Green buttons (#2597)

# Description

Making buttons green
Closes #()

![image](https://github.com/user-attachments/assets/29417e03-664d-4a77-a3ca-80d0a8b76f07)

## Checklist

- [X ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ X] I have performed a self-review of my own code
- [X ] I have attached images of the change if it is UI based
- [ X] I have commented my code, particularly in hard-to-understand
areas
- [ X] If my code has heavily changed functionality I have updated
relevant docs on [Stirling-PDFs doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
- [ X] My changes generate no new warnings
- [ X] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

Co-authored-by: Reece Browne <reece@stirling.pdf>

src/main/resources/templates/sign.html

@@ -212,7 +212,7 @@
                 <span class="btn-tooltip" th:text="#{sign.last}"></span>
               </button>
               <button id="download-pdf" class="btn btn-outline-secondary"
-                style="color: green;border-color: green; background: rgba(0, 128, 0, 0.2);">
+                style="border-color: green; color:#b2e3a8; background: rgba(24, 122, 5, 1)">
                 <span class="material-symbols-rounded">
                   download
                 </span>