/* === 24ppt.com — 全站统一样式 === */
:root {
  --bg: #0a0a0b; --bg2: #111114; --bg3: #1a1a1f;
  --border: #2a2a33; --text: #e8e8ed; --text2: #9999a6; --text3: #666673;
  --red: #ff4444; --orange: #ff6b35; --amber: #f59e0b; --green: #22c55e;
  --gradient: linear-gradient(135deg, var(--red), var(--orange));
  --gradient-text: linear-gradient(135deg, var(--orange), var(--red), var(--orange));
  --radius: 12px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg); color: var(--text); line-height: 1.7;
  -webkit-font-smoothing: antialiased; padding-bottom: 80px;
}
a { color: var(--orange); text-decoration: none; transition: color .2s; }
a:hover { color: #fff; }

/* === NAV（全站统一）=== */
.nav { position: fixed; top: 0; left: 0; right: 0; z-index: 100; background: rgba(10,10,11,.88); backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px); border-bottom: 1px solid var(--border); padding: 0 16px; }
.nav-inner { max-width: 1200px; margin: 0 auto; display: flex; align-items: center; justify-content: space-between; height: 56px; }
.nav-logo { font-size: 19px; font-weight: 900; background: var(--gradient-text); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.nav-links { display: flex; gap: 20px; list-style: none; }
.nav-links a { color: var(--text2); font-size: 13px; font-weight: 500; padding: 6px 0; border-bottom: 2px solid transparent; transition: all .2s; }
.nav-links a:hover, .nav-links a.active { color: var(--text); border-bottom-color: var(--orange); }
.nav-links .nav-cta { background: var(--gradient); color: #fff !important; padding: 7px 18px !important; border-radius: 18px; font-weight: 700; font-size: 12px !important; border-bottom: none !important; }
.nav-links .nav-cta:hover { transform: translateY(-1px); box-shadow: 0 4px 16px rgba(255,68,68,.3); color: #fff !important; }
.nav-toggle { display: none; background: none; border: none; color: var(--text); font-size: 22px; cursor: pointer; }

/* === FOOTER（全站统一）=== */
.footer { padding: 36px 16px; text-align: center; font-size: 12px; color: var(--text3); border-top: 1px solid var(--border); }
.footer a { color: var(--text2); }
.footer a:hover { color: var(--orange); }

/* === BUTTONS === */
.btn { display: inline-block; padding: 15px 36px; border-radius: 30px; font-size: 15px; font-weight: 700; letter-spacing: .5px; transition: all .25s; cursor: pointer; border: none; text-decoration: none; }
.btn-primary { background: var(--gradient); color: #fff; }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 30px rgba(255,68,68,.4); color: #fff; }
.btn-outline { background: transparent; color: var(--text); border: 1px solid var(--border); }
.btn-outline:hover { border-color: var(--orange); color: var(--orange); }

/* === FIXED CTA（移动端）=== */
.fixed-cta { display: none; position: fixed; bottom: 0; left: 0; right: 0; padding: 10px 16px; background: rgba(10,10,11,.92); backdrop-filter: blur(20px); border-top: 1px solid var(--border); z-index: 50; }
.fixed-cta .btn { width: 100%; text-align: center; max-width: 100%; }

/* === BACK TO TOP === */
.back-top { position: fixed; bottom: 24px; right: 24px; width: 44px; height: 44px; border-radius: 50%; background: var(--bg2); border: 1px solid var(--border); display: flex; align-items: center; justify-content: center; cursor: pointer; font-size: 18px; color: var(--text2); transition: all .2s; z-index: 40; opacity: 0; pointer-events: none; }
.back-top.show { opacity: 1; pointer-events: auto; }
.back-top:hover { border-color: var(--orange); color: var(--orange); }

/* === MOBILE === */
@media (max-width: 768px) {
  .nav-links { display: none; }
  .nav-links.open { display: flex; flex-direction: column; position: absolute; top: 56px; left: 0; right: 0; background: var(--bg2); border-bottom: 1px solid var(--border); padding: 16px 24px; gap: 12px; }
  .nav-links.open a { padding: 8px 0; }
  .nav-toggle { display: block; }
  .fixed-cta { display: block; }
  body { padding-bottom: 80px; }
}