Title: 回不去的回車 (Backspace in CSS)

In CSS, the backspace key (`) is used to remove characters from the current line. However, this does not work in some cases, such as when using the backspace key to remove a space between two characters. This is because the backspace key is not a valid character in CSS, and it is instead used as a key for selecting all the characters on the current line.

To overcome this issue, the `text-overflow: ellipsis` property can be used to display an ellipsisellipsis when a space is removed between two characters. This allows the user to continue typing into the field, but it will not display the rest of the characters on the current line.

Another alternative is to use the `text-overflow` property and set it to `overflow-wrap: break-word`. This will display an ellipsisellipsis when a space is removed between two characters, but it will also break the word into multiple characters if the space is removed before the end of the word.

However, this approach may not work well in all cases, as it depends on the specific layout and design of the website. In some cases, the `text-overflow` property may not be sufficient, and a more complex solution may be needed.

In conclusion, the backspace key in CSS is not a valid character for certain uses, and it can be used to remove characters from the current line in some cases. To overcome this issue, the `text-overflow` property can be used to display an ellipsisellipsis when a space is removed between two characters, or a more complex solution may be needed in some cases.