.post-cover-preview{display:block;width:min(420px,100%);aspect-ratio:16/9;object-fit:cover;border-radius:10px;margin:8px 0 12px;border:1px solid #dfe3e8;box-shadow:0 8px 24px rgba(15,41,77,.12)}.post-cover-hint{display:block;margin-top:6px;color:#718096;font-weight:400}