:root {
  --navy: #0f172a;
  --navy-mid: #1b2b4a;
  --ink: #0f172a;
  --ink-soft: #2a3550;
  --mist: #5b6478;
  --paper: #f4f6fb;
  --foam: #eef1f8;
  --cyan: #22d3ee;
  --purple: #8b5cf6;
  --amber: #ffc554;
  --orange: #ff7a45;
  --ok: #0f766e;
  --no: #b45309;
  --line: rgba(15, 23, 42, 0.1);
  --max: 1120px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
#top,
#features,
#requirements,
#download,
#faq,
.section {
  scroll-margin-top: 5.2rem;
}
body {
  margin: 0;
  color: var(--ink);
  font-family: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--paper);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
img, svg { display: block; max-width: 100%; }

.skip-link {
  position: absolute;
  left: 1rem;
  top: -4rem;
  z-index: 80;
  padding: 0.55rem 0.9rem;
  background: #fff;
  color: var(--ink);
  border-radius: 8px;
}
.skip-link:focus { top: 0.75rem; }

.site-nav {
  position: sticky;
  top: 0;
  z-index: 40;
  backdrop-filter: blur(16px);
  background: var(--navy);
  border-bottom: 1px solid transparent;
  transition: background 0.3s var(--ease), border-color 0.3s var(--ease);
}
.site-nav.is-scrolled {
  background: rgba(244, 246, 251, 0.92);
  border-bottom-color: var(--line);
}
.nav-inner {
  width: min(var(--max), calc(100% - 2.5rem));
  margin: 0 auto;
  height: 4.15rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
}
.nav-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  font-family: "Noto Serif SC", "Songti SC", serif;
  font-weight: 700;
  font-size: 1.12rem;
  letter-spacing: 0.06em;
  color: #f8fafc;
  transition: color 0.25s ease;
}
.site-nav.is-scrolled .nav-brand { color: var(--ink); }
.nav-brand img {
  width: 36px;
  height: 36px;
  border-radius: 9px;
}
.nav-links {
  display: flex;
  align-items: center;
  gap: 1.75rem;
  font-size: 0.9rem;
  color: rgba(248, 250, 252, 0.78);
}
.site-nav.is-scrolled .nav-links { color: var(--ink-soft); }
.nav-links a {
  position: relative;
  transition: color 0.2s ease;
}
.nav-links a:hover { color: var(--cyan); }
.site-nav.is-scrolled .nav-links a:hover { color: var(--purple); }
.nav-links a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -4px;
  width: 100%;
  height: 1.5px;
  background: var(--cyan);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.28s var(--ease);
}
.site-nav.is-scrolled .nav-links a::after { background: var(--purple); }
.nav-links a:hover::after { transform: scaleX(1); }
.nav-cta {
  display: inline-flex;
  align-items: center;
  padding: 0.45rem 1rem;
  background: linear-gradient(135deg, var(--amber) 0%, var(--orange) 100%);
  color: var(--navy) !important;
  font-size: 0.85rem;
  font-weight: 600;
  border-radius: 999px;
  transition: transform 0.2s var(--ease), filter 0.2s ease;
}
.nav-cta:hover {
  transform: translateY(-1px);
  filter: brightness(1.06);
}
.nav-cta::after { display: none !important; }

