Fix: correct ::root to :root in all CSS stylesheets

Co-authored-by: tassan <7563760+tassan@users.noreply.github.com>

Author: Copilot

public/assets/css/diagnostico.css

@@ -4,7 +4,7 @@
     padding: 0;
 }
 
-::root {
+:root {
     --bg-primary: #0D0D0F;
     --bg-secondary: #1A1A1F;
     --bg-card: #242429;

public/assets/css/privacidade.css

@@ -2,7 +2,7 @@
     box-sizing: border-box;
 }
 
-::root {
+:root {
     --bg-primary: #0D0D0F;
     --bg-secondary: #1A1A1F;
     --bg-card: #242429;

public/assets/css/style.css

@@ -5,7 +5,7 @@
   box-sizing: border-box;
 }
 
-::root {
+:root {
   --bg-primary: #0D0D0F;
   --bg-secondary: #1A1A1F;
   --bg-card: #242429;