/* paperduet.com: one page, light and dark, Apple-style type, glass and soft light. */
:root {
  --bg: #fbfbfd;
  --bg-2: #f2f2f6;
  --text: #1d1d1f;
  --muted: #6e6e73;
  --line: rgba(0, 0, 0, 0.08);
  --card: rgba(255, 255, 255, 0.72);
  --card-solid: #ffffff;
  --accent: #0a84ff;
  --accent-2: #5e5ce6;
  --accent-3: #bf5af2;
  --green: #30d158;
  --glow: rgba(10, 132, 255, 0.28);
  --shadow: 0 40px 90px -30px rgba(15, 23, 42, 0.45), 0 12px 30px -12px rgba(15, 23, 42, 0.18);
  --radius: 22px;
  --ease: cubic-bezier(0.2, 0.7, 0.2, 1);
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Inter", "Segoe UI", "Helvetica Neue", Arial,
    "PingFang TC", "Hiragino Sans", sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #000000;
    --bg-2: #0d0d12;
    --text: #f5f5f7;
    --muted: #a1a1a6;
    --line: rgba(255, 255, 255, 0.1);
    --card: rgba(28, 28, 34, 0.66);
    --card-solid: #141418;
    --glow: rgba(94, 92, 230, 0.4);
    --shadow: 0 40px 100px -30px rgba(0, 0, 0, 0.9), 0 0 0 1px rgba(255, 255, 255, 0.06);
  }
}

/* Type for each language (also on the language menu's own items). */
:lang(zh-CN) { --font: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif; }
:lang(zh-TW) { --font: -apple-system, BlinkMacSystemFont, "PingFang TC", "Microsoft JhengHei", "Noto Sans TC", sans-serif; }
:lang(ja) { --font: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Yu Gothic", "Noto Sans JP", sans-serif; }
:lang(ko) { --font: -apple-system, BlinkMacSystemFont, "Apple SD Gothic Neo", "Malgun Gothic", "Noto Sans KR", sans-serif; }

* { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.55 var(--font);
  letter-spacing: -0.011em;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; height: auto; display: block; }
code {
  font: 0.86em var(--mono);
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 0.1em 0.4em;
  word-break: break-word;
}
main > section, #features > section { padding: 0 24px; }

/* Navigation: glass bar. */
.nav {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 50;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 0 max(20px, calc(50% - 560px));
  background: color-mix(in srgb, var(--bg) 70%, transparent);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s;
}
.nav.scrolled { border-bottom-color: var(--line); }
.brand { display: flex; align-items: center; gap: 9px; color: var(--text); font-weight: 650; font-size: 17px; }
.brand:hover { text-decoration: none; }
.brand img { border-radius: 6px; }
.links { display: flex; gap: 28px; }
.links a { color: var(--muted); font-size: 14px; }
.links a:hover { color: var(--text); text-decoration: none; }
.actions { display: flex; align-items: center; gap: 14px; }
.gh { color: var(--muted); display: flex; }
.gh svg { width: 20px; height: 20px; }
.gh:hover { color: var(--text); }
.nav-dl {
  background: var(--accent);
  color: #fff;
  font-size: 13px;
  font-weight: 600;
  padding: 6px 14px;
  border-radius: 999px;
}
.nav-dl:hover { text-decoration: none; filter: brightness(1.08); }
@media (max-width: 760px) { .links { display: none; } }

/* Buttons. */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 17px;
  font-weight: 600;
  padding: 14px 26px;
  border-radius: 999px;
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease), background 0.25s;
}
.btn:hover { text-decoration: none; transform: translateY(-2px); }
.btn.primary {
  color: #fff;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  box-shadow: 0 10px 30px -8px var(--glow), inset 0 1px 0 rgba(255, 255, 255, 0.25);
}
.btn.primary:hover { box-shadow: 0 16px 40px -10px var(--glow), inset 0 1px 0 rgba(255, 255, 255, 0.25); }
.btn.ghost { color: var(--text); background: var(--card); border: 1px solid var(--line); backdrop-filter: blur(12px); }
.apple { width: 15px; height: 18px; margin-top: -2px; }

