/* ==========================================
 * 字母社区 - 暗黑深红渐变 & 毛玻璃主题
 * ========================================== */
:root {
  --text-main: #e0e0e0;
  --text-muted: #a09090;
  --accent-red: #ff3333;
  --accent-light: #ffb3b3;
  --glass-bg: rgba(20, 0, 5, 0.55);
  --glass-border: rgba(255, 50, 50, 0.15);
  --glass-shadow: 0 10px 40px rgba(0, 0, 0, 0.8), 0 0 20px rgba(139, 0, 0, 0.3);
  --font-stack: 'Helvetica Neue', Helvetica, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --gutter: clamp(20px, 4vw, 50px);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-stack);
  color: var(--text-main);
  background-color: #000;
  overflow-x: hidden;
  line-height: 1.8;
}
a { text-decoration: none; color: inherit; }
h1, h2, h3, h4 { color: var(--accent-light); font-weight: 400; text-shadow: 0 0 15px rgba(255, 0, 50, 0.6); }

/* ==========================================
 * 动态暗黑背景与发光氛围
 * ========================================== */
.bg-animation {
  position: fixed; inset: 0; z-index: -10;
  background: linear-gradient(-45deg, #080000, #1a0000, #3a0005, #000000);
  background-size: 400% 400%;
  animation: gradientBG 15s ease infinite;
}
@keyframes gradientBG { 0% { background-position: 0% 50%; } 50% { background-position: 100% 50%; } 100% { background-position: 0% 50%; } }

.ambient-glow-1, .ambient-glow-2 {
  position: fixed; width: 50vw; height: 50vh; filter: blur(70px); z-index: -5; pointer-events: none; opacity: 0.8;
}
.ambient-glow-1 { top: -20%; left: -10%; background: radial-gradient(circle, rgba(139,0,0,0.15) 0%, transparent 70%); }
.ambient-glow-2 { bottom: -20%; right: -10%; background: radial-gradient(circle, rgba(220,20,60,0.1) 0%, transparent 70%); }

.reveal { opacity: 0; transform: translateY(30px); transition: all 0.8s cubic-bezier(0.25, 0.46, 0.45, 0.94); }
.reveal.reveal-visible { opacity: 1; transform: translateY(0); }

/* ==========================================
 * 通用组件: 毛玻璃面板、渐变按钮
 * ========================================== */
.glass-panel {
  background: var(--glass-bg);
  backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  border-radius: 20px;
  box-shadow: var(--glass-shadow);
  padding: 40px;
}
.highlight { color: var(--accent-red); font-weight: 600; }
.divider { width: 40%; height: 1px; background: linear-gradient(90deg, transparent, rgba(220, 20, 60, 0.5), transparent); margin: 30px auto; border: none; }
.num { display: block; font-size: 16px; font-weight: 700; color: var(--accent-red); letter-spacing: 2px; margin-bottom: 10px; }

/* 诱惑发光按钮设计 */
.glow-btn {
  display: flex; flex-direction: column; justify-content: center; align-items: center;
  padding: 12px 25px; min-width: 180px;
  color: #ffcccc; border: 1px solid rgba(220, 20, 60, 0.4); border-radius: 50px;
  background: rgba(0, 0, 0, 0.4);
  transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  position: relative; overflow: hidden;
}
.glow-btn::before {
  content: ''; position: absolute; top: 0; left: -100%; width: 100%; height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.15), transparent);
  transition: all 0.4s ease;
}
.glow-btn:hover {
  background: rgba(139, 0, 0, 0.7); color: #ffffff; border-color: var(--accent-red);
  box-shadow: 0 0 20px rgba(220, 20, 60, 0.6), inset 0 0 10px rgba(255, 255, 255, 0.1);
  transform: scale(1.03);
}
.glow-btn:hover::before { left: 100%; transition: all 0.6s ease; }
.glow-btn strong { font-size: 16px; font-weight: 600; letter-spacing: 1px; margin-bottom: 3px; }
.glow-btn small { font-size: 11px; opacity: 0.7; }
.ios-btn { border-color: rgba(150, 100, 200, 0.4); }
.ios-btn:hover { background: rgba(80, 0, 100, 0.6); border-color: #b57de8; box-shadow: 0 0 20px rgba(150, 100, 200, 0.5); }

/* ==========================================
 * 导航栏
 * ========================================== */
.crimson-header { position: fixed; top: 0; width: 100%; z-index: 100; background: rgba(8, 0, 0, 0.7); backdrop-filter: blur(10px); 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(--gutter); }
.brand-logo { display: flex; align-items: center; gap: 12px; }
.brand-logo img { width: 32px; height: 32px; filter: drop-shadow(0 0 10px rgba(220,20,60,0.5)); }
.brand-name { font-size: 18px; font-weight: 700; letter-spacing: 2px; color: var(--accent-light); }
.desktop-nav { display: flex; gap: 30px; }
.desktop-nav a { font-size: 14px; color: var(--text-muted); transition: color 0.3s; }
.desktop-nav a:hover { color: #fff; text-shadow: 0 0 10px var(--accent-red); }
.mobile-menu-btn { display: none; background: transparent; border: 1px solid var(--glass-border); color: var(--accent-light); padding: 8px 15px; border-radius: 6px; cursor: pointer; }

