在 R Markdown 中编织到 PDF 时，KableExtra 列宽不起作用

问：

编织为 PDF 时，我无法调整表格中的列宽。我想知道它是否与我应用于参数的对象有关。返回的错误是：column_spec()KableExtracnamescol.names =

! Paragraph ended before \mcell@tabular was complete.
<to be read again> 
                   \par 
1.129 
Execution halted Error: LaTex failed to compile TestDoc.tex. 
See https://yihui.org/tinytex/r/#debugging for debugging tips. 
See TestDoc.log for more info.
Execution halted.

我之所以这么说，是因为只有第 1 列的宽度调整可以正常工作，而且该列的标题中没有 LaTeX 代码。我确实需要保持对象不变，因为需要在我的真实数据的标题中包含分布在两行上的度量单位。cnames

下面是一些示例代码来复制该错误。真的希望有人有解决方案。谢谢！

---
title: >
  `\vspace{-1.8cm}`{=latex}
header-includes:
 - \usepackage{geometry}
 - \geometry{margin=0.2in}
 - \usepackage[default]{sourcesanspro}
 - \usepackage[T1]{fontenc}
 - \usepackage{makecell}
 - \usepackage{fancyhdr}
 - \pagestyle{fancy}
 - \usepackage[export]{adjustbox}
 - \fancyhf{}
 - \pagenumbering{gobble}
mainfont: SourceSansPro
output: pdf_document
editor_options:
  chunk_output_type: console
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(
  echo = FALSE,
  message = FALSE,
  warning = FALSE,
  dev = "cairo_pdf"
  )
```

```{r}
library(kableExtra)

set.seed(10)
df <- data.frame(
  activity = paste("Activity", 1:10),
  var1 = round(rnorm(10, 1000, 500)),
  var2 = round(rnorm(10, 1000, 500)),
  var3 = round(rnorm(10, 1000, 500))
)

cnames <- c(
  "Period",
  "\\makecell[ct]{Time\\\\(mins)}",
  "\\makecell[ct]{Volume\\\\(m)}",
  "\\makecell[ct]{Speed\\\\(s)}"
  )

kbl(df,
      booktabs = TRUE,
      escape = FALSE,
      col.names = cnames,
      align = c("l", rep("c", ncol(df) - 1)),
      linesep = "\\addlinespace") %>%
  kable_styling(latex_options = c("HOLD_position"),
                font_size = 8) %>%
  column_spec(column = 1, width = "2in") %>%
  column_spec(column = c(2:4), width = "1in")
```