テック系チュートリアル用サムネイル（UIモックアップ付き）

A clean modern YouTube thumbnail on a bright white background, split visually between bold text on the left and a cropped presenter on the right. On the left, place a massive stacked headline in heavy black sans-serif uppercase reading {argument name="headline text" default="CLAUDE DESIGN"}, aligned top-left across two lines. Below it, add a large rounded rectangular orange banner with a subtle drop shadow containing bold white uppercase text with an orange outline that reads {argument name="subheadline text" default="IN 6 MINS"}. Near the headline, include 2 orange starburst spark shapes, one small beside the text and one much larger in the far right background. In the lower-left quadrant, show a floating app interface mockup for a design tool dashboard with a soft off-white panel, thin borders, rounded corners, and a faint shadow. The interface should have a left sidebar with 4 menu items labeled exactly: "Recent", "Your designs", "Examples", and "Design systems". The main panel header should say "Recent" and contain 3 project cards arranged in a grid, labeled exactly: "Thumio Design System", "Thumio Startup", and "Design System". On the right half, show a cropped photorealistic young adult man from chest up wearing a white turtleneck sweater, with messy light brown hair and light facial hair, positioned close to camera. His face is intentionally obscured by a solid tan rectangle placeholder covering most of the face area. He points with one hand toward the interface panel on the left, finger extended. Use a warm orange and white brand palette, high contrast, minimal clutter, polished creator-economy thumbnail styling, subtle shadows, and a composition designed for tech tutorial content.