def merge_intervals(intervals):
    if not intervals:
        return []

    sorted_intervals = sorted(intervals, key=lambda x: x[0])
    merged = []
    
    for interval in sorted_intervals:
        if not merged or interval[0] > merged[-1][1]:
            merged.append(list(interval))
        else:
            merged[-1][1] = max(merged[-1][1], interval[1])
            
    return merged