/* ══ 主页 ══════════════════════════════════════════ */

.nav {
  position: sticky; top: 0; z-index: 40;
  display: flex; align-items: center; gap: 16px;
  padding: 15px clamp(16px, 5vw, 56px);
  background: rgba(255,255,255,.72);
  backdrop-filter: blur(18px) saturate(140%);
  -webkit-backdrop-filter: blur(18px) saturate(140%);
  border-bottom: 1px solid transparent;
  transition: border-color .3s, background .3s;
}
.nav.scrolled { border-bottom-color: var(--border); background: rgba(255,255,255,.92); }
.nav .grow { flex: 1; }
.nav a.lnk { font-size: 13.5px; color: var(--text-2); font-weight: 550; }
.nav a.lnk:hover { color: var(--text); }

.wrap { max-width: 1180px; margin: 0 auto; padding: 0 clamp(16px, 5vw, 40px); }

/* ── Hero ─────────────────────────────────── */
.hero { padding: clamp(72px, 13vw, 140px) 0 clamp(60px, 9vw, 100px); text-align: center; }

.hero .eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 5px 14px 5px 8px; border-radius: 99px; margin-bottom: 26px;
  font-size: 12.5px; font-weight: 600; color: var(--text-2);
  background: var(--surface); border: 1px solid var(--border);
  animation: rise .7s var(--ease) both;
}
.hero .eyebrow i {
  width: 6px; height: 6px; border-radius: 50%; background: var(--emerald);
  animation: pulse-dot 2.2s var(--ease-io) infinite;
}
@keyframes pulse-dot { 50% { opacity: .35; transform: scale(.8); } }

.hero h1 {
  font-size: clamp(38px, 7.2vw, 78px); line-height: 1.04;
  font-weight: 800; letter-spacing: -.045em; margin-bottom: 22px;
  animation: rise .8s var(--ease) both .08s;
}
.hero h1 .l2 { display: block; }

.hero p.lead {
  max-width: 620px; margin: 0 auto 34px;
  font-size: clamp(15px, 2vw, 18px); color: var(--text-2); line-height: 1.7;
  animation: rise .8s var(--ease) both .16s;
}
.hero .cta { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap;
             animation: rise .8s var(--ease) both .24s; }
.hero .cta .btn { padding: 13px 26px; font-size: 14.5px; }

@keyframes rise { from { opacity: 0; transform: translateY(20px); } to { opacity: 1; transform: none; } }

/* ── 数字条 ───────────────────────────────── */
.figures {
  display: grid; gap: 1px; margin: 56px 0 0;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  background: var(--border); border: 1px solid var(--border); border-radius: var(--r-lg);
  overflow: hidden;
  animation: rise .9s var(--ease) both .32s;
}
.figures div { background: #fff; padding: 22px 18px; text-align: center; }
.figures b { display: block; font-size: 27px; font-weight: 780; letter-spacing: -.035em; }
.figures span { font-size: 12px; color: var(--muted); }

/* ── 通用区块 ─────────────────────────────── */
.sec { padding: clamp(56px, 9vw, 104px) 0; }
.sec-head { max-width: 640px; margin-bottom: 40px; }
.sec-head .tag {
  font-size: 12px; font-weight: 700; letter-spacing: .1em; text-transform: uppercase;
  color: var(--teal); margin-bottom: 12px;
}
.sec-head h2 { font-size: clamp(25px, 4vw, 38px); font-weight: 750; letter-spacing: -.03em; line-height: 1.2; }
.sec-head p { margin-top: 13px; color: var(--text-2); font-size: 15.5px; line-height: 1.75; }

