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                <div class="resize">
  <div class="auto-grid" style="
                              --auto-grid-max-columns: 4;
                              --auto-grid-min-size: 18rem;
                              --auto-grid-gap: 1rem;">
    <div class="item"></div>
    <div class="item"></div>
    <div class="item"></div>
    <div class="item"></div>
    <div class="item"></div>
    <div class="item"></div>
    <div class="item"></div>


 * This CSS utility creates a responsive grid layout that automatically adjusts the number of columns
 * based on the available space and specified constraints. It aims to fit as many cells as possible
 * in a single row, while respecting minimum cell width and maximum columns constraints.
 * Customizable Properties:
 * --auto-grid-min-size: Sets the minimum width for each cell in the grid.
 *                       Default is 10rem.
 * --auto-grid-max-columns: Sets the maximum number of columns in the grid.
 *                          Default is 'infinity' (as many as can fit).
 * --auto-grid-gap: Sets the horizontal gap between grid cells. It also sets
 *                  the vertical gap if --auto-grid-gap-vertical is not defined.
 *                  Default is 1rem.
 * --auto-grid-gap-vertical: Specifically sets the vertical gap between rows
 *                           of cells. If not set, it falls back to the value
 *                           of '--auto-grid-gap'.
 * The grid utilizes CSS 'display: grid' with the 'auto-fit' feature and the 'minmax()'
 * function to ensure that cells expand to fill available space while maintaining
 * the set minimum size.
 * Example Usage:
 * <div class="auto-grid" style="--auto-grid-min-size: 10rem; --auto-grid-max-columns: 3; --auto-grid-gap: 0.5rem;">
 *   <!-- grid items here -->
 * </div>
 * The above example will create a grid with a minimum cell width of 10rem, a maximum
 * of 3 columns, and a gap of 0.5rem between both rows and columns.

.auto-grid {
  --max-column-width: 100% / var(--auto-grid-max-columns, infinity) - var(--auto-grid-gap);
  --column-width: max(
    min(var(--auto-grid-min-size, 10rem), 100%)

  display: grid;

  grid-template-columns: repeat(auto-fit, minmax(var(--column-width), 1fr));

  /* vertical gap falls back to general gap then falls back to 1rem*/
  gap: var(--auto-grid-gap-vertical, var(--auto-grid-gap, 1rem))
    var(--auto-grid-gap, 1rem);

* {
  box-sizing: border-box;

body {
  background: #003;
  padding: 2rem;
  color: #fff;

.resize {
  padding: 1rem;
  border-radius: 1rem;
  border-end-end-radius: 0;
  border: 1px solid rgb(255 255 255 / 0.8);
  background: rgb(255 255 255 / 0.1);
  resize: horizontal;
  overflow: hidden;
  position: relative;
  max-width: 100%;
  &:after {
    content: "Resize me";
    position: absolute;
    inset: auto 0.5rem 0.5rem auto;
    padding: 0.25em 1.25em;
    background: rgb(0 0 50 / 0.8);
    border-radius: calc(1px * infinity);

.item {
  height: 10rem;
  background: #f09;
  border: 4px solid white;
  border-radius: 0.5rem;