# Cart and Checkout Blocks Theming <!-- omit in toc -->

**Important: we strongly discourage writing CSS code based on existing block class names, prioritize using global styles when possible. We specially discourage writing CSS selectors that rely on a specific block being a descendant of another one, as users can move blocks around freely, so they are prone to breaking. Similar to WordPress itself, we consider the HTML structure within components, blocks, and block templates to be “private”, and subject to further change in the future, so using CSS to target the internals of a block or a block template is _not recommended or supported_.**

## Table of Contents <!-- omit in toc -->

-   [Buttons](#buttons)
-   [Mobile submit container](#mobile-submit-container)
-   [Item quantity badge](#item-quantity-badge)

## Buttons

WC Blocks introduces the button component, it differs from a generic `button` in that it has some default styles to make it correctly fit in the Blocks design.

![Button screenshot](https://user-images.githubusercontent.com/3616980/86381945-e6fd6c00-bc8d-11ea-8811-7e546bea69b9.png)

Themes can still style them to match theme colors or styles as follows:

```css
.wc-block-components-button {
	background-color: #d5502f;
	color: #fff;
	/* More rules can be added to modify the border, shadow, etc. */
}
/* It might be needed to modify the hover, focus, active and disabled states too */
```

![Button screenshot with custom styles](https://user-images.githubusercontent.com/3616980/86381505-b6b5cd80-bc8d-11ea-8ceb-cfbe84b411d4.png)

Notice the button component doesn't have the `.button` class name. So themes that wrote some styles for buttons might want to apply some (or all) of those styles to the button component as well.

## Mobile submit container

In small viewports, the Cart block displays the _Proceed to Checkout_ button inside a container fixed at the bottom of the screen.

![Submit container screenshot](https://user-images.githubusercontent.com/3616980/86382876-393e8d00-bc8e-11ea-8d0b-e4e347ea4773.png)

By default, the container has a white background so it plays well with the button component default colors. Themes that want to apply the same background color as the rest of the page can do it with the following code snippet:

```css
.wc-block-cart__submit-container {
	background-color: #f9f4ee;
}
```

Take into consideration the container has a top box shadow that might not play well with some dark background colors. If needed, it can be modified directly setting the `color` property (internally, shadow color uses `currentColor`, so it honors the `color` property):

```css
.wc-block-cart__submit-container::before {
	color: rgba( 214, 209, 203, 0.5 );
}
```

Alternatively, themes can override the `box-shadow` property completely:

```css
.wc-block-cart__submit-container::before {
	box-shadow: 0 -10px 20px 10px rgba( 214, 209, 203, 0.5 );
}
```

![Submit container screenshot with custom styles](https://user-images.githubusercontent.com/3616980/86382693-27f58080-bc8e-11ea-894e-de378af3e2bb.png)

## Item quantity badge

The item quantity badge is the number that appears next to the image in the _Order summary_ section of the _Checkout_ block sidebar.

![Order summary screenshot](https://user-images.githubusercontent.com/3616980/83862844-c8559500-a722-11ea-9653-2fc8bcd544d2.png)

By default, it uses a combination of black and white borders and shadows so it has enough contrast with themes with light and dark backgrounds. Themes can modify the colors with their own palette with a single CSS selector and four properties. For example:

```css
.wc-block-components-order-summary-item__quantity {
	background-color: #f9f4ee;
	border-color: #4b3918;
	box-shadow: 0 0 0 2px #f9f4ee;
	color: #4b3918;
}
```

![Order summary screenshot with custom styles for the item quantity badge](https://user-images.githubusercontent.com/3616980/83863109-2e421c80-a723-11ea-9bf7-2033a96cf5b2.png)

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