feat: 完善 Alpha 详情页布局与提交检查，增加描述生成与验证功能

frontend/src/style.css

@@ -875,3 +875,64 @@ label:not(.semi-checkbox):not(.semi-radio) {
     gap: var(--space-3);
   }
 }
+
+/* The sheet header and tab bar stay outside the single scrolling flex child. */
+.alpha-detail .semi-sidesheet-body {
+  display: flex;
+  flex-direction: column;
+  min-height: 0;
+  overflow: hidden;
+}
+.alpha-detail .detail-title {
+  flex-shrink: 0;
+  margin-bottom: 8px;
+}
+.alpha-detail-tabs {
+  display: flex;
+  flex-direction: column;
+  flex: 1;
+  min-height: 0;
+  min-width: 0;
+}
+.alpha-detail-tabs > .semi-tabs-bar {
+  flex-shrink: 0;
+}
+.alpha-detail-tabs > .semi-tabs-content {
+  flex: 1;
+  min-height: 0;
+  overflow-y: auto;
+  overflow-x: hidden;
+  padding-top: 12px;
+}
+.alpha-detail .detail-section {
+  padding: 8px 0;
+}
+.alpha-detail h3 {
+  margin: 8px 0;
+}
+.alpha-detail h4 {
+  margin: 6px 0;
+}
+.alpha-detail label {
+  margin-bottom: 8px;
+}
+.alpha-detail .semi-divider-horizontal {
+  margin: 16px 0;
+}
+.alpha-detail .semi-descriptions table {
+  table-layout: fixed;
+  width: 100%;
+}
+.alpha-detail .semi-descriptions th,
+.alpha-detail .semi-descriptions td {
+  padding-bottom: 6px;
+  vertical-align: top;
+  overflow-wrap: anywhere;
+  text-align: left;
+}
+.alpha-detail .nested-descriptions {
+  margin-bottom: 0;
+}
+.alpha-detail .nested-descriptions th {
+  width: 45%;
+}