style(ui): unify sky-atlas visual system

Centralize interactive component styles, adopt the fresh eucalyptus palette, and keep map controls square with hard shadows. Update project guidance and the OpenCloud style skill to match the implementation.

src/components/cloud/ImageDetailModal.vue

@@ -187,7 +187,7 @@ onBeforeUnmount(() => {
           <button
             type="button"
             @click="close"
-            class="image-detail-close-button absolute right-4 top-4 z-30 flex h-10 min-h-10 w-10 min-w-10 max-w-10 appearance-none items-center justify-center overflow-hidden border-0 bg-transparent p-0 text-white/70 shadow-none transition-colors hover:text-white [&_svg]:stroke-[2.5]"
+            class="image-detail-close-button oc-overlay-button absolute right-4 top-4 z-30 h-10 w-10 rounded-full [&_svg]:stroke-[2.5]"
             aria-label="关闭大图"
             title="关闭大图"
           >
@@ -223,7 +223,7 @@ onBeforeUnmount(() => {
             <button
               type="button"
               @click="toggleInfo"
-              class="absolute bottom-4 right-4 z-30 flex h-11 w-11 items-center justify-center rounded-full bg-transparent text-white drop-shadow-[0_2px_8px_rgba(15,23,42,0.9)] transition-colors hover:text-sky-100"
+              class="oc-overlay-button absolute bottom-4 right-4 z-30 h-11 w-11 rounded-full drop-shadow-[0_2px_8px_rgba(15,23,42,0.9)]"
               :aria-label="infoOpen ? '隐藏详细信息' : '查看详细信息'"
               :title="infoOpen ? '隐藏详细信息' : '查看详细信息'"
             >
@@ -254,7 +254,7 @@ onBeforeUnmount(() => {
                 <button
                   type="button"
                   @click="infoOpen = false"
-                  class="absolute right-3 top-3 rounded-full p-2 text-slate-400 transition-colors hover:bg-slate-100 hover:text-slate-700"
+                  class="oc-icon-button oc-icon-button--small absolute right-3 top-3 rounded-full"
                   aria-label="隐藏详细信息"
                   title="隐藏详细信息"
                 >