diff --git a/src/styles.css b/src/styles.css
index c88e7a4..550b3a1 100644
--- a/src/styles.css
+++ b/src/styles.css
@@ -620,6 +620,10 @@ body {
 }
 
 @media (max-width: 768px) {
+  html {
+    font-size: clamp(14px, 4.2667vw, 16px);
+  }
+
   .layout-shell > .sidebar {
     display: none;
   }
@@ -632,12 +636,12 @@ body {
   }
 
   .mobile-topbar {
-    height: 48px;
+    height: 3rem;
     flex: 0 0 auto;
     display: flex;
     align-items: center;
-    gap: 8px;
-    padding: 0 8px;
+    gap: 0.5rem;
+    padding: 0 0.5rem;
     border-bottom: 1px solid var(--color-border);
     background: var(--color-surface);
   }
@@ -664,9 +668,9 @@ body {
 
   .chat-header {
     height: auto;
-    min-height: 56px;
-    padding: 10px 12px;
-    gap: 10px;
+    min-height: 3.5rem;
+    padding: 0.625rem 0.75rem;
+    gap: 0.625rem;
     flex-wrap: wrap;
     align-items: center;
     background-color: transparent;
@@ -684,18 +688,18 @@ body {
 
   .chat-body .messages-container {
     max-width: 100%;
-    padding: 18px 12px 96px;
+    padding: 1.125rem 0.75rem 6rem;
   }
 
   .bubble {
     max-width: 92%;
-    padding: 12px 14px;
-    font-size: 14px;
+    padding: 0.75rem 0.875rem;
+    font-size: 0.875rem;
   }
 
   .chat-input-wrapper {
     max-width: 100%;
-    padding: 0 12px 16px;
+    padding: 0 0.75rem 1rem;
   }
 
   .chat-input-actions {
@@ -705,7 +709,34 @@ body {
 
   .chat-model-select {
     min-width: 0;
-    max-width: 220px;
+    max-width: 100%;
+    flex: 1 1 auto;
+  }
+
+  .chat-input-toolbar {
+    flex-wrap: wrap;
+    gap: 0.5rem;
+  }
+
+  .chat-input-toolbar-left {
+    gap: 0.5rem;
+    flex: 1 1 auto;
+    min-width: 0;
+  }
+
+  .chat-input-toolbar .chat-send-button {
+    margin-left: auto;
+  }
+
+  .chat-model-select .ant-select-selector {
+    padding: 0 1.25rem 0 0 !important;
+  }
+
+  .chat-model-select .ant-select-selection-item {
+    max-width: 10rem;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    white-space: nowrap;
   }
 }
 
@@ -983,11 +1014,9 @@ body {
 }
 
 .session-sidebar {
-  width: 420px;
   height: 100%;
   display: flex;
   flex-direction: column;
-  padding: 0 4px;
   box-sizing: border-box;
 }