/* ==========================================
 *                社交风 CSS
 * ========================================== */
:root {
  --bg-color: #0b0714;
  --glass-bg: rgba(255, 255, 255, 0.04);
  --glass-border: rgba(255, 255, 255, 0.08);
  --text-main: #f3f0f8;
  --text-muted: #a39cae;
  --accent-pink: #ff3366;
  --accent-purple: #9d4edd;
  --gradient-neon: linear-gradient(135deg, var(--accent-pink), var(--accent-purple));
  --font-stack: -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue", sans-serif;
  --spacing-container: clamp(20px, 5vw, 60px);
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0; padding: 0;
  background-color: var(--bg-color); color: var(--text-main);
  font-family: var(--font-stack); line-height: 1.8;
  overflow-x: hidden;
}
a { text-decoration: none; color: inherit; transition: all 0.3s ease; }
h1, h2, h3, p { margin: 0; }
ul, ol { margin: 0; padding-left: 20px; }

/* ==========================================
 * 背景特效与全局动效
 * ========================================== */
.ambient-glow { position: fixed; inset: 0; z-index: -1; pointer-events: none; overflow: hidden; }
.glow-orb { position: absolute; border-radius: 50%; filter: blur(140px); opacity: 0.35; animation: float 15s infinite alternate ease-in-out; }
.orb-primary { width: 500px; height: 500px; background: var(--accent-pink); top: -150px; left: -100px; }
.orb-secondary { width: 600px; height: 600px; background: var(--accent-purple); bottom: -200px; right: -200px; animation-delay: -5s; }
.orb-accent { width: 300px; height: 300px; background: #5a189a; top: 40%; left: 60%; animation-duration: 20s; }
@keyframes float { 0% { transform: translate(0,0) scale(1); } 100% { transform: translate(100px, 100px) scale(1.1); } }

.reveal { opacity: 0; transform: translateY(40px); transition: all 0.8s cubic-bezier(0.25, 0.46, 0.45, 0.94); }
.reveal.reveal-visible { opacity: 1; transform: translateY(0); }

/* ==========================================
 * 通用 UI 组件
 * ========================================== */
.gradient-text { background: var(--gradient-neon); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.glass-panel { background: var(--glass-bg); backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px); border: 1px solid var(--glass-border); border-radius: 24px; padding: 40px; }
.glass-card { background: var(--glass-bg); backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px); border: 1px solid var(--glass-border); border-radius: 16px; padding: 30px; transition: transform 0.3s; }
.glass-card:hover { transform: translateY(-5px); background: rgba(255,255,255,0.06); }
.kicker { display: inline-block; font-size: 11px; font-weight: 700; letter-spacing: 2px; color: var(--accent-pink); margin-bottom: 12px; }

/* ==========================================
 * 导航栏
 * ========================================== */
.social-header { position: fixed; top: 0; width: 100%; z-index: 100; background: rgba(11,7,20,0.7); backdrop-filter: blur(15px); border-bottom: 1px solid var(--glass-border); }
.header-inner { display: flex; justify-content: space-between; align-items: center; max-width: 1200px; margin: 0 auto; padding: 15px var(--spacing-container); }
.brand-logo { display: flex; align-items: center; gap: 12px; }
.brand-logo img { border-radius: 10px; }
.brand-text strong { display: block; font-size: 18px; font-weight: 700; letter-spacing: 2px; }
.brand-text span { font-size: 9px; color: var(--text-muted); letter-spacing: 1px; }
.desktop-nav { display: flex; gap: 30px; align-items: center; }
.desktop-nav a { font-size: 14px; color: var(--text-muted); font-weight: 500; }
.desktop-nav a:hover { color: #fff; }
.nav-highlight { padding: 8px 20px; background: var(--gradient-neon); color: #fff !important; border-radius: 30px; font-size: 13px; }
.mobile-menu-btn { display: none; background: transparent; border: 1px solid var(--glass-border); padding: 10px; border-radius: 8px; color: #fff; }

