RSI (Custom Background) KDM

This code is a custom version of the RSI (Relative Strength Index) indicator.
Its main purpose is to compare recent price gains and losses to determine whether the market is in an overbought or oversold condition.

30–50 zone (purple tone): represents a weak or pullback area.
50–70 zone (green tone): represents a strengthening or dominant buying area.

Additionally, when the RSI line moves above 70, a green gradient background highlights the overbought region; when it moves below 30, a red gradient background emphasizes the oversold region.
Like the classic RSI, this version is a momentum indicator showing whether the price is losing or gaining strength.

The key difference is the colored background, which allows you to visually identify the RSI zones (e.g., 30–50 weak, 50–70 strong) much faster and more clearly.