a softly glowing rectangular portal window floating in deep, velvety darkness, warm luminous light emanating outward toward the viewer, interior filled with layered pearlescent gradients and subtle atmospheric depth, suggesting an expansive space beyond without revealing a specific world, inviting yet quietly mysterious, gentle contrast between light and shadow, subtle CRT light spill and fine analog film grain, dreamwave retrofuturist aesthetic, soft cyan and warm ivory glow with faint muted magenta at the edges, controlled darkness surrounding the portal, perfectly centered symmetrical composition, timeless liminal mood, visual symbol of welcome, curiosity, and passage into other worlds, square format, instagram profile picture, minimal, iconic, logo-like