Create a bright, ultra-saturated anime YouTube-style promotional thumbnail for {argument name="brand name" default="Sousaku AI"}, in a magical-girl music theme. The scene shows exactly 2 cute brown-haired magical girls sitting side by side in the center, both smiling with eyes closed and sharing wired earphones while listening to music from exactly 1 smartphone placed between them; the phone screen displays a colorful equalizer with playback controls. The left girl wears a yellow-and-white frilly magical-girl dress with small wing-like accents, star decorations, yellow bows, and a tiny banana-shaped crown accessory, suggesting a banana-themed variant; the right girl wears a pink-and-white frilly magical-girl dress with blue ribbon twin-tail bows, star brooch, white gloves, and soft angel-wing accents. Use glossy idol-anime rendering, big sparkling eyes style even though the eyes are closed, soft blush, detailed frills, ribbons, and polished highlights. The background is an explosive rainbow concert-fantasy design filled with neon gradients, sparkles, starbursts, glowing staff lines, and exactly 3 major music-themed icon groups: oversized musical notes scattered across the image, a large treble clef on the left, and speaker/headphone graphics on the sides. Add colorful waveform and equalizer bars stretching horizontally behind the characters, plus a piano keyboard along the lower left edge. Include exactly 4 visible text elements: a huge top headline in Japanese reading {argument name="headline text" default="♪AI楽曲生成♪"} with thick white outline, dark drop shadow, and pink-to-yellow-to-blue gradient fill; a small handwritten-style Japanese tagline near the lower left reading {argument name="tagline text" default="音楽の世界へ♪"}; a large curved bottom ribbon title reading {argument name="bottom title" default="Sousaku AI"}; and a top-right rounded white logo badge reading {argument name="logo text" default="Sousaku.AI"} with a small red origami bird icon. Compose for a 16:9 thumbnail, extremely eye-catching, high contrast, dense kawaii visual effects, celebratory music-generation advertising mood, crisp readable typography, no empty areas.