/* 91PO视频官网 · 91os.xyz — Obsidian Cinema Theme */
:root {
  --bg-deep: #060608;
  --bg-panel: #0f1016;
  --bg-card: #14151d;
  --bg-elevated: #1a1b25;
  --orange: #ff6a00;
  --orange-light: #ff8533;
  --orange-glow: rgba(255, 106, 0, 0.35);
  --purple: #8b5cf6;
  --purple-dim: rgba(139, 92, 246, 0.15);
  --text-primary: #f4f4f8;
  --text-secondary: #9a9ab0;
  --text-muted: #63637a;
  --border: rgba(255, 255, 255, 0.06);
  --border-accent: rgba(255, 106, 0, 0.25);
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --shadow-glow: 0 0 60px rgba(255, 106, 0, 0.08);
  --font: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
  --header-h: 62px;
  --sticky-h: 88px;
  --wrap: 1120px;
}

*, *::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;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--orange-light); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--orange); }
.wrap { width: min(var(--wrap), 92vw); margin: 0 auto; }

/* ── Header ── */
.site-header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  height: var(--header-h);
  background: rgba(6, 6, 8, 0.92);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 100%;
}
.brand {
  display: flex; align-items: center; gap: 12px;
  color: var(--text-primary);
}
.brand img { width: 42px; height: 42px; border-radius: 10px; }
.brand-text { display: flex; flex-direction: column; line-height: 1.2; }
.brand-text strong { font-size: 15px; letter-spacing: 0.5px; }
.brand-text em { font-size: 11px; color: var(--text-muted); font-style: normal; letter-spacing: 1px; }
.main-nav { display: flex; gap: 6px; }
.main-nav a {
  padding: 8px 14px; border-radius: var(--radius-sm);
  color: var(--text-secondary); font-size: 14px;
  transition: background 0.2s, color 0.2s;
}
.main-nav a:hover, .main-nav a.active {
  color: var(--text-primary); background: var(--purple-dim);
}
.menu-toggle {
  display: none; flex-direction: column; gap: 5px;
  background: none; border: none; cursor: pointer; padding: 6px;
}
.menu-toggle span {
  display: block; width: 22px; height: 2px;
  background: var(--text-primary); border-radius: 2px;
  transition: transform 0.25s;
}
.mobile-nav {
  display: none; position: fixed; top: var(--header-h); left: 0; right: 0;
  background: var(--bg-panel); border-bottom: 1px solid var(--border);
  padding: 12px 0; z-index: 999; transform: translateY(-110%);
  transition: transform 0.3s;
}
.mobile-nav.open { transform: translateY(0); }
.mobile-nav a {
  display: block; padding: 12px 24px;
  color: var(--text-secondary); font-size: 15px;
}
.mobile-nav a.active { color: var(--orange); }

/* ── Sticky Download Bar ── */
.sticky-dl {
  position: fixed; top: var(--header-h); left: 0; right: 0; z-index: 998;
  background: rgba(15, 16, 22, 0.96);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-accent);
  padding: 8px 0;
  transform: translateY(-120%);
  opacity: 0;
  transition: transform 0.35s, opacity 0.35s;
  pointer-events: none;
}
.sticky-dl.visible { transform: translateY(0); opacity: 1; pointer-events: auto; }
.sticky-dl .ad-grid {
  display: flex; flex-wrap: wrap; justify-content: center;
  gap: 6px 10px;
}
.sticky-dl .ad-grid > div { width: calc(12.5% - 10px); min-width: 70px; max-width: 80px; }
.sticky-dl .ad-grid img { width: 100%; aspect-ratio: 1; border-radius: 14px; object-fit: cover; }
.sticky-dl .ad-grid .caption { font-size: 10px; color: var(--text-muted); text-align: center; margin-top: 2px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

