How to center a gt table in a Quarto pdf document?

How can I center this table in a pdf? The line table.align = "center", is ignored. I have tried wrapping my code with cat("\\clearpage\n\\begin{center}\n") and cat("\n\\end{center}") in a variety of ways with no luck. The header centers properly, but the table is aligned to the left. I know that one solution is to use kableExtra, but it doesn't handle small tables well. I can only get it to render nicely using kableExtra if I add a blank row to the bottom, which looks odd. I'd prefer to use gt but I'd be happy for a solution with kableExtra that doesn't require adding a blank row.

```{r wald_table_gt, results='asis', echo=FALSE, message=FALSE, warning=FALSE}

library(tibble)
library(dplyr)
library(gt)

# Construct table
table_data_wald <- tribble(
  ~Statistic,                       ~Value,
  "t-statistic",                    "-80.883",
  "Degrees of Freedom",             "12,482",
  "p-value",                        "< 0.001",
  "Alternative Hypothesis",         "true mean ≠ -1",
  "Mean of RTS",                    "-1.201",
  "95% Confidence Interval",        "[-1.206, -1.196]"
)

# Build table
table_data_wald %>%
  gt() %>%
  tab_header(
    title = md("**Table A1: Wald Test**") 
  ) %>%
  cols_label(Statistic = "Statistic", Value = "Value") %>%
  tab_options(
    table.align = "center", 
    heading.align = "center",
    column_labels.font.size = px(11),
    table.font.size = px(11),
    table.width = pct(70),
    footnotes.font.size = px(9),
    footnotes.multiline = TRUE
  ) 
```

Solution

Here is a possibility where we post-process the gt LaTeX using as_latex() for inserting a \centering after the \begin{table}:

---
format: pdf
keep-tex: true
---

```{r wald_table_gt, results='asis', echo=FALSE, message=FALSE, warning=FALSE}

library(tibble)
library(dplyr)
library(gt)

# Construct table
table_data_wald <- tribble(
  ~Statistic,                       ~Value,
  "t-statistic",                    "-80.883",
  "Degrees of Freedom",             "12,482",
  "p-value",                        "< 0.001",
  "Alternative Hypothesis",         "true mean ≠ -1",
  "Mean of RTS",                    "-1.201",
  "95% Confidence Interval",        "[-1.206, -1.196]"
)

# Build table
latex_table <- table_data_wald %>%
  gt() %>%
  tab_header(
    title = md("**Table A1: Wald Test**") 
  ) %>%
  cols_label(Statistic = "Statistic", Value = "Value") %>%
  tab_options(
    table.align = "center", 
    heading.align = "center",
    column_labels.font.size = px(11),
    table.font.size = px(11),
    table.width = pct(70),
    footnotes.font.size = px(9),
    footnotes.multiline = TRUE
  ) |>
  as_latex()

latex_table[[1]] <- sub(
  "\\begin{table}", 
  "\\begin{table}\\centering", 
  latex_table[[1]], 
  fixed = TRUE
) 

latex_table
```