Roblox Block Tower Thumbnail

Goal: Create a bright square Roblox-style promotional game thumbnail for {argument name="game title" default="巨大アスレチック ブロックタワーを駆け上がれ！"}, an exciting block-tower obby where players climb a giant toy-brick tower and collect treasure chests to spin a gacha.

Canvas: Square 1:1 thumbnail, 768x768 or larger, ultra-saturated colors, high-contrast mobile-game advertising composition, thick white and black sticker outlines around every character and text element.

Layout: Put the red-and-white ROBLOX logo at the top left. Fill the background with a huge vertical tower made from colorful LEGO-like plastic studs and brick platforms, receding upward into a blue sky with clouds. Place the main Japanese headline across the upper-middle in giant layered text: a small black rounded label reading 「巨大アスレチック」 above enormous rainbow block letters reading 「ブロックタワー」, followed by bold white text with black outline reading 「を駆け上がれ！」 with yellow star icons on both sides. Under the title, add a blue banner with white text: 「宝箱を集めてガチャを回そう！」. Add two game HUD counters at the top right: exactly 2 rounded black panels, one showing a gold coin icon and 「1,234」, the other showing a treasure chest icon and 「宝箱 7/10」.

Characters and objects: Include exactly 8 main visible characters: 1 cheerful orange-haired chibi girl in a yellow martial-arts outfit running in the foreground, 1 smiling panda companion at bottom left, 1 green-haired crowned chibi girl in a green outfit on the left, 1 red-kimono chibi girl near center, 1 black-haired ponytail chibi adventurer in green at center, 1 gray-helmet chibi girl with a small round helmet to the right of center, 1 purple wolf-eared chibi boy on the right, and 1 dark ninja boy flying at the upper right holding a small black cat. Include exactly 3 small pet/mascot creatures near the right group: a tiny black cat with the ninja, a yellow chick-like mascot, and a pink bunny-like mascot. Add exactly 1 golden treasure chest in the lower center foreground and exactly 1 red-and-gold capsule gacha machine at the lower right filled with multicolored balls and topped with a gold star. Scatter a few sparkling gold coins and star effects around the scene.

Callouts and UI: Add a jagged red-yellow burst callout near the gacha machine reading 「宝箱の数だけ ガチャが回せる！」. Along the bottom edge, add exactly 4 black rounded instruction cards with orange outlines and icons: 1 chest icon card reading 「宝箱を集めて ガチャを回そう！」, 1 stopwatch icon card reading 「タイムアタックで ランキング上位を目指そう！」, 1 badge icon card reading 「バッジを集めて 図鑑をコンプリート！」, and 1 checkpoint flag icon card reading 「セーブポイントで どこでも復帰！」.

Visual style: Roblox-inspired toy-block world, glossy 3D plastic bricks, chibi anime characters with oversized heads, big expressive eyes, joyful adventurous expressions, dynamic running poses, cartoon lighting, sparkle effects, strong drop shadows, thick outlines, vivid red yellow green blue purple palette, busy but readable YouTube thumbnail composition.

Constraints: Keep all visible text in Japanese exactly as specified, make the headline the dominant focal point, use exactly 8 main characters, exactly 3 small pet mascots, exactly 2 top-right HUD counters, and exactly 4 bottom instruction cards. No photorealism, no watermark, no extra logos beyond ROBLOX.