/* 91PO Official Site — Dark Premium Mobile-First Theme */
:root {
  --bg-deep: #08080f;
  --bg-card: #12121c;
  --bg-elevated: #1a1a28;
  --brand-orange: #f5920a;
  --brand-orange-light: #ffb347;
  --accent-purple: #7c5cfc;
  --accent-blue: #4d9fff;
  --text-primary: #f4f4f8;
  --text-secondary: #9a9ab0;
  --text-muted: #6b6b82;
  --border-subtle: rgba(255, 255, 255, 0.06);
  --gradient-brand: linear-gradient(135deg, #f5920a 0%, #e86a00 100%);
  --gradient-accent: linear-gradient(135deg, #7c5cfc 0%, #4d9fff 100%);
  --shadow-glow: 0 0 40px rgba(245, 146, 10, 0.15);
  --header-h: 60px;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --max-w: 1120px;
  --font: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font);
  background: var(--bg-deep);
  color: var(--text-primary);
  line-height: 1.75;
  font-size: 15px;
  overflow-x: hidden;
}

body.has-sticky-ads { padding-bottom: 100px; }
body.has-sticky-ads-pc { padding-top: 0; }

img { max-width: 100%; height: auto; display: block; }
a { color: var(--brand-orange-light); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--brand-orange); }

.container {
  width: 100%;
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 20px;
}

/* ===== Header ===== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--header-h);
  background: rgba(8, 8, 15, 0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-subtle);
  transition: box-shadow 0.3s;
}

.site-header.scrolled { box-shadow: 0 4px 24px rgba(0, 0, 0, 0.4); }

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-h);
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 20px;
}

.logo-link {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text-primary);
  font-weight: 700;
  font-size: 17px;
  letter-spacing: 0.02em;
}

.logo-link img { width: 36px; height: 36px; border-radius: 10px; }

.nav-toggle {
  display: flex;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: 0.3s;
}

.nav-toggle.active span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.nav-toggle.active span:nth-child(2) { opacity: 0; }
.nav-toggle.active span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

.main-nav {
  position: fixed;
  top: var(--header-h);
  left: 0;
  right: 0;
  background: var(--bg-card);
  border-bottom: 1px solid var(--border-subtle);
  padding: 16px 20px;
  transform: translateY(-120%);
  opacity: 0;
  transition: 0.3s;
  z-index: 999;
}

.main-nav.open { transform: translateY(0); opacity: 1; }

.main-nav ul { list-style: none; }
.main-nav li { border-bottom: 1px solid var(--border-subtle); }
.main-nav li:last-child { border: none; }
.main-nav a {
  display: block;
  padding: 14px 0;
  color: var(--text-secondary);
  font-size: 15px;
}
.main-nav a:hover, .main-nav a.active { color: var(--brand-orange); }

/* ===== Sticky Ads Bar ===== */
#ads-sticky-bar {
  position: fixed;
  left: 0;
  right: 0;
  z-index: 998;
  background: rgba(12, 12, 20, 0.97);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-subtle);
  padding: 8px 12px;
  transform: translateY(-110%);
  opacity: 0;
  transition: 0.35s;
  pointer-events: none;
}

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

#ads-sticky-bar .ads-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: flex-start;
  gap: 6px 8px;
  max-width: var(--max-w);
  margin: 0 auto;
}

#ads-sticky-bar .ads-inner > div {
  width: calc(25% - 6px);
  flex: 0 0 calc(25% - 6px);
}

#ads-sticky-bar .ads-inner figure {
  margin: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

#ads-sticky-bar .ads-inner a {
  display: block;
  border-radius: 14px;
  line-height: 0;
}

#ads-sticky-bar .ads-inner img {
  width: 50px;
  height: 50px;
  max-width: 50px;
  object-fit: cover;
  border-radius: 13px;
  box-shadow: 0 3px 10px rgba(0, 0, 0, 0.28);
  transition: transform 0.18s;
}

#ads-sticky-bar .ads-inner a:hover img {
  transform: translateY(-2px);
}

#ads-sticky-bar .caption {
  display: block;
  width: 100%;
  font-size: 10px;
  line-height: 1.3;
  color: var(--text-muted);
  text-align: center;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  padding: 0 2px;
}

