Encodes an uploaded asset or pasted text into a data URI and writes the CSS that uses it — background-image for images, @font-face with font-display: swap for fonts, @import for stylesheets — with the size overhead reported. SVG and other text can be percent-encoded UTF-8 instead of Base64 to stay smaller. Paste a data URI (or a url("data:…") value) to decode it: the real type is sniffed from magic numbers and compared with the declared one, text payloads are shown in full and binaries as a hex head. Everything runs locally.