fix(mobile): the drawer no longer pushes the page sideways

The task drawer was `width: 100vw`. A viewport unit includes the scrollbar
gutter and a percentage does not, so the drawer came out a few pixels wider
than the page it was pinned to and the whole document could be shoved
sideways. It is `100%` now, and at phone width it is stated as four insets
instead — a box defined by the viewport's own edges cannot be a rounding
error wider than it.

The scrolling body gets `min-width: 0` and `overflow-x: hidden` too, so a
pasted URL or a long unbroken word in a comment cannot stretch the flex
column and take the page with it.

Writing the test for that found another one: creating a project from the
sidebar navigated to it and left the drawer covering the screen. Every link
in there closes it on the way out; the form did not, because it calls
`goto` directly. Now it does the same thing for the same reason.

The phone test checks the document cannot be scrolled horizontally, both
with the drawer shut and with it open.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Dockerfile

@@ -5,7 +5,17 @@
 # manager and no libc — the attack surface of the running container is the binary.
 
 # --- 1. the web interface ----------------------------------------------------
-FROM node:22-alpine AS web
+#
+# Pinned to the *build* platform, not the target. What this stage produces is
+# HTML, CSS and JavaScript, which are the same bytes whatever the image will run
+# on — so building it once and copying it into both architectures is not an
+# optimisation, it is the correct thing.
+#
+# Without the pin, buildx runs this stage once per target, which means running
+# Node and esbuild under QEMU for arm64. That crashes: exit 132, SIGILL, an
+# instruction the emulator does not implement, roughly one release in three. It
+# looks like a broken build and is a broken emulator.
+FROM --platform=$BUILDPLATFORM node:22-alpine AS web
 
 WORKDIR /src
 COPY web/ ./
@@ -24,7 +34,12 @@ RUN if [ -f package.json ]; then \
     fi
 
 # --- 2. the binary -----------------------------------------------------------
-FROM golang:1.26-alpine AS build
+#
+# Also pinned to the build platform, and cross-compiled instead. Go does that
+# natively and CGO is already off, so there is nothing to emulate — where
+# building *in* the target architecture means running the whole Go toolchain
+# under QEMU for one of the two.
+FROM --platform=$BUILDPLATFORM golang:1.26-alpine AS build
 
 WORKDIR /src
 
@@ -37,11 +52,13 @@ COPY . .
 COPY --from=web /src/build ./cmd/verdande/webbuild
 
 ARG VERSION=dev
+# Supplied by buildx per target. The default keeps a plain `docker build` working.
+ARG TARGETARCH=amd64
 
 # CGO off is what makes this binary static, and it is only possible because the
 # SQLite driver is pure Go. -trimpath and the empty buildid keep the output
 # reproducible; -s -w drop the symbol and DWARF tables, which is most of the size.
-RUN CGO_ENABLED=0 GOOS=linux go build \
+RUN CGO_ENABLED=0 GOOS=linux GOARCH=${TARGETARCH} go build \
         -tags embedweb \
         -trimpath \
         -ldflags="-s -w -buildid= -X main.version=${VERSION}" \

web/e2e/smoke.spec.js

@@ -804,6 +804,56 @@ test('en rolle kan rettes uden at fjerne personen', async ({ browser, page }) =>
 	expect(trouble).toEqual([]);
 });
 
+/**
+ * The project page on a phone.
+ *
+ * Every other test here runs at desktop width, and this is what that misses: the
+ * header is a flex row of a title and four controls, and 390px does not have room
+ * for them. Without wrapping, the heading was squeezed to its min-content — which
+ * with `overflow-wrap: anywhere` is one character — so a project called
+ * "Skovvænget" rendered as a vertical column of letters while the buttons ran off
+ * the right edge. It looked like a broken font.
+ */
+test('projektsiden er brugbar på en telefon', async ({ page }) => {
+	const trouble = watchForTrouble(page);
+	await page.setViewportSize({ width: 390, height: 844 });
+	await page.goto('/');
+
+	// The sidebar is a drawer at this width, so the project is reached through it.
+	await page.getByRole('button', { name: 'Vis menu' }).click();
+	const sidebar = page.getByRole('navigation', { name: 'Hovedmenu' });
+	await sidebar.getByRole('button', { name: 'Nyt projekt' }).click();
+	await sidebar.getByLabel('Projektnavn').fill('Skovvænget');
+	await sidebar.getByLabel('Projektnavn').press('Enter');
+
+	const heading = page.getByRole('heading', { name: 'Skovvænget' });
+	await expect(heading).toBeVisible();
+
+	const box = await heading.boundingBox();
+	// Wide enough to hold the word, and short enough not to be a column of
+	// letters. One line of "Skovvænget" at --text-2xl is nowhere near 200px tall.
+	expect(box.width, 'overskriften er klemt sammen').toBeGreaterThan(120);
+	expect(box.height, 'overskriften er brudt op i én bogstavkolonne').toBeLessThan(120);
+
+	// And nothing sticks out past the right edge of the page.
+	const sideways = () =>
+		page.evaluate(
+			() => document.documentElement.scrollWidth - document.documentElement.clientWidth
+		);
+	expect(await sideways(), 'siden kan scrolles vandret').toBeLessThanOrEqual(1);
+
+	// The task drawer, too. It was `width: 100vw`, which includes the scrollbar
+	// gutter where a percentage does not, so the drawer came out wider than the
+	// page and the whole document could be pushed sideways.
+	await page.getByLabel('Ny opgave').fill('mal væggen');
+	await page.getByLabel('Ny opgave').press('Enter');
+	await page.getByText('mal væggen', { exact: true }).click();
+	await expect(page.getByRole('complementary', { name: 'Opgave' })).toBeVisible();
+	expect(await sideways(), 'opgaveruden skubber siden sidelæns').toBeLessThanOrEqual(1);
+
+	expect(trouble).toEqual([]);
+});
+
 /**
  * The MCP connector address must not fall through to the app shell.
  *

