/* 智芯源 OPC · 营销落地页 · 军师台设计系统（与 opc-platform-frontend 同源 tokens） */
:root{
  --bg:#faf9f5; --ink:#141413; --accent:#d97757; --blue:#6a9bcc;
  --green:#788c5d; --mut:#b0aea5; --line:#e8e6dc; --dark:#141413;
  --card:#ffffff; --dark-mut:#8a877e;
  --maxw:1140px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
html,body{margin:0}
body{
  background:var(--bg); color:var(--ink);
  font:16px/1.7 -apple-system,BlinkMacSystemFont,"PingFang SC","Source Han Sans SC","Noto Sans CJK SC","Microsoft YaHei",sans-serif;
  -webkit-font-smoothing:antialiased;
}
a{color:inherit;text-decoration:none}
button{font:inherit;cursor:pointer}
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 24px}
.kicker{color:var(--accent);font-weight:700;letter-spacing:2px;font-size:13px;text-transform:uppercase}
.sec-title{font-size:28px;font-weight:750;letter-spacing:-.3px;margin:0 0 10px}
.sec-sub{color:var(--mut);font-size:15px;max-width:560px;margin:0 auto 36px}
.center{text-align:center}

/* ===== 顶部导航 ===== */
.nav{position:sticky;top:0;z-index:20;background:rgba(250,249,245,.86);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.nav .wrap{display:flex;align-items:center;justify-content:space-between;height:62px}
.logo{display:flex;align-items:center;gap:9px;font-size:18px;font-weight:750}
.logo .dot{width:12px;height:12px;border-radius:3px;background:var(--accent)}
.nav-links{display:flex;gap:26px;font-size:14.5px;color:#55524c}
.nav-links a:hover{color:var(--ink)}
.nav-cta{display:flex;align-items:center;gap:12px}

/* ===== 按钮 ===== */
.btn{background:var(--accent);color:#fff;border:0;padding:11px 22px;border-radius:10px;font-weight:600;font-size:15px;display:inline-block;transition:.15s}
.btn:hover{filter:brightness(.96);transform:translateY(-1px)}
.btn.ghost{background:transparent;color:var(--ink);border:1px solid var(--line)}
.btn.ghost:hover{background:#f1efe8;filter:none}
.btn.sm{padding:8px 16px;font-size:14px}
.btn.lg{padding:14px 30px;font-size:16px}
.btn.light{background:#fff;color:var(--ink)}
.btn.light:hover{background:#f3f1ea}

/* ===== Hero ===== */
.hero{position:relative;text-align:center;padding:84px 0 64px;
  background:radial-gradient(1000px 540px at 70% -12%, #f3ece1 0%, var(--bg) 58%)}
.hero h1{font-size:52px;line-height:1.12;font-weight:800;letter-spacing:-1.2px;margin:18px auto 0;max-width:840px}
.hero h1 em{font-style:normal;color:var(--accent)}
.hero .lede{font-size:19px;color:#46433d;max-width:620px;margin:20px auto 0}
.hero .cta-row{display:flex;gap:14px;justify-content:center;margin-top:34px;flex-wrap:wrap}
.hero .note{margin-top:18px;color:var(--mut);font-size:13px}

/* ===== 统计条 ===== */
.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:18px;max-width:920px;margin:48px auto 0}
.stat{text-align:center}
.stat .n{font-size:38px;font-weight:800;letter-spacing:-1px;font-variant-numeric:tabular-nums}
.stat .l{color:var(--mut);font-size:13.5px;margin-top:2px}

/* ===== 安全合规条 ===== */
.security{display:flex;gap:12px;flex-wrap:wrap;justify-content:center;margin:44px auto 0;max-width:880px}
.pill{background:#f0f4ea;color:var(--green);border:1px solid #dde6d2;border-radius:99px;padding:9px 18px;font-size:14px;font-weight:600}

