```html
}
.error-message {
display: block;
font-family: monospace;
font-size: 2.5em;
text-align: center;
color: #fff;
/* O código hierárquico expressa a sobreposição */
}
.error-message {
opacity: 0;
animation: show-error 1s ease-in-out forwards;
}
```
This HTML file exemplifies the concept of "Illusory Content," manifesting the digital anxieties of code dysphoria. It uses: