Edit only the background environment.
Keep Himeno completely unchanged:
preserve her exact face, expression, eyepatch, hairstyle, body, anatomy, pose, legs, feet, hands, oversized T-shirt, chair, beer can, framing, camera angle, proportions, painterly rendering, brush texture, and overall illustration style exactly as they are.
Replace only the existing plain green background with a simple modern apartment balcony inspired by the balcony atmosphere from the Chainsaw Man anime.
A modest Japanese apartment balcony in daylight,
pale cool gray and slightly blue-gray exterior walls,
large sliding glass door / window behind her,
simple dark metal balcony railing visible in the background,
subtle neighboring building and pale blue sky softly visible beyond the railing,
minimal ordinary residential architecture,
clean but slightly lived-in atmosphere,
nothing luxurious or decorative.
Strong natural daytime sunlight entering from one side,
bright sunlit areas contrasted with distinct cool shadows,
a large diagonal geometric shadow cast across the wall and balcony,
subtle reflected daylight from the sky,
quiet summer-afternoon feeling,
slightly washed-out colors,
muted blue-gray, pale cyan, soft white and desaturated green tones.
IMPORTANT:
match the new balcony background to the original painting,
painterly anime illustration,
visible loose brush strokes,
soft opaque paint,
subtle canvas and paper-like texture,
slightly imperfect hand-painted edges,
do not make the background photorealistic,
do not make it cleaner or sharper than the character.
Preserve the original lighting on Himeno as much as possible,
only subtly integrate the environmental light around her edges so she naturally belongs in the balcony setting.
Background replacement only.
Do not redraw or alter Himeno, the chair, or the beer can.