diff -up ../st-0.8.3/config.def.h ./config.def.h
--- ../st-0.8.3/config.def.h	2020-04-27 13:58:27.000000000 +0200
+++ ./config.def.h	2020-05-24 18:27:19.179361165 +0200
@@ -4,9 +4,11 @@
  * appearance
  *
  * font: see http://freedesktop.org/software/fontconfig/fontconfig-user.html
+ * borderperc: percentage of cell width to use as a border
+ *		0 = no border, 100 = border width is same as cell width
  */
 static char *font = "Liberation Mono:pixelsize=12:antialias=true:autohint=true";
-static int borderpx = 2;
+static int borderperc = 20;

 /*
  * What program is execed by st depends of these precedence rules:
diff -up ../st-0.8.3/st.h ./st.h
--- ../st-0.8.3/st.h	2020-04-27 13:58:27.000000000 +0200
+++ ./st.h	2020-05-24 18:27:20.255369735 +0200
@@ -52,6 +52,7 @@ enum selection_snap {
 	SNAP_LINE = 2
 };

+int borderpx;
 typedef unsigned char uchar;
 typedef unsigned int uint;
 typedef unsigned long ulong;
diff -up ../st-0.8.3/x.c ./x.c
--- ../st-0.8.3/x.c	2020-04-27 13:58:27.000000000 +0200
+++ ./x.c	2020-05-24 18:27:17.551348200 +0200
@@ -1001,6 +1001,8 @@ xloadfonts(char *fontstr, double fontsiz
 	win.cw = ceilf(dc.font.width * cwscale);
 	win.ch = ceilf(dc.font.height * chscale);

+	borderpx = ceilf(((float)borderperc / 100) * win.cw);
+
 	FcPatternDel(pattern, FC_SLANT);
 	FcPatternAddInteger(pattern, FC_SLANT, FC_SLANT_ITALIC);
 	if (xloadfont(&dc.ifont, pattern))