/* ============================================================
   承信 · 官网样式
   品牌色：翡翠绿 #0E6B5C / 深绿 #123D37 / 金 #C28B38 / 背景 #F7FAF9
   ============================================================ */

:root {
  --bg: #F7FAF9;
  --primary: #0E6B5C;
  --primary-dark: #123D37;
  --primary-deep: #1D7C6B;
  --gold: #C28B38;
  --gold-bg: #FFF8E9;
  --slate-50: #F8FAFC;
  --slate-100: #F1F5F9;
  --slate-200: #E2E8F0;
  --slate-400: #94A3B8;
  --slate-500: #64748B;
  --slate-600: #475569;
  --slate-800: #1E293B;
  --white: #FFFFFF;
  --emerald-50: #ECFDF5;
  --sky-50: #F0F9FF;
  --sky-600: #0284C7;
  --amber-50: #FFFBEB;
  --amber-600: #D97706;
  --rose-50: #FFF1F2;
  --rose-600: #E11D48;
  --violet-50: #F5F3FF;
  --violet-600: #7C3AED;

  --radius-sm: 12px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-xl: 28px;

  --max-w: 1080px;
  --shadow: 0 10px 30px -12px rgba(18, 61, 55, 0.18);
  --shadow-sm: 0 4px 14px -8px rgba(18, 61, 55, 0.16);
}

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

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--slate-800);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
ul { list-style: none; }

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

/* ── 顶部导航 ── */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, 0.86);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--slate-100);
}
.nav-inner {
  max-width: var(--max-w); margin: 0 auto; padding: 0 20px;
  height: 64px; display: flex; align-items: center; gap: 12px;
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 18px; }
.brand-logo {
  width: 34px; height: 34px; border-radius: 10px;
  background: var(--primary); display: flex; align-items: center; justify-content: center;
  overflow: hidden;
}
.brand-logo img { width: 100%; height: 100%; object-fit: cover; }
.brand .tag { font-size: 12px; color: var(--slate-400); font-weight: 500; margin-left: 2px; }

.nav-links { margin-left: auto; display: flex; align-items: center; gap: 4px; }
.nav-links a {
  padding: 8px 14px; border-radius: 10px; font-size: 14px; color: var(--slate-600);
  transition: all .15s;
}
.nav-links a:hover { background: var(--slate-100); color: var(--slate-800); }
.nav-links a.active { color: var(--primary); font-weight: 600; background: var(--emerald-50); }
.nav-cta {
  margin-left: 8px; padding: 9px 18px; border-radius: 12px; font-size: 14px; font-weight: 600;
  background: var(--primary); color: #fff; transition: all .15s;
}
.nav-cta:hover { background: var(--primary-dark); }

.nav-burger { display: none; margin-left: auto; width: 40px; height: 40px; border: none;
  background: #fff; border: 1px solid var(--slate-200); border-radius: 12px; cursor: pointer; }
.nav-burger span { display: block; width: 18px; height: 2px; background: var(--slate-800);
  margin: 4px auto; border-radius: 2px; }

