Regarding the Hero Section and the Background Image

Hi, I have some questions regarding the hero section and the background image. My website: https://daichi-illust.com/ Hero Section 1. I'd like to set the movie on repeat. How can I set it on repeat? 2. I updated a video in the recommended size for the header, but it's not displayed in fullscreen size (both sizes are cut). To display it in fullscreen size, what should I do? 3. Although the video shows up on PC, it doesn't on smart phone devices. I'd like to show the video on smart phones, too. In that case, what should I do? Background Image 1. I'd like to set a background image, fixed to fullscreen size, but if I set it as "fullscreen" to PC, it looks quite rough on smart phones. I'd like it to look perfect on both devices. In this case, what should I do? I'm hoping to hearing some answers! Thank you very much in advance.   shoco