Create beautiful backgrounds or forms you need with the <svg> tag using the viewBox:

viewBox values: “ min-width min-height width height ”

<svg viewBox="0 0 2000 280" preserveAspectRatio="none" width="100%" height="280">
   <polygon points="0,280 2000,280 2000,20"
            style="fill:#f9f0e6; opacity: .65"/>
</svg>