---
id: 5d822fd413a79914d39e98fe
title: Part 54
challengeType: 0
dashedName: part-54
---
# --description--
Add these properties to `bb2a`:
```css
margin: auto;
width: 5vw;
height: 5vw;
border-top: 1vw solid #000;
border-bottom: 1vw solid #000;
border-left: 1vw solid #999;
border-right: 1vw solid #999;
```
After you add these, you can see how a thick border on an element gives you some angles where two sides meet. You are going to use that bottom border as the top of the building.
# --hints--
test-text
```js
const bb2a = code.match(/\.bb2a\s*{[\s\S]+?[^}]}/g)[0];
assert(
/margin\s*:\s*auto\s*(;|})/g.test(bb2a) &&
/width\s*:\s*5vw\s*(;|})/g.test(bb2a) &&
/height\s*:\s*5vw\s*(;|})/g.test(bb2a) &&
/border-top\s*:\s*1vw\s+solid\s+#000\s*(;|})/g.test(bb2a) &&
/border-bottom\s*:\s*1vw\s+solid\s+#000\s*(;|})/g.test(bb2a) &&
/border-left\s*:\s*1vw\s+solid\s+#999\s*(;|})/g.test(bb2a) &&
/border-right\s*:\s*1vw\s+solid\s+#999\s*(;|})/g.test(bb2a)
);
```
# --seed--
## --seed-contents--
```html
freeCodeCamp Skyline Project
```
# --solutions--
```html
freeCodeCamp Skyline Project
```