按钮样式：编辑绿底、删除红框无底

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

ft-app/app/templates/positions.html

@@ -72,7 +72,7 @@
         <button class="btn" style="background:var(--danger);color:#fff;font-size:0.78rem;padding:4px 14px;" onclick="confirmDelete(event, '确认 {{ round.contract_code }} 熔断清仓？', this.closest('form').action)">熔断</button>
       </form>
       <form method="post" action="/positions/{{ round.id }}/delete" style="display:inline;">
-        <button style="background:var(--danger-bg);color:var(--danger-fg);border:1px solid var(--danger);padding:3px 10px;border-radius:4px;cursor:pointer;font-size:0.78rem;" onclick="confirmDelete(event, '确定删除 {{ round.contract_code }} 整轮数据？', this.closest('form').action)">删除</button>
+        <button style="background:transparent;color:#dc2626;border:1px solid #ef4444;padding:3px 10px;border-radius:4px;cursor:pointer;font-size:0.78rem;" onclick="confirmDelete(event, '确定删除 {{ round.contract_code }} 整轮数据？', this.closest('form').action)">删除</button>
       </form>
     </span>
   </div>