The key to using CSS Grid to achieve a cascade layout is the coordination of grid-area and z-index. 1. Set the row and column ranges of different elements through grid-area to produce position overlap; 2. Use position and z-index to control the stacking order of elements to let specific elements appear on the upper layer; 3. Use translucent background to achieve visual fusion effect; 4. For complex layouts, you can use grid-template-areas to name areas to simplify the structure, and manually specify the coverage area through grid-area. Mastering these methods can flexibly achieve various stacked layout effects.

It is actually not difficult to implement a cascaded layout using CSS Grid. The key is to understand the combination of grid-area and positioning methods, and how to achieve visual overlap by setting the row-column ranges of different elements.

Use grid-area to control element position

Each child element in CSS Grid can be specified through grid-area which rows and columns it occupies. for example:

 .item-a {
  grid-area: 1 / 1 / 3 / 2;
}

This means that the element starts from the first row and spans to the third row, but only takes up one column. If you put another element also starts from the first row, but it occupies two columns, then the two elements will partially overlap.

You can write two elements like this:

 .item-a {
  grid-area: 1 / 1 / 3 / 2;
}

.item-b {
  grid-area: 1 / 1 / 2 / 3;
}

They will overlap in the upper left corner area. This is the basis for achieving the stacking effect.

Set z-index to control hierarchical relationships

It's not enough to just overlap, you might also want to control which element is displayed on it. At this time, z-index attribute needs to be used.

Note: z-index only takes effect on positioned elements (such as setting position: relative or absolute ). So in the Grid layout, if you want an element to "float" above other elements, you can write this:

 .item-b {
  grid-area: 1 / 1 / 2 / 3;
  position: relative;
  z-index: 2;
}

If other elements are not set z-index or have smaller values, they will be pressed down.

Visual fusion with transparent or translucent background

Sometimes you want to do not just simply overwrite it, but make the two elements look like they are "fusion" together. In this case, consider adding a translucent background color to one of the elements:

 .item-b {
  background-color: rgba(255, 0, 0, 0.5);
}

In this way, even if it overlaps with the elements below, it will not completely obstruct the content, but instead create a more layered design.

Tips: Use named areas to simplify complex layouts

If your layout is more complicated, you can first use grid-template-areas to define the names of each area, and then directly quote the names in the child elements:

 .container {
  display: grid;
  grid-template-areas:
    "header header"
    "main sidebar";
}

.header {
  grid-area: header;
}

.main {
  grid-area: main;
}

.sidebar {
  grid-area: sidebar;
}

Although this method does not automatically overlap, when you want to manually cover multiple areas, you can directly write it with grid-area :

 .overlay {
  grid-area: header;
}

This way it will cover the original header area and form a layered layer.

Basically these are the methods. As long as you master the use of grid-area , arrange z-index reasonably, and add some visual processing, you can easily make various stacked layouts.

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