diff --git a/src/index.css b/src/index.css
index 07fd0f3f0..3cdbc368b 100644
--- a/src/index.css
+++ b/src/index.css
@@ -270,6 +270,29 @@ html.focus-mode.dark *:focus-visible,
   color: #ffff00 !important;
 }
 
+/* Mockup da Landing Page - elementos de placeholder */
+.high-contrast .bg-gray-200,
+.high-contrast .bg-gray-300 {
+  background-color: #ffff00 !important;
+  border: 2px solid #000 !important;
+}
+
+.high-contrast .bg-blue-50,
+.high-contrast .bg-blue-100,
+.high-contrast .bg-purple-50,
+.high-contrast .bg-purple-100 {
+  background-color: #ffff00 !important;
+  border: 2px solid #000 !important;
+}
+
+.high-contrast .bg-blue-200,
+.high-contrast .bg-blue-800,
+.high-contrast .bg-purple-200,
+.high-contrast .bg-purple-800 {
+  background-color: #ffff00 !important;
+  border: 2px solid #000 !important;
+}
+
 /* Botões primários (verde/azul) */
 .high-contrast .bg-blue-600,
 .high-contrast .bg-blue-500,
@@ -297,7 +320,21 @@ html.focus-mode.dark *:focus-visible,
 }
 
 .high-contrast button {
-  border: 2px solid #ffff00 !important;
+  border: none !important;
+}
+
+/* Botões no header/navegação - sem borda */
+.high-contrast header button,
+.high-contrast nav button,
+.high-contrast header a,
+.high-contrast nav a {
+  background: transparent !important;
+  border: none !important;
+  outline: none !important;
+  box-shadow: none !important;
+  color: #ffff00 !important;
+  text-decoration: none !important;
+  font-weight: 700 !important;
 }
 
 /* Inputs e selects */