/* ==========================================
 * 页面布局与首屏 (Hero)
 * ========================================== */
.main-content { max-width: 1200px; margin: 0 auto; padding: 120px var(--spacing-container) 60px; }
.section-head { margin-bottom: 40px; }
.section-head h2 { font-size: clamp(28px, 4vw, 38px); line-height: 1.4; }
.section-head.text-center { text-align: center; }
.head-desc { color: var(--text-muted); font-size: 15px; margin-top: 15px; max-width: 700px; }

.hero-section { text-align: center; padding: 40px 0 80px; }
.hero-tags { margin-bottom: 25px; display: flex; justify-content: center; gap: 15px; flex-wrap: wrap; }
.tag { font-size: 10px; letter-spacing: 2px; padding: 6px 16px; border: 1px solid var(--glass-border); border-radius: 20px; color: var(--text-muted); }
.hero-title { font-size: clamp(32px, 6vw, 56px); font-weight: 800; line-height: 1.25; margin-bottom: 25px; }
.hero-desc { font-size: 16px; color: var(--text-muted); max-width: 800px; margin: 0 auto 45px; line-height: 1.9; }

/* 下载卡片 (支持双端带二维码) */
.hero-downloads { display: flex; justify-content: center; gap: 20px; flex-wrap: wrap; margin-bottom: 50px; }
.dl-card { padding: 15px; display: flex; align-items: center; gap: 15px; min-width: 260px; border-radius: 20px; }
.dl-qr { width: 70px; height: 70px; border-radius: 12px; background: #fff; padding: 4px; flex-shrink: 0; }
.dl-btn { display: flex; flex-direction: column; justify-content: center; flex: 1; padding: 12px 20px; border-radius: 12px; transition: transform 0.2s; }
.btn-android { background: #fff; color: #111; }
.btn-ios { background: #241b35; border: 1px solid var(--glass-border); color: #fff; }
.dl-btn:hover { transform: scale(1.03); }
.btn-title { font-size: 16px; font-weight: 700; margin-bottom: 4px; }
.btn-sub { font-size: 11px; opacity: 0.8; }

.hero-nav { display: flex; justify-content: center; gap: 30px; border-top: 1px solid var(--glass-border); padding-top: 30px; font-size: 11px; letter-spacing: 1.5px; color: var(--text-muted); }

/* ==========================================
 * 模块细节
 * ========================================== */
.info-section { margin-bottom: 120px; }
.content-box p { font-size: 15px; color: #d1ccda; margin-bottom: 20px; }
.content-box p:last-child { margin-bottom: 0; }
.source-note { margin-top: 30px; padding-top: 20px; border-top: 1px solid var(--glass-border); font-size: 12px; color: #847a96; }
.source-note a { color: var(--accent-pink); text-decoration: underline; }

.grid-section { margin-bottom: 120px; }
.feature-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 20px; }
.feature-grid h3 { font-size: 18px; margin-bottom: 15px; color: #fff; }
.feature-grid p { font-size: 14px; color: var(--text-muted); }

.guide-section { margin-bottom: 120px; }
.guide-layout { display: grid; grid-template-columns: 1fr 1.5fr; gap: 60px; }
.side-note { margin-top: 25px; padding-left: 20px; border-left: 2px solid var(--accent-pink); font-size: 13px; color: var(--text-muted); }
.guide-content { display: flex; flex-direction: column; gap: 25px; }
.guide-item h3 { font-size: 19px; margin-bottom: 15px; }
.guide-item p { font-size: 14px; color: var(--text-muted); }

.download-section { margin-bottom: 120px; }
.download-glass { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; align-items: center; background: linear-gradient(145deg, rgba(255,51,102,0.05), rgba(157,78,221,0.1)); border-color: rgba(255,51,102,0.2); }
.dl-text p { font-size: 14px; color: var(--text-muted); margin-top: 20px; line-height: 2; }
.dl-actions { display: flex; flex-direction: column; gap: 15px; }
.dl-box { display: flex; align-items: center; gap: 15px; background: rgba(0,0,0,0.4); padding: 15px; border-radius: 20px; border: 1px solid var(--glass-border); }
.dl-box .dl-btn { min-width: 180px; align-items: center; }
.dl-steps { grid-column: 1 / -1; margin-top: 20px; padding-top: 30px; border-top: 1px dashed rgba(255,255,255,0.1); font-size: 13px; color: #b8b1c5; }
.dl-steps li { margin-bottom: 10px; }

