✨feature: Add responsive styles

style.css

@@ -12,6 +12,8 @@ header {
   display: flex;
   justify-content: space-between;
   padding: 12px 16px;
+  flex-wrap: wrap;
+  gap: 8px;
 }
 
 h1 {
@@ -21,33 +23,38 @@ h1 {
 
 main {
   display: grid;
-  gap: 16px;
-  grid-template-columns: 300px 1fr;
-  padding: 16px;
+  gap: 12px;
+  grid-template-columns: 1fr;
+  padding: 12px;
+  max-width: 1200px;
+  margin: 0 auto;
 }
 
 .panel {
   background: #111827;
   border: 1px solid #27324a;
   border-radius: 8px;
+}
 
-  h2 {
-    color: #a3b5d9;
-    font-size: 14px;
-    margin: 0;
-    padding: 12px 12px 0;
-  }
+.panel h2 {
+  color: #a3b5d9;
+  font-size: 14px;
+  margin: 0;
+  padding: 12px 12px 0;
+}
 
-  .content { padding: 12px; }
+.panel .content { padding: 12px; }
 
-  &.log { grid-column: 1 / span 2; }
+.panel.log,
+.panel.state {
+  grid-column: 1 / -1;
 }
 
 #log {
   background: #0b1020;
   color: #e9eef8;
-  max-height: 60vh;
-  min-height: 360px;
+  max-height: 50vh;
+  min-height: 240px;
   overflow: auto;
   white-space: pre-wrap;
 }
@@ -58,20 +65,27 @@ main {
   gap: 8px;
 }
 
+/* Stack action buttons on small screens */
+.actions {
+  display: grid;
+  grid-template-columns: 1fr 1fr;
+  gap: 8px;
+}
+
 button {
   background: #1f2a44;
   border: 1px solid #2c3a5e;
   border-radius: 6px;
   color: #e9eef8;
   cursor: pointer;
-  padding: 8px 10px;
+  padding: 10px 12px;
+}
 
-  &:hover { background: #263356; }
+button:hover { background: #263356; }
 
-  &:disabled {
-    cursor: not-allowed;
-    opacity: 0.5;
-  }
+button:disabled {
+  cursor: not-allowed;
+  opacity: 0.5;
 }
 
 .hidden {
@@ -94,6 +108,42 @@ button {
   gap: 8px;
   justify-content: space-between;
   margin: 2px 0;
-
-  .label { color: #a3b5d9; }
+}
+
+.kv .label { color: #a3b5d9; }
+
+@media (min-width: 700px) {
+  main { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; padding: 16px; }
+  #log { max-height: 60vh; }
+  .actions { display: flex; flex-wrap: wrap; }
+}
+
+@media (min-width: 1024px) {
+  main { grid-template-columns: 320px 1fr; }
+}
+
+/* Back to Top */
+#backToTop {
+  position: fixed;
+  right: 16px;
+  bottom: 16px;
+  z-index: 1000;
+  background: #1f2a44;
+  border: 1px solid #2c3a5e;
+  color: #e9eef8;
+  border-radius: 999px;
+  padding: 10px 14px;
+  box-shadow: 0 6px 16px rgba(0,0,0,0.35);
+  opacity: 0;
+  pointer-events: none;
+  transform: translateY(10px);
+  transition: opacity .2s ease, transform .2s ease;
+}
+
+#backToTop:hover { background: #263356; }
+
+#backToTop.show {
+  opacity: 1;
+  pointer-events: auto;
+  transform: translateY(0);
 }