/* 91PO Official — Amber Noir Design System */
:root {
  --ink: #0a0a0c;
  --ink-soft: #141418;
  --ink-card: #1c1c22;
  --ink-line: rgba(255, 255, 255, 0.06);
  --amber: #f97316;
  --amber-bright: #fb923c;
  --amber-dim: rgba(249, 115, 22, 0.12);
  --amber-glow: rgba(249, 115, 22, 0.28);
  --cream: #faf7f2;
  --text-hi: #f5f5f4;
  --text-mid: #a8a29e;
  --text-lo: #78716c;
  --teal: #14b8a6;
  --nav-h: 58px;
  --radius: 12px;
  --radius-xl: 20px;
  --font-sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-serif: "Noto Serif SC", "Source Han Serif SC", "SimSun", serif;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: var(--font-sans);
  background: var(--ink);
  color: var(--text-hi);
  line-height: 1.8;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 50% at 20% -10%, var(--amber-glow), transparent 55%),
    radial-gradient(ellipse 60% 40% at 90% 20%, rgba(20, 184, 166, 0.08), transparent 50%);
  pointer-events: none;
  z-index: 0;
}

img { max-width: 100%; height: auto; display: block; }

a { color: var(--amber-bright); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--amber); }

.container { width: min(1120px, 92vw); margin: 0 auto; position: relative; z-index: 1; }

/* Header */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  height: var(--nav-h);
  background: rgba(10, 10, 12, 0.88);
  backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--ink-line);
}

.header-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--nav-h);
}

.logo-link {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text-hi);
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: 0.04em;
}

.logo-link img { width: 36px; height: 36px; border-radius: 9px; }

.nav-main { display: none; list-style: none; gap: 26px; }
.nav-main a {
  color: var(--text-mid);
  font-size: 0.9rem;
  font-weight: 500;
  position: relative;
}
.nav-main a.active,
.nav-main a:hover { color: var(--amber); }
.nav-main a.active::after {
  content: "";
  position: absolute;
  bottom: -6px;
  left: 0; right: 0;
  height: 2px;
  background: var(--amber);
  border-radius: 2px;
}

.btn-dl {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 18px;
  background: linear-gradient(135deg, var(--amber), #ea580c);
  color: #fff !important;
  font-size: 0.85rem;
  font-weight: 600;
  border-radius: 999px;
  border: none;
  cursor: pointer;
  box-shadow: 0 4px 20px var(--amber-glow);
  transition: transform 0.2s, box-shadow 0.2s;
}
.btn-dl:hover { transform: translateY(-1px); box-shadow: 0 6px 28px var(--amber-glow); color: #fff !important; }

.menu-btn {
  display: flex;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
}
.menu-btn i {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-hi);
  border-radius: 2px;
}

.nav-drawer {
  display: none;
  position: fixed;
  top: var(--nav-h);
  left: 0; right: 0;
  background: rgba(10, 10, 12, 0.97);
  border-bottom: 1px solid var(--ink-line);
  padding: 12px 0 20px;
  z-index: 999;
}
.nav-drawer.show { display: block; }
.nav-drawer ul { list-style: none; }
.nav-drawer a {
  display: block;
  padding: 13px 5vw;
  color: var(--text-mid);
  border-bottom: 1px solid var(--ink-line);
}
.nav-drawer a:hover { color: var(--amber); background: var(--amber-dim); }

/* Ads */
.ads-wrap {
  padding: calc(var(--nav-h) + 10px) 0 6px;
  background: var(--ink-soft);
  border-bottom: 1px solid var(--ink-line);
}

#ads {
  display: flex;
  justify-content: center;
  align-items: flex-start;
  flex-wrap: wrap;
  background: transparent;
  gap: 4px;
}

#ads > div {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 70px;
}

#ads img {
  width: 65px;
  height: 65px;
  object-fit: cover;
  border-radius: 16px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.35);
  transition: transform 0.18s, box-shadow 0.18s;
  border: 1px solid var(--ink-line);
}

#ads a { border-radius: 16px; display: inline-block; }
#ads img:hover { transform: translateY(-3px) scale(1.03); box-shadow: 0 8px 24px var(--amber-glow); }

#ads .caption {
  height: 15px;
  font-size: 11px;
  color: var(--text-lo);
  text-align: center;
  max-width: 68px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  margin-top: 4px;
}