@media (min-width: 768px) {
  body.has-sticky-ads { padding-bottom: 0; }

  #ads-sticky-bar {
    top: var(--header-h);
    bottom: auto;
    border-bottom: 1px solid var(--border-subtle);
    border-top: none;
    padding: 8px 16px;
  }

  body.has-sticky-ads-pc { padding-top: 78px; }

  #ads-sticky-bar .ads-inner {
    gap: 8px 10px;
  }

  #ads-sticky-bar .ads-inner > div {
    width: calc(12.5% - 9px);
    flex: 0 0 calc(12.5% - 9px);
  }

  #ads-sticky-bar .ads-inner img {
    width: 52px;
    height: 52px;
    max-width: 52px;
    border-radius: 14px;
  }

  #ads-sticky-bar .caption {
    font-size: 11px;
  }

  .nav-toggle { display: none; }

  .main-nav {
    position: static;
    transform: none;
    opacity: 1;
    background: none;
    border: none;
    padding: 0;
  }

  .main-nav ul { display: flex; gap: 28px; }
  .main-nav li { border: none; }
  .main-nav a { padding: 0; font-size: 14px; }
}

/* ===== Inline Ads Zone ===== */
#download-zone {
  scroll-margin-top: calc(var(--header-h) + 20px);
  padding: 16px 0 8px;
}

#ads {
  display: flex;
  justify-content: center;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: 10px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 16px 12px;
  margin: 0 auto;
  max-width: var(--max-w);
}

#ads > div {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: calc(25% - 8px);
}

#ads img {
  width: 100%;
  aspect-ratio: 1;
  max-width: 72px;
  object-fit: cover;
  border-radius: 16px;
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
  transition: transform 0.18s, box-shadow 0.18s;
  border: none;
}

#ads a { display: block; border-radius: 16px; }
#ads img:hover {
  transform: translateY(-3px) scale(1.04);
  box-shadow: 0 10px 28px rgba(245, 146, 10, 0.2);
}

#ads .caption {
  font-size: 11px;
  color: var(--text-muted);
  text-align: center;
  max-width: 80px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  margin-top: 5px;
}

@media (min-width: 768px) {
  #ads > div { width: calc(12.5% - 9px); }
  #ads img { max-width: 68px; }
}

.ads-label {
  text-align: center;
  font-size: 12px;
  color: var(--text-muted);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 10px;
}

/* ===== Hero ===== */
.hero {
  position: relative;
  padding: calc(var(--header-h) + 48px) 0 56px;
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 60% at 70% 20%, rgba(245, 146, 10, 0.12) 0%, transparent 60%),
    radial-gradient(ellipse 60% 50% at 10% 80%, rgba(124, 92, 252, 0.08) 0%, transparent 55%);
  pointer-events: none;
}

.hero-grid {
  display: grid;
  gap: 36px;
  align-items: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(245, 146, 10, 0.12);
  border: 1px solid rgba(245, 146, 10, 0.25);
  color: var(--brand-orange-light);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.08em;
  padding: 6px 14px;
  border-radius: 100px;
  margin-bottom: 20px;
}

.hero-badge::before {
  content: "";
  width: 6px;
  height: 6px;
  background: var(--brand-orange);
  border-radius: 50%;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

.hero h1 {
  font-size: clamp(26px, 6vw, 42px);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.02em;
  margin-bottom: 18px;
}

.hero h1 em {
  font-style: normal;
  background: var(--gradient-brand);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-desc {
  font-size: 16px;
  color: var(--text-secondary);
  max-width: 540px;
  margin-bottom: 28px;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
}

.stat-item {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 16px 12px;
  text-align: center;
}

.stat-num {
  font-size: 22px;
  font-weight: 800;
  color: var(--brand-orange);
  line-height: 1.2;
}

.stat-label {
  font-size: 11px;
  color: var(--text-muted);
  margin-top: 4px;
}

.hero-visual {
  position: relative;
  display: flex;
  justify-content: center;
}

.phone-frame {
  width: 240px;
  border-radius: 32px;
  border: 3px solid rgba(255, 255, 255, 0.08);
  box-shadow: var(--shadow-glow), 0 24px 60px rgba(0, 0, 0, 0.5);
  overflow: hidden;
}

.phone-frame img { width: 100%; }

@media (min-width: 768px) {
  .hero-grid { grid-template-columns: 1fr 1fr; }
  .phone-frame { width: 280px; }
}

