.prt-grid { display:flex; flex-wrap:wrap; gap:20px; }
.prt-grid .prt-grid-item { box-sizing:border-box; }
.prt-columns-1 .prt-grid-item { width:100%; }
.prt-columns-2 .prt-grid-item { width:calc(50% - 10px); }
.prt-columns-3 .prt-grid-item { width:calc(33.333% - 13.333px); }
.prt-columns-4 .prt-grid-item { width:calc(25% - 15px); }
.prt-thumb img { max-width:100%; height:auto; display:block; }
.prt-title { margin:8px 0 4px; font-size:1.1rem; }
.prt-excerpt { font-size:0.95rem; color:#666; }
.prt-filters { margin-bottom:16px; }
.prt-filter-btn { margin-right:8px; padding:6px 10px; cursor:pointer; }