/* ==========================================================
   默聊官网 - 样式表
   纯静态、轻量、响应式
   ========================================================== */

:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --grad: linear-gradient(135deg, #2563eb 0%, #06b6d4 100%);
  --text: #1e293b;
  --text-light: #64748b;
  --bg: #ffffff;
  --bg-alt: #f1f5f9;
  --radius: 16px;
  --shadow: 0 10px 30px rgba(37, 99, 235, .12);
  --shadow-lg: 0 20px 50px rgba(15, 23, 42, .15);
}

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

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  font-size: 16px;
}

img { max-width: 100%; display: block; }
a { color: var(--primary); text-decoration: none; }
a:hover { color: var(--primary-dark); }

.container { width: min(1120px, 92%); margin: 0 auto; }

/* ---------------- 顶部导航 ---------------- */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255, 255, 255, .92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid #eef2f7;
}
.nav-wrap { display: flex; align-items: center; justify-content: space-between; height: 64px; }

.brand { display: flex; align-items: center; gap: 10px; color: var(--text); }
.brand img { border-radius: 9px; }
.brand-name { font-size: 20px; font-weight: 700; letter-spacing: 1px; }

.site-nav { display: flex; align-items: center; gap: 28px; }
.site-nav a { color: var(--text); font-size: 15px; font-weight: 500; }
.site-nav a:hover { color: var(--primary); }
.site-nav .nav-download {
  background: var(--grad); color: #fff;
  padding: 8px 18px; border-radius: 999px; font-weight: 600;
}
.site-nav .nav-download:hover { color: #fff; opacity: .92; }

.nav-toggle { display: none; background: none; border: 0; cursor: pointer; padding: 6px; }
.nav-toggle span { display: block; width: 22px; height: 2px; background: var(--text); margin: 5px 0; border-radius: 2px; transition: .25s; }
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---------------- Hero ---------------- */
.hero {
  background: var(--grad);
  color: #fff;
  padding: 84px 0 96px;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: ""; position: absolute; inset: 0;
  background: radial-gradient(circle at 80% 20%, rgba(255,255,255,.14), transparent 45%);
}
.hero-grid { display: grid; grid-template-columns: 1.15fr .85fr; gap: 48px; align-items: center; position: relative; z-index: 1; }

.hero h1 { font-size: 44px; line-height: 1.25; font-weight: 800; letter-spacing: 1px; }
.hero-sub { display: block; font-size: 20px; font-weight: 500; opacity: .92; margin-top: 10px; letter-spacing: 2px; }
.hero-desc { margin: 22px 0 26px; font-size: 17px; opacity: .95; max-width: 560px; }

.hero-points { list-style: none; margin-bottom: 30px; display: grid; gap: 8px; }
.hero-points li { font-size: 15.5px; opacity: .97; }

.hero-actions { display: flex; gap: 16px; flex-wrap: wrap; align-items: center; }

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  border-radius: 999px; font-weight: 600; cursor: pointer;
  transition: transform .18s, box-shadow .18s, background .18s;
  border: 2px solid transparent; text-align: center;
}
.btn:hover { transform: translateY(-2px); }
.btn-lg { padding: 14px 32px; font-size: 17px; }
.btn-primary { background: #fff; color: var(--primary-dark); box-shadow: var(--shadow); }
.btn-primary:hover { box-shadow: var(--shadow-lg); color: var(--primary-dark); }
.btn-ghost { background: transparent; color: #fff; border-color: rgba(255,255,255,.65); }
.btn-ghost:hover { background: rgba(255,255,255,.12); color: #fff; }

.hero-meta { margin-top: 18px; font-size: 13.5px; opacity: .8; }

.hero-visual { display: flex; justify-content: center; }
.phone-mock { position: relative; width: 260px; height: 260px; display: flex; align-items: center; justify-content: center; }
.phone-mock img { border-radius: 32px; box-shadow: 0 30px 60px rgba(2, 6, 23, .35); position: relative; z-index: 2; }
.phone-glow {
  position: absolute; width: 190px; height: 190px; border-radius: 50%;
  background: rgba(255,255,255,.25); filter: blur(46px); animation: pulse 3.2s ease-in-out infinite;
}
@keyframes pulse { 0%,100% { transform: scale(1); opacity:.9; } 50% { transform: scale(1.25); opacity:.55; } }

