refactor: 抽离短信验证码倒计时 Composable 并拆分模块化 base.css 样式文件

frontend/src/styles/admin.css

@@ -0,0 +1,241 @@
+.admin-shell {
+  display: grid;
+  min-height: 100vh;
+  grid-template-columns: 260px 1fr;
+  background: #f5f7fb;
+}
+
+.admin-sidebar {
+  display: flex;
+  flex-direction: column;
+  min-width: 0;
+  border-right: 1px solid #dfe5ec;
+  background: #111827;
+  padding: 20px 16px;
+  color: #dbe4ee;
+}
+
+.admin-brand {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  min-height: 44px;
+  color: #ffffff;
+  font-weight: 700;
+}
+
+.admin-nav {
+  display: grid;
+  gap: 6px;
+  margin-top: 28px;
+}
+
+.admin-nav-link {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  min-height: 42px;
+  border-radius: 8px;
+  padding: 0 12px;
+  color: #b7c3d2;
+}
+
+.admin-nav-link.router-link-active {
+  background: #0f766e;
+  color: #ffffff;
+  font-weight: 600;
+}
+
+.admin-workspace {
+  min-width: 0;
+  overflow: hidden;
+}
+
+.admin-topbar {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  min-height: 64px;
+  border-bottom: 1px solid #e4e7ed;
+  background: #ffffff;
+  padding: 0 28px;
+}
+
+.admin-topbar span {
+  display: block;
+  color: #6b7785;
+  font-size: 12px;
+}
+
+.admin-topbar strong {
+  display: block;
+  margin-top: 3px;
+  color: #111827;
+}
+
+.admin-main {
+  width: 100%;
+  min-width: 0;
+  padding: 28px clamp(18px, 2.4vw, 36px);
+}
+
+.admin-main .page {
+  max-width: none;
+}
+
+.admin-login-shell {
+  display: grid;
+  min-height: 100vh;
+  place-items: center;
+  background: linear-gradient(
+      135deg,
+      rgba(15, 118, 110, 0.12),
+      rgba(17, 24, 39, 0.08)
+    ),
+    #f5f7fb;
+  padding: 24px;
+}
+
+.admin-login-panel {
+  width: min(420px, 100%);
+  border: 1px solid #e4e7ed;
+  border-radius: 8px;
+  background: #ffffff;
+  padding: 28px;
+  box-shadow: 0 20px 60px rgba(17, 24, 39, 0.1);
+}
+
+.admin-login-brand {
+  display: inline-flex;
+  align-items: center;
+  gap: 10px;
+  color: #111827;
+  font-weight: 700;
+}
+
+.admin-login-header {
+  margin: 28px 0 22px;
+}
+
+.admin-login-header h1 {
+  font-size: 30px;
+}
+
+.admin-login-header p:last-child {
+  margin: 10px 0 0;
+  color: #52616f;
+}
+
+.admin-captcha-row {
+  display: grid;
+  grid-template-columns: 1fr 132px;
+  gap: 10px;
+  width: 100%;
+}
+
+.captcha-image-button {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  height: 44px;
+  border: 1px solid #dcdfe6;
+  border-radius: 6px;
+  background: #ffffff;
+  padding: 0;
+  cursor: pointer;
+  overflow: hidden;
+}
+
+.captcha-image-button:disabled {
+  cursor: wait;
+  opacity: 0.7;
+}
+
+.captcha-image-button img {
+  display: block;
+  width: 132px;
+  height: 44px;
+}
+
+@media (max-width: 1180px) {
+  .admin-shell {
+    grid-template-columns: 220px 1fr;
+  }
+
+  .admin-sidebar {
+    padding: 18px 12px;
+  }
+
+  .admin-nav-link {
+    padding: 0 10px;
+  }
+}
+
+@media (max-width: 900px) {
+  .admin-shell {
+    grid-template-columns: 1fr;
+  }
+
+  .admin-sidebar {
+    position: sticky;
+    top: 0;
+    z-index: 10;
+    border-right: 0;
+    border-bottom: 1px solid #1f2937;
+    padding: 12px 14px;
+  }
+
+  .admin-brand {
+    min-height: 36px;
+  }
+
+  .admin-nav {
+    grid-auto-flow: column;
+    grid-auto-columns: max-content;
+    gap: 8px;
+    margin-top: 12px;
+    overflow-x: auto;
+    padding-bottom: 2px;
+  }
+
+  .admin-nav-link {
+    min-height: 38px;
+    white-space: nowrap;
+  }
+
+  .admin-topbar {
+    min-height: 58px;
+    padding: 0 16px;
+  }
+
+  .admin-main {
+    padding: 22px 16px;
+  }
+}
+
+@media (max-width: 520px) {
+  .admin-topbar {
+    align-items: flex-start;
+    flex-direction: column;
+    justify-content: center;
+    gap: 10px;
+    padding: 12px 16px;
+  }
+
+  .admin-topbar .el-button {
+    width: 100%;
+  }
+
+  .dashboard-panels {
+    grid-template-columns: 1fr;
+  }
+
+  .admin-captcha-row {
+    grid-template-columns: 1fr;
+  }
+
+  .captcha-image-button,
+  .captcha-image-button img {
+    width: 100%;
+  }
+}