diff --git a/JoshHeaps.Net/wwwroot/css/casino/holdem.css b/JoshHeaps.Net/wwwroot/css/casino/holdem.css
index f323aa9..840e565 100644
--- a/JoshHeaps.Net/wwwroot/css/casino/holdem.css
+++ b/JoshHeaps.Net/wwwroot/css/casino/holdem.css
@@ -90,6 +90,32 @@
     --gold-deep: #a9782f;
     --gold-tint: #3a2f18;
     --gold-shade: #241d0f;
+
+    /* The page is #141414 and never said so.
+
+       Everything above is a colour this stylesheet paints. `color-scheme` is the half
+       the stylesheet cannot paint: the browser draws the checkboxes, the dropdown a
+       <select> opens, the scrollbars, the caret, the spellcheck underline and the
+       autofill wash itself, and with no scheme declared it draws all of them for a
+       light page. Measured before this line: `color-scheme: normal`, three checkboxes
+       rendering as bright white squares in the Table Setup panel — the loudest objects
+       on a near-black screen, brighter than the gold — and a <select> whose menu opens
+       white over the felt.
+
+       One declaration moves every one of them, and it moves them *natively*, which is
+       the part worth having: a control the browser draws still answers Windows High
+       Contrast Mode, still matches the platform a dealer already knows, and cannot
+       lose its tick to a stylesheet. See .potWizardChoice input for what painting one
+       by hand costs, and what it has to pay back.
+
+       --accent-on is the checked colour, and it is the green this tool already uses for
+       yes: the same #1e8449 the pot wizard's hand-drawn box fills with, so the one
+       painted checkbox and the six native ones agree. Chrome picks the tick's own
+       colour from it, and against a green this dark that is white. */
+    --accent-on: #1e8449;
+
+    color-scheme: dark;
+    accent-color: var(--accent-on);
 }
 
 /* Every number that changes while the dealer is looking at it — the pot, the stacks,
@@ -1974,8 +2000,13 @@ button,
 
 /* A bare checkbox ships at 13x13, which misses the 24px minimum with a mouse as well
    as with a thumb. The row around it is the real target on touch, but the box itself
-   should be findable on any device. */
-#dedicatedDealerToggle {
+   should be findable on any device.
+
+   This said `#dedicatedDealerToggle` and fixed one box of six. The other five were
+   still 13x13 — measured — including the two in the seat sheet that a dealer uses far
+   more often than any setting. Said about checkboxes instead, since that is what the
+   sentence above is about. */
+input[type="checkbox"] {
     width: 24px;
     height: 24px;
 }
@@ -2888,7 +2919,13 @@ button,
     gap: var(--sp-2);
 }
 
+/* `flex: none` here for the same reason the coarse-pointer block already says it: a
+   stated width is only a suggestion to a flex item, and this one sits in a crowded row.
+   It was declared 32px wide and measured 22 with a mouse — under the 24px floor the
+   checkbox rule near the top of this file is written to clear, and squeezed by exactly
+   the mechanism that block had already been bitten by once. */
 .chipColorInput {
+    flex: none;
     width: 32px;
     height: 28px;
     background: none;
@@ -4554,17 +4591,23 @@ body.hasActionBar #toastHost {
     }
 }
 
-/* The last raw browser control in the tool.
-   `accent-color` only paints the tick; the box around it stayed the platform's own —
-   a bright white square, which on this near-black dialog was the loudest thing on
-   screen and read as unfinished next to controls that had all been drawn. Painted to
-   match the rest, on the same surface ramp and the same corner radius. */
+/* The one checkbox in the tool that is drawn rather than asked for.
+   The comment here called it "the last raw browser control", which was not true when
+   it was written — six more were still the platform's, and they were white because the
+   page had never declared `color-scheme`. That is fixed at the top of this file, and
+   fixing it there is what makes this one the exception rather than the rule.
+
+   It stays painted because it is not a setting: it is the control a dealer ticks to
+   move money, with players watching, and it wants a fill and a tick that read across a
+   table rather than the platform's 24px square. What painting costs is the browser's
+   own answer to forced-colors mode, which is bought back below.
+
+   It takes its size from the checkbox rule near the top rather than restating it, so
+   there is one number for how big a checkbox is here. */
 .potWizardChoice input {
     flex: none;
     appearance: none;
     -webkit-appearance: none;
-    width: 22px;
-    height: 22px;
     border: 2px solid var(--line-strong);
     border-radius: var(--r-sm);
     background: var(--surface-2);
@@ -4602,6 +4645,34 @@ body.hasActionBar #toastHost {
     }
 }
 