.sticky-ads-bar {
  position: fixed;
  top: var(--nav-h);
  left: 0; right: 0;
  z-index: 998;
  background: rgba(10, 10, 12, 0.95);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--ink-line);
  padding: 8px 0;
  transform: translateY(-110%);
  opacity: 0;
  transition: transform 0.3s, opacity 0.3s;
  pointer-events: none;
}

.sticky-ads-bar.show {
  transform: translateY(0);
  opacity: 1;
  pointer-events: auto;
}

#sticky-ads {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 2px;
}

#sticky-ads > div {
  width: calc(25% - 2px);
  display: flex;
  flex-direction: column;
  align-items: center;
}

#sticky-ads img {
  width: 52px;
  height: 52px;
  object-fit: cover;
  border-radius: 12px;
  border: 1px solid var(--ink-line);
}

#sticky-ads .caption {
  font-size: 10px;
  color: var(--text-lo);
  max-width: 56px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  text-align: center;
}

@media (min-width: 768px) {
  #sticky-ads > div { width: calc(12.5% - 4px); }
  #sticky-ads img { width: 58px; height: 58px; }
}

body.has-sticky { padding-top: 0; }

/* Hero */
.hero-zone {
  padding: calc(var(--nav-h) + 48px) 0 64px;
  position: relative;
}

.hero-inner {
  display: grid;
  gap: 40px;
  align-items: center;
}

.hero-copy h1 {
  font-family: var(--font-serif);
  font-size: clamp(1.75rem, 5vw, 2.6rem);
  line-height: 1.25;
  font-weight: 700;
  margin-bottom: 18px;
}

.hero-copy h1 em {
  font-style: normal;
  color: var(--amber);
}

.hero-lead {
  color: var(--text-mid);
  font-size: 1rem;
  margin-bottom: 22px;
  max-width: 540px;
}

.hero-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 0;
}

.hero-pill {
  padding: 6px 14px;
  background: var(--ink-card);
  border: 1px solid var(--ink-line);
  border-radius: 999px;
  font-size: 0.82rem;
  color: var(--text-mid);
}


.btn-outline {
  display: inline-flex;
  align-items: center;
  padding: 10px 22px;
  border: 1px solid var(--ink-line);
  border-radius: 999px;
  color: var(--text-hi) !important;
  font-size: 0.88rem;
  font-weight: 500;
  background: var(--ink-card);
}
.btn-outline:hover { border-color: var(--amber); color: var(--amber) !important; }

.hero-visual {
  width: 100%;
  display: flex;
  justify-content: center;
  padding: 12px 0 0;
}

.hero-stack {
  position: relative;
  width: min(360px, 88vw);
  height: 440px;
  flex-shrink: 0;
}

.hero-stack .shot {
  position: absolute;
  width: 56%;
  margin: 0;
  border-radius: 18px;
  border: 2px solid rgba(255, 255, 255, 0.1);
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.55);
  overflow: hidden;
  background: var(--ink-card);
}

.hero-stack .shot img {
  width: 100%;
  height: auto;
  vertical-align: top;
}

.hero-stack .shot:nth-child(1) { top: 0; left: 0; z-index: 4; transform: rotate(-5deg); }
.hero-stack .shot:nth-child(2) { top: 8%; right: -2%; z-index: 3; transform: rotate(5deg); }
.hero-stack .shot:nth-child(3) { bottom: 8%; left: 8%; z-index: 2; transform: rotate(-3deg); width: 50%; }
.hero-stack .shot:nth-child(4) { bottom: 0; right: 6%; z-index: 1; transform: rotate(2deg); width: 46%; }

.hero-badge {
  display: inline-block;
  padding: 5px 12px;
  background: var(--amber-dim);
  border: 1px solid rgba(249, 115, 22, 0.25);
  border-radius: 6px;
  font-size: 0.78rem;
  color: var(--amber-bright);
  margin-bottom: 14px;
  letter-spacing: 0.06em;
}

/* Metrics */
.metrics-band {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  margin: 48px 0;
}

.metric-cell {
  padding: 20px 16px;
  background: var(--ink-card);
  border: 1px solid var(--ink-line);
  border-radius: var(--radius);
  text-align: center;
}

