Adapted from Pikatscha's Skin Viewer on codepen: https://codepen.io/Pikatscha/pen/ZEPpzyP
Uses the Crafatar API to retrieve Minecraft skin data.
Whole model is done in CSS, with JavaScript to rotate the model to face the user's mouse.
Currently, the tool only supports slim models, but by tweaking a few values in the CSS code you could easily adapt this tool for classic (steve) style skins.