如何在kable表格中添加浅灰水平线并设置底部线为粗橙色

我有如下数据集：

structure(list(...1 = c("Catalunya", "PIB", "Demanda interna1", 
"Demanda externa1", "Espanya", "PIB", "Demanda interna1", "Demanda externa1", 
"Zona euro", "PIB", "Demanda interna1", "Demanda externa1", "PIB d'Alemanya", 
"PIB de França", "PIB d'Itàlia", "Internacional", "PIB de la UE-27", 
"PIB dels EUA", "PIB del Japó"), `2020` = c(NA, -11.9, -7.4, 
-4.5, NA, -11.2, -9, -2.2, NA, -6.1, -5.57, -0.53, -3.8, -7.5, 
-9, NA, -5.6, -2.2, -4.3), `2021` = c(NA, 6.2, 3.8, 2.4, NA, 
6.4, 5.9, 0.5, NA, 5.6, 4.24, 1.36, 3.2, 6.4, 8.3, NA, 5.7, 5.8, 
2.1), `2022` = c(NA, 5.5, 2.7, 2.8, NA, 5.5, 5.12183164381576, 
0.378168356184236, NA, 3.6, 3.76, -0.16, 1.8, 2.5, 3.7, NA, 3.5, 
1.9, 1.1), `1r 2023` = c(NA, 3.2, 1.1, 2.1, NA, 4.1, 1.3, 2.8, 
NA, 1.2, 0.63, 0.57, -0.2, 1, 2.1, NA, 1.1, 1.71772942152937, 
2), `2n 2023` = c(NA, 2.1, 1.2, 0.9, NA, 2, 2.2, -0.2, NA, 0.5, 
0.46, 0.04, 0.1, 1.1, 0.3, NA, 0.4, 2.38237207285343, 1.7), `3r 2023` = c(NA, 
2.1, NA, NA, NA, 1.8, 1.6, 0.2, NA, 0.1, NA, NA, -0.4, 0.7, 0, 
NA, 0.1, 3, 1.2)), row.names = c(NA, -19L), class = c("tbl_df", 
"tbl", "data.frame"))

我正在使用以下代码创建Markdown转PDF的表格：

options(knitr.kable.NA = "-")

p3_1[3,1] <- p3_1[7,1] <- p3_1[11,1] <- "$\\text{Demanda interna}^1$"
p3_1[4,1] <- p3_1[8,1] <- p3_1[12,1] <- "$\\text{Demanda externa}^1$"


kable(p3_1,
      align = "lrrrrrr",
      col.names = c("", names(p3_1[-1])),
      booktabs=TRUE,
      digits=1,
      format.args = list(big.mark="."),
      linesep = "" ,
      caption="Producte interior brut (\\% de variació interanual, llevat dels casos indicats)", escape = FALSE) %>%
  add_header_above(c("", "Any" = 3, "Trimestre" = 3), bold=T) %>% 
  kable_styling(latex_options=c("HOLD_position","scale_down"), bootstrap_options = c("condensed"), position="center") %>% 
  column_spec(1, bold=T, width="4cm") %>%
  column_spec(2:7, width="2cm") %>%
  row_spec(0, bold = T) %>%
  row_spec(c(1, 5, 9, 16), background="lightgray") %>%
  row_spec(19, extra_css = "border-bottom: 1px solid;") %>%
  footnote(general="Idescat; Eurostat; INE; BEA; ESRI; Agència Estatal d'Administració Tributària.", general_title = "Font:", footnote_as_chunk = T,)  %>%
  footnote(general="$^{A}$Dada avançada. $^{1}$Contribució al creixement. $^{2}$Sèrie original corregida d'efectes de calendari. 
           $^{3}$En valors constants. Exclou estacions de servei.",  escape = F, general_title = "Nota:", threeparttable = TRUE, footnote_as_chunk = T,) 

生成的表格效果如下：

请问如何为整个表格添加浅灰色水平线，并将底部线条设置为更粗的橙色？

由于你是生成PDF（基于LaTeX渲染），不能使用CSS样式，需要通过LaTeX命令来控制线条的颜色和粗细，以下是修改后的完整代码：

options(knitr.kable.NA = "-")

p3_1[3,1] <- p3_1[7,1] <- p3_1[11,1] <- "$\\text{Demanda interna}^1$"
p3_1[4,1] <- p3_1[8,1] <- p3_1[12,1] <- "$\\text{Demanda externa}^1$"

# 生成表格
kable(p3_1,
      align = "lrrrrrr",
      col.names = c("", names(p3_1[-1])),
      booktabs=TRUE,
      digits=1,
      format.args = list(big.mark="."),
      linesep = "" ,
      caption="Producte interior brut (\\% de variació interanual, llevat dels casos indicats)", escape = FALSE) %>%
  add_header_above(c("", "Any" = 3, "Trimestre" = 3), bold=T) %>% 
  kable_styling(latex_options=c("HOLD_position","scale_down"), bootstrap_options = c("condensed"), position="center") %>% 
  column_spec(1, bold=T, width="4cm") %>%
  column_spec(2:7, width="2cm") %>%
  row_spec(0, bold = T) %>%
  row_spec(c(1, 5, 9, 16), background="lightgray") %>%
  # 为除最后一行外的所有行添加浅灰色水平线
  row_spec(1:(nrow(p3_1)-1), extra_latex = "\\arrayrulecolor{gray!30}\\hline\\arrayrulecolor{black}") %>%
  # 为最后一行设置橙色粗底部线条（1.5pt为线条粗细，可按需调整）
  row_spec(nrow(p3_1), extra_latex = "\\arrayrulecolor{orange}\\specialrule{1.5pt}{0pt}{0pt}\\arrayrulecolor{black}") %>%
  footnote(general="Idescat; Eurostat; INE; BEA; ESRI; Agència Estatal d'Administració Tributària.", general_title = "Font:", footnote_as_chunk = T,)  %>%
  footnote(general="$^{A}$Dada avançada. $^{1}$Contribució al creixement. $^{2}$Sèrie original corregida d'efectes de calendari. 
           $^{3}$En valors constants. Exclou estacions de servei.",  escape = F, general_title = "Nota:", threeparttable = TRUE, footnote_as_chunk = T,) 

关键说明： #

1. LaTeX颜色支持：需要在你的R Markdown文档YAML头部添加颜色包引用，否则橙色和灰色线条无法正常显示：

   header-includes:
     - \usepackage{xcolor}
   

2. 浅灰色水平线：通过row_spec循环遍历除最后一行外的所有行，使用\\arrayrulecolor{gray!30}临时将线条颜色改为浅灰色，画完线后再改回黑色，避免影响后续元素。
3. 橙色粗底部线条：使用\\specialrule{1.5pt}{0pt}{0pt}自定义线条粗细（1.5pt），并通过\\arrayrulecolor{orange}设置线条颜色为橙色，最后恢复默认黑色。

内容的提问来源于stack exchange，提问作者Maria