/* 徐州千川网络科技有限公司 · 官网样式
   ---------------------------------------------------- */
:root{
  --ink:#0d1520;
  --ink-2:#48525e;
  --ink-3:#7d8794;
  --line:#e5eaf1;
  --line-2:#eff3f8;
  --bg:#f6f8fb;
  --card:#ffffff;
  --brand:#1450c8;
  --brand-2:#3b8ff0;
  --brand-bg:#eef4fe;
  --gold:#b8860b;
  --gold-bg:#fdf8ec;
  --green:#1f7a4d;
  --green-bg:#eef8f2;
  --red:#c0392b;
  --red-bg:#fdf2f1;
  --radius:16px;
  --shadow:0 1px 2px rgba(13,21,32,.04), 0 8px 24px -12px rgba(13,21,32,.12);
  --maxw:1120px;
}
*{box-sizing:border-box;margin:0;padding:0;}
html{scroll-behavior:smooth;background:#eaf2fb;}
body{
  background:transparent;
  color:var(--ink);
  font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Helvetica Neue",sans-serif;
  font-size:15px;
  line-height:1.75;
  -webkit-font-smoothing:antialiased;
}

/* ---------- 背景：高空俯瞰高原雪山 + 飘雪 ---------- */
#snowscape{
  position:fixed;top:0;left:0;
  width:100%;height:100%;
  z-index:-1;pointer-events:none;
  display:block;
}
@media (prefers-reduced-motion: reduce){
  #snowscape{opacity:.9;}
}
a{color:var(--brand);text-decoration:none;}
a:hover{text-decoration:underline;}
img{max-width:100%;display:block;}
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 22px;}

/* ---------- 顶部导航 ---------- */
.hd{
  position:sticky;top:0;z-index:50;
  background:rgba(255,255,255,.92);
  backdrop-filter:saturate(180%) blur(12px);
  border-bottom:1px solid var(--line);
}
.hd-in{
  max-width:var(--maxw);margin:0 auto;padding:12px 22px;
  display:flex;align-items:center;gap:22px;
}
.brand{display:flex;align-items:center;gap:11px;flex-shrink:0;}
.brand:hover{text-decoration:none;}
.logo{
  width:36px;height:36px;border-radius:10px;flex-shrink:0;
  background:linear-gradient(135deg,var(--brand),var(--brand-2));
  color:#fff;font-size:17px;font-weight:700;
  display:flex;align-items:center;justify-content:center;
  letter-spacing:0;
}
.bn{display:flex;flex-direction:column;line-height:1.25;}
.bn b{font-size:15px;font-weight:700;color:var(--ink);white-space:nowrap;}
.bn em{font-style:normal;font-size:11px;color:var(--ink-3);letter-spacing:.06em;}
.nav{display:flex;gap:4px;margin-left:auto;overflow-x:auto;scrollbar-width:none;}
.nav::-webkit-scrollbar{display:none;}
.nav a{
  font-size:14px;color:var(--ink-2);padding:7px 12px;border-radius:9px;white-space:nowrap;
}
.nav a:hover{background:var(--line-2);color:var(--ink);text-decoration:none;}
.nav a.on{color:var(--brand);background:var(--brand-bg);font-weight:600;}
.hd-cta{
  flex-shrink:0;font-size:13.5px;font-weight:600;color:#fff;background:var(--brand);
  padding:8px 16px;border-radius:9px;
}
.hd-cta:hover{background:#0f3fa3;text-decoration:none;}

/* ---------- Hero ---------- */
.hero{
  position:relative;overflow:hidden;
  background:
    radial-gradient(900px 420px at 12% -10%, rgba(255,255,255,.85) 0%, rgba(255,255,255,0) 62%),
    radial-gradient(760px 420px at 92% 0%, rgba(244,250,255,.66) 0%, rgba(244,250,255,0) 60%),
    linear-gradient(180deg,rgba(255,255,255,.56),rgba(255,255,255,.10));
  border-bottom:1px solid rgba(229,234,241,.72);
}
.hero-in{max-width:var(--maxw);margin:0 auto;padding:64px 22px 58px;}
.kicker{
  display:inline-flex;align-items:center;gap:8px;
  font-size:12px;font-weight:600;letter-spacing:.1em;color:var(--brand);
  background:#fff;border:1px solid #d8e4fb;border-radius:99px;padding:5px 14px;
  box-shadow:var(--shadow);
}
.kicker i{width:6px;height:6px;border-radius:50%;background:var(--brand);display:block;}
.hero h1{
  font-size:clamp(27px,4.2vw,42px);font-weight:800;letter-spacing:-.02em;
  line-height:1.25;margin:18px 0 0;max-width:23em;
}
.hero .sub{
  font-size:16px;color:var(--ink-2);margin-top:16px;max-width:46em;
}
.hero .sub b{color:var(--ink);}
.hero-acts{display:flex;flex-wrap:wrap;gap:12px;margin-top:28px;}
.btn{
  display:inline-flex;align-items:center;gap:7px;
  font-size:14.5px;font-weight:600;padding:11px 22px;border-radius:11px;
}
.btn.p{background:var(--brand);color:#fff;box-shadow:0 8px 20px -10px rgba(20,80,200,.7);}
.btn.p:hover{background:#0f3fa3;text-decoration:none;}
.btn.s{background:#fff;color:var(--ink);border:1px solid var(--line);}
.btn.s:hover{border-color:#c9d3e0;text-decoration:none;}