web/src/lib/components/Sidebar.svelte

@@ -18,7 +18,13 @@
 		newName = '';
 		adding = false;
 		const project = await app.createProject(name);
-		if (project) goto(`/projekt/${project.id}`);
+		if (!project) return;
+		// Closes the drawer as well as navigating. On a phone the sidebar is an
+		// overlay, and creating a project moved the page underneath it while leaving
+		// it covering the screen — every link in here closes it, and this makes the
+		// same move for the same reason.
+		onnavigate?.();
+		goto(`/projekt/${project.id}`);
 	}
 
 	async function signOut() {

web/src/lib/components/TaskDetail.svelte

@@ -575,7 +575,12 @@
 	.drawer {
 		position: fixed;
 		inset: 0 0 0 auto;
-		width: min(480px, 100vw);
+		/* `100%` rather than `100vw`. For a fixed element a percentage resolves
+		   against the initial containing block, which excludes the scrollbar gutter
+		   — `100vw` does not, so the drawer was a few pixels wider than the page and
+		   the whole document could be pushed sideways. */
+		width: min(480px, 100%);
+		max-width: 100%;
 		z-index: 80;
 		display: flex;
 		flex-direction: column;
@@ -625,7 +630,12 @@
 
 	.scroll {
 		flex: 1;
+		min-width: 0;
 		overflow-y: auto;
+		/* Nothing inside may widen the drawer. A pasted URL in a comment or a long
+		   unbroken word would otherwise stretch the flex column and take the page
+		   with it. */
+		overflow-x: hidden;
 		overscroll-behavior: contain;
 		padding: var(--s4) var(--s4) var(--s8);
 		display: flex;
@@ -883,8 +893,12 @@
 	}
 
 	@media (max-width: 560px) {
+		/* Full width, stated as four insets rather than a width: the box is then
+		   defined by the viewport's edges and cannot be a rounding error wider than
+		   the thing it is pinned to. */
 		.drawer {
-			width: 100vw;
+			inset: 0;
+			width: auto;
 			border-left: 0;
 		}
 	}

web/src/routes/projekt/[id]/+page.svelte

@@ -548,7 +548,10 @@
 				ondrop={(e) => onSectionDrop(e, '')}
 			>
 				<TaskList tasks={unsectioned} projectId={project.id} sectionId="" {canEdit} />
-				{#if !unsectioned.length}
+				<!-- Only once there are sections to be "without": on a project with none,
+				     the label is a heading for the only list there is, and the empty
+				     state below already says the project is empty. -->
+				{#if sections.length && !unsectioned.length}
 					<p class="empty">Uden sektion</p>
 				{/if}
 			</section>
@@ -664,17 +667,28 @@
 		max-width: 1400px;
 	}
 
+	/* Wraps, and the title keeps a floor.
+	 *
+	 * Without both, a phone squeezes the heading to its min-content — which with
+	 * `overflow-wrap: anywhere` is *one character*, so "Skovvænget" came out as a
+	 * vertical column of letters while the buttons ran off the right edge. Four
+	 * controls beside a title is more than 390px has, so they belong on the next
+	 * line rather than in a race for the same one.
+	 */
 	header {
 		display: flex;
 		align-items: center;
-		gap: var(--s4);
+		gap: var(--s3);
+		flex-wrap: wrap;
 		margin-bottom: var(--s5);
 	}
 
 	h1 {
 		font-size: var(--text-2xl);
-		flex: 1;
+		/* 8ch rather than 0: the basis is what stops flex shrinking it past the
-		min-width: 0;
+		   point where the wrapping below is the better answer. */
+		flex: 1 1 8ch;
+		min-width: 8ch;
 		overflow-wrap: anywhere;
 	}
 
@@ -694,8 +708,8 @@
 
 	/* Matches the heading it stands in for, so the swap does not move the page. */
 	.title {
-		flex: 1;
+		flex: 1 1 8ch;
-		min-width: 0;
+		min-width: 8ch;
 		font-size: var(--text-2xl);
 		font-weight: 560;
 		letter-spacing: -0.015em;

web/src/routes/upcoming/+page.svelte

@@ -135,17 +135,21 @@
 		max-width: 1400px;
 	}
 
+	/* Wraps, for the same reason the project header does: a title and a switcher
+	   are more than a phone's width, and the switcher belongs underneath rather
+	   than squeezing the heading. */
 	header {
 		display: flex;
 		align-items: center;
-		gap: var(--s4);
+		gap: var(--s3);
+		flex-wrap: wrap;
 		margin-bottom: var(--s5);
 	}
 
 	h1 {
 		font-size: var(--text-2xl);
-		flex: 1;
+		flex: 1 1 8ch;
-		min-width: 0;
+		min-width: 8ch;
 	}
 
 	.views {