/* ── 三层路由 ─────────────────────────────── */
.tiers { display: grid; gap: 14px; grid-template-columns: repeat(auto-fit, minmax(258px, 1fr)); }
.tier {
  position: relative; padding: 26px 24px; border-radius: var(--r-lg);
  background: var(--surface);
  border: 1px solid var(--border); overflow: hidden;
  transition: transform .3s var(--ease), border-color .3s;
}
.tier:hover { transform: translateY(-4px); border-color: var(--border-2); }
.tier .lv {
  font-family: var(--mono); font-size: 12px; font-weight: 700;
  color: var(--teal); letter-spacing: .08em; margin-bottom: 10px;
}
.tier h3 { font-size: 17px; font-weight: 700; margin-bottom: 9px; letter-spacing: -.015em; }
.tier p { font-size: 13.5px; color: var(--text-2); line-height: 1.7; }
.tier .cost {
  display: inline-block; margin-top: 15px; padding: 4px 11px; border-radius: 7px;
  font-size: 12px; font-weight: 650; font-family: var(--mono);
}
.tier.l1 { border-color: rgba(13,148,136,.32); }
.tier.l1 .cost { background: rgba(13,148,136,.10); color: var(--teal); }
.tier.l2 .cost { background: rgba(79,70,229,.10); color: var(--indigo); }
.tier.l3 .cost { background: rgba(180,83,9,.10); color: var(--amber); }
.tier::after {
  content: ''; position: absolute; inset: 0; pointer-events: none;
  background: radial-gradient(220px 110px at 88% -8%, var(--tint, rgba(13,148,136,.07)), transparent 70%);
}
.tier.l2::after { --tint: rgba(79,70,229,.07); }
.tier.l3::after { --tint: rgba(180,83,9,.07); }

.flow-note {
  margin-top: 20px; padding: 15px 18px; border-radius: var(--r);
  background: var(--surface); border: 1px solid var(--border);
  font-size: 13.5px; color: var(--text-2); line-height: 1.75;
}
.flow-note b { color: var(--teal); font-weight: 650; }

/* ── 四端 ─────────────────────────────────── */
.ends { display: grid; gap: 14px; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); }
.end {
  padding: 24px 22px; border-radius: var(--r-lg);
  background: var(--surface); border: 1px solid var(--border);
  transition: transform .3s var(--ease), border-color .3s, background .3s;
}
.end:hover { transform: translateY(-4px); background: var(--surface-2); border-color: var(--border-2); }
.end .ico {
  width: 40px; height: 40px; border-radius: 11px; display: grid; place-items: center;
  background: var(--grad-soft); border: 1px solid var(--border); margin-bottom: 15px;
  font-size: 18px;
}
.end h3 { font-size: 15.5px; font-weight: 700; margin-bottom: 7px; display: flex; align-items: center; gap: 8px; }
.end p { font-size: 13.5px; color: var(--text-2); line-height: 1.7; }

/* ── 自救阶梯 ─────────────────────────────── */
.ladder { display: grid; gap: 8px; }
.rung {
  display: grid; grid-template-columns: 52px 1fr auto; gap: 16px; align-items: center;
  padding: 14px 18px; border-radius: var(--r);
  background: var(--surface); border: 1px solid var(--border);
  transition: background .25s, border-color .25s, transform .25s var(--ease);
}
.rung:hover { background: var(--surface-2); border-color: var(--border-2); transform: translateX(4px); }
.rung .lv { font-family: var(--mono); font-weight: 700; font-size: 13.5px; color: var(--teal); }
.rung .what { font-size: 14px; font-weight: 600; }
.rung .when { font-size: 12.5px; color: var(--muted); text-align: right; }
.rung:nth-child(n+6) .lv { color: var(--amber); }
.rung:last-child .lv { color: var(--rose); }

@media (max-width: 560px) {
  .rung { grid-template-columns: 44px 1fr; }
  .rung .when { grid-column: 2; text-align: left; }
}

/* ── 结尾 ─────────────────────────────────── */
.tail {
  margin: 40px 0 0; padding: clamp(40px, 7vw, 64px) clamp(24px, 5vw, 56px);
  border-radius: var(--r-xl); text-align: center;
  background: var(--surface);
  border: 1px solid var(--border-2);
  box-shadow: var(--shadow-lg);
}
.tail h2 { font-size: clamp(23px, 3.6vw, 33px); font-weight: 760; letter-spacing: -.03em; margin-bottom: 12px; }
.tail p { color: var(--text-2); margin-bottom: 26px; font-size: 15px; }