.hero {
  position: relative;
  min-height: min(92vh, 860px);
  display: flex;
  align-items: center;
  overflow: hidden;
  color: #f8fafc;
  isolation: isolate;
  background: var(--navy);
}
.hero-bg {
  position: absolute;
  inset: 0;
  z-index: -2;
  background:
    radial-gradient(ellipse 55% 50% at 78% 38%, rgba(139, 92, 246, 0.28) 0%, transparent 62%),
    radial-gradient(ellipse 45% 55% at 12% 82%, rgba(34, 211, 238, 0.16) 0%, transparent 55%),
    radial-gradient(ellipse 30% 30% at 42% 18%, rgba(255, 197, 84, 0.1) 0%, transparent 60%),
    linear-gradient(160deg, #0b1220 0%, #0f172a 42%, #16233f 100%);
}
.hero-arcs {
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  overflow: hidden;
}
.hero-arcs svg {
  position: absolute;
  right: -8%;
  top: 50%;
  width: min(780px, 72vw);
  height: min(780px, 72vw);
  transform: translateY(-50%);
  opacity: 0.55;
}
.hero-arcs .orbit {
  animation: orbit-spin 28s linear infinite;
  transform-origin: 400px 400px;
}
.hero-arcs .orbit.slow {
  animation-duration: 42s;
  animation-direction: reverse;
}
@keyframes orbit-spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}
@keyframes rise {
  from { opacity: 0; transform: translateY(28px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes float-shot {
  from { transform: translateY(0); }
  to { transform: translateY(-8px); }
}
@keyframes float-shot-a {
  from { transform: rotate(-9deg) translateY(0); }
  to { transform: rotate(-9deg) translateY(-8px); }
}
@keyframes float-shot-b {
  from { transform: rotate(7deg) translateY(0); }
  to { transform: rotate(7deg) translateY(-8px); }
}
.hero-inner {
  width: min(var(--max), calc(100% - 2.5rem));
  margin: 0 auto;
  padding: 7.5rem 0 5rem;
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 3rem;
  align-items: center;
}
.hero-kicker {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  margin: 0 0 1.1rem;
  padding: 0.28rem 0.7rem 0.28rem 0.28rem;
  border: 1px solid rgba(34, 211, 238, 0.28);
  border-radius: 999px;
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  color: rgba(248, 250, 252, 0.78);
  background: rgba(34, 211, 238, 0.08);
  opacity: 0;
  animation: rise 0.9s 0.1s var(--ease) forwards;
}
.hero-kicker img {
  width: 22px;
  height: 22px;
  border-radius: 6px;
}
.hero-brand {
  font-family: "Noto Serif SC", "Songti SC", serif;
  font-size: clamp(2.8rem, 7vw, 4.8rem);
  font-weight: 700;
  line-height: 1.08;
  letter-spacing: 0.08em;
  margin: 0 0 1.1rem;
  opacity: 0;
  animation: rise 0.9s 0.22s var(--ease) forwards;
}
.hero-lead {
  max-width: 30rem;
  margin: 0 0 2rem;
  font-size: clamp(1.05rem, 2.2vw, 1.22rem);
  color: rgba(248, 250, 252, 0.78);
  line-height: 1.7;
  opacity: 0;
  animation: rise 0.9s 0.4s var(--ease) forwards;
}
.hero-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.85rem 1.25rem;
  opacity: 0;
  animation: rise 0.9s 0.55s var(--ease) forwards;
}
.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.9rem 1.7rem;
  background: linear-gradient(135deg, var(--amber) 0%, var(--orange) 100%);
  color: var(--navy);
  font-size: 1rem;
  font-weight: 700;
  border-radius: 999px;
  border: none;
  cursor: pointer;
  transition: transform 0.25s var(--ease), filter 0.2s ease, box-shadow 0.25s var(--ease);
}
.btn-primary:hover {
  transform: translateY(-2px);
  filter: brightness(1.05);
  box-shadow: 0 14px 32px rgba(255, 122, 69, 0.28);
}
.btn-primary.disabled {
  background: rgba(248, 250, 252, 0.18);
  color: rgba(248, 250, 252, 0.5);
  pointer-events: none;
  box-shadow: none;
}
.btn-ghost {
  display: inline-flex;
  align-items: center;
  padding: 0.85rem 0.4rem;
  color: rgba(248, 250, 252, 0.78);
  font-size: 0.95rem;
  font-weight: 500;
  border-bottom: 1px solid rgba(34, 211, 238, 0.4);
  transition: color 0.2s ease, border-color 0.2s ease;
}
.btn-ghost:hover {
  color: #fff;
  border-bottom-color: var(--cyan);
}
.hero-meta {
  margin-top: 1.15rem;
  font-size: 0.85rem;
  color: rgba(248, 250, 252, 0.5);
  opacity: 0;
  animation: rise 0.9s 0.7s var(--ease) forwards;
}