/* Soft moving light behind the hero and the last call to action. */
.aurora { position: absolute; inset: 0; overflow: hidden; pointer-events: none; z-index: -1; }
.aurora span {
  position: absolute;
  width: 60vmax;
  height: 60vmax;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.35;
  animation: drift 22s ease-in-out infinite alternate;
}
.aurora span:nth-child(1) { background: #0a84ff; top: -30vmax; left: -15vmax; }
.aurora span:nth-child(2) { background: #bf5af2; top: -25vmax; right: -20vmax; animation-delay: -7s; }
.aurora span:nth-child(3) { background: #64d2ff; top: 10vmax; left: 25vmax; opacity: 0.22; animation-delay: -14s; }
@media (prefers-color-scheme: dark) { .aurora span { opacity: 0.28; } }
@keyframes drift {
  0% { transform: translate3d(0, 0, 0) scale(1); }
  100% { transform: translate3d(6vmax, 4vmax, 0) scale(1.15); }
}

/* Hero. */
.hero {
  position: relative;
  isolation: isolate;
  text-align: center;
  padding: 140px 24px 40px;
}
.app-icon {
  margin: 0 auto 22px;
  border-radius: 28px;
  filter: drop-shadow(0 18px 40px var(--glow));
}
h1 {
  margin: 0;
  font-size: clamp(56px, 9vw, 112px);
  line-height: 1;
  font-weight: 800;
  letter-spacing: -0.045em;
}
.slogan {
  margin: 18px auto 0;
  max-width: 900px;
  font-size: clamp(24px, 3.4vw, 40px);
  line-height: 1.15;
  font-weight: 700;
  letter-spacing: -0.03em;
  background: linear-gradient(90deg, var(--accent), var(--accent-2) 50%, var(--accent-3));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.tags { margin: 22px auto 0; max-width: 680px; color: var(--muted); font-size: clamp(17px, 1.6vw, 20px); }
.cta { margin-top: 32px; display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.req { margin: 16px 0 0; color: var(--muted); font-size: 13px; }

/* Screenshots and recordings: a framed window with a glow behind it. */
.shot { margin: 0; position: relative; }
.shot::before {
  content: "";
  position: absolute;
  inset: 10% 6% -4%;
  background: radial-gradient(closest-side, var(--glow), transparent);
  filter: blur(40px);
  z-index: -1;
}
.frame { border-radius: 16px; overflow: hidden; box-shadow: var(--shadow); background: var(--card-solid); }
.frame img { width: 100%; }
.hero-shot { margin: 64px auto 0; max-width: 1180px; perspective: 1800px; }
.hero-shot .shot.tilt .frame {
  transform: rotateX(var(--tilt, 0deg)) scale(var(--s, 1));
  transform-origin: 50% 0;
  will-change: transform;
}
.caption { color: var(--muted); font-size: 13px; margin: 22px 0 0; }

/* Intro paragraph. */
.intro { max-width: 860px; margin: 120px auto 40px; text-align: center; }
.intro p { font-size: clamp(22px, 2.6vw, 32px); line-height: 1.35; font-weight: 600; letter-spacing: -0.02em; margin: 0; }

/* Features: text and recording side by side, alternating. */
.feature {
  max-width: 1200px;
  margin: 140px auto;
  display: grid;
  grid-template-columns: minmax(0, 4fr) minmax(0, 7fr);
  gap: 64px;
  align-items: center;
}
.feature.flip { grid-template-columns: minmax(0, 7fr) minmax(0, 4fr); }
.feature.flip .text { order: 2; }
.eyebrow {
  margin: 0 0 10px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
}
.feature h2, .section-title {
  margin: 0;
  font-size: clamp(32px, 4vw, 52px);
  line-height: 1.05;
  font-weight: 750;
  letter-spacing: -0.035em;
}
.feature .text p:last-child { color: var(--muted); font-size: 19px; margin: 18px 0 0; }
@media (max-width: 900px) {
  .feature, .feature.flip { grid-template-columns: 1fr; gap: 32px; margin: 96px auto; }
  .feature.flip .text { order: 0; }
}

.section-title { text-align: center; }
.lead { max-width: 760px; margin: 18px auto 0; text-align: center; color: var(--muted); font-size: 19px; }
.more, .models, .privacy, .start, .faq { max-width: 1200px; margin: 160px auto; }

