/* luckgram.cc — the look of the feature videos: black, the chat-bubble blue, the violet of the phone rim. */
@font-face { font-family: Sora; font-weight: 600; font-display: swap; src: url(fonts/sora-latin-600-normal.woff2) format("woff2"); }
@font-face { font-family: Sora; font-weight: 700; font-display: swap; src: url(fonts/sora-latin-700-normal.woff2) format("woff2"); }
@font-face { font-family: Sora; font-weight: 800; font-display: swap; src: url(fonts/sora-latin-800-normal.woff2) format("woff2"); }
@font-face { font-family: Inter; font-weight: 400; font-display: swap; src: url(fonts/inter-latin-400-normal.woff2) format("woff2"); }
@font-face { font-family: Inter; font-weight: 500; font-display: swap; src: url(fonts/inter-latin-500-normal.woff2) format("woff2"); }
@font-face { font-family: Inter; font-weight: 600; font-display: swap; src: url(fonts/inter-latin-600-normal.woff2) format("woff2"); }

:root {
  --void: #000;
  --raise: rgba(255, 255, 255, .035);
  --line: rgba(255, 255, 255, .11);
  --line-soft: rgba(255, 255, 255, .06);
  --ink: #f2f3f8;
  --muted: #9095a8;
  --blue: #4f8ff9;
  --violet: #b44cff;
  --live: #34c759;
  --wip: #f5b94a;
  --max: 1200px;
  --cjk: "PingFang SC", "HarmonyOS Sans SC", "MiSans", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", "Source Han Sans SC";
  --display: Sora, Inter, var(--cjk), system-ui, sans-serif;
  --body: Inter, var(--cjk), system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  color-scheme: dark;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; background: var(--void); }
body { margin: 0; background: var(--void); color: var(--ink); font: 16px/1.65 var(--body); -webkit-font-smoothing: antialiased; }
a { color: inherit; }
img, video { max-width: 100%; height: auto; display: block; }
:focus-visible { outline: 2px solid var(--blue); outline-offset: 3px; border-radius: 4px; }
.wrap { max-width: var(--max); margin: 0 auto; padding: 0 24px; }
h1, h2, h3 { font-family: var(--display); font-weight: 700; letter-spacing: -.02em; line-height: 1.12; margin: 0; }
h2 { font-size: clamp(30px, 4.2vw, 48px); }
h3 { font-size: 19px; letter-spacing: -.01em; line-height: 1.3; }
p { margin: 0; }
html[lang="zh-CN"] h1, html[lang="zh-CN"] h2, html[lang="zh-CN"] h3 { letter-spacing: 0; font-weight: 700; }

/* Header */
.site-header { position: sticky; top: 0; z-index: 20; background: rgba(0, 0, 0, .72); backdrop-filter: saturate(1.5) blur(14px); -webkit-backdrop-filter: saturate(1.5) blur(14px); border-bottom: 1px solid var(--line-soft); }
.site-header .wrap { display: flex; align-items: center; justify-content: space-between; gap: 16px; height: 64px; }
.logo { display: flex; align-items: center; gap: 10px; font: 700 19px/1 var(--display); letter-spacing: -.02em; text-decoration: none; flex-shrink: 0; }
.logo img { width: 30px; height: 25px; object-fit: contain; filter: drop-shadow(0 0 8px rgba(140, 160, 255, .55)); }
.nav { display: flex; align-items: center; gap: 26px; font-size: 15px; }
.nav a { text-decoration: none; color: var(--muted); transition: color .15s; }
.nav a:hover, .nav a[aria-current] { color: var(--ink); }
.nav a.lang { padding: 3px 11px; border: 1px solid var(--line); border-radius: 999px; font-size: 13px; font-weight: 600; white-space: nowrap; color: var(--ink); }
.nav a.get { padding: 7px 16px; border-radius: 999px; background: var(--ink); color: #000; font-weight: 600; }
@media (max-width: 760px) { .nav a.opt { display: none; } .nav { gap: 16px; } }
@media (max-width: 420px) { .nav { gap: 13px; font-size: 14px; } .nav a.get { display: none; } }

/* Buttons */
.btns { display: flex; flex-wrap: wrap; gap: 12px; }
.btn { display: inline-flex; align-items: center; gap: 10px; padding: 13px 22px; border-radius: 14px; font: 600 15px/1.2 var(--body); text-decoration: none; border: 1px solid var(--line); background: var(--raise); transition: border-color .15s, background .15s; }
.btn:hover { border-color: rgba(255, 255, 255, .3); background: rgba(255, 255, 255, .07); }
.btn.primary { background: var(--ink); color: #000; border-color: var(--ink); }
.btn.primary:hover { background: #fff; }
.btn svg { width: 20px; height: 20px; flex-shrink: 0; }
.btn small { display: block; font-size: 12px; font-weight: 500; opacity: .62; margin-bottom: 2px; }
.btn.platform { padding: 11px 22px 11px 18px; }

