*{margin:0;padding:0;box-sizing:border-box}
body{background:#f7f8fa;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif;color:#222}
.wp-topbar{display:flex;align-items:center;gap:14px;max-width:1300px;margin:0 auto;padding:14px 20px 0}
.wp-back{font-size:13px;color:#ef4444;text-decoration:none;border:1px solid #f3caca;background:#fff;padding:6px 12px;border-radius:16px}
.wp-back:hover{background:#ef4444;color:#fff}
.wp-title{font-size:17px;font-weight:700;color:#333}
.desktop-layout{display:grid;grid-template-columns:220px 1fr;gap:24px;max-width:1300px;margin:0 auto;padding:20px}
@media (max-width:920px){.desktop-layout{grid-template-columns:1fr;padding:12px;}.sidebar{display:none;}}
.sidebar{position:sticky;top:20px;height:calc(100vh - 40px);overflow-y:auto;background:#fff;border-radius:16px;box-shadow:0 2px 10px rgba(0,0,0,0.04);padding:20px 14px}
.sidebar-title{font-size:15px;font-weight:600;margin-bottom:14px;text-align:center}
.cat-item{width:100%;padding:10px 8px;border-radius:8px;margin-bottom:6px;cursor:pointer;font-size:14px;text-align:center;background:#f3f4f6;transition:all 0.2s}
.cat-item.active{background:#ef4444;color:#fff}
.mobile-cats{display:none;padding:0 12px 12px}
.mobile-grid{display:grid;grid-template-columns:1fr 1fr;gap:8px}
.mobile-cat{padding:10px;border-radius:8px;background:#fff;text-align:center;font-size:14px;cursor:pointer}
.mobile-cat.active{background:#ef4444;color:#fff}
@media (max-width:920px){.mobile-cats{display:block;}}
/* 瀑布流：CSS columns 多列独立堆叠（替代 grid 等宽行——grid 会强制行内卡片等高，
   图片纵横比不同时矮图下方会留大片白色） */
.wall-grid{column-count:3;column-gap:20px}
.wall-grid.single{column-count:1 !important;max-width:900px;margin:0 auto}
.wall-card{display:inline-block;width:100%;margin-bottom:20px;border-radius:16px;overflow:hidden;background:#e5e7eb;break-inside:avoid;page-break-inside:avoid;transition:all 0.2s}
@media (max-width:920px){.wall-grid{column-count:2;column-gap:14px}.wall-card{margin-bottom:14px}}
@media (max-width:520px){.wall-grid{column-count:1}}
.wall-card img{width:100%;height:auto;display:block;opacity:0;transition:opacity 0.3s}
.wall-card img.loaded{opacity:1}
.card-bottom{padding:10px 12px;display:flex;justify-content:space-between;align-items:center;background:#fff}
.tag{font-size:12px;color:#666}
.down-btn{font-size:13px;color:#ef4444;font-weight:500;cursor:pointer}
.loading{text-align:center;padding:16px;color:#666;display:none}
.preview{position:fixed;inset:0;background:rgba(0,0,0,0.97);display:none;place-items:center;z-index:9999}
.preview img{max-width:94%;max-height:94vh;border-radius:14px}
.close{position:absolute;top:24px;right:32px;color:#fff;font-size:32px;cursor:pointer}