/* ── Hero ── */
.hero { position: relative; overflow: hidden; color: #fff; }
.hero-bg {
  background: linear-gradient(135deg, var(--primary-dark) 0%, var(--primary) 55%, var(--primary-deep) 100%);
  padding: 72px 0 96px;
}
.hero::before {
  content: ""; position: absolute; top: -80px; right: -80px; width: 320px; height: 320px;
  background: var(--primary-deep); opacity: .5; border-radius: 50%;
}
.hero::after {
  content: ""; position: absolute; right: 48px; bottom: 32px; width: 160px; height: 160px;
  border: 1px solid rgba(255,255,255,.18); border-radius: 50%;
}
.hero .container { position: relative; z-index: 1; }
.hero-badge {
  display: inline-flex; align-items: center; gap: 7px; padding: 6px 14px;
  background: rgba(255,255,255,.12); border-radius: 999px; font-size: 13px;
}
.hero h1 {
  font-size: 44px; line-height: 1.22; font-weight: 800; margin: 24px 0 16px;
  letter-spacing: .5px;
}
.hero p.sub {
  font-size: 17px; line-height: 1.7; color: rgba(207, 245, 236, .9);
  max-width: 560px; margin-bottom: 32px;
}
.hero-actions { display: flex; gap: 14px; flex-wrap: wrap; }
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 14px 28px; border-radius: 14px; font-size: 16px; font-weight: 600; cursor: pointer;
  transition: all .15s; border: none;
}
.btn-primary { background: #fff; color: var(--primary); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 12px 28px -12px rgba(0,0,0,.4); }
.btn-ghost { background: rgba(255,255,255,.12); color: #fff; border: 1px solid rgba(255,255,255,.25); }
.btn-ghost:hover { background: rgba(255,255,255,.2); }
.btn-gold { background: var(--gold); color: #fff; }
.btn-gold:hover { background: #a9752e; transform: translateY(-2px); }

/* ── 区块通用 ── */
.section { padding: 72px 0; }
.section.alt { background: #fff; }
.section-head { text-align: center; margin-bottom: 44px; }
.section-head .eyebrow {
  font-size: 13px; font-weight: 600; letter-spacing: 3px; color: var(--gold);
  text-transform: uppercase;
}
.section-head h2 { font-size: 30px; font-weight: 800; margin: 8px 0 12px; }
.section-head p { font-size: 15px; color: var(--slate-500); max-width: 560px; margin: 0 auto; }

/* ── 三步卡片 ── */
.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.step {
  background: #fff; border: 1px solid var(--slate-100); border-radius: var(--radius-md);
  padding: 28px 24px; transition: all .2s;
}
.step:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.step-icon {
  width: 48px; height: 48px; border-radius: 14px; display: flex; align-items: center;
  justify-content: center; font-size: 22px; margin-bottom: 18px;
}
.step .no { font-size: 13px; font-weight: 700; }
.step h3 { font-size: 17px; font-weight: 700; margin: 6px 0 8px; }
.step p { font-size: 14px; color: var(--slate-500); line-height: 1.6; }

/* ── 功能宫格 ── */
.grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.feature {
  background: #fff; border: 1px solid var(--slate-100); border-radius: var(--radius-md);
  padding: 26px 24px; transition: all .2s;
}
.feature:hover { box-shadow: var(--shadow-sm); }
.feature-icon {
  width: 44px; height: 44px; border-radius: 12px; display: flex; align-items: center;
  justify-content: center; font-size: 22px; margin-bottom: 14px;
}
.feature h3 { font-size: 16px; font-weight: 700; margin-bottom: 6px; }
.feature p { font-size: 13px; color: var(--slate-500); line-height: 1.6; }

/* ── 提示条 ── */
.notice {
  display: flex; gap: 12px; align-items: flex-start; padding: 18px 20px;
  background: var(--gold-bg); border: 1px solid #FDE68A; border-radius: var(--radius-md);
  max-width: 720px; margin: 0 auto;
}
.notice p { font-size: 14px; color: var(--slate-600); line-height: 1.7; }

/* ── CTA 横幅 ── */
.cta {
  background: linear-gradient(135deg, var(--primary-dark), var(--primary));
  border-radius: var(--radius-xl); padding: 48px 40px; color: #fff; text-align: center;
  position: relative; overflow: hidden;
}
.cta h2 { font-size: 28px; font-weight: 800; margin-bottom: 12px; }
.cta p { color: rgba(207,245,236,.9); margin-bottom: 28px; font-size: 15px; }