.figs{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin-top:40px;}
.fig{
  background:#fff;border:1px solid var(--line);border-radius:13px;padding:16px 18px;
}
.fig .fv{font-size:23px;font-weight:800;letter-spacing:-.02em;line-height:1.15;}
.fig .fv small{font-size:12.5px;font-weight:600;color:var(--ink-3);margin-left:3px;}
.fig .fl{font-size:12.5px;color:var(--ink-3);margin-top:4px;}

/* ---------- 通用区块 ---------- */
main{padding:0 0 70px;}
section.sec{padding:56px 0 0;}
.sec-h{max-width:52em;}
.sec-h .tag{
  font-size:12px;font-weight:700;letter-spacing:.12em;color:var(--ink-3);text-transform:uppercase;
}
.sec-h h2{
  font-size:clamp(21px,2.6vw,27px);font-weight:750;letter-spacing:-.015em;line-height:1.35;margin-top:8px;
}
.sec-h p{color:var(--ink-2);margin-top:12px;font-size:15px;}
.grid{display:grid;gap:16px;margin-top:26px;}
.g2{grid-template-columns:repeat(2,1fr);}
.g3{grid-template-columns:repeat(3,1fr);}
.g4{grid-template-columns:repeat(4,1fr);}
.card{
  background:var(--card);border:1px solid var(--line);border-radius:var(--radius);
  padding:24px 24px 22px;box-shadow:var(--shadow);
}
.card h3{font-size:16px;font-weight:700;margin-bottom:9px;letter-spacing:-.01em;}
.card p{font-size:14px;color:var(--ink-2);}
.card .ic{
  width:38px;height:38px;border-radius:11px;background:var(--brand-bg);color:var(--brand);
  display:flex;align-items:center;justify-content:center;margin-bottom:14px;
}
.card .ic svg{width:19px;height:19px;stroke:currentColor;fill:none;stroke-width:1.9;stroke-linecap:round;stroke-linejoin:round;}
.card.gold .ic{background:var(--gold-bg);color:var(--gold);}
.card.green .ic{background:var(--green-bg);color:var(--green);}
.card ul{margin-top:10px;}
.card li{font-size:13.5px;color:var(--ink-2);list-style:none;position:relative;padding-left:16px;margin-bottom:7px;}
.card li::before{content:"";position:absolute;left:2px;top:9px;width:5px;height:5px;border-radius:50%;background:#c3ccd8;}

ul.clean{list-style:none;margin-top:14px;}
ul.clean li{position:relative;padding-left:20px;font-size:14.5px;color:var(--ink-2);margin-bottom:10px;}
ul.clean li::before{content:"";position:absolute;left:3px;top:10px;width:6px;height:6px;border-radius:50%;background:var(--brand-2);}
ul.clean li b{color:var(--ink);}

/* 表格 */
table{width:100%;border-collapse:collapse;font-size:14px;margin-top:16px;background:#fff;border:1px solid var(--line);border-radius:12px;overflow:hidden;}
th,td{text-align:left;padding:12px 15px;border-bottom:1px solid var(--line-2);vertical-align:top;}
tr:last-child td,tr:last-child th{border-bottom:none;}
th{background:#fafbfd;font-weight:600;color:var(--ink-3);font-size:13px;width:190px;}
td{color:var(--ink);}
code{
  background:#eef1f6;padding:2px 7px;border-radius:5px;font-size:13px;
  font-family:ui-monospace,SFMono-Regular,Menlo,monospace;letter-spacing:.01em;color:#26313d;
}

/* 提示条 */
.note{font-size:13.5px;border-radius:11px;padding:14px 17px;line-height:1.8;margin-top:16px;}
.note.blue{background:var(--brand-bg);border:1px solid #d8e4fb;color:#17407f;}
.note.green{background:var(--green-bg);border:1px solid #cbe8d8;color:#1a5c3a;}
.note.gold{background:var(--gold-bg);border:1px solid #f0e2c0;color:#7a5a06;}
.note b{color:inherit;}

