---
id: 5d822fd413a79914d39e9910
title: Step 72
challengeType: 0
dashedName: step-72
---
# --description--
Aggiungi la nuova classe `window-wrap` all'elemento `.bb4c`.
# --hints--
Dovresti aggiungere la classe `window-wrap` a `.bb4c`.
```js
assert.exists(document.querySelector("div.bb4c.window-wrap"));
```
# --seed--
## --seed-contents--
```html
City Skyline
--fcc-editable-region--
--fcc-editable-region--
```
```css
:root {
--building-color1: #aa80ff;
--building-color2: #66cc99;
--building-color3: #cc6699;
--building-color4: #538cc6;
--window-color1: black;
--window-color2: #8cd9b3;
--window-color3: #d98cb3;
--window-color4: #8cb3d9;
}
* {
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;
}
.building-wrap {
display: flex;
flex-direction: column;
align-items: center;
}
.window-wrap {
display: flex;
align-items: center;
justify-content: space-evenly;
}
/* BACKGROUND BUILDINGS - "bb" stands for "background building" */
.bb1 {
width: 10%;
height: 70%;
}
.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%;
}
.bb2a {
border-bottom: 5vh solid var(--building-color2);
border-left: 5vw solid transparent;
border-right: 5vw solid transparent;
}
.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: repeating-linear-gradient(
90deg,
var(--building-color3),
var(--building-color3),
var(--window-color3) 15%
);
}
.bb4 {
width: 11%;
height: 58%;
}
.bb4a {
width: 3%;
height: 10%;
background-color: var(--building-color4);
}
.bb4b {
width: 80%;
height: 5%;
background-color: var(--building-color4);
}
.bb4c {
width: 100%;
height: 85%;
background-color: var(--building-color4);
}
.bb4-window {
width: 18%;
height: 90%;
background-color: var(--window-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);
}
```