feat: 打印预览组件化

miniprogram/mathPages/mathDraw/mathDraw.less

@@ -18,51 +18,6 @@ page {
     gap: 64rpx;
 }
 
-/* ===== 预览卡 ===== */
-.md-preview-wrap {
-    position: relative;
-}
-
-.md-preview-card {
-    background: @bg-white;
-    border-radius: @radius-xl;
-    box-shadow: @shadow;
-    padding: 40rpx;
-    border: @border;
-    box-sizing: border-box;
-    display: flex;
-    flex-direction: column;
-    align-items: stretch;
-}
-
-.md-preview-kicker {
-    display: block;
-    text-align: center;
-    font-size: @fs-section-head-title;
-    font-weight: bold;
-    color: @text-secondary;
-    letter-spacing: 0.12em;
-    text-transform: uppercase;
-    margin-bottom: 30rpx;
-}
-
-.md-canvas-wrap {
-    display: flex;
-    justify-content: center;
-    align-items: center;
-    min-height: 400rpx;
-    background: @bg-gray;
-    border-radius: @radius-sm;
-    border: 2rpx dashed rgba(50, 46, 37, 0.12);
-    overflow: hidden;
-}
-
-.md-canvas {
-    max-width: 100%;
-    border-radius: @radius-sm;
-    box-shadow: @shadow;
-}
-
 /* ===== 区块 ===== */
 .md-section {
     display: flex;