diff --git a/app/globals.css b/app/globals.css
index 90bf1a7..3ae3cb2 100644
--- a/app/globals.css
+++ b/app/globals.css
@@ -712,6 +712,13 @@ input[type="number"] {
   box-shadow: none;
 }
 
+@media (hover: none) {
+  .tab:hover {
+    color: var(--muted);
+    background: transparent;
+  }
+}
+
 .modal-overlay {
   position: fixed;
   inset: 0;
diff --git a/app/page.jsx b/app/page.jsx
index bf885ad..efcd05d 100644
--- a/app/page.jsx
+++ b/app/page.jsx
@@ -363,9 +363,10 @@ function DatePicker({ value, onChange }) {
             }}
           >
             <div className="calendar-header" style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center', marginBottom: 12 }}>
-              <button onClick={handlePrevMonth} className="icon-button" style={{ width: 24, height: 24 }}>&lt;</button>
+              <button type="button" onClick={handlePrevMonth} className="icon-button" style={{ width: 24, height: 24 }}>&lt;</button>
               <span style={{ fontWeight: 600 }}>{year}年 {month + 1}月</span>
               <button
+                type="button"
                 onClick={handleNextMonth}
                 className="icon-button"
                 style={{ width: 24, height: 24 }}