/* ============================================================
   空陆影迹·英语听力生成器 — 下载站样式
   ============================================================ */
:root {
  --bg: #070b18;
  --bg-2: #0b1124;
  --card: rgba(255, 255, 255, 0.045);
  --card-border: rgba(255, 255, 255, 0.09);
  --text: #e8ecf7;
  --text-dim: #9aa5c1;
  --text-faint: #6b7592;
  --accent: #4f8cff;
  --accent-2: #22d3ee;
  --accent-grad: linear-gradient(135deg, #4f8cff 0%, #22d3ee 100%);
  --radius: 18px;
  --maxw: 1120px;
  --shadow: 0 20px 60px rgba(0, 0, 0, 0.45);
}

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

html { scroll-behavior: smooth; }

body {
  font-family: "PingFang SC", "Microsoft YaHei UI", "Microsoft YaHei",
    "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }
.pc-br { display: inline; }

/* ---------- 背景装饰 ---------- */
.bg-decor { position: fixed; inset: 0; z-index: -1; overflow: hidden; background:
  radial-gradient(1200px 600px at 80% -10%, rgba(79,140,255,0.14), transparent 60%),
  radial-gradient(900px 500px at 10% 20%, rgba(34,211,238,0.08), transparent 55%),
  linear-gradient(180deg, var(--bg) 0%, var(--bg-2) 100%);
}
.grid-overlay {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.035) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(ellipse 90% 60% at 50% 0%, #000 20%, transparent 75%);
  -webkit-mask-image: radial-gradient(ellipse 90% 60% at 50% 0%, #000 20%, transparent 75%);
}
.orb { position: absolute; border-radius: 50%; filter: blur(90px); opacity: 0.5; }
.orb-1 { width: 420px; height: 420px; background: #2b5bd7; top: -120px; right: -80px; animation: float 14s ease-in-out infinite; }
.orb-2 { width: 320px; height: 320px; background: #0ea5b7; top: 40%; left: -140px; animation: float 18s ease-in-out infinite reverse; }
.orb-3 { width: 260px; height: 260px; background: #6d3fd9; bottom: -80px; right: 20%; animation: float 16s ease-in-out infinite; }
@keyframes float {
  0%, 100% { transform: translateY(0) scale(1); }
  50% { transform: translateY(-30px) scale(1.06); }
}

/* ---------- 顶部导航 ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  background: rgba(7, 11, 24, 0.62);
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--text); font-weight: 700; font-size: 17px; }
.brand-mark { font-size: 22px; }
.brand-text em { color: var(--accent-2); font-style: normal; }
.nav { display: flex; align-items: center; gap: 26px; }
.nav a { color: var(--text-dim); text-decoration: none; font-size: 14.5px; transition: color .2s; }
.nav a:hover { color: var(--text); }
.nav .nav-cta {
  background: var(--accent-grad); color: #fff !important; font-weight: 600;
  padding: 8px 18px; border-radius: 999px; box-shadow: 0 6px 20px rgba(79,140,255,0.35);
}
.nav-toggle { display: none; background: none; border: 0; cursor: pointer; padding: 8px; }
.nav-toggle span { display: block; width: 22px; height: 2px; background: var(--text); margin: 4px 0; border-radius: 2px; transition: .25s; }
.nav-toggle.open span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

/* ---------- Hero ---------- */
.hero { padding: 96px 0 72px; text-align: center; }
.hero-inner { display: flex; flex-direction: column; align-items: center; }
.hero-badge {
  display: inline-flex; align-items: center; gap: 6px;
  border: 1px solid rgba(79, 140, 255, 0.4); color: #9dc0ff;
  background: rgba(79, 140, 255, 0.1);
  padding: 6px 14px; border-radius: 999px; font-size: 13px; margin-bottom: 26px;
}
.hero-title {
  font-size: clamp(34px, 6vw, 62px); line-height: 1.22; font-weight: 800;
  letter-spacing: 1px; margin-bottom: 20px;
}
.grad-text {
  background: var(--accent-grad);
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent; color: transparent;
}
.hero-sub { color: var(--text-dim); font-size: clamp(15px, 2vw, 18px); margin-bottom: 36px; }
.hero-actions { display: flex; gap: 14px; flex-wrap: wrap; justify-content: center; margin-bottom: 30px; }
.hero-meta { display: flex; gap: 12px; flex-wrap: wrap; justify-content: center; }
.pill {
  border: 1px solid var(--card-border); background: var(--card);
  padding: 6px 14px; border-radius: 999px; font-size: 12.5px; color: var(--text-dim);
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 9px;
  text-decoration: none; border-radius: 12px; font-weight: 600;
  transition: transform .18s, box-shadow .25s, background .25s; cursor: pointer; border: 0;
}
.btn .ico { width: 19px; height: 19px; }
.btn-primary {
  background: var(--accent-grad); color: #fff;
  box-shadow: 0 10px 32px rgba(79, 140, 255, 0.4);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 14px 40px rgba(79, 140, 255, 0.55); }
.btn-ghost {
  background: rgba(255, 255, 255, 0.06); color: var(--text);
  border: 1px solid var(--card-border);
}
.btn-ghost:hover { background: rgba(255, 255, 255, 0.11); transform: translateY(-2px); }
.btn-lg { padding: 15px 30px; font-size: 16px; }
.btn-xl { padding: 19px 38px; font-size: 17.5px; border-radius: 14px; }