/* ===== 区块 ===== */
section.band{padding:78px 0}
section.band.alt{background:#fff;border-block:1px solid var(--line)}
section.band.dark{background:var(--dark);color:#ece9e1}
section.band.dark .sec-title{color:#fff}
section.band.dark .sec-sub{color:#a7a399}

/* ===== 卡片网格 ===== */
.grid{display:grid;gap:18px}
.cols-3{grid-template-columns:repeat(3,1fr)}
.cols-4{grid-template-columns:repeat(4,1fr)}
.cols-2{grid-template-columns:repeat(2,1fr)}
.card{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:24px}
.feat{display:flex;flex-direction:column;gap:10px;transition:.15s}
.feat:hover{border-color:var(--accent);transform:translateY(-3px);box-shadow:0 10px 28px rgba(217,119,87,.10)}
.feat .ic{width:46px;height:46px;border-radius:12px;background:#f5efe6;display:flex;align-items:center;justify-content:center;font-size:23px}
.feat .num{font-size:24px;font-weight:800;color:var(--accent);letter-spacing:-.5px;margin-bottom:4px;font-variant-numeric:tabular-nums}
.feat h3{margin:0;font-size:17px}
.feat p{margin:0;color:var(--mut);font-size:14px}

/* ===== 三步法 ===== */
.steps{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}
.step{text-align:center;padding:28px 22px}
.step .n{width:42px;height:42px;border-radius:50%;background:var(--accent);color:#fff;display:flex;align-items:center;justify-content:center;font-weight:700;font-size:18px;margin:0 auto 14px}
.step h3{margin:0 0 6px;font-size:18px}
.step p{margin:0;color:var(--mut);font-size:14px}

/* ===== 模型矩阵（深色区） ===== */
.models{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}
.model{background:#1d1d1b;border:1px solid #2c2c29;border-radius:14px;padding:20px}
.model .mono-chip{width:40px;height:40px;border-radius:11px;display:flex;align-items:center;justify-content:center;font-weight:800;font-size:18px;color:#fff;margin-bottom:12px}
.model h4{margin:0 0 4px;font-size:16px;color:#fff}
.model p{margin:0;color:#a7a399;font-size:13.5px}
.models-note{margin-top:22px;color:#8a877e;font-size:13px}

/* ===== 两个讲法 ===== */
.duo{display:grid;grid-template-columns:1fr 1fr;gap:18px}
.duo .card{padding:30px}
.duo .tag{display:inline-block;font-size:12px;font-weight:700;letter-spacing:1px;color:var(--accent);margin-bottom:8px}
.duo h3{margin:0 0 8px;font-size:20px}
.duo p{margin:0;color:#55524c;font-size:14.5px}

/* ===== CTA 收束 ===== */
.cta-band{text-align:center;padding:80px 0}
.cta-band h2{font-size:34px;font-weight:800;letter-spacing:-.5px;margin:0 0 12px}
.cta-band p{color:var(--mut);margin:0 0 28px}

/* ===== 页脚 ===== */
footer{background:#fff;border-top:1px solid var(--line);padding:38px 0;color:var(--mut);font-size:13.5px}
footer .wrap{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:16px}
footer .logo{font-size:16px;color:var(--ink)}
footer .links{display:flex;gap:20px}
footer .links a:hover{color:var(--ink)}

/* ===== 响应式 ===== */
@media(max-width:880px){
  .nav-links{display:none}
  .hero{padding:60px 0 48px}
  .hero h1{font-size:36px}
  .hero .lede{font-size:17px}
  .stats{grid-template-columns:repeat(2,1fr);gap:24px}
  .cols-3,.cols-4,.models{grid-template-columns:1fr 1fr}
  .steps,.duo{grid-template-columns:1fr}
  .sec-title{font-size:24px}
}
@media(max-width:520px){
  .cols-3,.cols-4,.models,.stats{grid-template-columns:1fr}
  .hero h1{font-size:30px}
}