config: change color format to 0xRRGGBBAA

The current format of #RRGGBBAA is problematic as # starts a comment
in POSIX compliant shells, requiring escaping/quoting and increasing
complexity.

This is a breaking change.

 doc/riverctl.1.scd       |  6 +++---
 example/init             |  5 +++++
 river/Config.zig         |  2 +-
 river/command.zig        |  2 +-
 river/command/config.zig | 16 +++++++++-------
 5 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/doc/riverctl.1.scd b/doc/riverctl.1.scd
index 6a8332a..ece7eee 100644
--- a/doc/riverctl.1.scd
+++ b/doc/riverctl.1.scd
@@ -230,13 +230,13 @@ A complete list may be found in _/usr/include/linux/input-event-codes.h_
 *attach-mode* *top*|*bottom*
 	Configure where new views should attach to the view stack.
 
-*background-color* _#RRGGBB_|_#RRGGBBAA_
+*background-color* _0xRRGGBB_|_0xRRGGBBAA_
 	Set the background color.
 
-*border-color-focused* _#RRGGBB_|_#RRGGBBAA_
+*border-color-focused* _0xRRGGBB_|_0xRRGGBBAA_
 	Set the border color of focused views.
 
-*border-color-unfocused* _#RRGGBB_|_#RRGGBBAA_
+*border-color-unfocused* _0xRRGGBB_|_0xRRGGBBAA_
 	Set the border color of unfocused views.
 
 *border-width* _pixels_
diff --git a/example/init b/example/init
index a00a5b1..5c7fa16 100755
--- a/example/init
+++ b/example/init
@@ -140,6 +140,11 @@ do
     riverctl map $mode None XF86MonBrightnessDown spawn 'light -U 5'
 done
 
+# Set background and border color
+riverctl background-color 0x002b36
+riverctl border-color-focused 0x93a1a1
+riverctl border-color-unfocused 0x586e75
+
 # Set repeat rate
 riverctl set-repeat 50 300
 
diff --git a/river/Config.zig b/river/Config.zig
index 63fef65..0ee14b4 100644
--- a/river/Config.zig
+++ b/river/Config.zig
@@ -48,7 +48,7 @@ border_width: u32 = 2,
 border_color_focused: [4]f32 = [_]f32{ 0.57647059, 0.63137255, 0.63137255, 1.0 }, // Solarized base1
 
 /// Color of border of unfocused window in RGBA
-border_color_unfocused: [4]f32 = [_]f32{ 0.34509804, 0.43137255, 0.45882353, 1.0 }, // Solarized base0
+border_color_unfocused: [4]f32 = [_]f32{ 0.34509804, 0.43137255, 0.45882353, 1.0 }, // Solarized base01
 
 /// Map of keymap mode name to mode id
 mode_to_id: std.StringHashMap(usize),
diff --git a/river/command.zig b/river/command.zig
index 47413ee..c67f15b 100644
--- a/river/command.zig
+++ b/river/command.zig
@@ -144,7 +144,7 @@ pub fn errToMsg(err: Error) [:0]const u8 {
         Error.InvalidDirection => "invalid direction. Must be 'next' or 'previous'",
         Error.InvalidPhysicalDirection => "invalid direction. Must be 'up', 'down', 'left' or 'right'",
         Error.InvalidOrientation => "invalid orientation. Must be 'horizontal', or 'vertical'",
-        Error.InvalidRgba => "invalid color format, must be #RRGGBB or #RRGGBBAA",
+        Error.InvalidRgba => "invalid color format, must be hexadecimal 0xRRGGBB or 0xRRGGBBAA",
         Error.InvalidValue => "invalid value",
         Error.OutOfMemory => "out of memory",
         Error.Other => unreachable,
diff --git a/river/command/config.zig b/river/command/config.zig
index 00a3494..9161c7d 100644
--- a/river/command/config.zig
+++ b/river/command/config.zig
@@ -16,6 +16,7 @@
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
 const std = @import("std");
+const fmt = std.fmt;
 
 const server = &@import("../main.zig").server;
 
@@ -32,7 +33,7 @@ pub fn borderWidth(
     if (args.len < 2) return Error.NotEnoughArguments;
     if (args.len > 2) return Error.TooManyArguments;
 
-    server.config.border_width = try std.fmt.parseInt(u32, args[1], 10);
+    server.config.border_width = try fmt.parseInt(u32, args[1], 10);
     server.root.arrangeAll();
     server.root.startTransaction();
 }
@@ -94,14 +95,15 @@ pub fn setCursorWarp(
         return Error.UnknownOption;
 }
 
-/// Parse a color in the format #RRGGBB or #RRGGBBAA
+/// Parse a color in the format 0xRRGGBB or 0xRRGGBBAA
 fn parseRgba(string: []const u8) ![4]f32 {
-    if ((string.len != 7 and string.len != 9) or string[0] != '#') return error.InvalidRgba;
+    if (string.len != 8 and string.len != 10) return error.InvalidRgba;
+    if (string[0] != '0' or string[1] != 'x') return error.InvalidRgba;
 
-    const r = try std.fmt.parseInt(u8, string[1..3], 16);
-    const g = try std.fmt.parseInt(u8, string[3..5], 16);
-    const b = try std.fmt.parseInt(u8, string[5..7], 16);
-    const a = if (string.len == 9) try std.fmt.parseInt(u8, string[7..9], 16) else 255;
+    const r = try fmt.parseInt(u8, string[2..4], 16);
+    const g = try fmt.parseInt(u8, string[4..6], 16);
+    const b = try fmt.parseInt(u8, string[6..8], 16);
+    const a = if (string.len == 10) try fmt.parseInt(u8, string[8..10], 16) else 255;
 
     return [4]f32{
         @intToFloat(f32, r) / 255.0,