Topic Preview Modal

Question: Why does the border-top of .topic-avatar end up appearing as a separator between the part of the previous post that remains visible during scrolling and the beginning of the current post? Is that the actual intention of this border-top, or is there some positioning/overflow rule causing it to behave this way?

@media (width >= 40rem) {
    .topic-avatar {
        border-top: 1px solid var(--content-border-color);
        padding-top: var(--space-4);
        width: var(--topic-avatar-width);
        float: left;
        z-index: 2;
        height: 100%;
        overflow-anchor: none;
    }
}
לייק 1