.timeline-container {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

.timeline-filters {
    display: flex;
    gap: 10px;
    margin-bottom: 30px;
    flex-wrap: wrap;
}

.decade-filter {
    padding: 8px 16px;
    border: 2px solid #e5e7eb;
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    background: white;
}

.decade-filter:hover {
    border-color: #3b82f6;
}

.decade-filter.active {
    background: #3b82f6;
    color: white;
    border-color: #3b82f6;
}

.year-group {
    margin: 40px 0;
    opacity: 0;
    transform: translateY(20px);
    transition: all 0.5s ease;
}

.year-group.visible {
    opacity: 1;
    transform: translateY(0);
}

.year-label {
    font-size: 1.5rem;
    font-weight: 700;
    color: #1f2937;
    margin: 30px 0 20px 20px;
    padding-bottom: 10px;
    border-bottom: 3px solid #3b82f6;
    display: inline-block;
}

.timeline-item {
    position: relative;
    padding: 40px 0;
    border-left: 2px solid #e5e7eb;
    margin-left: 20px;
    min-height: 150px;
    opacity: 0;
    transform: translateX(-20px);
    transition: all 0.5s ease;
}

.timeline-item.visible {
    opacity: 1;
    transform: translateX(0);
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: -9px;
    top: 44px;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: #3b82f6;
    border: 2px solid #fff;
}

.timeline-content {
    margin-left: 30px;
    transition: all 0.3s ease;
    background: white;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.timeline-date {
    font-weight: 700;
    color: #1f2937;
    margin-bottom: 12px;
    font-size: 1.2rem;
    background: #f3f4f6;
    display: inline-block;
    padding: 4px 12px;
    border-radius: 4px;
}

.timeline-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: #1f2937;
    margin-bottom: 8px;
}

.timeline-text {
    color: #4b5563;
    line-height: 1.5;
}

.timeline-image {
    margin-top: 12px;
    border-radius: 8px;
    overflow: hidden;
    max-width: 100%;
}

.timeline-image img {
    width: 100%;
    height: auto;
    display: block;
}

.loading {
    text-align: center;
    padding: 40px;
    color: #6b7280;
}

.error {
    text-align: center;
    padding: 40px;
    color: #ef4444;
}

@media (max-width: 640px) {
    .timeline-content {
        margin-left: 20px;
    }
    .decade-filter {
        font-size: 0.875rem;
        padding: 6px 12px;
    }
}