/* 368MEGA — 左右分栏：左内容流 + 右 sticky 钢梁桁架轨（m3- 前缀，原创样式） */

:root{
  --m3-bg:#17202B;
  --m3-bg2:#10161F;
  --m3-card:#1E2936;
  --m3-line:#31414F;
  --m3-ac:#FF9147;
  --m3-ac2:#E0732C;
  --m3-steel:#7C93A8;
  --m3-ink:#EDF2F7;
  --m3-dim:#A3B2C2;
  --m3-fd:'Anton',sans-serif;
  --m3-fb:'Fira Sans Condensed',sans-serif;
}

*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{
  background:var(--m3-bg);
  color:var(--m3-ink);
  font-family:var(--m3-fb);
  font-size:17px;
  line-height:1.7;
}
a{color:var(--m3-ac);text-decoration:none}
a:hover{text-decoration:underline}
img{max-width:100%;height:auto;display:block}
h1,h2,h3{font-family:var(--m3-fd);font-weight:400;letter-spacing:.8px;line-height:1.18;text-transform:uppercase}
h1{font-size:clamp(1.9rem,4.2vw,3.1rem)}
h2{font-size:clamp(1.45rem,2.8vw,2.05rem);color:var(--m3-ac)}
h3{font-size:1.28rem;color:var(--m3-ink)}
main{overflow-x:clip}

/* ---------- header ---------- */
.m3-head{
  position:sticky;top:0;z-index:60;
  background:rgba(16,22,31,.95);
  backdrop-filter:blur(8px);
  border-bottom:2px solid var(--m3-ac);
}
.m3-hd{
  max-width:1240px;margin:0 auto;
  display:flex;align-items:center;gap:1.5rem;
  padding:.65rem 1.2rem;
}
.m3-logo{display:flex;align-items:center;gap:.55rem;min-width:0}
.m3-logo:hover{text-decoration:none}
.m3-tri{
  display:inline-flex;
  width:34px;height:30px;position:relative;
}
.m3-tri b{
  position:absolute;bottom:0;
  width:2px;height:20px;background:var(--m3-steel);
}
.m3-tri b:nth-child(1){left:2px;transform:rotate(18deg)}
.m3-tri b:nth-child(2){left:16px;transform:rotate(-18deg)}
.m3-tri b:nth-child(3){left:15px;height:26px;background:var(--m3-ac);transform:rotate(0)}
.m3-tri::after{
  content:"";position:absolute;left:0;right:0;top:2px;height:2px;
  background:var(--m3-steel);
}
.m3-word{
  font-family:var(--m3-fd);
  font-size:1.55rem;color:var(--m3-ink);letter-spacing:1.5px;
}
.m3-nav{display:flex;gap:1.35rem;margin-left:auto;min-width:0}
.m3-nav a{
  color:var(--m3-dim);font-weight:500;font-size:1.02rem;
  padding:.25rem .1rem;border-bottom:3px solid transparent;
  text-transform:uppercase;letter-spacing:.6px;
}
.m3-nav a:hover{color:var(--m3-ink);text-decoration:none}
.m3-nav a.m3-on{color:var(--m3-ac);border-bottom-color:var(--m3-ac)}
.m3-hact{display:flex;gap:.55rem}
.m3-btn{
  display:inline-block;
  font-family:var(--m3-fd);
  font-size:1.02rem;letter-spacing:1.4px;text-transform:uppercase;
  padding:.34rem 1.15rem .42rem;
  border-radius:6px;
  border:2px solid var(--m3-ac);
  transition:transform .15s ease,box-shadow .15s ease;
}
.m3-btn:hover{text-decoration:none;transform:translateY(-1px)}
.m3-btn-main{
  background:linear-gradient(180deg,var(--m3-ac),var(--m3-ac2));
  color:#10161F;
  box-shadow:0 0 18px rgba(255,145,71,.4);
}
.m3-btn-ghost{color:var(--m3-ac);background:transparent}
.m3-burger{display:none;cursor:pointer;flex-direction:column;gap:5px;padding:6px}
.m3-burger span{width:24px;height:2px;background:var(--m3-ink);border-radius:2px}
.m3-navtog{display:none}
.m3-mnav{display:none}

