A vast coastal landscape featuring a monumental natural sea arch carved into pale weathered cliffs. The main focal point is the tall irregular stone arch placed slightly left of center, with a clear opening that frames the luminous blue sea and a distant hazy coastline. The scene should feel ancient, quiet, majestic, and untouched by time. Use a foreground of steep rocky slopes, fractured stone ledges, sparse coastal grass, and small patches of moss clinging to cracks in the cliff. The developed midground should be dominated by the massive arch, its vertical rock pillars, deep shadowed cavities, and layered geological surfaces. A narrow glimpse of turquoise water should appear through the arch opening. In the background, show a calm open sea, a distant low coastline, and one isolated sea stack rising from the water on the right. The arch should create the main visual pathway, guiding the viewer’s eye through the dark stone opening toward the bright sea and atmospheric horizon. Keep the composition spacious and structurally simple, with large areas of open water and sky balancing the heavy rock forms. The lighting is soft clear coastal daylight, with warm cream and muted golden highlights on the sunlit rock faces, cool blue-gray shadows inside the arch, and a pale atmospheric haze above the horizon. Use a restrained palette of pale limestone, warm ochre, weathered gray, moss green, turquoise, soft sea blue, and muted sky blue. The rock formations should feel geologically believable, with fractured edges, vertical erosion lines, layered stone surfaces, narrow crevices, and irregular silhouettes. The sea should remain calm but alive, with gentle ripples, subtle depth changes, and soft broken reflections near the cliffs. Render the scene as a refined classical oil painting with soft academic realism and romantic landscape treatment. Use visible layered brushwork, atmospheric perspective, controlled geological detail, softly blended sky transitions, believable materials, and a clear monumental silhouette. The image should feel hand-painted, serene, timeless, and slightly idealized rather than glossy or digitally sterile.