/* Source Serif 4, hosted here so visitors' addresses don't go to Google: the variable
   font, latin subset, every weight and optical size (licence in fonts/). */
@font-face {
  font-family: "Source Serif 4";
  src: url("/fonts/SourceSerif4-v15-latin.woff2") format("woff2");
  font-weight: 200 900;
  font-style: normal;
  font-display: swap;
}

:root {
  --oxblood: #8B2E23;
  --paper: #FBF8F3;
  --card: #FFFFFF;
  --ink: #1D1A17;
  --muted: #6B625A;
  --line: rgba(29, 26, 23, 0.10);
  --link: var(--oxblood);
  --serif: "Source Serif 4", Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  /* Above each section (and the footer), and between a section's words and its pictures */
  --space-section: 72px;
  --space-first: 56px;
  --space-media: 36px;
}

@media (min-width: 900px) {
  :root { --space-section: 104px; --space-first: 72px; }
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper: #151211;
    --card: #201B19;
    --ink: #F2ECE6;
    --muted: #A99F96;
    --line: rgba(242, 236, 230, 0.12);
    --link: #E58C7E;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 17px/1.55 var(--sans);
  -webkit-font-smoothing: antialiased;
}

img, video { display: block; max-width: 100%; height: auto; }
a { color: var(--link); }
/* A keyboard focus ring in the link's own colour: white on oxblood, oxblood on paper. */
a:focus-visible { outline: 2px solid currentColor; outline-offset: 3px; border-radius: 4px; }

h1, h2, h3 { font-family: var(--serif); font-weight: 700; line-height: 1.15; margin: 0; }
h2 { font-size: clamp(28px, 4vw, 40px); margin-bottom: 12px; }
h3 { font-size: 21px; margin-bottom: 6px; }
p { margin: 0; }

.wrap { width: 100%; max-width: 1080px; margin: 0 auto; padding: 0 16px; }
@media (min-width: 700px) { .wrap { padding: 0 32px; } }

/* Hero: the App Store's oxblood over a dimmed wall of covers */

.hero {
  color: #FFF;
  background:
    linear-gradient(color-mix(in srgb, var(--oxblood) 88%, transparent), color-mix(in srgb, var(--oxblood) 88%, transparent)),
    url("images/cover-wall.jpg") center / cover var(--oxblood);
  padding: 56px 0 48px;
}
.hero-grid { display: grid; gap: 40px; align-items: center; }
@media (min-width: 900px) {
  .hero { padding: 88px 0; }
  .hero-grid { grid-template-columns: 5fr 7fr; }
}
.icon { width: 88px; height: 88px; border-radius: 22%; box-shadow: 0 6px 20px rgba(0, 0, 0, 0.25); margin-bottom: 20px; }
.hero h1 { font-size: clamp(44px, 7vw, 64px); }
.lede { font-family: var(--serif); font-weight: 600; font-size: clamp(22px, 2.6vw, 27px); line-height: 1.3; margin-top: 12px; }
.sub { color: rgba(255, 255, 255, 0.82); margin-top: 14px; }
.actions { display: flex; flex-wrap: wrap; align-items: center; gap: 12px 20px; margin-top: 28px; }

/* A stand-in for Apple's badge until the app is live */
.store {
  display: inline-flex; flex-direction: column; justify-content: center;
  height: 52px; padding: 0 20px; border-radius: 10px;
  background: #000; color: #FFF; line-height: 1.1;
  border: 1px solid rgba(255, 255, 255, 0.35);
}
.store-small { font-size: 11px; }
.store-big { font-size: 21px; font-weight: 600; letter-spacing: -0.01em; }
.secondary { display: inline-flex; align-items: center; min-height: 44px; color: #FFF; font-weight: 600; text-underline-offset: 3px; }

/* The video plays in the Duo frame's screen opening (120, 120, 2853 × 2007 of 3093 × 2247). */
.duo-video { position: relative; }
/* The shadow sits on a still shape behind the device (58, 50, 2985 × 2139, corners about 290),
   so it isn't redrawn with every frame of the video. */
.duo-video::before {
  content: "";
  position: absolute;
  left: 1.88%; top: 2.23%; width: 96.51%; height: 95.19%;
  border-radius: 9.7% / 13.6%;
  box-shadow: 0 18px 40px rgba(0, 0, 0, 0.35);
}
.duo-video video {
  position: absolute;
  left: 3.88%; top: 5.34%; width: 92.24%; height: 89.32%;
  object-fit: fill;
  /* The frame's corners are rounded outside and in: show the video only through its screen. */
  -webkit-mask: url("images/duo-screen-mask.png") 0 0 / 100% 100% no-repeat;
  mask: url("images/duo-screen-mask.png") 0 0 / 100% 100% no-repeat;
}
.duo-frame { position: relative; width: 100%; pointer-events: none; }