/* ---------- 通用区块 ---------- */
.section { padding: 88px 0; }
.section-alt { background: rgba(255, 255, 255, 0.02); border-top: 1px solid rgba(255,255,255,0.05); border-bottom: 1px solid rgba(255,255,255,0.05); }
.section-head { text-align: center; margin-bottom: 52px; }
.section-tag {
  display: inline-block; font-size: 12px; letter-spacing: 3px; color: var(--accent-2);
  font-weight: 700; margin-bottom: 10px;
}
.section-title { font-size: clamp(26px, 4vw, 38px); font-weight: 800; margin-bottom: 12px; }
.section-desc { color: var(--text-dim); font-size: 15.5px; }

/* ---------- 特性卡片 ---------- */
.grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.card {
  background: var(--card); border: 1px solid var(--card-border); border-radius: var(--radius);
  padding: 30px 26px; backdrop-filter: blur(8px); transition: transform .25s, border-color .25s, background .25s;
}
.card:hover { transform: translateY(-5px); border-color: rgba(79, 140, 255, 0.4); background: rgba(255, 255, 255, 0.065); }
.card-ico { font-size: 32px; margin-bottom: 16px; }
.card h3 { font-size: 18px; font-weight: 700; margin-bottom: 10px; }
.card p { color: var(--text-dim); font-size: 14px; }

/* ---------- 使用步骤 ---------- */
.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; counter-reset: step; }
.step {
  background: var(--card); border: 1px solid var(--card-border); border-radius: var(--radius);
  padding: 34px 28px; position: relative; overflow: hidden;
}
.step-num {
  width: 46px; height: 46px; border-radius: 14px; display: flex; align-items: center; justify-content: center;
  background: var(--accent-grad); color: #fff; font-size: 21px; font-weight: 800; margin-bottom: 18px;
  box-shadow: 0 8px 24px rgba(79, 140, 255, 0.4);
}
.step h3 { font-size: 18px; font-weight: 700; margin-bottom: 10px; }
.step p { color: var(--text-dim); font-size: 14px; }
.step code {
  background: rgba(255, 255, 255, 0.09); border: 1px solid var(--card-border);
  padding: 1px 7px; border-radius: 6px; font-size: 13px; color: #b7d4ff;
}

/* ---------- 时间线 ---------- */
.timeline { max-width: 760px; margin: 0 auto; display: flex; flex-direction: column; gap: 22px; }
.tl-item {
  background: var(--card); border: 1px solid var(--card-border); border-radius: var(--radius);
  padding: 28px 30px; position: relative; border-left: 4px solid var(--accent);
}
.tl-version { font-size: 20px; font-weight: 800; color: #fff; }
.tl-date { color: var(--text-faint); font-size: 13px; margin: 2px 0 12px; }
.tl-list { list-style: none; }
.tl-list li { color: var(--text-dim); font-size: 14.5px; padding: 5px 0 5px 20px; position: relative; }
.tl-list li::before { content: ""; position: absolute; left: 2px; top: 13px; width: 6px; height: 6px; border-radius: 50%; background: var(--accent-2); }
.tl-list b { color: var(--text); font-weight: 600; }

/* ---------- 下载区 ---------- */
.section-download { padding-top: 40px; }
.download-box {
  display: flex; align-items: center; justify-content: space-between; gap: 40px;
  background: linear-gradient(135deg, rgba(79,140,255,0.14), rgba(34,211,238,0.08));
  border: 1px solid rgba(79, 140, 255, 0.35);
  border-radius: 24px; padding: 48px 48px;
  box-shadow: var(--shadow);
}
.download-tag { font-size: 12px; letter-spacing: 3px; color: var(--accent-2); font-weight: 700; }
.download-title { font-size: clamp(22px, 3.4vw, 30px); font-weight: 800; margin: 8px 0 10px; }
.download-desc { color: var(--text-dim); font-size: 14.5px; margin-bottom: 18px; }
.download-points { list-style: none; }
.download-points li { color: var(--text-dim); font-size: 14px; padding: 4px 0; }
.download-actions { flex-shrink: 0; text-align: center; }
.download-hint { color: var(--text-faint); font-size: 12.5px; margin-top: 12px; }

/* ---------- 页脚 ---------- */
.site-footer { border-top: 1px solid rgba(255, 255, 255, 0.06); padding: 40px 0; margin-top: 40px; }
.footer-inner { display: flex; justify-content: space-between; align-items: flex-start; gap: 24px; flex-wrap: wrap; }
.footer-brand { font-weight: 700; font-size: 15px; }
.footer-sub { color: var(--text-faint); font-size: 13px; margin-top: 4px; }
.footer-note { color: var(--text-faint); font-size: 12.5px; max-width: 380px; text-align: right; }

/* ---------- 滚动显现动画 ---------- */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity .7s ease, transform .7s ease; }
.reveal.visible { opacity: 1; transform: translateY(0); }
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  html { scroll-behavior: auto; }
  .orb { animation: none; }
}

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  .grid, .steps { grid-template-columns: 1fr; }
  .download-box { flex-direction: column; text-align: center; padding: 36px 24px; }
  .download-actions { width: 100%; }
  .download-points { text-align: left; display: inline-block; }
  .footer-inner { flex-direction: column; }
  .footer-note { text-align: left; }
  .nav {
    position: fixed; top: 64px; left: 0; right: 0;
    flex-direction: column; gap: 0; background: rgba(7, 11, 24, 0.97);
    border-bottom: 1px solid var(--card-border); padding: 10px 0;
    transform: translateY(-8px); opacity: 0; pointer-events: none; transition: .25s;
  }
  .nav.open { transform: translateY(0); opacity: 1; pointer-events: auto; }
  .nav a { padding: 13px 24px; font-size: 16px; width: 100%; }
  .nav .nav-cta { margin: 8px 24px; text-align: center; }
  .nav-toggle { display: block; }
}