.hero-stage {
  position: relative;
  min-height: 420px;
  opacity: 0;
  animation: rise 1s 0.35s var(--ease) forwards;
}
.shot {
  position: absolute;
  border-radius: 18px;
  border: 1px solid rgba(255, 255, 255, 0.12);
  background: linear-gradient(180deg, rgba(27, 43, 74, 0.88) 0%, rgba(15, 23, 42, 0.92) 100%);
  box-shadow: 0 24px 50px rgba(0, 0, 0, 0.28);
  overflow: hidden;
}
.shot-chrome {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 0.7rem 0.9rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}
.shot-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: rgba(248, 250, 252, 0.22);
}
.shot-dot:first-child { background: #ff7a45; }
.shot-dot:nth-child(2) { background: #ffc554; }
.shot-dot:nth-child(3) { background: #22d3ee; }
.shot-label {
  margin-left: 0.4rem;
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  color: rgba(248, 250, 252, 0.45);
}
.shot-a {
  width: 58%;
  height: 58%;
  left: 0;
  top: 18%;
  animation: float-shot-a 4.2s ease-in-out infinite alternate;
}
.shot-b {
  width: 54%;
  height: 52%;
  right: 0;
  top: 8%;
  animation: float-shot-b 5s 0.4s ease-in-out infinite alternate;
}
.shot-c {
  width: 62%;
  height: 68%;
  left: 18%;
  top: 22%;
  z-index: 2;
  border-color: rgba(139, 92, 246, 0.45);
  animation: float-shot 4.6s 0.2s ease-in-out infinite alternate;
}
.shot-body {
  display: flex;
  align-items: center;
  justify-content: center;
  height: calc(100% - 2.2rem);
}
.shot-c .shot-body img {
  width: min(168px, 58%);
  height: auto;
  border-radius: 28%;
  filter: drop-shadow(0 12px 28px rgba(139, 92, 246, 0.35));
}
.shot-fill {
  width: 78%;
  height: 54%;
  border-radius: 10px;
  background:
    linear-gradient(135deg, rgba(34, 211, 238, 0.18), rgba(139, 92, 246, 0.12) 55%, transparent),
    repeating-linear-gradient(90deg, rgba(248, 250, 252, 0.04) 0 12px, transparent 12px 28px);
}

.section {
  width: min(var(--max), calc(100% - 2.5rem));
  margin: 0 auto;
  padding: 5.5rem 0;
}
.section-label {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--purple);
  margin: 0 0 0.75rem;
}
.section-title {
  font-family: "Noto Serif SC", "Songti SC", serif;
  font-size: clamp(1.65rem, 3.5vw, 2.2rem);
  font-weight: 700;
  line-height: 1.25;
  margin: 0 0 0.85rem;
  color: var(--ink);
}
.section-desc {
  max-width: 38rem;
  margin: 0 0 3rem;
  color: var(--mist);
  font-size: 1.02rem;
}

.features {
  background: linear-gradient(180deg, var(--foam) 0%, var(--paper) 100%);
  border-top: 1px solid var(--line);
}
.feature-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
}
.feature-item,
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease), border-color 0.2s ease;
}
.feature-item.is-visible,
.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}
.feature-item {
  padding: 1.6rem 1.55rem 1.5rem;
  border-radius: 16px;
  background: #fff;
  border: 1px solid var(--line);
  box-shadow: 0 10px 28px rgba(15, 23, 42, 0.04);
}
.feature-item:hover {
  border-color: rgba(139, 92, 246, 0.28);
}
.feature-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 2.1rem;
  padding: 0.12rem 0.45rem;
  margin-bottom: 0.7rem;
  border: 1px solid rgba(139, 92, 246, 0.28);
  border-radius: 6px;
  font-family: "Noto Serif SC", serif;
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  color: var(--purple);
  background: rgba(139, 92, 246, 0.06);
}
.feature-item h3 {
  margin: 0 0 0.5rem;
  font-size: 1.12rem;
  font-weight: 600;
}
.feature-item p {
  margin: 0;
  color: var(--mist);
  font-size: 0.95rem;
  line-height: 1.7;
}

.req-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.1rem;
  margin-bottom: 1.75rem;
}
.req-card {
  padding: 1.4rem 1.3rem 1.3rem;
  border-radius: 16px;
  background: #fff;
  border: 1px solid var(--line);
}
.req-kicker {
  margin: 0 0 0.55rem;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.12em;
}
.req-card h3 {
  margin: 0 0 0.45rem;
  font-size: 1.08rem;
}
.req-card p {
  margin: 0;
  color: var(--mist);
  font-size: 0.92rem;
  line-height: 1.65;
}
.req-ok {
  border-color: rgba(15, 118, 110, 0.28);
  background: linear-gradient(180deg, rgba(15, 118, 110, 0.06), #fff 42%);
}
.req-ok .req-kicker { color: var(--ok); }
.req-no {
  border-color: rgba(180, 83, 9, 0.22);
  background: linear-gradient(180deg, rgba(180, 83, 9, 0.05), #fff 42%);
}
.req-no .req-kicker { color: var(--no); }
.req-list {
  margin: 0;
  padding: 1.25rem 1.4rem;
  border-radius: 14px;
  background: var(--foam);
  color: var(--ink-soft);
  font-size: 0.95rem;
  line-height: 1.85;
}
.req-list li + li { margin-top: 0.2rem; }

