Réponse :
<div class="texte-multicolor">
<span style="color:#ff5f00">T</span><span style="color:#ffbf00">e</span><span style="color:#dfff00">x</span><span style="color:#7fff00">t</span><span style="color:#1fff00">e</span> <span style="color:#00ff9f">m</span><span style="color:#00ffff">u</span><span style="color:#009fff">l</span><span style="color:#003fff">t</span><span style="color:#1f00ff">i</span><span style="color:#7f00ff">c</span><span style="color:#df00ff">o</span><span style="color:#ff00bf">l</span><span style="color:#ff005f">o</span><span style="color:#ff0000">r</span>
</div>
J'espère que sa t'aide, c'est un texte multicolor mais pas animé, dis le moi si tu as besoin d'une version animé.
