How can I get CSS blend modes to work on a background video element in Webflow? Is it possible to remove the black background in the video and show only the smoke over the image? Also, why won't the video autoplay on an iPhone running iOS 10.2?

To apply CSS blend modes to a background video element in Webflow, you can follow these steps:

1. Add a video element: Drag and drop a video element onto your Webflow canvas.
2. Set the video as a background: Select the video element and go to the Style panel on the right. Under the Background section, check the "Use video" option and upload your video file.
3. Adjust the video settings: Click on the gear icon next to the "Use video" option to open the video settings. Here, you can define the video's properties like autoplay, loop, and mute.
4. Apply blend modes: With the video element still selected, go to the Styles panel and add a new class or apply the blending directly to the element. Under the Background section, scroll down and find the "Blend mode" option. Select the desired blend mode from the dropdown menu.
5. Fine-tune blend mode: If the blend mode affects the entire video, you can try placing the video element inside a container element, apply the blend mode to the container, and adjust its position to achieve the desired effect.

To remove the black background in the video and show only the smoke over the image, you can use a blend mode like "screen" or "overlay". These blend modes will allow the video to blend with the content below, revealing only the lighter areas such as the smoke.

As for the video autoplay issue on iOS 10.2, autoplay on mobile devices, including iPhones, is generally disabled to provide a better user experience and prevent unnecessary data usage. This restriction is imposed by iOS itself, and there's no direct solution to force autoplay on these devices.

To mitigate this, you can trigger the video to play when a user interacts with your site, such as clicking a button or scrolling the page. You can use Webflow's interactions feature to accomplish this. By creating a custom interaction, you can set the video to play on a specific event like button click or page load.

Additionally, consider providing a clear play button or a prominent call-to-action to encourage users to manually play the video if autoplay is not available on their device.

It's worth noting that newer versions of iOS have relaxed these restrictions on autoplaying videos with sound, but older versions like iOS 10.2 may still enforce the policy.