/* Status pills */
.tag { display: inline-flex; align-items: center; gap: 7px; font-size: 13px; font-weight: 600; color: var(--muted); }
.tag::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: currentColor; }
.tag.ok { color: var(--live); }
.tag.part { color: var(--blue); }
.tag.wip { color: var(--wip); }

/* Hero */
.hero { position: relative; overflow: hidden; border-bottom: 1px solid var(--line-soft); }
.hero::before { content: ""; position: absolute; inset: -20% -10% auto auto; width: 70%; height: 140%; background: radial-gradient(closest-side, rgba(79, 143, 249, .28), transparent 70%), radial-gradient(closest-side at 30% 75%, rgba(180, 76, 255, .26), transparent 70%); pointer-events: none; }
.hero .wrap { position: relative; display: grid; grid-template-columns: 1.05fr .95fr; gap: 56px; align-items: center; padding-top: 88px; padding-bottom: 96px; }
.hero h1 { font-size: clamp(44px, 6.6vw, 84px); font-weight: 800; line-height: 1.02; letter-spacing: -.035em; }
html[lang="zh-CN"] .hero h1 { font-size: clamp(42px, 6vw, 76px); line-height: 1.1; letter-spacing: -.01em; }
.hero .lede { margin-top: 26px; max-width: 34em; font-size: 18px; color: var(--muted); }
.hero .btns { margin-top: 36px; }
.hero .fine { margin-top: 18px; font-size: 14px; color: var(--muted); }
.hero .fine a { color: var(--ink); }
.stage { position: relative; justify-self: center; width: min(100%, 500px); }
.stage video { width: 100%; aspect-ratio: 1; border-radius: 28px; background: #000; box-shadow: 0 0 0 1px rgba(150, 140, 255, .25), 0 30px 120px -20px rgba(91, 80, 255, .55); }
.stage figcaption { margin-top: 14px; display: flex; justify-content: center; font-size: 14px; color: var(--muted); gap: 8px; }
/* The paper plane flies its route once when the page opens. */
.route { position: absolute; left: 0; top: 0; width: 100%; height: 100%; pointer-events: none; overflow: visible; }
.route path { fill: none; stroke: rgba(200, 210, 255, .28); stroke-width: 1.4; stroke-dasharray: 2 9; stroke-linecap: round; }
.plane { position: absolute; left: 0; top: 0; width: 44px; height: 37px; background: url(logo-white-144.png) center/contain no-repeat; filter: drop-shadow(0 0 6px #fff) drop-shadow(0 0 18px rgba(140, 160, 255, .9)); offset-rotate: auto 8deg; offset-distance: 100%; animation: fly 2.6s cubic-bezier(.45, .05, .25, 1) .3s both; }
@keyframes fly { from { offset-distance: 0%; opacity: 0; } 12% { opacity: 1; } to { offset-distance: 100%; opacity: 1; } }
@media (prefers-reduced-motion: reduce) { .plane { animation: none; } }

/* Section scaffolding */
.block { padding: 112px 0; border-bottom: 1px solid var(--line-soft); }
.head { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; align-items: end; margin-bottom: 56px; }
.head p { color: var(--muted); font-size: 17px; max-width: 32em; justify-self: end; }
.head.solo { grid-template-columns: 1fr; }
.head.solo p { justify-self: start; margin-top: 18px; }

/* Works-today list: a ruled table, not cards */
.today { display: grid; grid-template-columns: repeat(3, 1fr); border-top: 1px solid var(--line); }
.today div { padding: 26px 28px 30px 0; border-bottom: 1px solid var(--line); }
.today div:not(:nth-child(3n+1)) { padding-left: 28px; border-left: 1px solid var(--line); }
.today h3 { font-size: 18px; margin: 12px 0 8px; }
.today p { color: var(--muted); font-size: 15px; }

/* Video wall */
.wall { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1px; background: var(--line); border: 1px solid var(--line); border-radius: 24px; overflow: hidden; }
.cell { background: var(--void); padding: 22px 22px 28px; display: flex; flex-direction: column; }
.cell video { width: 100%; aspect-ratio: 1; border-radius: 16px; background: #050508; }
.cell .tag { margin-top: 20px; }
.cell h3 { margin-top: 8px; }
.cell p { margin-top: 8px; color: var(--muted); font-size: 15px; }
.wall-foot { margin-top: 28px; display: flex; justify-content: space-between; align-items: center; gap: 20px; flex-wrap: wrap; color: var(--muted); font-size: 15px; }