.metric-cell strong {
  display: block;
  font-family: var(--font-serif);
  font-size: 1.5rem;
  color: var(--amber);
  margin-bottom: 4px;
}

.metric-cell span { font-size: 0.82rem; color: var(--text-lo); }

/* Sections */
.section { padding: 56px 0; }
.section-alt { background: var(--ink-soft); }

.section-head {
  margin-bottom: 36px;
  max-width: 680px;
}

.section-tag {
  display: inline-block;
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--teal);
  margin-bottom: 10px;
}

.section-head h2 {
  font-family: var(--font-serif);
  font-size: clamp(1.4rem, 3.5vw, 1.9rem);
  line-height: 1.35;
  margin-bottom: 12px;
}

.section-head p { color: var(--text-mid); font-size: 0.95rem; }

/* Split 3:7 */
.split-row {
  display: grid;
  gap: 28px;
  margin-bottom: 48px;
  align-items: start;
}

.split-media {
  border-radius: var(--radius-xl);
  overflow: hidden;
  border: 1px solid var(--ink-line);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.4);
}

.split-media img { width: 100%; }

.split-body h3 {
  font-size: 1.15rem;
  margin-bottom: 12px;
  color: var(--text-hi);
}

.split-body p {
  color: var(--text-mid);
  font-size: 0.93rem;
  margin-bottom: 12px;
}

.split-body ul {
  list-style: none;
  margin-top: 14px;
}

.split-body li {
  position: relative;
  padding-left: 18px;
  margin-bottom: 8px;
  color: var(--text-mid);
  font-size: 0.9rem;
}

.split-body li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 6px;
  height: 6px;
  background: var(--amber);
  border-radius: 50%;
}

.text-block {
  padding: 28px 24px;
  background: var(--ink-card);
  border: 1px solid var(--ink-line);
  border-radius: var(--radius-xl);
  margin-bottom: 24px;
}

.text-block h3 {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  margin-bottom: 14px;
  color: var(--text-hi);
}

.text-block p {
  color: var(--text-mid);
  font-size: 0.93rem;
  margin-bottom: 12px;
}

.text-block p:last-child { margin-bottom: 0; }

.text-columns {
  display: grid;
  gap: 20px;
}

@media (min-width: 768px) {
  .text-columns { grid-template-columns: 1fr 1fr; }
}

@media (min-width: 900px) {
  .hero-inner { grid-template-columns: 1fr 1fr; gap: 32px; }
  .hero-stack { height: 480px; width: 380px; }
  .nav-main { display: flex; }
  .menu-btn { display: none; }
  .metrics-band { grid-template-columns: repeat(4, 1fr); }
  .split-row { grid-template-columns: 3fr 7fr; gap: 36px; }
  .split-row.reverse { grid-template-columns: 7fr 3fr; }
  .split-row.reverse .split-media { order: 2; }
  .split-row.reverse .split-body { order: 1; }
}

/* Feature cards */
.feat-grid {
  display: grid;
  gap: 16px;
  grid-template-columns: 1fr;
}

.feat-card {
  padding: 24px 22px;
  background: var(--ink-card);
  border: 1px solid var(--ink-line);
  border-radius: var(--radius);
  transition: border-color 0.25s;
}

.feat-card:hover { border-color: rgba(249, 115, 22, 0.3); }

.feat-num {
  font-family: var(--font-serif);
  font-size: 2rem;
  color: var(--amber);
  opacity: 0.5;
  line-height: 1;
  margin-bottom: 10px;
}

.feat-card h3 { font-size: 1rem; margin-bottom: 8px; }
.feat-card p { font-size: 0.88rem; color: var(--text-mid); }

@media (min-width: 640px) { .feat-grid { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 960px) { .feat-grid { grid-template-columns: repeat(3, 1fr); } }

/* Steps */
.steps-list { counter-reset: step; }

.step-item {
  display: grid;
  gap: 16px;
  padding: 24px 0;
  border-bottom: 1px solid var(--ink-line);
}

.step-item:last-child { border-bottom: none; }

.step-item::before {
  counter-increment: step;
  content: counter(step, decimal-leading-zero);
  font-family: var(--font-serif);
  font-size: 1.8rem;
  color: var(--amber);
  opacity: 0.6;
}