/* ── Ad Zone ── */
.dl-zone {
  padding-top: calc(var(--header-h) + 24px);
  padding-bottom: 20px;
  background: linear-gradient(180deg, var(--bg-panel) 0%, var(--bg-deep) 100%);
}
.dl-zone-head { text-align: center; margin-bottom: 16px; }
.dl-zone-head h2 { font-size: clamp(18px, 4vw, 24px); font-weight: 600; margin-bottom: 6px; }
.dl-zone-head p { color: var(--text-secondary); font-size: 14px; }
#ads {
  display: flex; justify-content: center; align-items: flex-start;
  flex-wrap: wrap; gap: 8px 14px; margin: 10px 0;
}
#ads > div { display: flex; flex-direction: column; align-items: center; width: 70px; }
#ads img {
  width: 65px; height: 65px; object-fit: cover;
  border-radius: 18px; border: 2px solid var(--border-accent);
  box-shadow: 0 6px 20px rgba(0,0,0,0.4);
  transition: transform 0.2s, box-shadow 0.2s;
}
#ads a { display: inline-block; border-radius: 15px; }
#ads img:hover { transform: translateY(-3px) scale(1.05); box-shadow: 0 10px 28px var(--orange-glow); }
#ads .caption { height: 15px; font-size: 11px; color: var(--text-muted); text-align: center; max-width: 100px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; margin-top: 4px; }

/* ── Hero ── */
.hero {
  position: relative; padding: 48px 0 64px;
  overflow: hidden;
}
.hero::before {
  content: ""; position: absolute; inset: 0;
  background: radial-gradient(ellipse 70% 50% at 20% 40%, rgba(255,106,0,0.07) 0%, transparent 70%),
              radial-gradient(ellipse 50% 40% at 80% 60%, rgba(139,92,246,0.06) 0%, transparent 70%);
  pointer-events: none;
}
.hero-grid {
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 40px; align-items: center;
}
.hero-badge {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 6px 14px; border-radius: 999px;
  background: rgba(255,106,0,0.1); border: 1px solid var(--border-accent);
  font-size: 12px; color: var(--orange-light); letter-spacing: 0.5px;
  margin-bottom: 20px;
}
.hero-badge::before { content: ""; width: 6px; height: 6px; border-radius: 50%; background: var(--orange); animation: pulse 2s infinite; }
@keyframes pulse { 0%,100% { opacity: 1; } 50% { opacity: 0.4; } }
.hero h1 {
  font-size: clamp(28px, 5.5vw, 44px);
  font-weight: 700; line-height: 1.25;
  margin-bottom: 18px;
  background: linear-gradient(135deg, #fff 40%, var(--orange-light));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-lead { color: var(--text-secondary); font-size: clamp(14px, 2.5vw, 17px); margin-bottom: 28px; max-width: 520px; }
.hero-tags { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 32px; }
.hero-tags span {
  padding: 5px 12px; border-radius: var(--radius-sm);
  background: var(--bg-card); border: 1px solid var(--border);
  font-size: 12px; color: var(--text-secondary);
}
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; }
.btn-primary {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 14px 28px; border-radius: var(--radius-md);
  background: linear-gradient(135deg, var(--orange) 0%, #e85d00 100%);
  color: #fff; font-size: 15px; font-weight: 600;
  border: none; cursor: pointer;
  box-shadow: 0 4px 24px var(--orange-glow);
  transition: transform 0.2s, box-shadow 0.2s;
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 32px var(--orange-glow); color: #fff; }
.btn-outline {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 14px 28px; border-radius: var(--radius-md);
  background: transparent; color: var(--text-primary);
  font-size: 15px; border: 1px solid var(--border);
  cursor: pointer; transition: border-color 0.2s, background 0.2s;
}
.btn-outline:hover { border-color: var(--orange); background: rgba(255,106,0,0.05); color: var(--text-primary); }

/* Hero Phone Stack */
.hero-phones {
  position: relative; height: 480px;
  display: flex; justify-content: center; align-items: center;
}
.phone-frame {
  position: absolute; width: 210px;
  border-radius: 28px; overflow: hidden;
  border: 3px solid rgba(255,255,255,0.08);
  box-shadow: 0 24px 60px rgba(0,0,0,0.55), var(--shadow-glow);
  transition: transform 0.4s;
}
.phone-frame img { width: 100%; aspect-ratio: 9/19.5; object-fit: cover; object-position: top; }
.phone-frame:nth-child(1) { transform: rotate(-8deg) translateX(-80px) translateY(20px); z-index: 1; }
.phone-frame:nth-child(2) { transform: rotate(2deg) translateX(0) translateY(-10px); z-index: 3; width: 230px; }
.phone-frame:nth-child(3) { transform: rotate(10deg) translateX(90px) translateY(30px); z-index: 2; }
.phone-frame:nth-child(4) { transform: rotate(-3deg) translateX(30px) translateY(60px); z-index: 0; width: 190px; opacity: 0.85; }

