Create a square black-and-white motivational poster with a high-fashion editorial portrait. The right half of the canvas is dominated by a close-up frontal portrait of a serious young man, {argument name="portrait subject" default="a handsome young Latino man in his 20s"}, with short dark curly hair, sharp eyebrows, trimmed stubble beard, neutral intense expression, direct eye contact, and a plain white crew-neck shirt. Use crisp studio lighting, realistic skin texture, high contrast monochrome photography, clean white background, and a cropped composition where the top of the hair and shoulders are partly cut off. On the left half, overlay huge condensed bold uppercase Spanish typography in five stacked lines, aligned left, spanning from near the top to near the lower third; the text should read {argument name="main slogan" default="SI PIENSAS QUE PUEDES HACERLO ENTONCES PUEDES"}. Make the type black, extremely tall and heavy, with tight line spacing, partially transparent or multiply-blended so the face subtly shows through where the letters cross into the portrait. At the bottom left, add a small spaced-out uppercase mantra in three lines reading {argument name="small mantra" default="CREE. ENFÓCATE. EJECUTA."}, then below it add a handwritten script signature-style phrase reading {argument name="signature phrase" default="Sigue adelante."} with a loose underline stroke. Keep the overall design minimalist, premium, motivational, and poster-like; no borders, no logos, no extra objects, no color.