+/* What the paint job owes back.
+   In forced-colors mode the OS replaces every colour on the page with its own palette,
+   and a tick drawn as a `background` on a pseudo-element is not a colour it knows how
+   to replace — it is simply gone. So this box, alone among the tool's checkboxes, had
+   no visible checked state at all in Windows High Contrast Mode, on the dialog that
+   pays the table. The system keywords are the fix: they are the only colours
+   guaranteed to survive, because they *are* the palette. */
+@media (forced-colors: active) {
+    .potWizardChoice input {
+        border-color: ButtonBorder;
+        background: Canvas;
+    }
+
+    .potWizardChoice input::before {
+        background: CanvasText;
+    }
+
+    .potWizardChoice input:checked {
+        border-color: Highlight;
+        background: Canvas;
+    }
+
+    /* The row's own chosen state is a background gradient, which goes the same way. */
+    .potWizardChoice.chosen {
+        outline: 2px solid Highlight;
+    }
+}
+
 /* Selected has to be obvious at a glance — a dealer confirms this with players
    watching, and a checkbox alone is easy to misread across a table. */
 .potWizardChoice.chosen {
@@ -5213,12 +5284,6 @@ body.hasActionBar #toastHost {
         min-height: 44px;
     }
 
-    /* A bare checkbox with no label box around it to grow. */
-    #dedicatedDealerToggle {
-        width: 24px;
-        height: 24px;
-    }
-
     /* An underlined word is a 14px-tall target; give it room without making it look
        like a button. */
     .linkBtn {
@@ -6047,11 +6112,6 @@ textarea:focus-visible {
         min-height: 44px;
     }
 
-    #dedicatedDealerToggle {
-        width: 24px;
-        height: 24px;
-    }
-
     /* An underlined word is a 14px-tall target; give it room without making it look
        like a button. */
     .linkBtn {
diff --git a/JoshHeaps.Net/wwwroot/css/casino/quicksplit.css b/JoshHeaps.Net/wwwroot/css/casino/quicksplit.css
index 252e3c7..a41684d 100644
--- a/JoshHeaps.Net/wwwroot/css/casino/quicksplit.css
+++ b/JoshHeaps.Net/wwwroot/css/casino/quicksplit.css
@@ -1,6 +1,15 @@
 /* Quick Split is phone-first: sized for one thumb at the table, then allowed to
    breathe on a laptop. Palette matches the dealer table so the two read as one tool. */
 
