.left-sidebar{background:#fff;border-radius:8px;min-height:600px;padding:16px}.sidebar-title{border-bottom:1px solid #f0f0f0;margin-bottom:12px;padding-bottom:8px;font-weight:500}.empty-tree{color:#bfbfbf;text-align:center;padding:32px 0}.subject-tree{background:0 0}.subject-tree .ant-tree-treenode{padding-bottom:4px}.subject-tree .ant-tree-node-content-wrapper{padding:2px 4px}.search-bar{background:#fff;border-radius:8px;margin-bottom:16px;padding:16px}.course-list{height:100%}.course-card-grid{grid-template-columns:repeat(auto-fill,minmax(300px,400px));grid-auto-rows:1fr;gap:16px;display:grid}.course-card{flex-direction:column;height:100%;display:flex;overflow:hidden}.course-card .ant-card-body{flex-direction:column;flex:1;padding:0;display:flex}.course-card-body{gap:8px;min-height:100%;display:flex}.course-card-cover-col{flex-shrink:0;width:80px}.course-card-cover{align-items:stretch;width:80px;height:100%;display:flex;overflow:hidden}.course-card-cover img{-o-object-fit:cover;object-fit:cover;width:100%;height:100%}.course-card-cover.default-cover{background:#f5f5f5}.course-card-cover .default-icon{text-align:center;justify-content:center;align-items:center;width:100%;font-size:48px;display:flex}.course-card-content-col{flex-direction:column;flex:1;justify-content:center;gap:6px;min-width:0;padding:12px;display:flex}.course-card-header{align-items:center;gap:8px;display:flex}.course-card-title{flex:1;font-size:16px;line-height:1.4}.excellent-tag{color:#cf1322;background:#fff1f0;border:none;border-radius:4px;flex-shrink:0;padding:0 6px;font-size:12px;font-style:italic;font-weight:600;line-height:20px}.course-card-meta,.course-card-date{font-size:12px;line-height:1.4}.pagination-container{justify-content:flex-end;margin-top:24px;display:flex}