A vibrant, classic rainbow pattern featuring the seven standard colors (red, orange, yellow, green, blue, indigo, violet) arranged in a horizontal arc. The colors should transition smoothly, with no harsh lines between them. The pattern should be approximately 1000 pixels wide by 500 pixels high, at a resolution of 300 DPI. The pattern should be seamless, meaning it could be tiled horizontally or vertically without visible breaks. I'd like the pattern to have a slight, subtle texture, perhaps a very fine grain, to add depth and prevent it from looking too flat. The overall style should be clean, modern, and versatile enough for use in various applications, from website backgrounds to fabric prints. The color saturation should be relatively high, creating a bold and eye-catching effect. Finally, the output should be in a high-resolution PNG format.