:root {
  --paper: #f4f1e9;
  --paper-soft: #ebe5d8;
  --ink: #20211e;
  --muted: #6b6b63;
  --line: rgba(32, 33, 30, 0.2);
  --red: #e2482e;
  --white: #fffdf8;
  --shadow: 0 25px 70px rgba(44, 42, 35, 0.13);
  --maxw: 1180px;
}

html[data-theme="dark"] {
  --paper: #171816;
  --paper-soft: #22231f;
  --ink: #f0eee7;
  --muted: #aaa99f;
  --line: rgba(240, 238, 231, 0.2);
  --white: #22231f;
  --shadow: 0 25px 70px rgba(0, 0, 0, 0.3);
}

* { box-sizing: border-box; }
html { overflow-x: clip; scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: "PingFang SC", "Noto Sans CJK SC", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  transition: color .3s ease, background-color .3s ease;
  overflow-x: clip;
}
img { display: block; max-width: 100%; height: auto; }
a { color: inherit; text-decoration: none; }
button { color: inherit; font: inherit; }
h1, h2, h3, p { margin-top: 0; }

.container { width: min(var(--maxw), 90vw); margin-inline: auto; }
.skip-link { position: fixed; z-index: 100; top: 1rem; left: 1rem; padding: .65rem 1rem; color: var(--paper); background: var(--ink); transform: translateY(-200%); }
.skip-link:focus { transform: none; }

.site-header {
  position: fixed;
  z-index: 50;
  inset: 0 0 auto;
  height: 78px;
  border-bottom: 1px solid transparent;
  transition: background .3s ease, border-color .3s ease, backdrop-filter .3s ease;
}
.site-header.is-scrolled { background: color-mix(in srgb, var(--paper) 87%, transparent); border-color: var(--line); backdrop-filter: blur(14px); }
.header-inner { position: relative; display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; height: 100%; }
.brand { display: inline-flex; align-items: center; gap: .65rem; width: fit-content; font-size: .88rem; font-weight: 700; letter-spacing: .08em; }
.brand-mark { display: block; width: 30px; height: 30px; flex: 0 0 auto; border: none; border-radius: 50%; background: transparent; box-shadow: none; object-fit: cover; }
.site-nav { display: flex; gap: 2.2rem; font-size: .78rem; letter-spacing: .08em; }
.site-nav a { position: relative; }
.site-nav a::after { position: absolute; right: 0; bottom: -.4rem; left: 0; height: 1px; background: var(--red); content: ""; transform: scaleX(0); transform-origin: right; transition: transform .25s ease; }
.site-nav a:hover::after, .site-nav a:focus-visible::after { transform: scaleX(1); transform-origin: left; }
.header-actions { display: flex; justify-content: flex-end; align-items: center; gap: .6rem; }
.theme-toggle, .menu-toggle { padding: .55rem .8rem; border: 1px solid var(--line); border-radius: 100px; background: transparent; font-size: .68rem; letter-spacing: .1em; cursor: pointer; }
.theme-toggle:hover, .menu-toggle:hover { color: var(--paper); background: var(--ink); }
.menu-toggle { display: none; }
.mobile-nav { position: absolute; top: 77px; right: -5vw; left: -5vw; padding: 1.5rem 5vw 2rem; border-bottom: 1px solid var(--line); background: var(--paper); box-shadow: var(--shadow); }
.mobile-nav a { display: block; padding: .65rem 0; font-family: "Songti SC", SimSun, Georgia, serif; font-size: 1.35rem; }

.btn { display: inline-flex; align-items: center; justify-content: center; min-height: 48px; padding: .75rem 1.3rem; border: 1px solid var(--ink); border-radius: 100px; font-size: .76rem; font-weight: 700; letter-spacing: .06em; transition: transform .25s ease, color .25s ease, background .25s ease; }
.btn:hover { color: var(--paper); background: var(--ink); transform: translateY(-2px); }
.btn-small { min-height: 38px; padding: .5rem 1rem; color: var(--paper); background: var(--ink); }
.btn-small:hover { color: var(--paper); background: var(--red); border-color: var(--red); }
.btn-ghost { color: var(--ink); background: transparent; }