/* ===== Section Common ===== */
.section {
  padding: 56px 0;
}

.section-label {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--brand-orange);
  margin-bottom: 10px;
}

.section-title {
  font-size: clamp(22px, 4vw, 30px);
  font-weight: 800;
  line-height: 1.3;
  margin-bottom: 14px;
}

.section-desc {
  color: var(--text-secondary);
  max-width: 640px;
  margin-bottom: 36px;
}

/* ===== Feature Cards ===== */
.features-grid {
  display: grid;
  gap: 16px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 24px 20px;
  transition: border-color 0.25s, transform 0.25s;
}

.feature-card:hover {
  border-color: rgba(245, 146, 10, 0.3);
  transform: translateY(-2px);
}

.feature-icon {
  width: 44px;
  height: 44px;
  background: rgba(245, 146, 10, 0.1);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 14px;
}

.feature-icon svg { width: 22px; height: 22px; stroke: var(--brand-orange); fill: none; stroke-width: 1.8; }

.feature-card h3 {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 8px;
}

.feature-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.65;
}

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

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

/* ===== Content Blocks (3:7 ratio) ===== */
.content-block {
  display: grid;
  gap: 28px;
  margin-bottom: 48px;
  align-items: start;
}

.content-block.reverse .block-media { order: -1; }

.block-media {
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border-subtle);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.35);
}

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

.block-text h3 {
  font-size: 20px;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.block-text p {
  color: var(--text-secondary);
  font-size: 14.5px;
  margin-bottom: 12px;
}

.block-text ul {
  list-style: none;
  margin: 14px 0;
}

.block-text li {
  position: relative;
  padding-left: 18px;
  color: var(--text-secondary);
  font-size: 14px;
  margin-bottom: 8px;
}

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

.block-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 14px;
  font-weight: 600;
  color: var(--brand-orange);
  margin-top: 8px;
}

@media (min-width: 768px) {
  .content-block {
    grid-template-columns: 3fr 7fr;
    gap: 36px;
  }

  .content-block.reverse {
    grid-template-columns: 7fr 3fr;
  }

  .content-block.reverse .block-media { order: 2; }
  .content-block.reverse .block-text { order: 1; }
}

/* ===== CTA Banner ===== */
.cta-banner {
  background: var(--bg-card);
  border: 1px solid rgba(245, 146, 10, 0.2);
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.cta-banner::before {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 50% 0%, rgba(245, 146, 10, 0.08) 0%, transparent 60%);
}

.cta-banner h2 {
  font-size: clamp(20px, 4vw, 26px);
  font-weight: 800;
  margin-bottom: 12px;
  position: relative;
}

.cta-banner p {
  color: var(--text-secondary);
  margin-bottom: 24px;
  position: relative;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--gradient-brand);
  color: #fff;
  font-size: 15px;
  font-weight: 700;
  padding: 14px 32px;
  border-radius: 100px;
  border: none;
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s;
  position: relative;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(245, 146, 10, 0.35);
  color: #fff;
}

/* ===== FAQ ===== */
.faq-list { display: flex; flex-direction: column; gap: 12px; }

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

.faq-q {
  width: 100%;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 15px;
  font-weight: 600;
  text-align: left;
  padding: 18px 20px;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-family: var(--font);
}

.faq-q::after {
  content: "+";
  font-size: 20px;
  color: var(--brand-orange);
  transition: 0.3s;
  flex-shrink: 0;
  margin-left: 12px;
}

.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 18px;
  color: var(--text-secondary);
  font-size: 14px;
}

.faq-item.open .faq-a { max-height: 400px; }

/* ===== Breadcrumb ===== */
.breadcrumb {
  padding: calc(var(--header-h) + 24px) 0 0;
  font-size: 13px;
  color: var(--text-muted);
}

.breadcrumb a { color: var(--text-secondary); }
.breadcrumb a:hover { color: var(--brand-orange); }
.breadcrumb span { margin: 0 8px; opacity: 0.4; }

/* ===== Subpage Content ===== */
.page-hero {
  padding: 28px 0 36px;
  border-bottom: 1px solid var(--border-subtle);
  margin-bottom: 36px;
}

.page-hero h1 {
  font-size: clamp(24px, 5vw, 32px);
  font-weight: 800;
  margin-bottom: 10px;
}

