使用css减少在R闪烁中垂直对齐的框之间的空间

Question

请参阅快照，使用以下脚本显示R闪亮仪表板中的三个框。我希望在上面两个框和下框之间完全缩小空间，我希望必要的命令包含在我的标签$ head中。请帮助和谢谢。

box(title = "",status = "primary",solidHeader = T,height = "287",width = "6", plotlyOutput("user_hist")),
box(title = "User Activity Mapping", status = "primary",height = "287" ,width = "6",solidHeader = T,plotlyOutput("sankey_plot",height = "216")),
tags$head(tags$style(HTML("div.col-sm-12 {padding:1px}; float:up;"))),
box( title = "Case Details", status = "primary", height = "169",width = "12",solidHeader = T,dataTableOutput("sankey_table"))