style(admin): 统一后台表单组件高度与排版规范

- 为 Button、TextInput、SelectDropdown 和 DatePicker 统一设置 line-height: 1.5
- 标准化 md 与 sm 尺寸下的 font-size（md: 0.95rem, sm: 0.85rem）
- 精调各个组件的上下 padding，确保它们在同一行并排显示时视觉高度完全一致，彻底解决单行输入框与按钮高度参差不齐的问题

src/lib/components/admin/Button.svelte

@@ -58,7 +58,7 @@
 		align-items: center;
 		justify-content: center;
 		box-sizing: border-box;
-		padding: 10px 20px;
+		padding: 8px 20px;
 		text-decoration: none;
 		font-size: 0.95rem;
 		font-weight: 600;
@@ -70,7 +70,7 @@
 		font-family: inherit;
 		text-transform: uppercase;
 		letter-spacing: 1px;
-		line-height: 1;
+		line-height: 1.5;
 	}
 
 	.btn.w-full {
@@ -79,7 +79,7 @@
 	}
 
 	.btn-sm {
-		padding: 6px 12px;
+		padding: 4px 12px;
 		font-size: 0.85rem;
 	}
 

src/lib/components/admin/DatePicker.svelte

@@ -137,12 +137,13 @@
 
 	.input-wrapper input {
 		width: 100%;
-		padding: 10px 14px;
+		padding: 8px 14px;
 		padding-right: 35px; /* for icon */
 		border: 1px solid rgba(0, 0, 0, 0.15);
 		background: rgba(0, 0, 0, 0.02);
 		font-family: inherit;
-		font-size: 1rem;
+		font-size: 0.95rem;
+		line-height: 1.5;
 		color: var(--text-color);
 		border-radius: 0;
 		transition: all 0.2s;

src/lib/components/admin/SelectDropdown.svelte

@@ -169,13 +169,14 @@
 		align-items: center;
 		justify-content: space-between;
 		width: 100%;
-		padding: 10px 0;
+		padding: 8px 0;
 		border: none;
 		border-bottom: 2px solid rgba(0, 0, 0, 0.1);
 		background: transparent;
 		color: var(--text-color);
 		font-family: inherit;
-		font-size: 1rem;
+		font-size: 0.95rem;
+		line-height: 1.5;
 		text-align: left;
 		cursor: pointer;
 		transition:
@@ -242,6 +243,7 @@
 		color: var(--text-color);
 		font-family: inherit;
 		font-size: 0.85rem;
+		line-height: 1.5;
 		font-weight: 600;
 		text-align: left;
 		cursor: pointer;

src/lib/components/admin/TextInput.svelte

@@ -24,6 +24,7 @@
 		font-family: inherit;
 		color: var(--text-color);
 		box-sizing: border-box;
+		line-height: 1.5;
 	}
 
 	.admin-input:focus {
@@ -57,8 +58,8 @@
 
 	/* size: md (default for main forms) */
 	.admin-input.size-md {
-		padding: 10px 14px;
-		font-size: 1rem;
+		padding: 8px 14px;
+		font-size: 0.95rem;
 	}
 	/* override padding for underline which traditionally uses less padding */
 	.admin-input.underline.size-md {
@@ -67,10 +68,10 @@
 
 	/* size: sm (default for tables / sidebars) */
 	.admin-input.size-sm {
-		padding: 8px 10px;
-		font-size: 0.95rem;
+		padding: 4px 10px;
+		font-size: 0.85rem;
 	}
 	.admin-input.underline.size-sm {
-		padding: 8px 0;
+		padding: 4px 0;
 	}
 </style>