.knowledge-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
}

.back-button {
    text-decoration: none;
    color: #2196F3;
    font-weight: 500;
}

.filters {
    margin-bottom: 20px;
    display: flex;
    gap: 10px;
}

.filter-btn {
    padding: 8px 16px;
    border: 1px solid #ddd;
    border-radius: 20px;
    background: white;
    cursor: pointer;
    transition: all 0.2s;
}

.filter-btn.active {
    background: #2196F3;
    color: white;
    border-color: #2196F3;
}

.timeline {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.timeline-item {
    border: 1px solid #eee;
    border-radius: 8px;
    padding: 20px;
    background: white;
    position: relative;
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: -20px;
    top: 50%;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: #2196F3;
}

.timeline-date {
    color: #666;
    font-size: 0.9em;
    margin-bottom: 10px;
}

.timeline-chart {
    margin-top: 15px;
    height: 200px;
}

.delete-btn {
    position: absolute;
    top: 10px;
    right: 10px;
    background: none;
    border: none;
    color: #ff4444;
    cursor: pointer;
    opacity: 0.7;
    transition: opacity 0.2s;
}

.delete-btn:hover {
    opacity: 1;
}