The opacity attribute specifies the transparency of an object or of a group of objects, that is, the degree to which the background behind the element is overlaid.
Note: As a presentation attribute, opacity can be used as a CSS property. See the CSS opacity property for more information.
You can use this attribute with the following SVG elements:
The uniform opacity setting to be applied across an entire object, as a <number>. Any values outside the range 0.0 (fully transparent) to 1.0 (fully opaque) will be clamped to this range.