fix: dark mode contrast and visibility issues

Override --font--colors--title-dm/paragraph-dm variables that resolved
to near-black after neutral color inversion. Add comprehensive dark
mode overrides for header nav links (#222 hardcoded), footer text/links/
borders, cards, CTA sections, contact page elements, and more.

Remove inline color styles from contact components that blocked CSS
dark mode overrides. Fix truncated about section text and add w-mod-ix3
class to html element.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

components/contact/HeroSection.tsx

@@ -41,7 +41,7 @@ export default function HeroSection() {
                   <div className="contact-icon-wrapper">
                     <div style={{"width": "0%", "height": "100%"}} className="contact-icon-bg">
                     </div>
-                    <svg style={{"color": "rgb(22,22,22)"}} xmlns="http://www.w3.org/2000/svg" width="100%" viewBox="0 0 24 24" fill="none" className="contact-icon">
+                    <svg xmlns="http://www.w3.org/2000/svg" width="100%" viewBox="0 0 24 24" fill="none" className="contact-icon">
                       <path fillRule="evenodd" clipRule="evenodd" d="M0 2H24V4.31556L12.0001 10.861L0 4.31546V2ZM0 6.59364V22H24V6.59373L12.0001 13.1391L0 6.59364Z" fill="currentColor">
                       </path>
                     </svg>
@@ -77,7 +77,7 @@ export default function HeroSection() {
                   <div className="contact-icon-wrapper">
                     <div style={{"width": "0%", "height": "100%"}} className="contact-icon-bg">
                     </div>
-                    <svg style={{"color": "rgb(22,22,22)"}} xmlns="http://www.w3.org/2000/svg" width="100%" viewBox="0 0 32 33" fill="none" className="contact-icon">
+                    <svg xmlns="http://www.w3.org/2000/svg" width="100%" viewBox="0 0 32 33" fill="none" className="contact-icon">
                       <g clipPath="url(#clip0_16077_4034)">
                         <path fillRule="evenodd" clipRule="evenodd" d="M17.4208 23.0719L19.6275 19.3745L20.2074 18.403L21.2951 18.7137L30.7718 21.4215L31.9775 21.7659L31.8283 23.011L30.907 30.7015L30.7429 32.0718L29.3648 31.9954C24.7899 31.7419 20.2596 30.4521 16.1565 28.1239C13.8427 26.8111 11.6667 25.1692 9.69696 23.1995C7.72725 21.2298 6.08529 19.0538 4.77246 16.74C2.44438 12.6369 1.15446 8.1065 0.901036 3.53162L0.824707 2.1536L2.19504 1.98942L9.8854 1.06812L11.1305 0.918945L11.4751 2.12475L14.1827 11.6014L14.4934 12.6892L13.522 13.269L9.82445 15.4758C10.8063 16.9482 11.9474 18.3468 13.2482 19.6476C14.5492 20.9486 15.9481 22.0899 17.4208 23.0719Z" fill="currentColor">
                         </path>