Rules and chrome scale with the display's density; dark pages get visible separators and focus tints

Density: dp() in gui.zig draws every size given in pixels in logical
pixels (SDL's window display scale, rounded, at least one), as acme scales
Border, ButtonBorder and Scrollgap: the rules (rule_px), the tag rule, the
grip's ring, its dirty gap and mode bars, the rail's gap to the text and
its minimum, the thumb's inset, the rim, a bar cursor's minimum width,
underline and strikethrough thickness (the atlas is dropped on a scale
change), the rule-grab margin, and the Crt's scanline and mask periods
(pardesScale in the post prefix). Cell- and tagline-measured sizes stay:
the rail's width, Lift's blur and offsets, every motion; iResolution,
fragCoord and iMouse stay in the display's pixels, as ghostty's.
PARDES_TEST_SCALE forces a density in a harness (a test window is 1x
otherwise, whatever display it lands on) and sizes the test font with it.

Colours: a separator that stands off its page by less than 1.5:1 is lifted
toward the text to 1.6:1 (helix, atelier, paper; a theme with no page,
dark, is judged against #121212), and empty_col follows it. forge's own
rule already stands at 3.83:1; what hid it was density: 2 device pixels
on a 3x screen, now 6 (dp). A focused tag's tint closer than 1.5:1 to the
plain tag on a dark page (1.25:1 on a light one) is pushed further the way
it leans, as far as its text keeps its own contrast or 4.5: forge
1.23 -> 1.51 (#2d3440 -> #374253), and likewise dusk, orchard, ink,
lagoon, clay, harvest, spectrum, solarium, forge_soft; daybreak, atelier,
paper to 1.25. dark and helix gain a tint of their own (dark: #484566
under #c8c8c8, 1.54:1; helix: ramp 237 under 250, 1.65:1).

Tag caret: past a full row's end, the G3 glide box sits on the tag's right
edge, where the layer's caret and the pixel shell's are.

Tests: every native theme's separator >= 1.5 and every dark one has a
tint >= 1.25 with readable text; forge keeps its own border; the tag caret
glide box at a full row; at 2x the spine, tag rule, ring, rail start and
gap, and bar cursor double. Legacy-ThemeFile test strips helix's new pair.

Goldens: snapshot goldens change in colour rows only, the tints (orchard
#283a2f -> #314738 at boot, forge, helix and dark in theme/themesel).
GUI goldens: the harness's single Del of the renamed wide pane is refused
since ysqnkyoy (a rename counted as unsaved; fixed on the 9P line in
wkzlsqvy), so scenes 09-17 were recorded with that pane open and the file
was stale since the merge (08 and 18 also moved with ykvnltvs's full-row
tag wrap). The goldens here were recorded with that pane closed (as
wkzlsqvy will close it); against the parent's binary under the same
conditions they differ only in the tints: 01-13 forge's (#2d3440 ->
#374253, and the glyph edges on it), 14 ink's; 15-18 are byte-identical.
Until wkzlsqvy is merged, a run here fails 09-17. Each commit reproduces its own
recorded goldens on this machine (checked at kvtmqkyn). A test window is
1x unless PARDES_TEST_SCALE says otherwise, whatever display it opens on.
Prebuilt shaders refreshed from their sources.
Captures: .scratch/render/dark-borders/{before,after,compare,scale2,scale3}.

