The Window.devicePixelRatio read-only property returns the ratio of the (vertical) size of one physical pixel on the current display device to the size of one device independent pixels(dips).
The ::-ms-fill-lowerCSSpseudo-element represents the portion of the "track" (the groove in which the indicator aka thumb slides) of an <input> of type="range", which corresponds to values lower than the value currently selected by the thumb.
The ::-ms-fill-upperCSSpseudo-element represents the portion of the "track" (the groove in which the indicator aka thumb slides) of an <input> of type="range", which corresponds to values greater than the value currently selected by the thumb.
The ::-ms-thumb CSS pseudo-element represents the "thumb" that the user can move within the "groove" of an <input> of type="range" to alter its numerical value.