/* ---------- 桁架灯带（横向分隔条） ---------- */
.m3-trussbar{
  display:flex;align-items:center;justify-content:center;gap:1.6rem;
  padding:.5rem 1rem;
  background:
    repeating-linear-gradient(135deg,transparent 0 14px,rgba(124,147,168,.18) 14px 16px),
    #131B25;
  border-top:1px solid var(--m3-line);
  border-bottom:1px solid var(--m3-line);
  overflow:hidden;
}
.m3-trussbar span{
  color:var(--m3-ac);
  font-size:1.05rem;line-height:1;
  text-shadow:0 0 10px rgba(255,145,71,.9);
  animation:m3-pulse 2.6s ease-in-out infinite;
}
.m3-trussbar span:nth-child(3){animation-delay:.4s}
.m3-trussbar span:nth-child(4){animation-delay:.8s}
.m3-trussbar span:nth-child(5){animation-delay:1.2s}
.m3-chord{flex:1 1 60px;min-width:24px;height:2px;background:linear-gradient(90deg,transparent,var(--m3-steel));}
@keyframes m3-pulse{0%,100%{opacity:.55}50%{opacity:1}}

/* ---------- 双栏外壳 ---------- */
.m3-shell{
  max-width:1240px;margin:0 auto;
  display:grid;
  grid-template-columns:minmax(0,1fr) 292px;
  gap:2.2rem;
  padding:2.8rem 1.2rem 3.4rem;
  align-items:start;
}
.m3-flow{min-width:0}

/* ---------- hero ---------- */
.m3-hero{
  border-left:4px solid var(--m3-ac);
  padding:0 0 0 1.4rem;
}
.m3-kick{
  font-family:var(--m3-fd);
  font-size:.98rem;letter-spacing:3px;text-transform:uppercase;
  color:var(--m3-steel);
}
.m3-lead{color:var(--m3-dim);margin:1rem 0 1.5rem}
.m3-cta{display:flex;flex-wrap:wrap;gap:.75rem;margin-bottom:1.6rem}

/* ---------- 工程 ol 大卡 ---------- */
.m3-projects{margin-top:1.2rem}
.m3-prp{color:var(--m3-dim);margin:.4rem 0 1.1rem}
.m3-list{list-style:none}
.m3-list li{
  position:relative;
  display:grid;
  grid-template-columns:64px minmax(0,1fr);
  gap:1rem;
  background:var(--m3-card);
  border:1px solid var(--m3-line);
  border-radius:12px;
  padding:1.05rem 1.15rem;
  margin-bottom:.9rem;
  min-width:0;
  transition:border-color .2s ease,box-shadow .2s ease;
}
.m3-list li:hover{border-color:var(--m3-ac);box-shadow:0 0 18px rgba(255,145,71,.15)}
.m3-num{
  display:grid;place-items:center;
  width:64px;height:64px;
  font-family:var(--m3-fd);font-size:2rem;
  color:#10161F;
  background:linear-gradient(180deg,var(--m3-ac),var(--m3-ac2));
  border-radius:10px;
  box-shadow:0 0 14px rgba(255,145,71,.35);
}
.m3-list h3{margin-bottom:.25rem}
.m3-list p{color:var(--m3-dim);font-size:.95rem;margin-bottom:.5rem}
.m3-plink{font-family:var(--m3-fd);font-size:.98rem;letter-spacing:1px;text-transform:uppercase}

/* ---------- 叙述 ---------- */
.m3-story h2{margin-bottom:.9rem}
.m3-story p{color:var(--m3-dim);margin-bottom:1rem}
.m3-quote{
  border-left:4px solid var(--m3-ac);
  background:#131B25;
  padding:.95rem 1.2rem;
  border-radius:0 10px 10px 0;
  color:var(--m3-ink);
  font-style:italic;
  margin:1.2rem 0;
}
.m3-fig{
  margin:1.6rem 0 0;
  border:1px solid var(--m3-line);
  border-radius:12px;
  overflow:hidden;
  background:var(--m3-card);
}
.m3-fig img{width:100%}
.m3-fig figcaption{
  padding:.55rem 1rem;
  font-size:.82rem;color:var(--m3-dim);
  border-top:1px solid var(--m3-line);
}

/* ---------- 优势 ---------- */
.m3-why{margin-top:2.6rem;background:#131B25;border:1px solid var(--m3-line);border-radius:14px;padding:1.8rem 1.4rem}
.m3-whylist{list-style:none;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:.9rem;margin-top:1rem}
.m3-whylist li{
  border-top:2px solid var(--m3-ac);
  background:var(--m3-card);
  border-radius:0 0 10px 10px;
  padding:.85rem 1rem;
  min-width:0;
}
.m3-whylist h3{font-size:1.15rem;color:var(--m3-ac)}
.m3-whylist p{font-size:.92rem;color:var(--m3-dim)}

