fix(admin): 修复设置页面 CSP style-src 违规导致加载失败

- 移除 site-settings 模板中的内联 style 属性（display:none, width:100px）
- 将内联样式迁移至 site-settings.css 的 CSS 类中
- site-settings-theme.js 用 className 替代 style.display 操作

templates/admin/html/site-settings/index.html

@@ -227,7 +227,7 @@
                         <span class="setting-desc">强制阅读时的倒计时秒数</span>
                     </div>
                     <div class="setting-input-wrap">
-                        <input type="number" id="setting-guidelines-timer" class="setting-input" placeholder="60" min="1" style="width:100px" value="{{.GuidelinesTimer}}">
+                        <input type="number" id="setting-guidelines-timer" class="setting-input setting-input-narrow" placeholder="60" min="1" value="{{.GuidelinesTimer}}">
                         <button class="btn btn-sm btn-primary btn-save" data-key="registration.guidelines_timer" data-input="setting-guidelines-timer">保存</button>
                     </div>
                 </div>

templates/admin/html/site-settings/registration.html

@@ -46,7 +46,7 @@
                         <span class="setting-desc">强制阅读时的倒计时秒数</span>
                     </div>
                     <div class="setting-input-wrap">
-                        <input type="number" id="setting-guidelines-timer" class="setting-input" placeholder="60" min="1" style="width:100px" value="{{.GuidelinesTimer}}">
+                        <input type="number" id="setting-guidelines-timer" class="setting-input setting-input-narrow" placeholder="60" min="1" value="{{.GuidelinesTimer}}">
                         <button class="btn btn-sm btn-primary btn-save" data-key="registration.guidelines_timer" data-input="setting-guidelines-timer">保存</button>
                     </div>
                 </div>

templates/admin/html/site-settings/theme.html

@@ -33,7 +33,7 @@
             </div>
         </div>
 
-        <div id="theme-status" class="settings-section" style="display:none">
+        <div id="theme-status" class="settings-section">
             <div class="section-body">
                 <div class="setting-item">
                     <span id="theme-status-msg"></span>

templates/admin/static/css/site-settings.css

@@ -141,6 +141,13 @@
     font-size: 13px; color: var(--text-muted);
 }
 
+/* --- 隐藏工具类 --- */
+#theme-status { display: none; }
+#theme-status.visible { display: block; }
+
+/* --- 窄输入框 --- */
+.setting-input-narrow { width: 100px; }
+
 /* --- 主题状态提示 --- */
 .status-success .section-body {
     background: #e8f5e9; border-left: 3px solid #4caf50;

templates/admin/static/js/site-settings-theme.js

@@ -95,8 +95,7 @@
     }
 
     function showStatus(msg, type) {
-        statusSection.style.display = 'block';
-        statusSection.className = 'settings-section';
+        statusSection.className = 'settings-section visible';
         if (type === 'success') {
             statusSection.classList.add('status-success');
         } else if (type === 'error') {