.hero { position: relative; min-height: 100vh; min-height: 100svh; padding: clamp(150px, 21vh, 220px) 0 clamp(32px, 5vh, 60px); }
.hero-inner { display: grid; grid-template-columns: 1.12fr .88fr; gap: clamp(3rem, 7vw, 8rem); align-items: center; }
.hero-copy { position: relative; z-index: 2; }
.eyebrow { display: flex; align-items: center; gap: .6rem; margin-bottom: 1.8rem; font-size: .72rem; font-weight: 700; letter-spacing: .16em; text-transform: uppercase; }
.status-dot { width: 7px; height: 7px; border-radius: 50%; background: #57a66a; box-shadow: 0 0 0 4px color-mix(in srgb, #57a66a 18%, transparent); }
.hero h1 { max-width: 760px; margin: 0; font-family: "Songti SC", STSong, SimSun, Georgia, serif; font-size: clamp(3.8rem, 6.7vw, 7rem); font-weight: 400; line-height: 1.02; letter-spacing: -.07em; }
.hero h1 span { color: var(--red); font-style: italic; white-space: nowrap; }
.lead { max-width: 35em; margin: 2.4rem 0; color: var(--muted); font-size: clamp(.98rem, 1.2vw, 1.1rem); }
.hero-scan { display: flex; align-items: center; gap: 1.2rem; max-width: 520px; padding-top: 1.4rem; border-top: 1px solid var(--line); }
.hero-scan-qr { width: 112px; height: 112px; padding: .35rem; background: #fff; }
.hero-scan-text { flex: 1; }
.hero-scan-text strong { display: block; font-family: "Songti SC", STSong, SimSun, serif; font-size: 1.3rem; font-weight: 400; }
.hero-scan-text p { margin: .25rem 0 .8rem; color: var(--muted); font-size: .78rem; }
.hero-media { position: relative; justify-self: end; width: min(38vw, 470px); padding: 5%; background: var(--red); box-shadow: var(--shadow); transform: rotate(2.5deg); }
.hero-media::before { position: absolute; inset: -9% -15%; z-index: -1; border: 1px solid var(--line); border-radius: 50%; content: ""; transform: rotate(26deg); }
.hero-media img { aspect-ratio: 4 / 3; object-fit: cover; filter: saturate(.78) contrast(1.03); }
.hero-media-note { position: absolute; right: 1.2rem; bottom: .45rem; color: #f4f1e9; font: .54rem/1.2 ui-monospace, SFMono-Regular, Menlo, monospace; letter-spacing: .18em; }
.scroll-cue { position: absolute; bottom: 3vh; left: 5vw; color: var(--muted); font: .56rem ui-monospace, SFMono-Regular, Menlo, monospace; letter-spacing: .16em; writing-mode: vertical-rl; }

.section { padding: clamp(7rem, 12vw, 11rem) 0; border-top: 1px solid var(--line); scroll-margin-top: 78px; }
.section-soft { background: transparent; }
.section-label { display: flex; align-items: flex-start; gap: .8rem; margin-bottom: 4rem; font-size: .74rem; }
.section-label span { color: var(--red); font-family: Georgia, serif; font-style: italic; }
.section-label p { margin: 0; font-weight: 700; letter-spacing: .14em; }
.section-head { display: grid; grid-template-columns: 1.35fr .65fr; gap: 5rem; align-items: end; margin-bottom: 5rem; }
.section-head h2, .cta-copy h2 { margin: 0; font-family: "Songti SC", STSong, SimSun, Georgia, serif; font-size: clamp(2.7rem, 5.2vw, 5.3rem); font-weight: 400; line-height: 1.12; letter-spacing: -.05em; }
.section-sub { max-width: 37em; margin: 0; color: var(--muted); font-size: .92rem; }

.pain-grid, .feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0; margin: 0; padding: 0; list-style: none; border-top: 1px solid var(--ink); }
.card { min-width: 0; padding: 2rem 2rem 2.3rem 0; border: 0; border-bottom: 1px solid var(--line); background: transparent; }
.pain-grid .card + .card, .feature-grid .card + .card { padding-left: 2rem; border-left: 1px solid var(--line); }
.card h3 { margin: 0 0 .8rem; font-family: "Songti SC", STSong, SimSun, Georgia, serif; font-size: clamp(1.55rem, 2.2vw, 2.2rem); font-weight: 400; line-height: 1.25; }
.card p { margin: 0; color: var(--muted); font-size: .86rem; }
.feature-index { margin-bottom: 3.2rem !important; color: var(--red) !important; font: italic .68rem Georgia, serif !important; letter-spacing: .08em; }

