/*
 * Mobile first: the base rules are the phone layout; wider screens build on them.
 * Black on white, like the app: legible on e-ink browsers too.
 */
:root {
	--ink: #000;
	--paper: #fff;
	--gutter: 16px;
	--content: 1120px;
}

* {
	box-sizing: border-box;
}

html {
	-webkit-text-size-adjust: 100%;
	text-size-adjust: 100%;
}

body {
	margin: 0;
	background: var(--paper);
	color: var(--ink);
	font-family: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
	font-size: 1.0625rem;
	line-height: 1.5;
}

a {
	color: var(--ink);
}

h1,
h2,
h3 {
	line-height: 1.2;
}

/* --- Hero: the name, the promise and both actions on the first screen of a phone. --- */

.hero {
	padding: 32px var(--gutter);
	text-align: center;
}

.logo {
	display: block;
	width: 112px;
	height: 112px;
	margin: 0 auto;
}

h1 {
	margin: 8px 0 4px;
	font-size: 2.25rem;
	letter-spacing: 0.02em;
}

.tagline {
	max-width: 22em;
	margin: 0 auto 24px;
	font-size: 1.1875rem;
}

/* Stacked, full-width buttons: big targets for a thumb. */
.actions {
	display: grid;
	gap: 12px;
	max-width: 360px;
	margin: 0 auto;
}

.button {
	display: block;
	padding: 14px 20px;
	border: 2px solid var(--ink);
	font-weight: 600;
	text-align: center;
	text-decoration: none;
}

.button.primary,
.button:hover,
.button:focus-visible {
	background: var(--ink);
	color: var(--paper);
}

.button.primary:hover,
.button.primary:focus-visible {
	background: var(--paper);
	color: var(--ink);
}

/* Not yet available: shown, but not a link. */
.button[aria-disabled='true'] {
	pointer-events: none;
}

.note {
	max-width: 30em;
	margin: 16px auto 0;
	font-size: 0.9375rem;
}

main {
	border-top: 2px solid var(--ink);
}

section h2 {
	margin: 0 0 20px;
	padding: 0 var(--gutter);
	text-align: center;
	font-size: 1.5rem;
}

/* --- Screenshots: one at a time on phones, swiped sideways with the next peeking in. - */

.screenshots {
	max-width: var(--content);
	margin: 0 auto;
	padding: 32px 0 8px;
}

.screenshots ul {
	display: grid;
	grid-auto-flow: column;
	grid-auto-columns: 72%;
	gap: 16px;
	margin: 0;
	padding: 0 var(--gutter) 16px;
	list-style: none;
	overflow-x: auto;
	overscroll-behavior-x: contain;
	scroll-snap-type: x mandatory;
	scroll-padding: 0 var(--gutter);
	scrollbar-width: none;
}

.screenshots ul::-webkit-scrollbar {
	display: none;
}

.screenshots li {
	scroll-snap-align: center;
}

.screenshots figure {
	margin: 0;
}

.screenshots img {
	display: block;
	width: 100%;
	height: auto;
	border: 2px solid var(--ink);
}

.screenshots figcaption {
	margin-top: 10px;
	text-align: center;
	font-size: 0.9375rem;
}

/* --- Features: a plain list between rules on phones; cards once there is room. ------- */

.features {
	max-width: var(--content);
	margin: 0 auto;
	padding: 32px var(--gutter) 40px;
}

.features ul {
	margin: 0;
	padding: 0;
	list-style: none;
	border-bottom: 1px solid var(--ink);
}

.features li {
	padding: 18px 0;
	border-top: 1px solid var(--ink);
}

.features h3 {
	margin: 0 0 6px;
	font-size: 1.125rem;
}

.features p {
	margin: 0;
}

footer {
	padding: 16px var(--gutter) 32px;
	border-top: 2px solid var(--ink);
	text-align: center;
}

footer a {
	display: inline-block;
	padding: 12px;
}

/* --- Privacy policy: one readable column. ------------------------------------------- */

.policy {
	max-width: 42rem;
	margin: 0 auto;
	padding: 24px var(--gutter) 40px;
}

.policy h1 {
	margin-top: 16px;
}

.policy h2 {
	margin: 32px 0 8px;
	font-size: 1.375rem;
	text-align: left;
}

.policy li {
	margin-bottom: 8px;
}

/* --- Default reader: the two dialogs, stacked on phones and side by side on wider screens. */

.default-steps {
	display: grid;
	gap: 32px;
	margin: 24px 0 0;
	padding: 0;
	list-style: none;
}

.default-steps figure {
	max-width: 320px;
	margin: 0 auto;
}

.default-steps img {
	display: block;
	width: 100%;
	height: auto;
	border: 2px solid var(--ink);
}

.default-steps figcaption {
	margin-top: 12px;
}

.default-steps ol {
	margin: 4px 0 0;
	padding-left: 1.5em;
}

/* --- Large phones in landscape and small tablets ------------------------------------ */

@media (min-width: 600px) {
	.hero {
		padding-top: 48px;
		padding-bottom: 40px;
	}

	.logo {
		width: 144px;
		height: 144px;
	}

	h1 {
		font-size: 3rem;
	}

	.tagline {
		font-size: 1.25rem;
	}

	/* Side by side once both fit. */
	.actions {
		display: flex;
		flex-wrap: wrap;
		justify-content: center;
		max-width: none;
	}

	.button {
		min-width: 220px;
	}

	.screenshots ul {
		grid-auto-columns: 42%;
	}

	.features ul {
		display: grid;
		grid-template-columns: repeat(2, minmax(0, 1fr));
		gap: 16px;
		border-bottom: 0;
	}

	.features li {
		padding: 20px;
		border: 1px solid var(--ink);
	}

	.default-steps {
		grid-template-columns: repeat(2, minmax(0, 1fr));
		align-items: start;
	}
}

/* --- Desktop: all six screenshots in a row, three feature cards across ------------- */

@media (min-width: 960px) {
	.hero {
		padding-top: 56px;
	}

	.screenshots {
		padding-top: 40px;
	}

	.screenshots ul {
		grid-auto-flow: row;
		grid-template-columns: repeat(6, minmax(0, 1fr));
		overflow: visible;
	}

	.features {
		padding-top: 40px;
		padding-bottom: 48px;
	}

	.features ul {
		grid-template-columns: repeat(3, minmax(0, 1fr));
	}
}