/* Open source */
.open { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0; border-top: 1px solid var(--line); }
.open > div { padding: 30px 32px 6px 0; }
.open > div + div { padding-left: 32px; border-left: 1px solid var(--line); }
.open h3 { margin-bottom: 10px; }
.open p { color: var(--muted); font-size: 15px; }
.repos { margin-top: 48px; display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.repo { display: flex; align-items: center; gap: 16px; padding: 22px 24px; border: 1px solid var(--line); border-radius: 18px; text-decoration: none; background: var(--raise); transition: border-color .15s; }
.repo:hover { border-color: rgba(255, 255, 255, .32); }
.repo svg { width: 30px; height: 30px; flex-shrink: 0; }
.repo b { display: block; font: 600 16px/1.3 var(--display); }
.repo span { font-size: 14px; color: var(--muted); }

/* Download band */
.cta { position: relative; overflow: hidden; text-align: center; padding: 128px 0; border-bottom: 1px solid var(--line-soft); }
.cta::before { content: ""; position: absolute; left: 50%; top: 50%; width: 900px; height: 520px; transform: translate(-50%, -50%); background: radial-gradient(closest-side, rgba(110, 90, 255, .38), rgba(79, 143, 249, .12) 55%, transparent 75%); pointer-events: none; }
.cta .wrap { position: relative; }
.cta .mark { width: 96px; height: 80px; margin: 0 auto 34px; background: url(logo-white-144.png) center/contain no-repeat; filter: drop-shadow(0 0 4px #fff) drop-shadow(0 0 22px rgba(150, 165, 255, .95)) drop-shadow(0 0 48px rgba(120, 100, 255, .7)); }
.cta h2 { font-size: clamp(36px, 5.4vw, 64px); font-weight: 800; }
.cta p { margin: 18px auto 0; max-width: 30em; color: var(--muted); font-size: 17px; }
.cta .btns { justify-content: center; margin-top: 38px; }

/* FAQ */
.faq { display: grid; grid-template-columns: 1fr 1.5fr; gap: 56px; align-items: start; }
.faq .head { margin: 0; position: sticky; top: 100px; }
.faq .head p { justify-self: start; margin-top: 18px; }
.qa { border-top: 1px solid var(--line); }
details { border-bottom: 1px solid var(--line); }
summary { cursor: pointer; list-style: none; display: flex; justify-content: space-between; gap: 20px; padding: 22px 0; font-weight: 600; font-size: 17px; }
summary::-webkit-details-marker { display: none; }
summary::after { content: "+"; font: 400 24px/1 var(--display); color: var(--muted); transition: transform .2s; }
details[open] summary::after { transform: rotate(45deg); }
details p { padding: 0 0 24px; color: var(--muted); max-width: 40em; }
details a { color: var(--ink); }

/* Footer */
.site-footer { padding: 72px 0 48px; font-size: 14px; color: var(--muted); }
.site-footer .top { display: grid; grid-template-columns: 1.4fr repeat(4, 1fr); gap: 32px; }
.site-footer .logo { color: var(--ink); margin-bottom: 14px; }
.site-footer h4 { margin: 0 0 14px; color: var(--ink); font-size: 14px; font-weight: 600; }
.site-footer ul { list-style: none; margin: 0; padding: 0; display: grid; gap: 10px; }
.site-footer a { text-decoration: none; }
.site-footer a:hover { color: var(--ink); }
.site-footer .legal { margin-top: 56px; padding-top: 24px; border-top: 1px solid var(--line-soft); display: flex; justify-content: space-between; gap: 24px; flex-wrap: wrap; font-size: 13px; }
.site-footer .legal p { max-width: 60em; }

/* Page heads (features, download) */
.page-head { position: relative; overflow: hidden; padding: 96px 0 72px; text-align: center; border-bottom: 1px solid var(--line-soft); }
.page-head::before { content: ""; position: absolute; left: 50%; top: 0; width: 1000px; height: 420px; transform: translate(-50%, -45%); background: radial-gradient(closest-side, rgba(100, 100, 255, .32), transparent 72%); pointer-events: none; }
.page-head .wrap { position: relative; }
.page-head h1 { font-size: clamp(40px, 6vw, 72px); font-weight: 800; letter-spacing: -.03em; }
.page-head p { margin: 22px auto 0; max-width: 40em; color: var(--muted); font-size: 17px; }

