/* AI 文章封面：统一 16:9 画幅与完整/填满两种展示，配色融入靛蓝灰白主题。 */
.card-cover,.article-cover{display:block;position:relative;width:100%;aspect-ratio:16/9;background:linear-gradient(145deg,#f0f3f9,#e6ebf3);overflow:hidden;border:1px solid var(--line);border-radius:7px}
.card-cover{margin:0 0 20px;flex-shrink:0}
.article-cover{margin:0 0 30px}
.card-cover img,.article-cover img{display:block;position:absolute;inset:0;width:100%;height:100%;object-position:center}
.cover-fit-contain img{object-fit:contain}
.cover-fit-cover img{object-fit:cover}
.post-card:has(.card-cover) h3{margin-bottom:12px}
@media(max-width:620px){.card-cover{margin-bottom:16px}.article-cover{margin-bottom:22px;border-radius:6px}}
@media(prefers-reduced-motion:no-preference){.card-cover img{transition:transform .4s ease}.card-cover:hover img{transform:scale(1.025)}}