.foot {
  padding: 34px 0 44px; text-align: center;
  font-size: 12.5px; color: var(--muted);
  border-top: 1px solid var(--border); margin-top: 56px;
}
.foot a { color: var(--text-2); }

/* 进入视口再显现。
   用 .js 门控：脚本没跑起来（被拦截 / 报错 / 老浏览器）时内容照常可见，
   而不是留下一片永远 opacity:0 的空白页。 */
.js .reveal { opacity: 0; transform: translateY(22px); transition: opacity .7s var(--ease), transform .7s var(--ease); }
.js .reveal.in { opacity: 1; transform: none; }

/* ── 对话演示 ─────────────────────────────── */
.demo {
  max-width: 620px; margin: 0 auto;
  border-radius: var(--r-xl); overflow: hidden;
  background: var(--surface);
  border: 1px solid var(--border-2); box-shadow: var(--shadow-lg);
}
.demo-head {
  display: flex; align-items: center; gap: 7px;
  padding: 11px 16px; border-bottom: 1px solid var(--border);
  background: var(--bg-2);
}
.demo-head .dot { width: 10px; height: 10px; border-radius: 50%; }
.demo-head .dot.r { background: #ff5f57; }
.demo-head .dot.y { background: #febc2e; }
.demo-head .dot.g { background: #28c840; }
.demo-title { margin-left: 8px; font-size: 12.5px; color: var(--muted); }

.demo-body { padding: 20px; display: flex; flex-direction: column; gap: 11px; }
.dm { max-width: 78%; padding: 10px 14px; border-radius: 14px; font-size: 13.5px; line-height: 1.6; }
.dm.me {
  align-self: flex-end; border-bottom-right-radius: 5px; font-weight: 500;
  background: var(--grad); color: #fff;
}
.dm.bot {
  align-self: flex-start; border-bottom-left-radius: 5px;
  background: var(--surface-2); border: 1px solid var(--border); color: var(--text);
}
.dm.bot.img { padding: 7px; max-width: 82%; }
.mini-shot {
  aspect-ratio: 16/9; border-radius: 9px; display: grid; place-items: center;
  background: var(--bg-3);
  border: 1px solid var(--border); font-size: 11.5px; color: var(--muted);
  position: relative; overflow: hidden;
}
.mini-shot::after {
  content: ''; position: absolute; inset: 0;
  background: linear-gradient(180deg, transparent, rgba(13,148,136,.16) 50%, transparent);
  animation: scan 3s var(--ease-io) infinite;
}
@keyframes scan { 0% { transform: translateY(-100%); } 100% { transform: translateY(100%); } }

.dm.typing { display: flex; gap: 4px; padding: 13px 15px; }
.dm.typing i { width: 6px; height: 6px; border-radius: 50%; background: var(--teal); animation: bounce 1.3s var(--ease-io) infinite; }
.dm.typing i:nth-child(2) { animation-delay: .17s; }
.dm.typing i:nth-child(3) { animation-delay: .34s; }
@keyframes bounce { 0%,60%,100% { opacity:.25; transform: translateY(0); } 30% { opacity:1; transform: translateY(-3px); } }

/* ── 特点网格 ─────────────────────────────── */
.feats { display: grid; gap: 14px; grid-template-columns: repeat(auto-fit, minmax(276px, 1fr)); }
.feat {
  padding: 20px 22px; border-radius: var(--r-lg);
  background: var(--surface); border: 1px solid var(--border);
  transition: transform .3s var(--ease), border-color .3s, background .3s;
}
.feat:hover { transform: translateY(-3px); background: var(--surface-2); border-color: var(--border-2); }
.feat b { display: block; font-size: 14.5px; margin-bottom: 7px; letter-spacing: -.01em; }
.feat p { font-size: 13.5px; color: var(--text-2); line-height: 1.7; }