/* Sections */

/* `main >` outranks `.wrap`'s own padding. */
main > .wrap { padding-top: var(--space-section); }
main > .wrap:first-child { padding-top: var(--space-first); }

/* The one style for words under a heading */
.intro { color: var(--muted); font-size: 19px; max-width: 640px; }
.note { margin-top: 20px; }

/* Folded and open stand at the same height. */
.fold-row { display: flex; gap: 32px; margin-top: var(--space-media); align-items: flex-end; }
.fold-row figure { margin: 0; flex: 1.377 1 0; }
.fold-row figure:first-child { flex: 0.717 1 0; }
@media (max-width: 640px) {
  .fold-row { flex-direction: column; align-items: center; }
  .fold-row figure { flex: none; width: 100%; }
  .fold-row figure:first-child { width: 52%; }
}
.fold-row img { width: 100%; }
figcaption { color: var(--muted); font-size: 15px; margin-top: 12px; text-align: center; }

.phone, .tablet, .fold-row img { filter: drop-shadow(0 12px 28px rgba(0, 0, 0, 0.18)); }
.phone { width: 100%; max-width: 280px; }

/* In one column the heading comes first, so the screenshot has its words before it. */
.feature { display: grid; gap: 32px; justify-items: center; }
.feature > div { order: -1; justify-self: stretch; }
@media (min-width: 760px) {
  .feature { grid-template-columns: 1fr 1fr; align-items: center; justify-items: start; }
  .feature > div { order: 0; }
  .feature .phone { justify-self: center; }
  .feature.flip .phone { order: 2; }
}

.cards { display: grid; gap: 16px; margin-top: var(--space-media); }
@media (min-width: 640px) { .cards { grid-template-columns: 1fr 1fr; } }
@media (min-width: 980px) { .cards { grid-template-columns: repeat(4, 1fr); } }
.card { background: var(--card); border: 1px solid var(--line); border-radius: 16px; padding: 22px; }
.card p { color: var(--muted); font-size: 16px; }

.devices-row { display: flex; gap: 24px; align-items: flex-end; justify-content: center; margin-top: var(--space-media); }
/* iPad 13" (282 mm) and iPhone 6.3" (150 mm) at their real sizes against each other:
   the phone's frame is 0.34 of the tablet's width. */
.devices-row .tablet { width: 58%; max-width: 520px; }
.devices-row .phone { width: 19.7%; max-width: 177px; }
/* On a phone that would leave the iPhone too small to read, so each gets a readable size. */
@media (max-width: 640px) {
  .devices-row { flex-direction: column; align-items: center; gap: 32px; }
  .devices-row .tablet { width: 100%; }
  .devices-row .phone { width: 60%; max-width: 280px; }
}

/* Other pages: a thin oxblood bar home, then one column of words */

.bar { background: var(--oxblood); color: #FFF; }
.bar .wrap { display: flex; align-items: center; height: 64px; }
.bar a { display: inline-flex; align-items: center; gap: 12px; min-height: 44px; color: #FFF; text-decoration: none; font-family: var(--serif); font-weight: 700; font-size: 24px; }
.bar img { width: 36px; height: 36px; border-radius: 22%; }

/* The column starts where the bar's name and the footer do. */
.doc { padding-top: var(--space-first); }
.doc > * { max-width: 720px; }
.doc h1 { font-size: clamp(34px, 5vw, 44px); }
.doc .updated { color: var(--muted); margin-top: 8px; }
.doc h2 { font-size: 24px; margin: 40px 0 8px; }
.doc p, .doc ul { margin: 12px 0 0; }
.doc ul { padding-left: 22px; }
.doc li + li { margin-top: 8px; }
.doc .lead { font-size: 19px; margin-top: 20px; }
.doc code { font: 15px ui-monospace, SFMono-Regular, Menlo, monospace; background: var(--card); border: 1px solid var(--line); border-radius: 6px; padding: 1px 5px; }

.footer {
  margin-top: var(--space-section); padding-top: 28px; padding-bottom: 48px;
  border-top: 1px solid var(--line);
  color: var(--muted); font-size: 15px;
}
/* Links at least 44 px tall, the touch size Apple asks for. */
.footer nav { display: flex; flex-wrap: wrap; gap: 0 24px; margin: -10px 0 4px; }
.footer nav a { display: inline-flex; align-items: center; min-height: 44px; font-weight: 600; text-decoration: none; }
.footer p + p { margin-top: 6px; }