Vexor CTA — Référence de design web et prompt

# Prompt: Vexor signup CTA and footer

Build a single-file **signup call-to-action with a footer for a fictional global payments company, Vexor**. Use plain HTML, CSS and vanilla JS, with no framework and no build step. The look is pure black with one framed CTA card filled with slowly swirling coral and crimson smoke, a white headline, a dark waitlist input with a coral button, and a minimal footer underneath.