“4th birthday”是使用 FontVibe AI 创作的寒冰冻结文字效果。封进厚实的坚冰里——冰块棱角锋利，内部布满深层霜裂纹，还挂着垂落的冰锥。写实的冻水质感。

rendered in deep-frozen solid ice letterforms — each letter a massive glacial ice block. Surface: smooth-polished outer ice face with faint frost micro-crystal bloom at letter edges and surface rim frost texture. Body: thick translucent ice with pale blue-white tint, internal air bubble inclusions caught as bright white spherical highlights, faint crack networks branching inward from surface stress points. Internal: deep cold glow emanating from letter center — subsurface scattering of cold light through the ice mass, brighter at core, fading toward edges. Optical behavior: incoming light refracts at the polished ice surface creating bright rim caustic lines at letter edges; internal ice density variation bends light into cold blue-white spectral micro-prisms; icicle extensions at letter bases show pure refraction clarity — crisp cold caustic light fans below. Peak visual moment: cold internal glow + surface frost bloom + refracted rim light + hanging icicle drips = letters physically frozen in time. Reference: blue glacier ice cave walls / Arctic sea ice block at dawn / Jökulsárlón glacial lagoon ice / professional ice sculptor competition piece under cold spotlight. Render the exact text "4th birthday" as monumental deep-frozen solid ice letterforms, with "4th" carrying stronger scale and visual weight than "birthday". Each character is carved from thick translucent glacial ice with a pale blue-white body, smooth polished faces, sharply refracted edges, and a fine bloom of frost micro-crystals across exposed rims. Bright white spherical air bubbles are suspended within the ice mass; delicate branching crack networks travel inward from surface stress points. A deep cyan-white internal glow radiates through the letters via subsurface scattering, brightest through dense central ice and fading into blue translucent margins. Refracted rim caustics trace the contours and spill onto the frozen surface beneath; clear icicle drips hang from lower ice edges, with tiny frozen droplets at their tips. Add a restrained birthday detail: small ice-carved starbursts, translucent frozen confetti shards, and four crystalline snowflake-like sparkles around the wording, all rendered in the same blue-white spectrum. Near-black arctic midnight background with a broad blue-teal aurora borealis glow, drifting airborne ice crystals, cold spotlight reflections, ray-traced ice refraction, zero warm tones, high-detail cinematic ice sculpture render.