/* 1+3 结构块 */
.oneplus{display:grid;grid-template-columns:1fr 1.55fr;gap:16px;margin-top:26px;}
.op-main,.op-three{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:26px;box-shadow:var(--shadow);}
.op-badge{
  display:inline-flex;align-items:center;justify-content:center;
  width:42px;height:42px;border-radius:12px;font-size:19px;font-weight:800;
  background:linear-gradient(135deg,var(--brand),var(--brand-2));color:#fff;margin-bottom:14px;
}
.op-main h3,.op-three h3{font-size:16.5px;font-weight:750;margin-bottom:8px;}
.op-main p{font-size:14px;color:var(--ink-2);}
.op-list{list-style:none;display:grid;gap:12px;margin-top:4px;}
.op-list li{display:flex;gap:13px;align-items:flex-start;}
.op-list .n{
  flex-shrink:0;width:25px;height:25px;border-radius:8px;background:var(--brand-bg);color:var(--brand);
  font-size:12.5px;font-weight:700;display:flex;align-items:center;justify-content:center;margin-top:2px;
}
.op-list .tx b{display:block;font-size:14.5px;font-weight:650;color:var(--ink);}
.op-list .tx span{font-size:13.5px;color:var(--ink-2);line-height:1.7;}

/* FAQ */
.faqbox{margin-top:22px;background:#fff;border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow);}
details{border-bottom:1px solid var(--line-2);}
details:last-child{border-bottom:none;}
summary{
  cursor:pointer;list-style:none;padding:16px 22px;
  font-size:14.8px;font-weight:650;color:var(--ink);
  display:flex;align-items:center;gap:11px;
}
summary::-webkit-details-marker{display:none;}
summary::after{
  content:"+";margin-left:auto;color:var(--ink-3);font-weight:400;font-size:18px;line-height:1;
  flex-shrink:0;
}
details[open] summary::after{content:"–";}
details[open] summary{background:#fcfdff;}
.ans{padding:0 22px 18px 22px;font-size:14px;color:var(--ink-2);line-height:1.85;}
.ans b{color:var(--ink);}
details.key summary{color:#94291f;}
details.key{background:linear-gradient(180deg,#fefaf9,#fff);}

/* CTA 带 */
.band{
  margin-top:56px;border-radius:var(--radius);padding:36px 34px;
  background:linear-gradient(120deg,#0d1520,#17335f 62%,#1450c8);
  color:#fff;display:flex;align-items:center;justify-content:space-between;gap:26px;flex-wrap:wrap;
}
.band h3{font-size:20px;font-weight:750;letter-spacing:-.01em;}
.band p{font-size:14px;color:#c3cede;margin-top:8px;max-width:38em;}
.band .btn.p{background:#fff;color:#12335f;box-shadow:none;}
.band .btn.p:hover{background:#e9eef6;}

/* 页脚 */
.ft{background:#0d1520;color:#9fabb9;margin-top:64px;padding:44px 0 26px;font-size:13.5px;}
.ft-cols{display:grid;grid-template-columns:1.5fr 1fr 1fr;gap:30px;}
.ft h4{color:#fff;font-size:14px;font-weight:650;margin-bottom:12px;}
.ft a{color:#c3cede;}
.ft a:hover{color:#fff;}
.ft ul{list-style:none;}
.ft li{margin-bottom:8px;}
.ft-brand{display:flex;align-items:center;gap:10px;margin-bottom:14px;}
.ft-brand .logo{width:32px;height:32px;font-size:15px;border-radius:9px;}
.ft-brand b{color:#fff;font-size:15px;}
.ft-bot{
  border-top:1px solid #253040;margin-top:30px;padding-top:20px;
  display:flex;justify-content:space-between;gap:16px;flex-wrap:wrap;font-size:12.5px;color:#78859a;
}

/* 面包屑 */
.crumb{font-size:12.5px;color:var(--ink-3);padding:22px 0 0;}
.crumb a{color:var(--ink-3);}
.crumb span{margin:0 7px;color:#c3ccd8;}

/* 页面头 */
.phead{padding:34px 0 0;}
.phead h1{font-size:clamp(24px,3.2vw,33px);font-weight:800;letter-spacing:-.02em;line-height:1.3;}
.phead .lead{font-size:15.5px;color:var(--ink-2);margin-top:14px;max-width:50em;}

@media(max-width:900px){
  .g4{grid-template-columns:repeat(2,1fr);}
  .g3{grid-template-columns:repeat(2,1fr);}
  .oneplus{grid-template-columns:1fr;}
  .ft-cols{grid-template-columns:1fr 1fr;}
}
@media(max-width:640px){
  .bn em{display:none;}
  .figs{grid-template-columns:repeat(2,1fr);}
  .g2,.g3,.g4{grid-template-columns:1fr;}
  .hero-in{padding:44px 22px 40px;}
  .ft-cols{grid-template-columns:1fr;}
  .hd-cta{display:none;}
  table{font-size:13.5px;}
  th{width:120px;}
  .band{padding:28px 22px;}
}