DOCS: promocards + features

Signed-off-by: jokob-sk <jokob.sk@gmail.com>

docs/stylesheets/custom.css

@@ -0,0 +1,71 @@
+/**
+ * Copyright 2026 UCP Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* --- PROMO CARDS  --- */
+.promo-card-wrapper {
+  display: flex;
+  gap: 24px;
+  max-width: 1200px;
+  margin: 60px auto;
+  flex-wrap: wrap;
+}
+
+.promo-card {
+  flex: 1;
+  min-width: 300px;
+  background-color: #f8f9fa;
+  border-radius: 24px;
+  padding: 16px 24px;
+  display: flex;
+  flex-direction: column;
+  align-items: flex-start;
+}
+
+.promo-card h3 {
+  color: #202124;
+  margin-top: 0;
+  margin-bottom: 12px;
+}
+
+.promo-card p {
+  margin-bottom: 16px;
+  flex-grow: 1;
+}
+
+.promo-button,
+.learn-more-btn {
+  display: inline-block;
+  padding: 0.5rem 1.2rem;
+  border: 1px solid #000;
+  border-radius: 50px; /* Pill shape */
+  text-decoration: none;
+  color: #000;
+  font-weight: 500;
+  font-size: 0.8rem;
+  transition: background-color 0.2s ease-in-out;
+  background-color: transparent;
+}
+
+/* Ensure link buttons don't inherit blue color */
+:is(a.promo-button, a.learn-more-btn):is(:link, :visited) {
+  color: #000;
+}
+
+.promo-button:hover,
+.learn-more-btn:hover {
+  background-color: #e9ecef;
+  color: #000;
+}