/* "And there's more": a bento grid of glass cards. */
.bento {
  list-style: none;
  padding: 0;
  margin: 48px 0 0;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px;
  backdrop-filter: blur(20px);
  transition: transform 0.35s var(--ease), box-shadow 0.35s var(--ease);
}
.card:hover { transform: translateY(-4px); box-shadow: 0 24px 50px -24px rgba(0, 0, 0, 0.3); }
.card.wide { grid-column: span 2; }
.card.full { grid-column: 1 / -1; display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 2fr); gap: 32px; align-items: center; }
.card.full .badge-ic, .card.full h3, .card.full p { grid-column: 1; }
.card.full .shot { grid-column: 2; grid-row: 1 / span 3; }
.card h3 { margin: 16px 0 8px; font-size: 20px; letter-spacing: -0.02em; }
.card p { margin: 0; color: var(--muted); font-size: 15.5px; }
.badge-ic {
  display: inline-grid;
  place-items: center;
  width: 44px;
  height: 44px;
  border-radius: 12px;
  color: #fff;
  background: linear-gradient(135deg, var(--accent), var(--accent-3));
  box-shadow: 0 8px 20px -8px var(--glow);
}
.ic { width: 24px; height: 24px; }
@media (max-width: 900px) {
  .bento { grid-template-columns: 1fr; }
  .card.wide { grid-column: auto; }
  .card.full { grid-template-columns: 1fr; }
  .card.full .shot { grid-column: 1; grid-row: auto; margin-top: 12px; }
}

/* Models. */
.model-grid {
  list-style: none;
  padding: 0;
  margin: 48px 0 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 14px;
}
.model {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 22px;
}
.model.rec { border-color: color-mix(in srgb, var(--accent) 55%, transparent); box-shadow: 0 0 0 4px color-mix(in srgb, var(--accent) 12%, transparent); }
.m-head { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.m-head a { color: var(--text); font-weight: 700; font-size: 17px; }
.m-meta { margin-top: 6px; color: var(--muted); font-size: 13px; }
.model p { margin: 12px 0 0; font-size: 15px; }
.pill { font-size: 11px; font-weight: 700; padding: 3px 8px; border-radius: 999px; text-transform: uppercase; letter-spacing: 0.04em; }
.pill.rec { background: color-mix(in srgb, var(--accent) 16%, transparent); color: var(--accent); }
.pill.exp { background: var(--bg-2); color: var(--muted); }
.note { max-width: 860px; margin: 32px auto 0; text-align: center; color: var(--muted); font-size: 15px; }

/* Privacy. */
.checks { list-style: none; padding: 0; margin: 48px auto 0; display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; }
.checks li {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 24px;
  font-size: 17px;
}
.check { flex: none; width: 26px; height: 26px; color: #fff; background: var(--green); border-radius: 50%; padding: 4px; stroke-width: 3; }
@media (max-width: 900px) { .checks { grid-template-columns: 1fr; } }

/* Get started. */
.steps { list-style: none; padding: 0; margin: 48px 0 32px; display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 16px; counter-reset: s; }
.step { background: var(--card); border: 1px solid var(--line); border-radius: 18px; padding: 24px; }
.step p { margin: 14px 0 0; font-size: 15.5px; }
.num {
  display: inline-grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  font-weight: 700;
  color: #fff;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
}
@media (max-width: 1000px) { .steps { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (max-width: 640px) { .steps { grid-template-columns: 1fr; } }

/* FAQ. */
.faq { max-width: 860px; }
.faq details { border-bottom: 1px solid var(--line); padding: 22px 0; }
.faq details:first-of-type { margin-top: 40px; border-top: 1px solid var(--line); }
.faq summary { cursor: pointer; list-style: none; font-size: 20px; font-weight: 650; display: flex; justify-content: space-between; gap: 16px; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; color: var(--muted); font-weight: 400; font-size: 26px; line-height: 1; transition: transform 0.3s var(--ease); }
.faq details[open] summary::after { transform: rotate(45deg); }
.faq details p { color: var(--muted); margin: 12px 0 0; }

/* Last call to action. */
.final {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  max-width: 1200px;
  margin: 160px auto 120px;
  padding: 96px 24px;
  text-align: center;
  border-radius: 32px;
  border: 1px solid var(--line);
  background: var(--card);
}
.final img { margin: 0 auto 20px; border-radius: 20px; }
.final h2 { margin: 0; font-size: clamp(32px, 4.5vw, 56px); letter-spacing: -0.035em; line-height: 1.05; }
.final > p:not(.req) { color: var(--muted); font-size: 19px; margin: 14px 0 30px; }

/* Footer. */
footer { border-top: 1px solid var(--line); padding: 40px max(24px, calc(50% - 560px)) 56px; color: var(--muted); font-size: 13px; }
.foot { display: flex; justify-content: space-between; align-items: center; gap: 20px; flex-wrap: wrap; margin-bottom: 18px; }
.foot nav { display: flex; gap: 22px; }
.foot nav a { color: var(--muted); }
footer p { max-width: 900px; margin: 8px 0; }
.copy { margin-top: 18px; }

