Bugzilla

The restyle/reflow/repaint here is all to do with the :hover-triggered blue "tile" at the far left edge of each log entry:
```css
.message:hover::before {
  content: "";
  position: absolute;
  inset-inline: 0;
  top: 0;
  bottom: 0;
  background: var(--theme-highlight-blue);
  width: 3px;
}
```

That element insertion/removal on hover/unhover is what's causing all the work here. You can optimize this a great deal if you just cause that pseudo-element to be always present, and simply change its color to be visible/invisible on hover. In particular, just add this rule (same as the one above, but without "hover" and with `background:transparent`):
```css
.message::before {
    content: "";
    position: absolute;
    inset-inline: 0;
    top: 0;
    bottom: 0;
    background: transparent;
    width: 3px;
}
```

With that change, the long reflows disappear from my profile, and I don't notice any white flashing.

Does that work for you?

The restyle/reflow/repaint here is all to do with the :hover-triggered blue "tile" at the far left edge of each log entry:
```css
.message:hover::before {
  content: "";
  position: absolute;
  inset-inline: 0;
  top: 0;
  bottom: 0;
  background: var(--theme-highlight-blue);
  width: 3px;
}
```

That pseudo-element insertion/removal on hover/unhover is what's causing all the work here. You can optimize this a great deal if you just cause that pseudo-element to be always present, and simply change its color to be visible/invisible on hover. In particular, just add this rule (same as the one above, but without "hover" and with `background:transparent`):
```css
.message::before {
    content: "";
    position: absolute;
    inset-inline: 0;
    top: 0;
    bottom: 0;
    background: transparent;
    width: 3px;
}
```

With that change, the long reflows disappear from my profile, and I don't notice any white flashing.

Does that work for you?