I try to make project with react.But when i click to input, mobile keyboard resize to viewport how can i prevent that ? And if you noticed when opened to my deploy my second issues is my login and signup images doesnt move smooth at first time.And i would be glad if you check my project and give me feedback.
deploy: https://mook-f2b4e.web.app
github link: https://github.com/UmutPalabiyik/mook

This is likely because the font size on your inputs is lower than 16px. Most mobile browsers will zoom the viewport in when an input or textarea gets focus if the size is below 16px.
input, select, textarea {
font-size: 16px;
}
Once the input elements have a 16px size, that viewport zoom should no longer happen. If your web site/application is responsive, you could include these styles in a media query to only have 16px inputs on mobile.