.mode-gallery {
  display: flex;
  gap: 10px;
  width: 100%;
  height: 500px;
  perspective: 1400px;
  perspective-origin: 50% 50%;
}
.mode-panel {
  position: relative;
  display: block;
  flex: 1 1 0;
  min-width: 0;
  min-height: 0;
  padding: 0;
  overflow: hidden;
  border: 0;
  border-radius: 2px;
  outline: none;
  color: #fff;
  background: #20211e;
  box-shadow: 0 18px 45px rgba(44, 42, 35, .16);
  cursor: pointer;
  transform: rotateY(-4deg);
  transform-style: preserve-3d;
  transform-origin: center;
  transition: flex-grow .6s cubic-bezier(.22, 1, .36, 1), transform .6s cubic-bezier(.22, 1, .36, 1), box-shadow .35s ease;
  -webkit-tap-highlight-color: transparent;
}
.mode-panel:first-child { transform: rotateY(4deg); }
.mode-panel.is-active { flex-grow: 3.3; z-index: 2; transform: rotateY(0); box-shadow: 0 24px 70px rgba(44, 42, 35, .22); }
.mode-panel:focus-visible { box-shadow: 0 0 0 3px var(--red), 0 24px 70px rgba(44, 42, 35, .22); }
.mode-panel-media { position: absolute; inset: 0; overflow: hidden; background: var(--paper-soft); }
.mode-panel-media img { position: absolute; inset: 0; width: 100%; height: 100%; padding: clamp(.8rem, 2vw, 1.6rem); object-fit: contain; filter: grayscale(1) contrast(.94); transform: scale(1.08); transition: filter .6s ease, transform .8s cubic-bezier(.22, 1, .36, 1); user-select: none; }
.mode-panel.is-active .mode-panel-media img { filter: grayscale(0); transform: scale(1); }
.mode-panel-shade { position: absolute; inset: 0; background: rgba(20, 21, 19, .28); transition: background-color .5s ease; pointer-events: none; }
.mode-panel.is-active .mode-panel-shade { background: rgba(20, 21, 19, .16); }
.mode-panel-index { position: absolute; z-index: 2; top: 1.15rem; left: 1.2rem; font: italic .72rem Georgia, serif; letter-spacing: .08em; text-shadow: 0 1px 8px rgba(0, 0, 0, .5); }
.mode-panel-copy { position: absolute; z-index: 2; right: 1.25rem; bottom: 1.25rem; left: 1.25rem; display: flex; align-items: flex-end; gap: 1.1rem; opacity: 0; transform: translateX(-14px); transition: opacity .35s ease, transform .5s cubic-bezier(.22, 1, .36, 1); pointer-events: none; }
.mode-panel-copy::before { width: 3px; height: 30px; flex: 0 0 auto; background: var(--red); content: ""; }
.mode-panel.is-active .mode-panel-copy { opacity: 1; transform: none; transition-delay: .16s; }
.mode-panel-copy strong { font-family: "Songti SC", STSong, SimSun, Georgia, serif; font-size: clamp(1.8rem, 3vw, 3.1rem); font-weight: 400; line-height: 1; white-space: nowrap; text-shadow: 0 2px 15px rgba(0, 0, 0, .58); }
.mode-panel-copy small { max-width: 19em; margin-bottom: .1rem; font-size: .76rem; line-height: 1.55; text-align: left; text-shadow: 0 2px 12px rgba(0, 0, 0, .7); }

.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0; margin: 0; padding: 0; list-style: none; border-top: 1px solid var(--ink); }
.steps li { min-height: 260px; padding: 1.5rem 2rem 2rem 0; border-bottom: 1px solid var(--line); }
.steps li + li { padding-left: 2rem; border-left: 1px solid var(--line); }
.step-num { display: block; margin-bottom: 5rem; color: var(--red); font: italic 1rem Georgia, serif; }
.steps h3 { margin: 0 0 .6rem; font-family: "Songti SC", STSong, SimSun, Georgia, serif; font-size: 1.8rem; font-weight: 400; }
.steps p { margin: 0; color: var(--muted); font-size: .86rem; }

.section-cta { color: #f4f1e9; background: var(--red); border-top: 0; }
.cta-inner { display: grid; grid-template-columns: 1.45fr .55fr; gap: 5rem; align-items: center; }
.cta-copy h2 { max-width: 780px; color: #f4f1e9; font-size: clamp(3.2rem, 6vw, 6.5rem); }
.cta-copy p:not(.eyebrow) { max-width: 34em; margin: 2rem 0 0; color: rgba(244, 241, 233, .78); }
.cta-qr { justify-self: end; text-align: center; }
.cta-qr img { width: min(250px, 65vw); padding: .7rem; background: #fff; box-shadow: 18px 20px 0 rgba(120, 31, 19, .45); transform: rotate(2deg); }
.cta-qr p { margin: 1.2rem 0 0; font-size: .72rem; font-weight: 700; letter-spacing: .12em; }