/* ── Metrics Strip ── */
.metrics {
  padding: 32px 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  background: var(--bg-panel);
}
.metrics-grid {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px;
  text-align: center;
}
.metric-num {
  font-size: clamp(24px, 4vw, 32px); font-weight: 700;
  color: var(--orange); line-height: 1.2;
}
.metric-label { font-size: 13px; color: var(--text-muted); margin-top: 4px; }

/* ── Section Common ── */
.section { padding: 64px 0; }
.section-label {
  display: inline-block; font-size: 11px; letter-spacing: 2px;
  text-transform: uppercase; color: var(--orange);
  margin-bottom: 10px; font-weight: 600;
}
.section-title {
  font-size: clamp(22px, 4vw, 32px); font-weight: 700;
  margin-bottom: 14px; line-height: 1.3;
}
.section-desc { color: var(--text-secondary); max-width: 640px; margin-bottom: 40px; font-size: 15px; }

/* ── Intro Block (text-heavy SEO) ── */
.intro-block {
  background: var(--bg-panel);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}
.intro-content { max-width: 820px; }
.intro-content h2 { font-size: clamp(20px, 3.5vw, 28px); margin-bottom: 20px; }
.intro-content h3 { font-size: 18px; margin: 28px 0 12px; color: var(--orange-light); }
.intro-content p { color: var(--text-secondary); margin-bottom: 16px; text-align: justify; }
.intro-content ul { margin: 12px 0 20px 20px; color: var(--text-secondary); }
.intro-content li { margin-bottom: 8px; }

/* ── Feature Cards ── */
.features-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px;
}
.feat-card {
  background: var(--bg-card); border-radius: var(--radius-lg);
  padding: 28px 24px; border: 1px solid var(--border);
  border-left: 3px solid var(--orange);
  transition: transform 0.25s, box-shadow 0.25s;
}
.feat-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-glow); }
.feat-icon {
  width: 44px; height: 44px; border-radius: 12px;
  background: var(--purple-dim); display: flex;
  align-items: center; justify-content: center;
  font-size: 20px; margin-bottom: 16px;
}
.feat-card h3 { font-size: 17px; margin-bottom: 10px; }
.feat-card p { font-size: 14px; color: var(--text-secondary); line-height: 1.65; }

/* ── Showcase Rows (3:7 text:image) ── */
.showcase {
  display: grid; grid-template-columns: 7fr 3fr;
  gap: 40px; align-items: center;
  padding: 48px 0;
  border-bottom: 1px solid var(--border);
}
.showcase.reverse { grid-template-columns: 3fr 7fr; }
.showcase.reverse .showcase-text { order: 2; }
.showcase.reverse .showcase-visual { order: 1; }
.showcase-text h3 { font-size: 22px; margin-bottom: 14px; }
.showcase-text p { color: var(--text-secondary); margin-bottom: 12px; font-size: 14px; text-align: justify; }
.showcase-text ul { margin: 10px 0 0 18px; color: var(--text-secondary); font-size: 14px; }
.showcase-text li { margin-bottom: 6px; }
.showcase-visual {
  position: relative; border-radius: var(--radius-lg);
  overflow: hidden; border: 1px solid var(--border);
  box-shadow: 0 16px 48px rgba(0,0,0,0.4);
}
.showcase-visual img { width: 100%; aspect-ratio: 9/16; object-fit: cover; object-position: top; max-height: 420px; }
.showcase-visual::after {
  content: ""; position: absolute; inset: 0;
  background: linear-gradient(180deg, transparent 60%, rgba(6,6,8,0.5) 100%);
  pointer-events: none;
}

/* ── Module Tabs ── */
.modules-grid {
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px;
}
.module-card {
  background: var(--bg-card); border-radius: var(--radius-lg);
  padding: 24px; border: 1px solid var(--border);
  display: flex; gap: 18px; align-items: flex-start;
}
.module-card .mod-num {
  flex-shrink: 0; width: 36px; height: 36px;
  border-radius: 10px; background: var(--orange);
  color: #fff; font-weight: 700; font-size: 14px;
  display: flex; align-items: center; justify-content: center;
}
.module-card h3 { font-size: 16px; margin-bottom: 8px; }
.module-card p { font-size: 13px; color: var(--text-secondary); line-height: 1.6; }