1 files changed, 10 insertions, 10 deletions

diff --git a/test/snapshots/ninep.golden b/test/snapshots/ninep.golden
index 82bdb39c..82971a49 100644
--- a/test/snapshots/ninep.golden
+++ b/test/snapshots/ninep.golden
@@ -11,8 +11,8 @@
 |     7
 == style opened grid=90x15
 |0: 0-70 #b2c3b8,#1d2824, 71-89 d,#1d2824,
-|1: 0-1 #ffffff,#887455, 2-2 d,#26362d, 3-34 #becfc4,#26362d, 35-89 d,#26362d,
-|2: 0-1 #000000,#add38a, 2-2 d,#26362d, 3-29 #becfc4,#26362d, 30-37 #dfbce5,#26362d, 38-71 #becfc4,#26362d, 72-89 d,#26362d,
+|1: 0-1 #ffffff,#887455, 2-2 d,#314738, 3-34 #becfc4,#314738, 35-89 d,#314738,
+|2: 0-1 #000000,#add38a, 2-2 d,#314738, 3-29 #becfc4,#314738, 30-37 #dfbce5,#314738, 38-71 #becfc4,#314738, 72-89 d,#314738,
 |3: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #616f64,#0d1410,b 7-23 #e5eee5,#0d1410, 24-32 #b8d88a,#0d1410, 33-33 d,d, 34-36 #b8d88a,#0d1410, 37-37 #e5eee5,#0d1410, 38-89 d,#0d1410,
 |4: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-89 d,#0d1410,
 |5: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-10 #e5eee5,#0d1410, 11-12 #c9a7ed,#0d1410, 13-35 #e5eee5,#0d1410, 36-89 d,#0d1410,
@@ -29,9 +29,9 @@
 |0: Newcol Joincol Find Grep Help Changelog Tutor Dump NextColor Debug Exit
 @0: 0-70 #b2c3b8,#1d2824,,tagline 71-89 d,#1d2824,,tagline
 |1:    New Tty Find Grep Joincol Delcol
-@1: 0-1 #ffffff,#887455,,tagline 2-2 d,#26362d,,tagline 3-34 #becfc4,#26362d,,tagline 35-89 d,#26362d,,tagline
+@1: 0-1 #ffffff,#887455,,tagline 2-2 d,#314738,,tagline 3-34 #becfc4,#314738,,tagline 35-89 d,#314738,,tagline
 |2:    /tmp/pardes-snap/ninep/cwd/demo.zig Save Tty Collapse Del TreeContext
-@2: 0-1 #000000,#add38a,,tagline 2-2 d,#26362d,,tagline 3-29 #becfc4,#26362d,,tagline 30-37 #dfbce5,#26362d,,tagline 38-71 #becfc4,#26362d,,tagline 72-89 d,#26362d,,tagline
+@2: 0-1 #000000,#add38a,,tagline 2-2 d,#314738,,tagline 3-29 #becfc4,#314738,,tagline 30-37 #dfbce5,#314738,,tagline 38-71 #becfc4,#314738,,tagline 72-89 d,#314738,,tagline
 |3:      1 const greeting = "café λ 界 é";
 +3: 28="é" 30="λ" 32="界" 33="" 35="é"
 @3: 0-0 d,#608269,,body 1-1 d,#0d1410,,body 2-6 #616f64,#0d1410,b,body 7-23 #e5eee5,#0d1410,,body 24-36 #b8d88a,#0d1410,,body 37-37 #e5eee5,#0d1410,,body 38-89 d,#0d1410,,body
@@ -84,7 +84,7 @@
 |10:      8
 == 9p edited-with-colors-off grid=90x15 cursor=7,4,block
 |2:  * /tmp/pardes-snap/ninep/cwd/demo.zig Save Tty Collapse Del TreeContext
-@2: 0-0 #000000,#add38a,,tagline 1-1 #000000,#f9cb70,b,tagline 2-2 d,#26362d,,tagline 3-29 #becfc4,#26362d,,tagline 30-37 #dfbce5,#26362d,,tagline 38-71 #becfc4,#26362d,,tagline 72-89 d,#26362d,,tagline
+@2: 0-0 #000000,#add38a,,tagline 1-1 #000000,#f9cb70,b,tagline 2-2 d,#314738,,tagline 3-29 #becfc4,#314738,,tagline 30-37 #dfbce5,#314738,,tagline 38-71 #becfc4,#314738,,tagline 72-89 d,#314738,,tagline
 |3:      1 // café λ 界
 +3: 13="é" 15="λ" 17="界" 18=""
 @3: 0-0 d,#608269,,body 1-1 d,#0d1410,,body 2-6 #59675c,#0d1410,,body 7-18 #e5eee5,#0d1410,,body 19-89 d,#0d1410,,body
@@ -104,7 +104,7 @@
 |10:      8
 @10: 0-0 d,#608269,,body 1-1 d,#0d1410,,body 2-6 #59675c,#0d1410,,body 7-89 d,#0d1410,,body
 == style colors-on grid=90x15
