"""Safe per-device block CSS using validated data-block identifiers."""
import re,json

def editor_css(blocks):
    tablet=[];mobile=[]
    for b in blocks:
        uid=b.get('id','')
        if not re.fullmatch('[a-zA-Z0-9_-]{4,50}',uid):continue
        s=b.get('style') or {}
        try:
            tp=min(120,max(0,int(s.get('tablet_padding',50))))
            mp=min(120,max(0,int(s.get('mobile_padding',28))))
        except (TypeError,ValueError):tp,mp=50,28
        tablet.append(f'.sf-section[data-block="{uid}"]{{--sf-pad:{tp}px}}')
        mobile.append(f'.sf-section[data-block="{uid}"]{{--sf-pad:{mp}px}}')
        if s.get('hide_tablet') is True:tablet.append(f'.sf-section[data-block="{uid}"]{{display:none}}')
        if s.get('hide_mobile') is True:mobile.append(f'.sf-section[data-block="{uid}"]{{display:none}}')
    return '@media(max-width:820px){'+''.join(tablet)+'}@media(max-width:540px){'+''.join(mobile)+'}'

def site_css(entries):
    items=[]
    for entry in entries:
        meta=json.loads(entry.get('meta_json') or '{}')
        items.extend(meta.get('blocks',[]) if isinstance(meta.get('blocks'),list) else [])
    return editor_css(items)