diff --git a/xiaohongshu-platform/src/App.css b/xiaohongshu-platform/src/App.css
new file mode 100644
index 0000000..3377645
--- /dev/null
+++ b/xiaohongshu-platform/src/App.css
@@ -0,0 +1,233 @@
+.app {
+  display: flex;
+  flex-direction: column;
+  min-height: 100vh;
+  background-color: #f5f5f5;
+}
+
+/* Header Styles */
+.header {
+  background: white;
+  border-bottom: 1px solid #e0e0e0;
+  position: fixed;
+  top: 0;
+  left: 0;
+  right: 0;
+  z-index: 100;
+}
+
+.header-content {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  padding: 1rem 2rem;
+  max-width: 1200px;
+  margin: 0 auto;
+}
+
+.logo {
+  font-size: 1.5rem;
+  font-weight: bold;
+  color: #ff2442;
+  margin: 0;
+}
+
+.search-bar {
+  display: flex;
+  align-items: center;
+  background: #f8f8f8;
+  border-radius: 20px;
+  padding: 0.5rem 1rem;
+  flex: 1;
+  max-width: 400px;
+  margin: 0 2rem;
+}
+
+.search-bar input {
+  border: none;
+  background: none;
+  outline: none;
+  margin-left: 0.5rem;
+  width: 100%;
+}
+
+.header-actions {
+  display: flex;
+  gap: 1rem;
+  align-items: center;
+}
+
+.header-actions svg {
+  cursor: pointer;
+  color: #666;
+}
+
+/* Main Content */
+.main-content {
+  flex: 1;
+  padding-top: 80px;
+  padding-bottom: 80px;
+}
+
+.posts-container {
+  display: grid;
+  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
+  gap: 1rem;
+  padding: 1rem;
+  max-width: 1200px;
+  margin: 0 auto;
+}
+
+/* Post Card Styles */
+.post-card {
+  background: white;
+  border-radius: 12px;
+  overflow: hidden;
+  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
+  transition: transform 0.2s ease;
+  cursor: pointer;
+}
+
+.post-card:hover {
+  transform: translateY(-2px);
+}
+
+.post-image {
+  width: 100%;
+  height: 200px;
+  overflow: hidden;
+}
+
+.post-image img {
+  width: 100%;
+  height: 100%;
+  object-fit: cover;
+}
+
+.post-content {
+  padding: 1rem;
+}
+
+.post-title {
+  font-size: 1rem;
+  font-weight: 600;
+  margin: 0 0 0.5rem 0;
+  color: #333;
+  line-height: 1.3;
+}
+
+.post-description {
+  font-size: 0.9rem;
+  color: #666;
+  margin: 0 0 1rem 0;
+  line-height: 1.4;
+}
+
+.post-author {
+  display: flex;
+  align-items: center;
+  margin-bottom: 1rem;
+}
+
+.author-avatar {
+  width: 24px;
+  height: 24px;
+  border-radius: 50%;
+  margin-right: 0.5rem;
+}
+
+.author-name {
+  font-size: 0.8rem;
+  color: #666;
+}
+
+/* Post Actions */
+.post-actions {
+  display: flex;
+  align-items: center;
+  gap: 1rem;
+}
+
+.action-btn {
+  display: flex;
+  align-items: center;
+  gap: 0.3rem;
+  background: none;
+  border: none;
+  color: #666;
+  cursor: pointer;
+  font-size: 0.8rem;
+  padding: 0.3rem;
+  border-radius: 4px;
+  transition: all 0.2s ease;
+}
+
+.action-btn:hover {
+  background: #f0f0f0;
+}
+
+.action-btn.liked {
+  color: #ff4757;
+}
+
+.action-btn.saved {
+  color: #ffa502;
+}
+
+/* Bottom Navigation */
+.bottom-nav {
+  position: fixed;
+  bottom: 0;
+  left: 0;
+  right: 0;
+  background: white;
+  border-top: 1px solid #e0e0e0;
+  display: flex;
+  justify-content: space-around;
+  padding: 0.5rem 0;
+  z-index: 100;
+}
+
+.nav-btn {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  background: none;
+  border: none;
+  color: #999;
+  cursor: pointer;
+  padding: 0.5rem;
+  transition: color 0.2s ease;
+}
+
+.nav-btn.active {
+  color: #ff2442;
+}
+
+.nav-btn span {
+  font-size: 0.7rem;
+  margin-top: 0.2rem;
+}
+
+/* Responsive Design */
+@media (max-width: 768px) {
+  .header-content {
+    padding: 1rem;
+  }
+  
+  .search-bar {
+    margin: 0 1rem;
+  }
+  
+  .posts-container {
+    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
+    padding: 0.5rem;
+    gap: 0.5rem;
+  }
+}
+
+@media (max-width: 480px) {
+  .posts-container {
+    grid-template-columns: repeat(2, 1fr);
+  }
+}