/* ---------- 精选 ---------- */
.m3-picks{margin-top:2.4rem}
.m3-picklist{list-style:none;counter-reset:m3pk;margin-top:1rem}
.m3-picklist li{
  counter-increment:m3pk;
  position:relative;
  padding:.8rem .9rem .8rem 3.2rem;
  border-bottom:1px dashed var(--m3-line);
  min-width:0;
}
.m3-picklist li::before{
  content:counter(m3pk,decimal-leading-zero);
  position:absolute;left:.4rem;top:.85rem;
  font-family:var(--m3-fd);
  color:var(--m3-ac);
  font-size:1.5rem;
}
.m3-picklist h3 a{color:var(--m3-ink)}
.m3-picklist p{font-size:.9rem;color:var(--m3-dim)}

/* ---------- FAQ / 信任 ---------- */
.m3-faqsec{margin-top:2.4rem}
.m3-faqsec details{
  background:var(--m3-card);
  border:1px solid var(--m3-line);
  border-radius:10px;
  padding:.8rem 1.05rem;
  margin-bottom:.65rem;
}
.m3-faqsec summary{cursor:pointer;font-weight:700;color:var(--m3-ink)}
.m3-faqsec details[open] summary{color:var(--m3-ac)}
.m3-faqsec details p{color:var(--m3-dim);font-size:.93rem;margin-top:.45rem}
.m3-trust{margin-top:2.4rem;border:1px dashed var(--m3-line);border-radius:14px;padding:1.4rem 1.3rem;background:#121A24}
.m3-trust p{color:var(--m3-dim)}
.m3-trustlnk{font-family:var(--m3-fd);font-size:1.02rem;letter-spacing:1px;text-transform:uppercase;display:inline-block;margin-top:.6rem}

/* ---------- 右侧钢梁桁架轨 ---------- */
.m3-rail{min-width:0}
.m3-railin{
  position:sticky;top:86px;
  background:
    repeating-linear-gradient(0deg,transparent 0 46px,rgba(124,147,168,.14) 46px 48px),
    var(--m3-bg2);
  border:1px solid var(--m3-line);
  border-radius:14px;
  padding:1.1rem 1rem 1.2rem;
  overflow:hidden;
}
.m3-railh{
  font-size:1.2rem;
  text-align:center;
  border-bottom:2px solid var(--m3-ac);
  padding-bottom:.5rem;
  margin-bottom:.9rem;
}
.m3-truss{display:flex;flex-direction:column}
.m3-node{
  display:grid;
  grid-template-columns:44px minmax(0,1fr);
  align-items:center;gap:.7rem;
  padding:.5rem .2rem;
  border-bottom:1px solid rgba(124,147,168,.25);
  min-width:0;
}
.m3-node:last-child{border-bottom:none}
.m3-node:hover{text-decoration:none;background:rgba(255,145,71,.06)}
.m3-lamp{
  display:grid;place-items:center;
  width:40px;height:40px;
  border-radius:50%;
  background:#0C1219;
  border:1px solid var(--m3-ac);
  color:var(--m3-ac);
  font-size:1.05rem;
  box-shadow:0 0 12px rgba(255,145,71,.55);
}
.m3-node b{
  font-size:.92rem;font-weight:500;
  color:var(--m3-ink);line-height:1.3;
}
.m3-railfoot{
  display:block;
  margin-top:.9rem;
  color:var(--m3-dim);font-size:.74rem;line-height:1.45;
  text-align:center;
}

