```css
.lightbox {
position: fixed;
top: 0;
left: 0;
width: 100%;
height: 100%;
background-color: rgba(0, 0, 0, 0.8);
display: none;
justify-content: center;
align-items: center;
z-index: 1000;
}
.lightbox img {
max-width: 90%;
max-height: 90%;
object-fit: contain;
}
.lightbox .close-button {
position: absolute;
top: 20px;
right: 30px;
color: #f1f1f1;
font-size: 40px;
font-weight: bold;
transition: 0.3s;
cursor: pointer;
}
.lightbox .close-button:hover,
.lightbox .close-button:focus {
color: #bbb;
text-decoration: none;
cursor: pointer;
}
```