/* ==========================================
 * 主体内容区布局
 * ========================================== */
.main-container { max-width: 1200px; margin: 0 auto; padding: 100px var(--gutter) 60px; }
.hero-section { text-align: center; margin-bottom: 60px; }
.hero-panel { padding: 60px 40px; }
.hero-tags span { display: inline-block; padding: 5px 15px; border: 1px solid var(--glass-border); border-radius: 20px; font-size: 11px; letter-spacing: 2px; color: var(--text-muted); margin-bottom: 25px; }
.hero-panel h1 { font-size: clamp(30px, 5vw, 48px); line-height: 1.4; margin-bottom: 25px; letter-spacing: 2px; }
.hero-desc { font-size: 15px; color: var(--text-muted); max-width: 700px; margin: 0 auto 30px; }
.hero-note { font-size: 11px; color: #665555; margin-top: 30px; }

/* 下载网格 (二维码+按钮) */
.dl-grid { display: flex; justify-content: center; gap: 30px; flex-wrap: wrap; margin-top: 30px; }
.dl-item { display: flex; align-items: center; gap: 15px; background: rgba(0,0,0,0.3); padding: 15px; border-radius: 16px; border: 1px solid var(--glass-border); }
.dl-qr { width: 70px; height: 70px; border-radius: 8px; padding: 4px; background: #fff; }

.value-bar { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 20px; margin-bottom: 80px; text-align: center; }
.mini-panel { padding: 25px; }
.mini-panel strong { display: block; font-size: 18px; color: var(--accent-red); letter-spacing: 1px; margin-bottom: 5px; }
.mini-panel span { font-size: 13px; color: var(--text-muted); }

/* 详情板块 */
.content-section { margin-bottom: 100px; }
.section-title { margin-bottom: 30px; }
.section-title h2 { font-size: clamp(26px, 4vw, 36px); line-height: 1.4; letter-spacing: 1px; }
.section-sub { font-size: 14px; color: var(--text-muted); margin-top: 15px; }
.text-center { text-align: center; }

.card-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 20px; }
.card { padding: 30px; transition: transform 0.3s; }
.card:hover { transform: translateY(-5px); background: rgba(40,0,10,0.55); }
.card h3 { font-size: 18px; margin-bottom: 15px; color: #ffcccc; }
.card p { font-size: 14px; color: var(--text-muted); }
.card-tag { display: inline-block; font-size: 10px; color: var(--accent-red); margin-bottom: 10px; border-bottom: 1px solid var(--glass-border); padding-bottom: 4px; }

.guide-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }

.vision-panel { display: flex; flex-wrap: wrap; gap: 40px; align-items: center; }
.vision-text { flex: 1; min-width: 300px; }
.vision-list { flex: 1.5; display: flex; flex-direction: column; gap: 20px; border-left: 1px solid var(--glass-border); padding-left: 30px; }
.v-item h4 { font-size: 16px; margin-bottom: 5px; }
.v-item p { font-size: 13px; color: var(--text-muted); }

.faq-panel { padding: 20px 40px; }
details { padding: 20px 0; border-bottom: 1px solid var(--glass-border); }
details:last-child { border-bottom: none; }
summary { font-size: 15px; font-weight: 600; color: #ffcccc; cursor: pointer; list-style: none; display: flex; align-items: center; }
summary::-webkit-details-marker { display: none; }
summary::before { content: "» "; color: var(--accent-red); margin-right: 10px; font-size: 18px; }
details p { margin-top: 15px; padding-left: 25px; font-size: 13.5px; color: var(--text-muted); }

/* ==========================================
 * 页脚
 * ========================================== */
.glass-footer { background: rgba(5,0,0,0.8); border-top: 1px solid var(--glass-border); padding: 50px var(--gutter) 20px; }
.footer-content { max-width: 1200px; margin: 0 auto 40px; display: flex; justify-content: space-between; flex-wrap: wrap; gap: 30px; }
.footer-content .brand h2 { font-size: 22px; margin-bottom: 10px; letter-spacing: 2px; }
.footer-content .slogan { text-align: right; font-size: 13px; color: var(--text-muted); }
.copyright { max-width: 1200px; margin: 0 auto; border-top: 1px solid rgba(255,255,255,0.05); padding-top: 20px; text-align: center; font-size: 12px; color: #665555; }

/* ==========================================
 * 移动端适配
 * ========================================== */
@media (max-width: 900px) {
  .guide-grid { grid-template-columns: 1fr; }
  .vision-panel { flex-direction: column; }
  .vision-list { border-left: none; padding-left: 0; border-top: 1px solid var(--glass-border); padding-top: 20px; }
  .dl-grid { flex-direction: column; align-items: center; }
  .dl-item { width: 100%; max-width: 320px; }
}

@media (max-width: 768px) {
  .desktop-nav { display: none; position: absolute; top: 60px; left: 0; width: 100%; background: #000; flex-direction: column; padding: 20px 0; border-bottom: 1px solid var(--glass-border); }
  .desktop-nav.active { display: flex; }
  .mobile-menu-btn { display: block; }
  .mobile-menu-btn::after { content: "≡"; font-size: 20px; }
  .glass-panel { padding: 30px 20px; }
  .faq-panel { padding: 10px 20px; }
  .footer-content { flex-direction: column; text-align: center; }
  .footer-content .slogan { text-align: center; }
}