===== POST 1/5 · Concept =====
Create a high-quality, Retro Grid-style image for an Instagram/LinkedIn carousel about "Train / Validation / Test Splits" (Machine Learning, angle: Concept).

Art direction: y2k journal, graph-paper sticker collage. Modern, polished, social-media ready.
Format: vertical 4:5 aspect ratio (1080×1350 px), with clean negative space near the top for a headline overlay.
Color palette — use ONLY these colors: background #EBE9CC, surface #FFFFFF, primary accent #E94F2E, secondary accent #D8CFF0, tertiary accent #8FA84E, ink/text #1F3A2E.
Subject: a single clear focal concept representing Train / Validation / Test Splits, rendered in the Retro Grid aesthetic.
No text, no letters, no logos, no watermarks, no UI elements. High detail, crisp edges, professional finish.

Aspect ratio 4:5.

===== POST 2/5 · Why It Matters =====
Create a high-quality, Retro Grid-style image for an Instagram/LinkedIn carousel about "Train / Validation / Test Splits" (Machine Learning, angle: Why It Matters).

Art direction: y2k journal, graph-paper sticker collage. Modern, polished, social-media ready.
Format: vertical 4:5 aspect ratio (1080×1350 px), with clean negative space near the top for a headline overlay.
Color palette — use ONLY these colors: background #EBE9CC, surface #FFFFFF, primary accent #E94F2E, secondary accent #D8CFF0, tertiary accent #8FA84E, ink/text #1F3A2E.
Subject: a single clear focal concept representing Train / Validation / Test Splits, rendered in the Retro Grid aesthetic.
No text, no letters, no logos, no watermarks, no UI elements. High detail, crisp edges, professional finish.

Aspect ratio 4:5.

===== POST 3/5 · How It Works =====
Create a high-quality, Retro Grid-style image for an Instagram/LinkedIn carousel about "Train / Validation / Test Splits" (Machine Learning, angle: How It Works).

Art direction: y2k journal, graph-paper sticker collage. Modern, polished, social-media ready.
Format: vertical 4:5 aspect ratio (1080×1350 px), with clean negative space near the top for a headline overlay.
Color palette — use ONLY these colors: background #EBE9CC, surface #FFFFFF, primary accent #E94F2E, secondary accent #D8CFF0, tertiary accent #8FA84E, ink/text #1F3A2E.
Subject: a single clear focal concept representing Train / Validation / Test Splits, rendered in the Retro Grid aesthetic.
No text, no letters, no logos, no watermarks, no UI elements. High detail, crisp edges, professional finish.

Aspect ratio 4:5.

===== POST 4/5 · Code Example =====
Create a high-quality, Retro Grid-style image for an Instagram/LinkedIn carousel about "Train / Validation / Test Splits" (Machine Learning, angle: Code Example).

Art direction: y2k journal, graph-paper sticker collage. Modern, polished, social-media ready.
Format: vertical 4:5 aspect ratio (1080×1350 px), with clean negative space near the top for a headline overlay.
Color palette — use ONLY these colors: background #EBE9CC, surface #FFFFFF, primary accent #E94F2E, secondary accent #D8CFF0, tertiary accent #8FA84E, ink/text #1F3A2E.
Subject: a single clear focal concept representing Train / Validation / Test Splits, rendered in the Retro Grid aesthetic.
No text, no letters, no logos, no watermarks, no UI elements. High detail, crisp edges, professional finish.

Aspect ratio 4:5.

===== POST 5/5 · Common Mistakes =====
Create a high-quality, Retro Grid-style image for an Instagram/LinkedIn carousel about "Train / Validation / Test Splits" (Machine Learning, angle: Common Mistakes).

Art direction: y2k journal, graph-paper sticker collage. Modern, polished, social-media ready.
Format: vertical 4:5 aspect ratio (1080×1350 px), with clean negative space near the top for a headline overlay.
Color palette — use ONLY these colors: background #EBE9CC, surface #FFFFFF, primary accent #E94F2E, secondary accent #D8CFF0, tertiary accent #8FA84E, ink/text #1F3A2E.
Subject: a single clear focal concept representing Train / Validation / Test Splits, rendered in the Retro Grid aesthetic.
No text, no letters, no logos, no watermarks, no UI elements. High detail, crisp edges, professional finish.

Aspect ratio 4:5.

Paste into Midjourney, DALL·E, Ideogram, etc. Updates with the selected theme + palette.