Couple of things here:
Could be that you haven't installed sass yet. If this is the case do:
npm install sass
Change this
@import "../node_modules/bootstrap/scss/bootstrap";
$primary:#f3ced6;
to
// Custom variables
$primary:#f3ced6;
@import "../node_modules/bootstrap/scss/bootstrap";
You're adding variables after importing Bootstrap. Add them to the top, I usually create a file for this and do:
// Custom variables
@import "../scss/variables";
// Bootstrap core
@import "node_modules/bootstrap/scss/bootstrap";
As well create a file called _variables.scss where you can add your Bootstrap variables as usual.
To edit the colors you can override the theme colors like so:
$theme-colors: (
"primary": $primary,
"secondary": $secondary,
"success": $success,
"info": $info,
"warning": $warning,
"danger": $danger,
"light": $light,
"dark": $dark
);
You could change "primary": $primary, to "primary": #f3ced6, or you can use $primary:#f3ced6;(make sure this is at the top).