/* Entrances (only when the script runs, and not for reduced motion). */
.js .reveal { opacity: 0; transform: translateY(28px); transition: opacity 0.9s var(--ease), transform 0.9s var(--ease); }
.js .reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .js .reveal { opacity: 1; transform: none; transition: none; }
  .aurora span { animation: none; }
  html { scroll-behavior: auto; }
}

/* Chinese, Japanese and Korean set looser than Latin display type. */
html:is(:lang(zh-CN), :lang(zh-TW), :lang(ja), :lang(ko)) :is(.slogan, .intro p, h2, h3, .final h2) { letter-spacing: -0.005em; }
html:is(:lang(zh-CN), :lang(zh-TW), :lang(ja)) .feature h2 { line-height: 1.18; }
html:is(:lang(ja), :lang(ko)) .eyebrow { letter-spacing: 0.04em; }

/* Language button and its menu. */
.langs { position: relative; }
.lang-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  height: 32px;
  padding: 0 10px 0 9px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--card);
  color: var(--text);
  font: 500 13px var(--font);
  cursor: pointer;
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  transition: border-color 0.2s, box-shadow 0.25s var(--ease), background 0.2s;
}
.lang-btn:hover { border-color: color-mix(in srgb, var(--accent) 45%, var(--line)); }
.lang-btn:focus-visible { outline: none; box-shadow: 0 0 0 4px color-mix(in srgb, var(--accent) 25%, transparent); }
.lang-btn[aria-expanded="true"] {
  border-color: color-mix(in srgb, var(--accent) 60%, transparent);
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--accent) 16%, transparent);
}
.globe { width: 16px; height: 16px; color: var(--accent); }
.chev { width: 12px; height: 12px; color: var(--muted); transition: transform 0.35s var(--ease); }
.lang-btn[aria-expanded="true"] .chev { transform: rotate(180deg); }
.lang-menu {
  position: absolute;
  top: calc(100% + 10px);
  right: 0;
  z-index: 60;
  min-width: 248px;
  margin: 0;
  padding: 6px;
  list-style: none;
  border-radius: 18px;
  /* Nearly opaque: inside the blurred bar, its own blur would not reach the page. */
  background: color-mix(in srgb, var(--card-solid) 97%, transparent);
  border: 1px solid var(--line);
  box-shadow: 0 28px 70px -24px rgba(0, 0, 0, 0.4), 0 10px 24px -12px rgba(0, 0, 0, 0.22);
  transform-origin: top right;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transform: translateY(-10px) scale(0.94);
  transition: opacity 0.2s var(--ease), transform 0.38s cubic-bezier(0.2, 0.9, 0.25, 1.15), visibility 0s linear 0.38s;
}
.langs.open .lang-menu {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
  transform: none;
  transition: opacity 0.2s var(--ease), transform 0.38s cubic-bezier(0.2, 0.9, 0.25, 1.15), visibility 0s;
}
.lang-menu a {
  --d: 0ms;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto 16px;
  align-items: center;
  gap: 14px;
  padding: 9px 12px;
  border-radius: 11px;
  color: var(--text);
  font-family: var(--font);
  font-size: 15px;
  opacity: 0;
  transform: translateY(-6px);
  transition: background 0.15s, opacity 0.3s var(--ease) var(--d), transform 0.35s var(--ease) var(--d);
}
.langs.open .lang-menu a { --d: calc(var(--i) * 24ms + 50ms); opacity: 1; transform: none; }
.lang-menu a:hover, .lang-menu a:focus-visible {
  background: color-mix(in srgb, var(--accent) 12%, transparent);
  text-decoration: none;
  outline: none;
}
.lang-menu .en { color: var(--muted); font-size: 12px; }
.lang-menu .tick { width: 16px; height: 16px; color: var(--accent); opacity: 0; transform: scale(0.6); transition: opacity 0.2s, transform 0.3s var(--ease); }
.lang-menu a[aria-checked="true"] { font-weight: 600; background: color-mix(in srgb, var(--accent) 7%, transparent); }
.lang-menu a[aria-checked="true"] .tick { opacity: 1; transform: none; }
@media (max-width: 760px) { .lang-btn .cur { display: none; } .lang-menu { right: -64px; } }

/* Leaving for another language: the page fades before the next one loads. */
main, footer { transition: opacity 0.22s var(--ease), transform 0.22s var(--ease); }
.leaving main, .leaving footer { opacity: 0; transform: translateY(8px); }
@media (prefers-reduced-motion: reduce) {
  .lang-menu, .lang-menu a, .chev { transition: none; }
}