freeCodeCamp/curriculum/challenges/italian/14-responsive-web-design-22/learn-css-variables-by-buil.../5d822fd413a79914d39e98fe.md

---
id: 5d822fd413a79914d39e98fe
title: Step 54
challengeType: 0
dashedName: step-54
---

# --description--

Aggiungi queste proprietà a `.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;
```

Dopo averle aggiunte, potrai vedere come un bordo spesso su un elemento crea degli angoli dove i due lati si incontrano. Stai per utilizzare il bordo inferiore come la parte superiore dell'edificio.

# --hints--

Dovresti dare a `.bb2a` una proprietà `margin` impostata su`auto`.

```js
assert.equal(new __helpers.CSSHelp(document).getStyle('.bb2a')?.margin, "auto");
```

Dovresti dare a `.bb2a` una proprietà `width` impostata su `auto`.

```js
assert.equal(new __helpers.CSSHelp(document).getStyle('.bb2a')?.width, "5vw");
```

Dovresti dare a `.bb2a` una proprietà `height` di `5vw`.

```js
assert.equal(new __helpers.CSSHelp(document).getStyle('.bb2a')?.height, "5vw");
```

Dovresti dare a `.bb2a` una proprietà `border-top` con il valore `1vw solid #000`.

```js
assert.equal(new __helpers.CSSHelp(document).getStyle('.bb2a')?.borderTop, "1vw solid rgb(0, 0, 0)");
```

Dovresti dare a `.bb2a` una proprietà `border-bottom` con il valore `1vw solid #000`.

```js
assert.equal(new __helpers.CSSHelp(document).getStyle('.bb2a')?.borderBottom, "1vw solid rgb(0, 0, 0)");
```

Dovresti dare a `.bb2a` una proprietà `border-left` con il valore `1vw solid #999`.

```js
assert.equal(new __helpers.CSSHelp(document).getStyle('.bb2a')?.borderLeft, "1vw solid rgb(153, 153, 153)");
```

Dovresti dare a `.bb2a` una proprietà `border-right` con il valore `1vw solid #999`.

```js
assert.equal(new __helpers.CSSHelp(document).getStyle('.bb2a')?.borderRight, "1vw solid rgb(153, 153, 153)");
```

# --seed--

## --seed-contents--

```html
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>City Skyline</title>
    <link href="styles.css" rel="stylesheet" />
  </head>

  <body>
    <div class="background-buildings">
      <div></div>
      <div></div>
      <div class="bb1">
        <div class="bb1a bb1-window"></div>
        <div class="bb1b bb1-window"></div>
        <div class="bb1c bb1-window"></div>
        <div class="bb1d"></div>
      </div>
      <div class="bb2">
        <div class="bb2a"></div>
        <div class="bb2b"></div>
      </div>
      <div class="bb3"></div>
      <div></div>
      <div class="bb4"></div>
      <div></div>
      <div></div>
    </div>

    <div class="foreground-buildings">
      <div></div>
      <div></div>
      <div class="fb1"></div>
      <div class="fb2"></div>
      <div></div>
      <div class="fb3"></div>
      <div class="fb4"></div>
      <div class="fb5"></div>
      <div class="fb6"></div>
      <div></div>
      <div></div>
    </div>
  </body>
</html>
```

```css
:root {
  --building-color1: #aa80ff;
  --building-color2: #66cc99;
  --building-color3: #cc6699;
  --building-color4: #538cc6;
  --window-color1: black;
  --window-color2: #8cd9b3;
}

* {
  border: 1px solid black;
  box-sizing: border-box;
}

body {
  height: 100vh;
  margin: 0;
  overflow: hidden;
}

.background-buildings, .foreground-buildings {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: flex-end;
  justify-content: space-evenly;
  position: absolute;
  top: 0;
}

/* BACKGROUND BUILDINGS - "bb" stands for "background building" */
.bb1 {
  width: 10%;
  height: 70%;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.bb1a {
  width: 70%;
}

.bb1b {
  width: 80%;
}

.bb1c {
  width: 90%;
}

.bb1d {
  width: 100%;
  height: 70%;
  background: linear-gradient(
      var(--building-color1) 50%,
      var(--window-color1)
    );
}

.bb1-window {
  height: 10%;
  background: linear-gradient(
      var(--building-color1),
      var(--window-color1)
    );
}

.bb2 {
  width: 10%;
  height: 50%;
}
--fcc-editable-region--

--fcc-editable-region--
.bb2b {
  width: 100%;
  height: 100%;
  background: repeating-linear-gradient(
      var(--building-color2),
      var(--building-color2) 6%,
      var(--window-color2) 6%,
      var(--window-color2) 9%
    );
}

.bb3 {
  width: 10%;
  height: 55%;
  background-color: var(--building-color3);
}

.bb4 {
  width: 11%;
  height: 58%;
  background-color: var(--building-color4);
}

/* FOREGROUND BUILDINGS - "fb" stands for "foreground building" */
.fb1 {
  width: 10%;
  height: 60%;
  background-color: var(--building-color4);
}

.fb2 {
  width: 10%;
  height: 40%;
  background-color: var(--building-color3);
}

.fb3 {
  width: 10%;
  height: 35%;
  background-color: var(--building-color1);
}

.fb4 {
  width: 8%;
  height: 45%;
  background-color: var(--building-color1);
  position: relative;
  left: 10%;
}

.fb5 {
  width: 10%;
  height: 33%;
  background-color: var(--building-color2);
  position: relative;
  right: 10%;
}

.fb6 {
  width: 9%;
  height: 38%;
  background-color: var(--building-color3);
}

```