/* ── Steps ── */
.steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.step-item {
  text-align: center; padding: 24px 16px;
  background: var(--bg-card); border-radius: var(--radius-md);
  border: 1px solid var(--border);
}
.step-num {
  width: 40px; height: 40px; border-radius: 50%;
  background: linear-gradient(135deg, var(--orange), var(--purple));
  color: #fff; font-weight: 700; font-size: 16px;
  display: flex; align-items: center; justify-content: center;
  margin: 0 auto 14px;
}
.step-item h4 { font-size: 15px; margin-bottom: 8px; }
.step-item p { font-size: 13px; color: var(--text-muted); }

/* ── FAQ ── */
.faq-list { max-width: 780px; }
.faq-item { border-bottom: 1px solid var(--border); }
.faq-q {
  width: 100%; text-align: left; padding: 18px 0;
  background: none; border: none; color: var(--text-primary);
  font-size: 15px; font-weight: 600; cursor: pointer;
  display: flex; justify-content: space-between; align-items: center;
  font-family: var(--font);
}
.faq-q::after { content: "+"; font-size: 20px; color: var(--orange); 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; }
.faq-a-inner { padding: 0 0 18px; color: var(--text-secondary); font-size: 14px; line-height: 1.7; }
.faq-item.open .faq-a { max-height: 400px; }

/* ── SEO Rich Text Blocks ── */
.seo-rich {
  background: var(--bg-panel);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}
.seo-rich-inner { max-width: 860px; }
.seo-rich-inner h2 { font-size: clamp(20px, 3.5vw, 28px); margin-bottom: 18px; }
.seo-rich-inner h3 { font-size: 18px; margin: 26px 0 12px; color: var(--orange-light); }
.seo-rich-inner p { color: var(--text-secondary); margin-bottom: 14px; text-align: justify; font-size: 14px; line-height: 1.85; }
.seo-rich-inner ul, .seo-rich-inner ol { margin: 10px 0 18px 22px; color: var(--text-secondary); font-size: 14px; }
.seo-rich-inner li { margin-bottom: 8px; line-height: 1.7; }
.seo-columns {
  display: grid; grid-template-columns: 1fr 1fr; gap: 32px; margin-top: 24px;
}
.seo-col { background: var(--bg-card); border-radius: var(--radius-md); padding: 24px; border: 1px solid var(--border); }
.seo-col h4 { font-size: 16px; margin-bottom: 12px; color: var(--text-primary); }
.seo-col p { font-size: 13px; margin-bottom: 10px; }

/* ── Mini Gallery (inline screenshots) ── */
.mini-gallery {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin: 32px 0;
}
.mini-gallery figure {
  background: var(--bg-card); border-radius: var(--radius-md);
  overflow: hidden; border: 1px solid var(--border);
}
.mini-gallery img { width: 100%; aspect-ratio: 9/16; object-fit: cover; object-position: top; max-height: 280px; }
.mini-gallery figcaption { padding: 10px 12px; font-size: 12px; color: var(--text-muted); line-height: 1.5; }

/* ── Compare Table ── */
.compare-table {
  width: 100%; border-collapse: collapse; margin: 20px 0 28px; font-size: 14px;
}
.compare-table th, .compare-table td {
  padding: 12px 16px; border: 1px solid var(--border); text-align: left;
}
.compare-table th { background: var(--bg-card); color: var(--orange-light); font-weight: 600; }
.compare-table td { color: var(--text-secondary); }
.compare-table tr:nth-child(even) td { background: rgba(255,255,255,0.02); }

/* ── CTA Banner ── */
.cta-banner {
  padding: 56px 0; text-align: center;
  background: linear-gradient(135deg, rgba(255,106,0,0.08) 0%, rgba(139,92,246,0.06) 100%);
  border-top: 1px solid var(--border-accent);
  border-bottom: 1px solid var(--border-accent);
}
.cta-banner h2 { font-size: clamp(22px, 4vw, 30px); margin-bottom: 12px; }
.cta-banner p { color: var(--text-secondary); margin-bottom: 28px; font-size: 15px; }