.download-wrap {
  border-radius: 24px;
  padding: 2.4rem 2.2rem;
  background:
    radial-gradient(ellipse 70% 80% at 90% 10%, rgba(139, 92, 246, 0.22) 0%, transparent 55%),
    radial-gradient(ellipse 50% 60% at 8% 90%, rgba(34, 211, 238, 0.12) 0%, transparent 50%),
    linear-gradient(160deg, #0f172a 0%, #1b2b4a 100%);
  color: #f8fafc;
}
.download-wrap .section-label { color: var(--cyan); }
.download-wrap .section-title { color: #f8fafc; }
.download-wrap .section-desc {
  color: rgba(248, 250, 252, 0.68);
  margin-bottom: 2rem;
}
.download-panel {
  display: grid;
  grid-template-columns: 1.15fr 1fr;
  gap: 2.5rem;
  align-items: end;
}
.download-version {
  font-family: "Noto Serif SC", serif;
  font-size: 2.5rem;
  font-weight: 700;
  margin: 0 0 0.35rem;
  line-height: 1.1;
}
.download-meta {
  margin: 0 0 1.4rem;
  color: rgba(248, 250, 252, 0.62);
  font-size: 0.95rem;
}
.download-wrap .btn-primary {
  background: linear-gradient(135deg, var(--amber) 0%, var(--orange) 100%);
  color: var(--navy);
}
.install-steps {
  margin: 0;
  padding: 0 0 0 1.15rem;
  color: rgba(248, 250, 252, 0.72);
  font-size: 0.92rem;
  line-height: 1.85;
}
.install-steps li + li { margin-top: 0.35rem; }
.install-steps strong { color: #fff; font-weight: 600; }
.empty-state {
  color: rgba(248, 250, 252, 0.62);
  margin: 0 0 1rem;
}

.faq-list {
  display: grid;
  gap: 0.75rem;
}
.faq-item {
  border: 1px solid var(--line);
  border-radius: 14px;
  background: #fff;
  padding: 0 1.2rem;
}
.faq-item summary {
  cursor: pointer;
  list-style: none;
  padding: 1.05rem 1.6rem 1.05rem 0;
  font-weight: 600;
  position: relative;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+";
  position: absolute;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
  color: var(--purple);
  font-size: 1.2rem;
  font-weight: 500;
}
.faq-item[open] summary::after { content: "–"; }
.faq-item p {
  margin: 0 0 1.1rem;
  color: var(--mist);
  font-size: 0.95rem;
  line-height: 1.75;
}

.site-footer {
  background: var(--paper);
  border-top: 1px solid var(--line);
}
.footer-inner {
  width: min(var(--max), calc(100% - 2.5rem));
  margin: 0 auto;
  padding: 2.1rem 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  font-size: 0.85rem;
  color: var(--mist);
}
.footer-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: "Noto Serif SC", serif;
  font-weight: 600;
  color: var(--ink-soft);
}
.footer-brand img {
  width: 22px;
  height: 22px;
  border-radius: 6px;
}

@media (max-width: 860px) {
  .nav-inner {
    height: auto;
    min-height: 4.15rem;
    padding: 0.7rem 0;
    flex-wrap: wrap;
  }
  .nav-links {
    flex-wrap: wrap;
    justify-content: flex-end;
    gap: 0.65rem 1rem;
  }
  .hero {
    min-height: auto;
  }
  .hero-inner {
    grid-template-columns: 1fr;
    padding: 5.5rem 0 3rem;
    gap: 1.6rem;
  }
  .hero-stage {
    min-height: auto;
    max-width: 280px;
    margin: 0 auto;
    width: 100%;
    display: flex;
    justify-content: center;
  }
  .shot-a,
  .shot-b { display: none; }
  .shot-c {
    position: relative;
    left: auto;
    top: auto;
    width: 100%;
    height: 280px;
    animation: none;
  }
  .feature-grid,
  .req-grid,
  .download-panel {
    grid-template-columns: 1fr;
  }
  .download-wrap { padding: 1.7rem 1.25rem; }
  .section { padding: 4rem 0; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  .feature-item,
  .reveal {
    opacity: 1;
    transform: none;
  }
}