Replace random HSL gradients in homepage cards with header gradient

TODO.md

@@ -1,9 +1,4 @@
 # TODO
 
-## Fixes
+- [x] Remove random HSL gradients from homepage cards and use header's background gradient
-- [x] Typography: switch `--font-display` / title font from Combined to Ductus (`DuctusRegular.otf`)
+- [ ] Review other gradient usages (check if any leftover random hue generation anywhere)
-- [x] Replace `mb_strlen`/`mb_substr` with `strlen`/`substr` in TfeController, SearchController, Parsedown — mbstring extension not available on production server
-- [x] system.css: retheme to site light palette — remove all `--sys-bg/border/text` dark tokens from variables.css; replace with standard `--bg-*`, `--border-*`, `--text-*` tokens; remap `--sys-syntax-*` to light-appropriate colours; remove dark terminal aesthetic
-- [x] SystemController: PHP-FPM status check — dynamically probe `phpX.Y-fpm` unit derived from running PHP version before static fallback list; add `php8.4-fpm` to cover current production PHP 8.4
-- [x] Favicon: replace SVG placeholder with full PNG/ICO favicon set from `public/assets/favicon/` in `templates/head.php`
-- [x] Rebrand: replace "PostErg" with "XAMXAM" in admin header link, default `<title>`, and OG site_name fallback

public/assets/css/main.css

@@ -114,6 +114,15 @@
   text-align: center;
   box-sizing: border-box;
   border-radius: 7px 7px 0 0;
+  background: linear-gradient(
+    180deg,
+    var(--gradient-start) 0%,
+    var(--gradient-2) 20%,
+    var(--gradient-3) 40%,
+    var(--gradient-4) 60%,
+    var(--gradient-4) 88%,
+    var(--header-gradient-fade) 96%
+  );
 }
 
 .card__gradient-author {

public/index.php

@@ -48,12 +48,7 @@ extract($vars);
                                      loading="lazy">
                             </figure>
                         <?php else: ?>
-                            <?php
-                            $hue  = ($item['id'] * 47 + 160) % 360;
-                            $hue2 = ($hue + 40) % 360;
-                            ?>
                             <div class="card__media--gradient"
-                                 style="background:linear-gradient(135deg,hsl(<?= $hue ?>,55%,40%),hsl(<?= $hue2 ?>,50%,28%));"
                                  aria-hidden="true">
                                 <span class="card__gradient-author"><?= htmlspecialchars($item['authors'] ?? '') ?></span>
                                 <span class="card__gradient-title"><?= htmlspecialchars($item['title']) ?></span>