/* ── 下载页 ── */
.download-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; max-width: 760px; margin: 0 auto; }
.dl-card {
  background: #fff; border: 1px solid var(--slate-100); border-radius: var(--radius-lg);
  padding: 40px 32px; text-align: center; transition: all .2s;
}
.dl-card:hover { box-shadow: var(--shadow); transform: translateY(-4px); }
.dl-card .os { width: 64px; height: 64px; margin: 0 auto 20px; border-radius: 18px; display: flex;
  align-items: center; justify-content: center; font-size: 30px; }
.dl-card h3 { font-size: 20px; font-weight: 700; margin-bottom: 8px; }
.dl-card p { font-size: 13px; color: var(--slate-500); margin-bottom: 22px; }
.dl-card .coming {
  display: inline-block; padding: 6px 16px; border-radius: 999px; font-size: 13px;
  background: var(--slate-100); color: var(--slate-500);
}

/* ── 文章页（隐私/协议/关于）── */
.article { max-width: 760px; margin: 0 auto; }
.article .page-title { text-align: center; margin-bottom: 8px; }
.article .page-title h1 { font-size: 30px; font-weight: 800; }
.article .meta { text-align: center; font-size: 13px; color: var(--slate-400); margin-bottom: 40px; }
.article h2 { font-size: 19px; font-weight: 700; margin: 32px 0 12px; color: var(--slate-800); }
.article h3 { font-size: 16px; font-weight: 700; margin: 24px 0 8px; }
.article p { font-size: 15px; color: var(--slate-600); line-height: 1.8; margin-bottom: 14px; }
.article ul { margin: 0 0 14px 4px; }
.article ul li { font-size: 15px; color: var(--slate-600); line-height: 1.8; padding-left: 20px; position: relative; }
.article ul li::before { content: "·"; position: absolute; left: 4px; color: var(--primary); font-weight: 700; }
.article .card {
  background: #fff; border: 1px solid var(--slate-100); border-radius: var(--radius-md);
  padding: 24px; margin: 24px 0;
}
.article .card.tint { background: var(--emerald-50); border-color: #D1FAE5; }

/* ── 页脚 ── */
.footer { background: var(--primary-dark); color: rgba(255,255,255,.72); padding: 56px 0 40px; margin-top: 80px; }
.footer .container { display: grid; grid-template-columns: 1.6fr 1fr 1fr 1fr; gap: 32px; }
.footer .brand { color: #fff; }
.footer .brand .tag { color: rgba(255,255,255,.5); }
.footer .about-txt { font-size: 13px; line-height: 1.7; margin-top: 14px; color: rgba(255,255,255,.6); }
.footer h4 { color: #fff; font-size: 14px; font-weight: 700; margin-bottom: 16px; }
.footer-links li { margin-bottom: 10px; }
.footer-links a { font-size: 13px; color: rgba(255,255,255,.6); transition: color .15s; }
.footer-links a:hover { color: #fff; }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.12); margin-top: 40px; padding-top: 24px;
  display: flex; flex-wrap: wrap; gap: 12px; justify-content: space-between; align-items: center;
  font-size: 12px; color: rgba(255,255,255,.45);
}
.footer-bottom a { color: rgba(255,255,255,.6); }
.footer-bottom a:hover { color: #fff; }

/* ── 响应式 ── */
@media (max-width: 900px) {
  .steps, .grid { grid-template-columns: repeat(2, 1fr); }
  .footer .container { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 640px) {
  .nav-links { display: none; }
  .nav-links.open {
    display: flex; flex-direction: column; position: absolute; top: 64px; left: 0; right: 0;
    background: #fff; border-bottom: 1px solid var(--slate-100); padding: 8px 20px 16px;
    align-items: stretch; gap: 2px;
  }
  .nav-burger { display: block; }
  .hero-bg { padding: 48px 0 64px; }
  .hero h1 { font-size: 32px; }
  .steps, .grid { grid-template-columns: 1fr; }
  .download-grid { grid-template-columns: 1fr; }
  .section { padding: 52px 0; }
  .section-head h2 { font-size: 25px; }
  .cta { padding: 36px 24px; }
  .footer .container { grid-template-columns: 1fr; gap: 24px; }
  .footer-bottom { flex-direction: column; align-items: flex-start; }
}