/* Features page */
.feat-layout { display: grid; grid-template-columns: 220px 1fr; gap: 56px; align-items: start; padding-top: 56px; padding-bottom: 40px; }
.feat-toc { position: sticky; top: 88px; max-height: calc(100vh - 110px); overflow: auto; font-size: 14.5px; }
.feat-toc ul { list-style: none; margin: 0; padding: 0; }
.feat-toc li a { display: block; padding: 5px 0 5px 14px; text-decoration: none; color: var(--muted); border-left: 1px solid var(--line); }
.feat-toc li a:hover, .feat-toc li a.on { color: var(--ink); border-left-color: var(--blue); }
.feat-toc .toc-group { margin: 22px 0 8px; font-size: 13px; font-weight: 600; color: var(--ink); }
.feat-toc .toc-group:first-child { margin-top: 0; }
.feat { display: grid; grid-template-columns: minmax(0, 420px) 1fr; gap: 44px; align-items: center; padding: 44px 0; border-bottom: 1px solid var(--line-soft); scroll-margin-top: 80px; }
.feat:first-child { padding-top: 0; }
.feat-video { width: 100%; aspect-ratio: 1; border-radius: 22px; background: #050508; box-shadow: 0 0 0 1px rgba(150, 140, 255, .18), 0 24px 80px -30px rgba(91, 80, 255, .55); }
.feat h2 { margin-top: 12px; font-size: clamp(24px, 2.6vw, 32px); }
.feat-text > p { margin-top: 14px; color: var(--muted); font-size: 16px; max-width: 34em; }
.feat-more { margin-top: 18px !important; font-size: 15px !important; }
.feat-more a { color: var(--ink); text-decoration-color: var(--line); text-underline-offset: 4px; }
.feat-more a:hover { text-decoration-color: var(--ink); }

/* Download page */
.dl { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; padding: 64px 0 24px; }
.dl-card { position: relative; overflow: hidden; padding: 36px; border: 1px solid var(--line); border-radius: 24px; background: var(--raise); }
.dl-card svg.os { width: 40px; height: 40px; margin-bottom: 22px; }
.dl-card h2 { font-size: 30px; }
.dl-card ul { margin: 20px 0 30px; padding-left: 18px; color: var(--muted); }
.dl-card li + li { margin-top: 6px; }
.note { color: var(--muted); font-size: 14.5px; max-width: 52em; padding-bottom: 96px; }

/* Long text pages */
.prose { max-width: 720px; margin: 0 auto; padding: 88px 24px 112px; }
.prose h1 { font-size: clamp(36px, 5vw, 52px); font-weight: 800; }
.prose .meta { margin-top: 12px; color: var(--muted); }
.prose h2 { font-size: 22px; margin: 44px 0 12px; }
.prose p { margin: 0 0 14px; color: #c9ccd8; }
.prose a { color: var(--ink); text-underline-offset: 3px; }
.prose .note { padding: 0; margin-top: 32px; }

/* Responsive */
@media (max-width: 980px) {
  .hero .wrap { grid-template-columns: 1fr; gap: 48px; padding-top: 56px; padding-bottom: 72px; }
  .stage { width: min(100%, 440px); }
  .head { grid-template-columns: 1fr; gap: 16px; }
  .head p { justify-self: start; }
  .wall { grid-template-columns: 1fr 1fr; }
  .today { grid-template-columns: 1fr 1fr; }
  .today div, .today div:not(:nth-child(3n+1)) { padding: 24px 24px 26px 0; border-left: 0; }
  .today div:nth-child(2n) { padding-left: 24px; border-left: 1px solid var(--line); }
  .faq { grid-template-columns: 1fr; gap: 32px; }
  .faq .head { position: static; }
  .site-footer .top { grid-template-columns: 1fr 1fr; }
  .feat-layout { grid-template-columns: 1fr; gap: 0; padding-top: 0; }
  .feat-toc { position: sticky; top: 64px; z-index: 5; max-height: none; margin: 0 -24px; padding: 12px 24px; background: rgba(0, 0, 0, .85); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px); border-bottom: 1px solid var(--line-soft); overflow-x: auto; scrollbar-width: none; }
  .feat-toc ul { display: flex; gap: 8px; width: max-content; }
  .feat-toc .toc-group { display: none; }
  .feat-toc li a { padding: 6px 14px; border: 1px solid var(--line); border-radius: 999px; white-space: nowrap; }
  .feat-toc li a.on { border-color: var(--blue); }
  .feat { grid-template-columns: 1fr; gap: 24px; padding: 40px 0; }
  .feat:first-child { padding-top: 32px; }
}
@media (max-width: 640px) {
  .wrap { padding: 0 18px; }
  .block { padding: 80px 0; }
  .head { margin-bottom: 36px; }
  .wall { grid-template-columns: 1fr; border-radius: 20px; }
  .today { grid-template-columns: 1fr; }
  .today div, .today div:nth-child(2n) { padding: 22px 0; border-left: 0; }
  .open, .repos, .dl { grid-template-columns: 1fr; }
  .open > div + div { padding-left: 0; border-left: 0; border-top: 1px solid var(--line); }
  .open > div { padding: 26px 0; }
  .dl-card { padding: 28px 24px; }
  .cta { padding: 96px 0; }
  .site-footer .top { grid-template-columns: 1fr; }
  .feat-toc { margin: 0 -18px; padding: 12px 18px; }
}