# Corner brackets (B 151)

Category: Buttons  
Tags: bracket, corner-mark, rectangle, outline, hover-expand  
Page: https://designforai.dev/snippet/btn-151

## Prompt

A borderless uppercase 14px semibold button (#111827 text, 0.06em tracking, 14px by 28px padding) marked only by two 12px L-shaped corner brackets, 2px thick, at the top-left and bottom-right. On hover both brackets grow to the full width and height so they meet and form a complete rectangle, 250ms. Active colours text and brackets blue #2563eb. Focus 2px dark outline offset 4px.

## HTML

```html
<button class="btn-151">Select</button>
```

## CSS

```css
.btn-151 {
  position: relative;
  font: 600 14px/1 system-ui,sans-serif;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: #111827;
  background: transparent;
  border: 0;
  padding: 14px 28px;
  cursor: pointer;
  transition: color .2s
}
.btn-151::before,.btn-151::after {
  content: "";
  position: absolute;
  width: 12px;
  height: 12px;
  border: 2px solid #111827;
  transition: width .25s,height .25s,border-color .25s
}
.btn-151::before {
  top: 0;
  left: 0;
  border-right: 0;
  border-bottom: 0
}
.btn-151::after {
  bottom: 0;
  right: 0;
  border-left: 0;
  border-top: 0
}
.btn-151:hover::before,.btn-151:hover::after {
  width: 100%;
  height: 100%
}
.btn-151:focus-visible {
  outline: 2px solid #111827;
  outline-offset: 4px
}
.btn-151:active {
  color: #2563eb
}
.btn-151:active::before,.btn-151:active::after {
  border-color: #2563eb
}
```