# Box Sizing

Set the box sizing model for an element.

**Widely available.** This feature is well established and works across many devices and browser versions.

Chrome 10 · Edge 12 · Firefox 29 · Safari 5.1

| Class | Properties | Value |
|-------|------------|-------|
| `bs:bb` | box-sizing | `border-box` |
| `bs:cb` | box-sizing | `content-box` |

### Media Queries

Prefix a class with a breakpoint to apply it from that width up.

| Class | Properties | Value |
|-------|------------|-------|
| `bs:bb` | box-sizing | `border-box` |
| `bs:cb` | box-sizing | `content-box` |

### Pseudo Classes

Prefix a class with a state to apply it only while that state matches.

| Class | Properties | Value |
|-------|------------|-------|
| `bs:bb` | box-sizing | `border-box` |
| `bs:cb` | box-sizing | `content-box` |