Fix Animation Consistency

src/app/components/dropdown/dropdown.scss

@@ -27,6 +27,11 @@ $dropdown_animation_duration: 0.2s;
   cursor: pointer;
 
   max-width: 100%;
+  --dropdown-duration: #{$dropdown_animation_duration};
+
+  &.reduce-motion {
+    --dropdown-duration: 0s;
+  }
 
   &:focus-visible {
     box-shadow: 0 0 0 1px $dropdown_border_color inset, 0 0 0 2px white, 0 0 0 4px $dropdown_accent;
@@ -60,7 +65,7 @@ $dropdown_animation_duration: 0.2s;
   .chevron {
     width: 24px; height: 24px;
     flex-shrink: 0;
-    transition: transform $dropdown_animation_duration $dropdown_animation_timing;
+    transition: transform var(--dropdown-duration) $dropdown_animation_timing;
     user-select: none;
 
     &.open {
@@ -83,7 +88,7 @@ $dropdown_animation_duration: 0.2s;
   max-height: 240px;
   overflow-y: auto;
   box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
-  animation: slideIn $dropdown_animation_duration $dropdown_animation_timing;
+  animation: slideIn var(--dropdown-duration) $dropdown_animation_timing;
 
   // 자식 요소의 배경색이 테두리를 침범하지 못하도록 하는 사용자님의 핵심 설계 복구
   &::after {