/* ── Footer ── */
.site-footer {
  padding: 48px 0 32px;
  background: var(--bg-panel);
  border-top: 1px solid var(--border);
}
.footer-grid {
  display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 32px;
  margin-bottom: 32px;
}
.footer-brand p { color: var(--text-muted); font-size: 13px; margin-top: 12px; max-width: 320px; line-height: 1.6; }
.footer-col h4 { font-size: 14px; margin-bottom: 14px; color: var(--text-primary); }
.footer-col a { display: block; color: var(--text-muted); font-size: 13px; padding: 4px 0; }
.footer-col a:hover { color: var(--orange); }
.footer-bottom {
  padding-top: 24px; border-top: 1px solid var(--border);
  text-align: center; font-size: 12px; color: var(--text-muted);
}

/* ── Breadcrumb ── */
.breadcrumb {
  padding: calc(var(--header-h) + 20px) 0 16px;
  font-size: 13px; color: var(--text-muted);
}
.breadcrumb a { color: var(--text-secondary); }
.breadcrumb span { margin: 0 8px; }

/* ── Subpage Content ── */
.page-content { padding: 24px 0 64px; }
.page-content h1 { font-size: clamp(24px, 4vw, 32px); margin-bottom: 20px; }
.page-content h2 { font-size: 20px; margin: 32px 0 12px; color: var(--orange-light); }
.page-content h3 { font-size: 17px; margin: 24px 0 10px; }
.page-content p, .page-content li { color: var(--text-secondary); font-size: 14px; margin-bottom: 12px; text-align: justify; }
.page-content ul, .page-content ol { margin: 12px 0 20px 24px; }
.page-content ul li, .page-content ol li { margin-bottom: 8px; }

/* ── Error Pages ── */
.error-page {
  min-height: 70vh; display: flex; align-items: center; justify-content: center;
  text-align: center; padding: calc(var(--header-h) + 40px) 20px 60px;
}
.error-code { font-size: clamp(64px, 15vw, 120px); font-weight: 800; color: var(--orange); line-height: 1; opacity: 0.7; }
.error-page h1 { font-size: clamp(20px, 4vw, 28px); margin: 16px 0 12px; }
.error-page p { color: var(--text-secondary); margin-bottom: 28px; max-width: 440px; margin-left: auto; margin-right: auto; }

/* ── Responsive ── */
@media (max-width: 960px) {
  .hero-grid { grid-template-columns: 1fr; gap: 32px; }
  .hero-phones { height: 380px; order: -1; }
  .phone-frame { width: 160px; }
  .phone-frame:nth-child(2) { width: 180px; }
  .phone-frame:nth-child(4) { width: 150px; }
  .phone-frame:nth-child(1) { transform: rotate(-6deg) translateX(-60px) translateY(10px); }
  .phone-frame:nth-child(3) { transform: rotate(8deg) translateX(70px) translateY(20px); }
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .showcase, .showcase.reverse { grid-template-columns: 1fr; }
  .showcase.reverse .showcase-text, .showcase.reverse .showcase-visual { order: unset; }
  .steps { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr; gap: 24px; }
  .metrics-grid { grid-template-columns: repeat(2, 1fr); }
  .modules-grid { grid-template-columns: 1fr; }
}
@media (max-width: 768px) {
  .main-nav { display: none; }
  .menu-toggle { display: flex; }
  .mobile-nav { display: block; }
  .sticky-dl { padding: 4px 0; }
  .sticky-dl .ad-grid { gap: 3px 5px; }
  .sticky-dl .ad-grid > div { width: calc(25% - 5px); min-width: unset; max-width: 48px; }
  .sticky-dl .ad-grid img { border-radius: 10px; }
  .sticky-dl .ad-grid .caption { display: none; }
  .features-grid { grid-template-columns: 1fr; }
  .steps { grid-template-columns: 1fr; }
  .seo-columns { grid-template-columns: 1fr; }
  .mini-gallery { grid-template-columns: 1fr 1fr; gap: 10px; }
  .mini-gallery img { max-height: 200px; }
  .compare-table { display: block; overflow-x: auto; white-space: nowrap; font-size: 12px; }
  .compare-table th, .compare-table td { padding: 10px 12px; }
  .hero-phones { height: 320px; }
  .phone-frame { width: 130px; }
  .phone-frame:nth-child(2) { width: 150px; }
  .phone-frame:nth-child(4) { display: none; }
  .phone-frame:nth-child(1) { transform: rotate(-5deg) translateX(-45px); }
  .phone-frame:nth-child(3) { transform: rotate(6deg) translateX(55px); }
}
@media (min-width: 769px) {
  .sticky-dl .ad-grid > div { width: calc(12.5% - 10px); }
}