.page-hero p { color: var(--text-secondary); font-size: 15px; }

.prose {
  max-width: 780px;
  padding-bottom: 60px;
}

.prose h2 {
  font-size: 20px;
  font-weight: 700;
  margin: 32px 0 14px;
  color: var(--text-primary);
}

.prose h3 {
  font-size: 17px;
  font-weight: 600;
  margin: 24px 0 10px;
}

.prose p, .prose li {
  color: var(--text-secondary);
  font-size: 14.5px;
  margin-bottom: 12px;
}

.prose ul, .prose ol {
  padding-left: 22px;
  margin-bottom: 16px;
}

.prose li { margin-bottom: 6px; }

/* ===== Error Pages ===== */
.error-page {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: calc(var(--header-h) + 40px) 20px 60px;
}

.error-code {
  font-size: clamp(72px, 18vw, 120px);
  font-weight: 900;
  background: var(--gradient-brand);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
}

.error-page h1 { font-size: 22px; margin: 16px 0 10px; }
.error-page p { color: var(--text-secondary); margin-bottom: 28px; max-width: 400px; }

/* ===== Footer ===== */
.site-footer {
  background: var(--bg-card);
  border-top: 1px solid var(--border-subtle);
  padding: 40px 0 28px;
  margin-top: 20px;
}

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

.footer-brand img { width: 40px; border-radius: 10px; margin-bottom: 12px; }
.footer-brand p { font-size: 13px; color: var(--text-muted); max-width: 280px; }

.footer-nav h4 {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.06em;
  margin-bottom: 14px;
  color: var(--text-primary);
}

.footer-nav ul { list-style: none; }
.footer-nav li { margin-bottom: 8px; }
.footer-nav a { font-size: 13px; color: var(--text-muted); }
.footer-nav a:hover { color: var(--brand-orange); }

.footer-bottom {
  border-top: 1px solid var(--border-subtle);
  padding-top: 20px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 12px;
  color: var(--text-muted);
}

@media (min-width: 640px) {
  .footer-grid { grid-template-columns: 2fr 1fr 1fr; }
  .footer-bottom { flex-direction: row; justify-content: space-between; }
}

/* ===== SEO Text Modules ===== */
.seo-columns {
  display: grid;
  gap: 20px;
  margin-top: 8px;
}

@media (min-width: 768px) {
  .seo-columns { grid-template-columns: repeat(2, 1fr); }
}

.text-module {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 24px 22px;
}

.text-module h3 {
  font-size: 17px;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.text-module p {
  font-size: 14px;
  color: var(--text-secondary);
  margin-bottom: 10px;
  line-height: 1.75;
}

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

.seo-prose-block {
  margin-bottom: 32px;
}

.seo-prose-block h3 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.seo-prose-block p {
  font-size: 14.5px;
  color: var(--text-secondary);
  margin-bottom: 12px;
  line-height: 1.8;
}

.img-showcase {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
  margin: 28px 0 36px;
}

.img-showcase-item {
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--border-subtle);
  background: var(--bg-card);
}

.img-showcase-item img {
  width: 100%;
  aspect-ratio: 9/16;
  object-fit: cover;
  object-position: top;
}

.img-showcase-item figcaption {
  padding: 10px 12px;
  font-size: 12px;
  color: var(--text-muted);
  line-height: 1.5;
  border-top: 1px solid var(--border-subtle);
}

@media (min-width: 768px) {
  .img-showcase { grid-template-columns: repeat(4, 1fr); }
}

.highlight-box {
  background: rgba(245, 146, 10, 0.06);
  border-left: 3px solid var(--brand-orange);
  padding: 16px 20px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 20px 0;
}

.highlight-box p {
  font-size: 14px;
  color: var(--text-secondary);
  margin: 0;
  line-height: 1.75;
}

/* ===== Mobile bottom sticky ads ===== */
@media (max-width: 767px) {
  #ads-sticky-bar {
    top: auto;
    bottom: 0;
    border-top: 1px solid var(--border-subtle);
    border-bottom: none;
    padding: 8px 6px calc(8px + env(safe-area-inset-bottom));
  }

  body.has-sticky-ads { padding-bottom: calc(82px + env(safe-area-inset-bottom)); }

  #ads-sticky-bar .ads-inner { gap: 4px 6px; }
}