/* 自定义滚动条 */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: #0f172a; }
::-webkit-scrollbar-thumb { background: #334155; border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: #475569; }

/* 分组标签样式 (日期/字母) */
.group-label {
    grid-column: 1 / -1; /* 占满整行 */
    background: linear-gradient(90deg, rgba(59,130,246,0.1) 0%, rgba(59,130,246,0) 100%);
    border-left: 4px solid #3b82f6;
    padding: 8px 16px;
    font-size: 14px;
    font-weight: bold;
    color: #93c5fd;
    border-radius: 0 4px 4px 0;
    margin-top: 12px;
    margin-bottom: 4px;
}

/* 卡片悬停动效 */
.resource-card {
    transition: all 0.2s ease;
}
.resource-card:hover {
    transform: translateY(-2px);
    border-color: #3b82f6;
    box-shadow: 0 4px 12px rgba(0,0,0,0.3);
}

/* 分类树激活状态 */
.category-active {
    background-color: #1e3a8a;
    color: white;
    font-weight: 600;
}