/* ---------------- 通用 section ---------------- */
.section { padding: 84px 0; }
.section-alt { background: var(--bg-alt); }
.section-title { font-size: 34px; font-weight: 800; text-align: center; letter-spacing: 1px; }
.section-sub { text-align: center; color: var(--text-light); margin: 10px 0 48px; font-size: 17px; }

/* ---------------- 功能卡片 ---------------- */
.feature-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; }
.feature-card {
  background: #fff; border-radius: var(--radius); padding: 30px 24px;
  box-shadow: 0 4px 16px rgba(15, 23, 42, .06);
  transition: transform .22s, box-shadow .22s;
  border: 1px solid #eef2f7;
}
.feature-card:hover { transform: translateY(-6px); box-shadow: var(--shadow); }
.feature-icon { font-size: 34px; margin-bottom: 14px; }
.feature-card h3 { font-size: 18px; margin-bottom: 10px; }
.feature-card p { font-size: 14.5px; color: var(--text-light); }

/* ---------------- 安全 ---------------- */
.security-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; max-width: 900px; margin: 0 auto; }
.security-item { background: #fff; border-radius: var(--radius); padding: 30px 26px; box-shadow: 0 4px 16px rgba(15,23,42,.06); }
.security-item h3 { font-size: 18px; margin-bottom: 10px; }
.security-item p { font-size: 14.5px; color: var(--text-light); }

/* ---------------- 下载 ---------------- */
.download-box { text-align: center; }
.download-card {
  display: flex; align-items: center; justify-content: center; gap: 34px; flex-wrap: wrap;
  background: #fff; border-radius: 20px; padding: 40px 44px;
  box-shadow: var(--shadow); border: 1px solid #eef2f7;
  max-width: 860px; margin: 0 auto;
}
.download-card img { border-radius: 20px; }
.download-info { text-align: left; }
.download-info h3 { font-size: 21px; margin-bottom: 12px; }
.download-info ul { list-style: none; display: grid; gap: 6px; color: var(--text-light); font-size: 15px; }
.download-tip { margin-top: 22px; font-size: 13.5px; color: var(--text-light); }

/* ---------------- 关于 ---------------- */
.about-content { max-width: 760px; margin: 0 auto; display: grid; gap: 16px; color: var(--text-light); font-size: 16px; text-align: center; }

/* ---------------- 页脚 ---------------- */
.site-footer { background: #0f172a; color: #94a3b8; padding: 34px 0; }
.footer-inner { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 14px; }
.footer-brand { display: flex; align-items: center; gap: 10px; color: #e2e8f0; font-weight: 600; }
.footer-brand img { border-radius: 7px; }
.footer-copy { font-size: 14px; }
.footer-copy a { color: #94a3b8; }
.footer-copy a:hover { color: #fff; }

/* ---------------- 移动端适配 ---------------- */
@media (max-width: 960px) {
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 760px) {
  .hero { padding: 56px 0 64px; }
  .hero-grid { grid-template-columns: 1fr; gap: 36px; }
  .hero h1 { font-size: 32px; }
  .hero-sub { font-size: 17px; }
  .section { padding: 60px 0; }
  .section-title { font-size: 27px; }
  .download-card { padding: 30px 22px; }

  .site-nav {
    display: none; position: absolute; top: 64px; left: 0; right: 0;
    background: #fff; flex-direction: column; gap: 4px;
    padding: 14px 6%; box-shadow: 0 16px 30px rgba(15,23,42,.12);
    border-bottom: 1px solid #eef2f7;
  }
  .site-nav.open { display: flex; }
  .site-nav a { padding: 12px 4px; font-size: 16px; border-bottom: 1px solid #f1f5f9; }
  .site-nav .nav-download { border: 0; text-align: center; }
  .nav-toggle { display: block; }
}

@media (max-width: 520px) {
  .feature-grid, .security-grid { grid-template-columns: 1fr; }
  .hero-actions .btn { width: 100%; }
}