plus justify-items, and it centres every item inside its own cell on both axes. For a single item, use place-self: center on that item instead.
How do I make a CSS grid responsive?
Use grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)) and it reflows at every width with no media queries at all. Add breakpoints only when the exact column count matters, or when the layout has to change shape rather than just wrap.
When should I use CSS Grid instead of Flexbox?
Use Grid when things must line up in two directions at once, and Flexbox when content flows along one axis. A page skeleton or dashboard is Grid; a navbar or row of buttons is Flexbox. They nest: Grid for the page, Flexbox inside the cells.

How to use it

  1. Open the pattern

    The three column layout loads into the editor already responsive, with every breakpoint set up.

  2. Change the tracks

    Edit the column and row sizes in the Tracks panel. Anything valid in a track list works.

  3. Redraw at another width

    Move the ruler past a breakpoint marker and rearrange. Only the placement changes.

  4. Copy the code

    Take CSS, HTML, Tailwind or a shadcn component. The media queries are already written.

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