https://www.color-hex.com/
background: rgba(255, 0, 0, 0.1)
background: rgba(255, 0, 0, 0.2)
background: rgba(255, 0, 0, 0.3)
background: rgba(255, 0, 0, 0.4)
background: rgba(255, 0, 0, 0.5)
background: rgba(255, 0, 0, 0.6)
background: rgba(255, 0, 0, 0.7)
background: rgba(255, 0, 0, 0.8)
background: rgba(255, 0, 0, 0.9)
background: rgba(255, 0, 0, 1.0)
background: rgb(255, 0, 0)