fix(ui): 适配前台浅色背景细节

- 学校 logo 替换为黑字版本，修改 useSiteConfig 默认值和 fallback
- 首页通知卡片补齐浅色样式：status-tag（三态）、unread-indicator、
  invite-actions、accept-btn、reject-btn
- 投稿区域状态徽章由绝对定位改为搜索标题行内布局，背景改为浅色
- 消息设置页面整体改为浅色主题，主色系改为 indigo 以匹配 ModernLight

app/components/Songs/RequestForm.vue

@@ -56,42 +56,46 @@
 
     <div class="form-container">
       <form class="song-request-form" @submit.prevent="handleSearch">
-        <div v-if="user && submissionStatus" class="submission-status-corner">
-          <div
-            :class="[
-              'submission-status-badge',
-              {
-                open: !submissionStatus.submissionClosed,
-                closed: submissionStatus.submissionClosed
-              }
-            ]"
-          >
-            <div class="badge-title">
-              {{ submissionStatus.submissionClosed ? '投稿未开放' : '投稿开放中' }}
-            </div>
-            <div
-              v-if="submissionStatus.timeLimitationEnabled"
-              class="badge-subtitle"
-            >
-              <template v-if="submissionStatus.currentTimePeriod">
-                {{ submissionStatus.currentTimePeriod.name }}
-              </template>
-              <template v-else-if="submissionStatus.nextTimePeriod">
-                下次开始：{{
-                  submissionStatus.nextTimePeriod.startTime
-                    ? formatBeijingDateTime(submissionStatus.nextTimePeriod.startTime)
-                    : submissionStatus.nextTimePeriod.name
-                }}
-              </template>
-            </div>
-          </div>
-        </div>
-
         <!-- 顶部行：搜索和联合投稿 -->
         <div class="form-header-row">
           <!-- 歌曲搜索区域 -->
           <div class="search-section">
-            <div class="search-label">歌曲搜索</div>
+            <div class="search-header-row">
+              <div class="search-label">歌曲搜索</div>
+              <div
+                v-if="user && submissionStatus"
+                class="submission-status-inline"
+              >
+                <div
+                  :class="[
+                    'submission-status-badge',
+                    {
+                      open: !submissionStatus.submissionClosed,
+                      closed: submissionStatus.submissionClosed
+                    }
+                  ]"
+                >
+                  <div class="badge-title">
+                    {{ submissionStatus.submissionClosed ? '投稿未开放' : '投稿开放中' }}
+                  </div>
+                  <div
+                    v-if="submissionStatus.timeLimitationEnabled"
+                    class="badge-subtitle"
+                  >
+                    <template v-if="submissionStatus.currentTimePeriod">
+                      {{ submissionStatus.currentTimePeriod.name }}
+                    </template>
+                    <template v-else-if="submissionStatus.nextTimePeriod">
+                      下次：{{
+                        submissionStatus.nextTimePeriod.startTime
+                          ? formatBeijingDateTime(submissionStatus.nextTimePeriod.startTime)
+                          : submissionStatus.nextTimePeriod.name
+                      }}
+                    </template>
+                  </div>
+                </div>
+              </div>
+            </div>
             <div class="search-input-group">
               <input
                 id="title"
@@ -3012,38 +3016,36 @@ defineExpose({
   position: relative;
 }
 
-.submission-status-corner {
-  position: absolute;
-  top: 0;
-  right: 0;
-  z-index: 30;
+.submission-status-inline {
+  display: flex;
+  align-items: center;
+  justify-content: flex-end;
 }
 
 .submission-status-badge {
   display: flex;
   flex-direction: column;
   gap: 2px;
-  padding: 8px 10px;
+  padding: 8px 12px;
   border-radius: 12px;
-  border: 1px solid var(--border-tertiary);
-  background: rgba(6, 15, 22, 0.9);
-  backdrop-filter: blur(8px);
+  border: 1px solid var(--border-primary);
+  background: var(--bg-primary, #ffffff);
+  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
   min-width: 140px;
   text-align: center;
 }
 
 @media (max-width: 640px) {
-  .submission-status-corner {
-    position: static;
-    align-self: flex-end;
-    margin-top: -6px;
-    margin-bottom: -2px;
+  .submission-status-inline {
+    justify-content: flex-start;
+    width: 100%;
   }
 
   .submission-status-badge {
     min-width: 0;
-    padding: 6px 9px;
+    padding: 6px 10px;
     border-radius: 10px;
+    flex: 1;
   }
 
   .badge-title {
@@ -3056,11 +3058,13 @@ defineExpose({
 }
 
 .submission-status-badge.open {
-  border-color: rgba(16, 185, 129, 0.35);
+  background: rgba(22, 163, 74, 0.06);
+  border-color: rgba(22, 163, 74, 0.2);
 }
 
 .submission-status-badge.closed {
-  border-color: rgba(239, 68, 68, 0.35);
+  background: rgba(239, 68, 68, 0.06);
+  border-color: rgba(239, 68, 68, 0.2);
 }
 
 .badge-title {
@@ -3070,7 +3074,7 @@ defineExpose({
 }
 
 .submission-status-badge.open .badge-title {
-  color: rgba(16, 185, 129, 0.95);
+  color: rgba(22, 163, 74, 0.95);
 }
 
 .submission-status-badge.closed .badge-title {
@@ -3083,6 +3087,23 @@ defineExpose({
   color: var(--text-secondary);
 }
 
+.search-header-row {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  width: 100%;
+  gap: 0.75rem;
+  margin-bottom: 0.5rem;
+}
+
+@media (max-width: 640px) {
+  .search-header-row {
+    flex-direction: column;
+    align-items: flex-start;
+    gap: 0.5rem;
+  }
+}
+
 .login-required-hint {
   margin-left: 0.5rem;
   display: flex;
@@ -3171,19 +3192,20 @@ defineExpose({
 
 .search-section {
   display: flex;
-  align-items: center;
-  gap: 0.75rem;
+  flex-direction: column;
+  align-items: stretch;
+  gap: 0.5rem;
   flex: 1.5;
-  min-width: 400px; /* 增加最小宽度，确保搜索框、标签和按钮有足够空间 */
+  min-width: 400px;
 }
 
 .search-label {
   font-family: 'MiSans', sans-serif;
   font-weight: 600;
   font-size: 15px;
-  color: var(--text-primary, #ffffff);
+  color: var(--text-primary, #09090b);
   white-space: nowrap;
-  flex-shrink: 0; /* 防止标签被压缩 */
+  flex-shrink: 0;
 }
 
 .search-input-group {