+/* And matches it in the half a stylesheet does not paint, for the same reason: this
+   page is #0a0a0a and had never told the browser so, which leaves the scrollbars, the
+   caret, the selection and the autofill wash drawn for a light page. It has no
+   checkboxes to go white, but a dealer who opens it from the felt should not find a
+   light scrollbar down the side of the darker of the two pages. */
+:root {
+    color-scheme: dark;
+}
+
 body {
     background: radial-gradient(ellipse at 50% -10%, #1c1c1c 0%, #101010 55%, #0a0a0a 100%);
     min-height: 100vh;
diff --git a/tests/holdem/nativeControls.test.js b/tests/holdem/nativeControls.test.js
new file mode 100644
index 0000000..76c263f
--- /dev/null
+++ b/tests/holdem/nativeControls.test.js
@@ -0,0 +1,121 @@
+// The half of the interface the stylesheet does not draw.
+//
+// The browser draws the checkboxes, the menu a <select> opens, the scrollbars, the
+// caret, the spellcheck underline and the autofill wash, and it draws all of them for a
+// light page unless the page says otherwise. This one never did: measured,
+// `color-scheme: normal` on a #141414 ground, with three checkboxes in the Table Setup
+// panel rendering as bright white squares — the loudest objects on the screen, brighter
+// than the gold — and two more in the seat sheet doing the same over the felt.
+//
+// The comment on the pot wizard's hand-painted checkbox called it "the last raw browser
+// control in the tool". Six others were still the platform's, and three of those were
+// still 13x13 against a 24px floor this stylesheet had already written down once and
+// applied to exactly one box.
+//
+// Painting is the expensive way to fix that, and the pot wizard's box shows the bill:
+// a tick drawn as a `background` on a pseudo-element is not a colour forced-colors mode
+// knows how to replace, so it simply disappears — no visible checked state at all, on
+// the dialog that pays the table. Declaring the scheme fixes six controls natively and
+// costs nothing; the seventh stays painted on purpose and pays its own way.
+const test = require("node:test");
+const { describe } = require("node:test");
+const assert = require("node:assert");
+const fs = require("fs");
+const path = require("path");
+
+const CSS = fs.readFileSync(
+    path.join(__dirname, "..", "..", "JoshHeaps.Net", "wwwroot", "css", "casino", "holdem.css"), "utf8");
+
+const ruleFor = selector => {
+    const at = CSS.indexOf(`\n${selector} {`);
+    assert.ok(at >= 0, `there is no \`${selector}\` rule`);
+    return CSS.slice(at, CSS.indexOf("}", at));
+};
+
+// The body of a whole at-rule block, braces balanced.
+const atRule = query => {
+    const at = CSS.indexOf(`@media ${query} {`);
+    assert.ok(at >= 0, `there is no \`@media ${query}\` block`);
+    let depth = 0;
+    for (let i = CSS.indexOf("{", at); i < CSS.length; i++) {
+        if (CSS[i] === "{") depth++;
+        else if (CSS[i] === "}" && --depth === 0) return CSS.slice(at, i + 1);
+    }
+    assert.fail(`\`@media ${query}\` never closes`);
+};
+
+// ---------------------------------------------------------------------------
+
+describe("the page says what colour it is", () => {
+    const root = ruleFor(":root");
+
+    test("dark, to the browser and not only to the eye", () => {
+        assert.match(root, /color-scheme:\s*dark/);
+    });
+
+    // The checked colour is the green this tool already uses for yes, so the one
+    // painted checkbox and the six native ones agree rather than nearly agree.
+    test("and the checked colour is the tool's own green, not the platform's blue", () => {
+        assert.match(root, /--accent-on:\s*#1e8449/);
+        assert.match(root, /accent-color:\s*var\(--accent-on\)/);
+        assert.match(ruleFor(".potWizardChoice input:checked"), /background:\s*#1e8449/);
+    });
+});
+
+describe("a checkbox is one size", () => {
+    test("every one of them, not the one that was noticed", () => {
+        assert.match(ruleFor('input[type="checkbox"]'), /width:\s*24px/);
+        assert.match(ruleFor('input[type="checkbox"]'), /height:\s*24px/);
+    });
+
+    test("and no box carries a size of its own any more", () => {
+        assert.ok(!/#dedicatedDealerToggle\s*\{/.test(CSS),
+            "one checkbox is still sized by id, which is how five got left behind");
+        assert.ok(!/width:\s*22px/.test(ruleFor(".potWizardChoice input")),
+            "the painted box restates its size instead of taking the one above");
+    });
+
+    // A stated width is only a suggestion to a flex item. The coarse-pointer block had
+    // already been bitten by this and said so; the mouse case had not.
+    test("a swatch in a crowded row keeps the width it was given", () => {
+        assert.match(ruleFor(".chipColorInput"), /flex:\s*none/);
+    });
+});
+
+describe("what painting a control costs, and who pays it", () => {
+    // If a future round paints another one, this is the bill it has to settle too.
+    test("nothing gives up the platform's drawing without answering forced colours", () => {
+        const forced = atRule("(forced-colors: active)");
+        const painted = [...CSS.matchAll(/\n([^\n{}]+)\s*\{[^}]*appearance:\s*none/g)]
+            .map(m => m[1].trim());
+        assert.ok(painted.length > 0, "nothing is painted, so this test is measuring nothing");
+        painted.forEach(selector => {
+            assert.ok(forced.includes(selector),
+                `\`${selector}\` drops the platform's control but has no forced-colors answer`);
+        });
+    });
+
+    // A tick drawn as a background is gone in forced-colors mode; a system keyword is
+    // the only colour guaranteed to survive, because it *is* the palette.
+    test("the tick that is drawn rather than typed survives the OS repainting it", () => {
+        const forced = atRule("(forced-colors: active)");
+        assert.match(forced, /\.potWizardChoice input::before\s*\{[^}]*background:\s*CanvasText/);
+    });
+
+    test("and so does the row's own chosen state, which is a gradient", () => {
+        const forced = atRule("(forced-colors: active)");
+        assert.match(forced, /\.potWizardChoice\.chosen\s*\{[^}]*outline:\s*2px solid Highlight/);
+    });
+});
+
+describe("the other page of the same tool", () => {
+    const QUICKSPLIT = fs.readFileSync(
+        path.join(__dirname, "..", "..", "JoshHeaps.Net", "wwwroot", "css", "casino", "quicksplit.css"), "utf8");
+
+    // It is the darker of the two pages and is opened from the felt mid-hand. It has no
+    // checkboxes to go white, but scrollbars, caret and selection were still drawn for
+    // a light page.
+    test("Quick Split says what colour it is too", () => {
+        assert.match(QUICKSPLIT, /:root\s*\{[^}]*color-scheme:\s*dark/);
+    });
+});