.faq-list { border-top: 1px solid var(--ink); }
.faq-item { border-bottom: 1px solid var(--line); }
.faq-item summary { display: grid; grid-template-columns: 1fr auto; gap: 2rem; align-items: center; padding: 1.5rem 0; cursor: pointer; list-style: none; font-family: "Songti SC", STSong, SimSun, Georgia, serif; font-size: clamp(1.3rem, 2vw, 1.8rem); }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after { color: var(--red); content: "+"; font-family: Arial, sans-serif; font-size: 1.3rem; font-weight: 300; transition: transform .2s ease; }
.faq-item[open] summary::after { transform: rotate(45deg); }
.faq-item p { max-width: 50em; margin: 0 0 1.8rem; color: var(--muted); font-size: .9rem; }

.site-footer { padding: 3rem 0 1.5rem; border-top: 1px solid var(--line); }
.footer-inner { display: flex; align-items: flex-end; justify-content: space-between; }
.footer-brand { display: flex; align-items: center; gap: .8rem; }
.footer-brand strong { font-size: .9rem; letter-spacing: .08em; }
.footer-brand p { margin: .1rem 0 0; color: var(--muted); font-size: .72rem; }
.footer-mark { width: 32px; height: 32px; }
.footer-qr { width: 86px; padding: .25rem; background: #fff; }
.footer-meta { margin-top: 2rem; padding-top: 1rem; border-top: 1px solid var(--line); color: var(--muted); font-size: .68rem; }
.footer-meta p { margin: 0; }
.footer-meta a { color: inherit; text-decoration: none; }
.footer-meta a:hover { color: var(--ink); text-decoration: underline; }

.reveal { opacity: 0; transform: translateY(22px); transition: opacity .7s ease, transform .7s ease; }
.reveal.is-visible { opacity: 1; transform: none; }
.pain-grid .reveal:nth-child(2), .feature-grid .reveal:nth-child(2), .steps .reveal:nth-child(2) { transition-delay: .08s; }
.pain-grid .reveal:nth-child(3), .feature-grid .reveal:nth-child(3), .steps .reveal:nth-child(3) { transition-delay: .16s; }

@media (max-width: 900px) {
  .header-inner { grid-template-columns: 1fr auto; }
  .site-nav, .header-actions .btn-small { display: none; }
  .menu-toggle { display: inline-flex; }
  .hero { padding-top: 130px; }
  .hero-inner { grid-template-columns: 1fr; }
  .hero-media { justify-self: center; width: min(78vw, 520px); margin-top: 2rem; }
  .scroll-cue { display: none; }
  .section-head { grid-template-columns: 1fr; gap: 1.5rem; }
  .mode-gallery { height: 440px; }
  .cta-inner { grid-template-columns: 1fr; }
  .cta-qr { justify-self: start; }
}

@media (max-width: 640px) {
  body { font-size: 15px; }
  .container { width: min(var(--maxw), calc(100vw - 2.2rem)); }
  .site-header { height: 68px; }
  .section { scroll-margin-top: 68px; }
  .mobile-nav { top: 67px; }
  .theme-toggle { display: none; }
  .hero { min-height: auto; padding: 120px 0 6rem; }
  .hero h1 { font-size: clamp(3rem, 13vw, 4.4rem); }
  .hero h1 span { white-space: normal; }
  .lead { margin: 1.8rem 0; }
  .hero-scan { align-items: flex-start; }
  .hero-scan-qr { width: 92px; height: 92px; }
  .hero-scan-text .btn { min-height: 40px; padding: .55rem .9rem; }
  .hero-media { width: 88vw; }
  .section { padding: 6rem 0; }
  .section-label { margin-bottom: 2.6rem; }
  .section-head { margin-bottom: 3rem; }
  .pain-grid, .feature-grid, .steps { grid-template-columns: 1fr; }
  .pain-grid .card + .card, .feature-grid .card + .card, .steps li + li { padding-left: 0; border-left: 0; }
  .card { padding: 1.5rem 0 2rem; }
  .feature-index { margin-bottom: 2rem !important; }
  .steps li { min-height: 0; padding: 1.5rem 0 2rem; }
  .step-num { margin-bottom: 2.5rem; }
  .mode-gallery { flex-direction: column; height: 570px; perspective: none; }
  .mode-panel, .mode-panel:first-child { min-height: 86px; transform: none; }
  .mode-panel.is-active { flex-grow: 4.4; transform: none; }
  .mode-panel-media img { padding: .75rem; }
  .mode-panel-copy { right: 1rem; bottom: 1rem; left: 1rem; gap: .75rem; }
  .mode-panel-copy strong { font-size: 1.8rem; }
  .mode-panel-copy small { font-size: .7rem; }
  .cta-copy h2 { font-size: clamp(3rem, 14vw, 4.5rem); }
  .footer-inner { align-items: center; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
  .reveal { opacity: 1; transform: none; }
  .mode-panel, .mode-panel-media img, .mode-panel-copy { transition: none; }
}