.covenant-section { margin-bottom: 120px; }
.covenant-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 25px; }
.covenant-grid h3 { font-size: 18px; margin-bottom: 15px; }
.covenant-grid p { font-size: 14px; color: var(--text-muted); }

.faq-section { margin-bottom: 80px; }
.faq-container { padding: 10px 40px; }
.faq-item { border-bottom: 1px solid var(--glass-border); padding: 25px 0; }
.faq-item:last-child { border-bottom: none; }
.faq-item summary { font-size: 16px; font-weight: 600; cursor: pointer; list-style: none; display: flex; align-items: center; }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::before { content: "Q."; color: var(--accent-pink); margin-right: 10px; font-weight: 800; font-size: 14px; }
.faq-item p { margin-top: 15px; padding-left: 28px; font-size: 14px; color: var(--text-muted); animation: fade 0.3s ease; }
@keyframes fade { from { opacity: 0; transform: translateY(-5px); } to { opacity: 1; transform: translateY(0); } }

/* ==========================================
 * 页脚
 * ========================================== */
.social-footer { border-top: 1px solid var(--glass-border); background: rgba(0,0,0,0.3); padding: 60px var(--spacing-container) 30px; }
.footer-inner { max-width: 1200px; margin: 0 auto 50px; display: grid; grid-template-columns: 1fr 1fr; gap: 40px; }
.brand-name { font-size: 22px; font-weight: 800; color: #fff; margin-bottom: 15px; display: inline-block; }
.footer-brand p { font-size: 15px; margin-bottom: 15px; }
.footer-sub { font-size: 12px; color: var(--text-muted); }
.footer-links nav { display: flex; flex-wrap: wrap; gap: 20px; justify-content: flex-end; }
.footer-links a { font-size: 13px; color: var(--text-muted); }
.footer-bottom { max-width: 1200px; margin: 0 auto; display: flex; justify-content: space-between; border-top: 1px solid var(--glass-border); padding-top: 20px; font-size: 12px; color: #6b637a; }
.highlight-note { color: var(--accent-purple); font-weight: 600; }

/* ==========================================
 * 移动端适配 & 底部悬浮
 * ========================================== */
.mobile-dock { display: none; }

@media (max-width: 992px) {
  .guide-layout { grid-template-columns: 1fr; gap: 40px; }
  .download-glass { grid-template-columns: 1fr; text-align: center; }
  .covenant-grid { grid-template-columns: 1fr; }
  .footer-inner { grid-template-columns: 1fr; text-align: center; }
  .footer-links nav { justify-content: center; }
  .footer-bottom { flex-direction: column; align-items: center; gap: 10px; }
}

@media (max-width: 768px) {
  body { padding-bottom: 90px; }
  .desktop-nav { display: none; position: absolute; top: 70px; left: 0; width: 100%; background: var(--bg-color); flex-direction: column; padding: 20px 0; border-bottom: 1px solid var(--glass-border); }
  .desktop-nav.active { display: flex; }
  .mobile-menu-btn { display: block; border: 1px solid var(--glass-border); background: transparent; color: #fff; padding: 8px 15px; border-radius: 6px; }
  .mobile-menu-btn::after { content: "菜单 ≡"; font-size: 12px; }
  
  .hero-title { font-size: 32px; }
  .hero-downloads { flex-direction: column; align-items: center; }
  .dl-card { width: 100%; }
  .hero-nav { display: none; }
  
  .glass-panel { padding: 25px 20px; }
  .faq-container { padding: 10px 20px; }
  .dl-actions { width: 100%; }
  
  .mobile-dock { display: flex; position: fixed; bottom: 0; left: 0; width: 100%; background: rgba(11,7,20,0.9); backdrop-filter: blur(10px); border-top: 1px solid var(--glass-border); padding: 10px var(--spacing-container); z-index: 100; gap: 15px; }
  .dock-btn { flex: 1; text-align: center; padding: 12px; border-radius: 12px; font-size: 14px; font-weight: 600; }
}