.step-item h3 { font-size: 1.05rem; margin-bottom: 6px; }
.step-item p { color: var(--text-mid); font-size: 0.9rem; }

@media (min-width: 768px) {
  .step-item { grid-template-columns: 80px 1fr; align-items: start; }
}

/* FAQ */
.faq-list { display: flex; flex-direction: column; gap: 10px; }

.faq-item {
  background: var(--ink-card);
  border: 1px solid var(--ink-line);
  border-radius: var(--radius);
  overflow: hidden;
}

.faq-q {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 20px;
  background: none;
  border: none;
  color: var(--text-hi);
  font-size: 0.95rem;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  font-family: inherit;
}

.faq-q::after {
  content: "+";
  font-size: 1.2rem;
  color: var(--amber);
  transition: transform 0.25s;
}

.faq-item.open .faq-q::after { transform: rotate(45deg); }

.faq-a {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease;
}

.faq-a-inner {
  padding: 0 20px 16px;
  color: var(--text-mid);
  font-size: 0.9rem;
}

/* CTA */
.cta-panel {
  margin: 48px 0 0;
  padding: 40px 28px;
  background: linear-gradient(145deg, var(--ink-card), var(--ink-soft));
  border: 1px solid rgba(249, 115, 22, 0.2);
  border-radius: var(--radius-xl);
  text-align: center;
}

.cta-panel h2 {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  margin-bottom: 12px;
}

.cta-panel p { color: var(--text-mid); margin-bottom: 22px; font-size: 0.93rem; }

/* Footer */
.site-footer {
  margin-top: 64px;
  padding: 40px 0 28px;
  background: var(--ink-soft);
  border-top: 1px solid var(--ink-line);
}

.footer-grid {
  display: grid;
  gap: 28px;
  margin-bottom: 32px;
}

.footer-brand img { width: 44px; border-radius: 10px; margin-bottom: 12px; }
.footer-brand p { color: var(--text-lo); font-size: 0.85rem; max-width: 280px; }

.footer-nav h4 {
  font-size: 0.82rem;
  color: var(--text-mid);
  margin-bottom: 12px;
  letter-spacing: 0.06em;
}

.footer-nav ul { list-style: none; }
.footer-nav li { margin-bottom: 8px; }
.footer-nav a { color: var(--text-lo); font-size: 0.85rem; }
.footer-nav a:hover { color: var(--amber); }

.footer-bottom {
  padding-top: 20px;
  border-top: 1px solid var(--ink-line);
  text-align: center;
  color: var(--text-lo);
  font-size: 0.8rem;
}

@media (min-width: 768px) {
  .footer-grid { grid-template-columns: 1.2fr 1fr 1fr; }
}

/* Subpages */
.page-hero {
  padding: calc(var(--nav-h) + 36px) 0 32px;
  background: var(--ink-soft);
  border-bottom: 1px solid var(--ink-line);
}

.page-hero h1 {
  font-family: var(--font-serif);
  font-size: clamp(1.5rem, 4vw, 2rem);
  margin-bottom: 8px;
}

.page-hero p { color: var(--text-mid); font-size: 0.92rem; }

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  font-size: 0.82rem;
  color: var(--text-lo);
  margin-bottom: 16px;
}

.breadcrumb a { color: var(--text-mid); }
.breadcrumb a:hover { color: var(--amber); }

.prose {
  padding: 40px 0 56px;
  max-width: 780px;
}

.prose h2 {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  margin: 32px 0 12px;
  color: var(--text-hi);
}

.prose h3 { font-size: 1.05rem; margin: 24px 0 10px; }
.prose p, .prose li { color: var(--text-mid); font-size: 0.92rem; margin-bottom: 12px; }
.prose ul, .prose ol { padding-left: 22px; margin-bottom: 16px; }
.prose a { color: var(--amber-bright); }

.error-page {
  min-height: 70vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: calc(var(--nav-h) + 40px) 20px 60px;
}

.error-code {
  font-family: var(--font-serif);
  font-size: 5rem;
  color: var(--amber);
  line-height: 1;
  margin-bottom: 12px;
}

.error-page h1 { font-size: 1.3rem; margin-bottom: 10px; }
.error-page p { color: var(--text-mid); margin-bottom: 24px; font-size: 0.92rem; }