import time
import datetime

def format_relative_time(timestamp: float) -> str:
    """Converts a timestamp to a human-readable relative format."""
    now = time.time()
    diff = now - timestamp
    seconds = int(diff)
    
    if seconds < 0:
        return "In the future"
    if seconds < 60:
        return "Just now"
    
    minutes = seconds // 60
    if minutes < 60:
        return f"{minutes}m ago"
    
    hours = minutes // 60
    if hours < 24:
        return f"{hours}h ago"
    
    days = hours // 24
    if days == 1:
        return "Yesterday"
    if days < 30:
        return f"{days}d ago"
    
    months = days // 30
    if months < 12:
        return f"{months}mo ago"
    
    dt = datetime.datetime.fromtimestamp(timestamp)
    return dt.strftime('%Y-%m-%d')