feat(contact-form): enhance validation and accessibility

src/styles/about.css

@@ -137,11 +137,26 @@ legend {
 }
 
 label {
-  display: block;
+  font-weight: 600;
+  font-size: 0.95rem;
+  color: #333;
   margin-bottom: 0.4rem;
+  display: block;
   font-weight: 500;
 }
 
+.error-message {
+  color: red;
+  font-size: 0.9em;
+  margin-top: 4px;
+  display: block;
+}
+
+input.error, textarea.error {
+  border-color: red;
+}
+
+
 input[type="text"],
 input[type="email"],
 input[type="tel"],
@@ -184,7 +199,13 @@ textarea:focus {
 }
 
 /* Button */
-button[type="submit"] {
+.submit-reset {
+  display: flex;
+  gap: 20px;
+  justify-content: center;
+}
+
+button[type="submit"], button[type="reset"] {
   margin:20px 0px 20px 0px;
   padding: 8px 25px;
   background-color: #ea7e0b;
@@ -196,7 +217,7 @@ button[type="submit"] {
   transition: background-color 0.3s ease;
 }
 
-button[type="submit"]:hover {
+button[type="submit"]:hover, button[type="reset"]:hover {
   background-color: #2e97be;
 }