-|2: 0-0 #000000,#add38a, 1-1 #000000,#f9cb70,b 2-2 d,#26362d, 3-29 #becfc4,#26362d, 30-37 #dfbce5,#26362d, 38-71 #becfc4,#26362d, 72-89 d,#26362d,
+|2: 0-0 #000000,#add38a, 1-1 #000000,#f9cb70,b 2-2 d,#314738, 3-29 #becfc4,#314738, 30-37 #dfbce5,#314738, 38-71 #becfc4,#314738, 72-89 d,#314738,
 |3: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-17 #b9f480,#0d1410, 18-18 d,d, 19-81 d,#0d1410, 82-82 d,#1d2824, 83-88 #b2c3b8,#1d2824, 89-89 d,#1d2824,
 |4: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #616f64,#0d1410,b 7-23 #e5eee5,#0d1410, 24-32 #b8d88a,#0d1410, 33-33 d,d, 34-36 #b8d88a,#0d1410, 37-37 #e5eee5,#0d1410, 38-89 d,#0d1410,
 |5: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-89 d,#0d1410,
@@ -127,8 +127,8 @@
 @8: 0-0 d,#608269,,body 1-1 d,#0d1410,,body 2-6 #59675c,#0d1410,,body 7-10 #e5eee5,#0d1410,,body 11-16 #c9a7ed,#0d1410,,body 17-17 #e5eee5,#0d1410,,body 18-18 #f8c082,#0d1410,,body 19-19 #e5eee5,#0d1410,,body 20-89 d,#0d1410,,body
 == style resized grid=105x20
 |0: 0-70 #b2c3b8,#1d2824, 71-104 d,#1d2824,
-|1: 0-1 #ffffff,#887455, 2-2 d,#26362d, 3-34 #becfc4,#26362d, 35-104 d,#26362d,
-|2: 0-0 #000000,#add38a, 1-1 #000000,#f9cb70,b 2-2 d,#26362d, 3-29 #becfc4,#26362d, 30-37 #dfbce5,#26362d, 38-71 #becfc4,#26362d, 72-104 d,#26362d,
+|1: 0-1 #ffffff,#887455, 2-2 d,#314738, 3-34 #becfc4,#314738, 35-104 d,#314738,
+|2: 0-0 #000000,#add38a, 1-1 #000000,#f9cb70,b 2-2 d,#314738, 3-29 #becfc4,#314738, 30-37 #dfbce5,#314738, 38-71 #becfc4,#314738, 72-104 d,#314738,
 |3: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-17 #b9f480,#0d1410, 18-18 d,d, 19-96 d,#0d1410, 97-97 d,#1d2824, 98-103 #b2c3b8,#1d2824, 104-104 d,#1d2824,
 |4: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #616f64,#0d1410,b 7-23 #e5eee5,#0d1410, 24-32 #b8d88a,#0d1410, 33-33 d,d, 34-36 #b8d88a,#0d1410, 37-37 #e5eee5,#0d1410, 38-104 d,#0d1410,
 |5: 0-0 d,#608269, 1-1 d,#0d1410, 2-6 #59675c,#0d1410, 7-104 d,#0d1410,
@@ -150,9 +150,9 @@
 |0: Newcol Joincol Find Grep Help Changelog Tutor Dump NextColor Debug Exit
 @0: 0-70 #b2c3b8,#1d2824,,tagline 71-104 d,#1d2824,,tagline
 |1:    New Tty Find Grep Joincol Delcol
-@1: 0-1 #ffffff,#887455,,tagline 2-2 d,#26362d,,tagline 3-34 #becfc4,#26362d,,tagline 35-104 d,#26362d,,tagline
+@1: 0-1 #ffffff,#887455,,tagline 2-2 d,#314738,,tagline 3-34 #becfc4,#314738,,tagline 35-104 d,#314738,,tagline
 |2:  * /tmp/pardes-snap/ninep/cwd/demo.zig Save Tty Collapse Del TreeContext
-@2: 0-0 #000000,#add38a,,tagline 1-1 #000000,#f9cb70,b,tagline 2-2 d,#26362d,,tagline 3-29 #becfc4,#26362d,,tagline 30-37 #dfbce5,#26362d,,tagline 38-71 #becfc4,#26362d,,tagline 72-104 d,#26362d,,tagline
+@2: 0-0 #000000,#add38a,,tagline 1-1 #000000,#f9cb70,b,tagline 2-2 d,#314738,,tagline 3-29 #becfc4,#314738,,tagline 30-37 #dfbce5,#314738,,tagline 38-71 #becfc4,#314738,,tagline 72-104 d,#314738,,tagline
 |3:      1 // café λ 界                                                                               Colors
 +3: 13="é" 15="λ" 17="界" 18=""
 @3: 0-0 d,#608269,,body 1-1 d,#0d1410,,body 2-6 #59675c,#0d1410,,body 7-18 #b9f480,#0d1410,,body 19-96 d,#0d1410,,body 97-97 d,#1d2824,,tagline 98-103 #b2c3b8,#1d2824,,tagline 104-104 d,#1d2824,,tagline