/* ---------- 通用文章纸 ---------- */
.m3-paper{padding:2.4rem 1.2rem 3.2rem}
.m3-edu,.m3-navpage{
  max-width:820px;margin:0 auto;
  background:var(--m3-card);
  border:1px solid var(--m3-line);
  border-top:3px solid var(--m3-ac);
  border-radius:12px;
  padding:2rem 1.7rem;
  min-width:0;
}
.m3-crumbs{font-size:.84rem;color:var(--m3-dim);margin-bottom:1rem}
.m3-crumbs span{color:var(--m3-ac)}
.m3-edulead,.m3-navintro{color:var(--m3-dim);margin:.7rem 0 1.2rem}
.m3-edu h2,.m3-navpage h2{font-size:1.4rem;margin:1.6rem 0 .6rem}
.m3-edu p,.m3-navpage p,.m3-pp{color:var(--m3-dim)}
.m3-edu .m3-fig-lead{margin:1.4rem 0}
.m3-steps2{list-style:none;margin:1rem 0}
.m3-steps2 li{
  display:grid;grid-template-columns:56px minmax(0,1fr);gap:.9rem;
  background:#131B25;
  border:1px solid var(--m3-line);
  border-radius:10px;
  padding:.85rem .95rem;
  margin-bottom:.7rem;
  min-width:0;
}
.m3-steps2 .m3-num{width:56px;height:56px;font-size:1.7rem}
.m3-steps2 h3{font-size:1.12rem;margin-bottom:.15rem}
.m3-steps2 p{font-size:.9rem}
.m3-glist{margin:.6rem 0 1rem 1.2rem;color:var(--m3-dim)}
.m3-glist li{margin-bottom:.4rem;font-size:.94rem}
.m3-navaside{
  margin-top:1.6rem;
  background:#131B25;
  border:1px dashed var(--m3-line);
  border-radius:10px;
  padding:1rem 1.1rem;
}
.m3-navaside h3{font-size:1.08rem;color:var(--m3-ac);margin-bottom:.3rem}
.m3-navaside a{display:block;padding:.2rem 0;font-size:.93rem}
.m3-note{
  border-left:4px solid var(--m3-ac);
  background:#131B25;
  padding:.8rem 1rem;border-radius:0 8px 8px 0;
  color:var(--m3-ink);font-size:.93rem;
  margin-top:1.2rem;
}
.m3-resp{
  margin-top:1.4rem;
  font-size:.8rem;color:var(--m3-dim);
  border-top:1px solid var(--m3-line);
  padding-top:.8rem;
}

/* ---------- 404 ---------- */
.m3-404{max-width:660px;margin:0 auto;text-align:center;padding:4.2rem 1.2rem}
.m3-404lamps{display:flex;justify-content:center;gap:.7rem;font-size:2.3rem;margin-bottom:1.1rem}
.m3-404lamps span{
  background:#0C1219;
  border:1px solid var(--m3-ac);
  border-radius:50%;
  width:64px;height:64px;
  display:grid;place-items:center;
  color:var(--m3-ac);
}
.m3-404 p{color:var(--m3-dim);margin:.8rem 0 1.4rem}
.m3-404act{display:flex;justify-content:center;flex-wrap:wrap;gap:.7rem}

/* ---------- footer ---------- */
.m3-foot{
  border-top:2px solid var(--m3-ac);
  background:var(--m3-bg2);
  padding:2.4rem 1.2rem 5.6rem;
}
.m3-fgrid{
  max-width:1240px;margin:0 auto;
  display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:1.6rem;
}
.m3-fcol h3{color:var(--m3-ac);font-size:1.1rem;margin-bottom:.45rem}
.m3-fcol a{display:block;color:var(--m3-dim);font-size:.92rem;padding:.16rem 0}
.m3-fcol a:hover{color:var(--m3-ac)}
.m3-fbrand p{font-size:.85rem;color:var(--m3-dim);margin:.6rem 0}
.m3-18{
  display:inline-block;
  border:2px solid var(--m3-ac);
  color:var(--m3-ac);
  border-radius:6px;
  font-weight:700;font-size:.8rem;
  padding:.02rem .7rem .08rem;
}
.m3-fbot{max-width:1240px;margin:1.8rem auto 0;border-top:1px solid var(--m3-line);padding-top:1rem}
.m3-fbot p{font-size:.78rem;color:var(--m3-dim);text-align:center}

/* ---------- 悬浮条 ---------- */
.m3-float{
  position:fixed;left:50%;bottom:14px;transform:translateX(-50%);
  z-index:80;
  width:min(94vw,560px);
}
.m3-floatin{
  display:flex;align-items:center;justify-content:center;gap:.9rem;
  background:rgba(16,22,31,.96);
  border:2px solid var(--m3-ac);
  border-radius:10px;
  padding:.5rem .95rem;
  box-shadow:0 0 24px rgba(255,145,71,.45);
  backdrop-filter:blur(6px);
}
.m3-tag{white-space:nowrap;font-size:.88rem;color:var(--m3-ink)}
.m3-blink{color:var(--m3-ac);animation:m3-bl 1.5s steps(2,start) infinite}
@keyframes m3-bl{to{visibility:hidden}}
.m3-enter{white-space:nowrap}

/* ---------- 响应式 ---------- */
@media (max-width:1100px){
  .m3-shell{grid-template-columns:1fr}
  .m3-railin{position:static}
  .m3-truss{flex-direction:row;flex-wrap:wrap;gap:.4rem}
  .m3-node{grid-template-columns:44px minmax(0,1fr);flex:1 1 200px;border-bottom:none;border-right:1px solid rgba(124,147,168,.25)}
}
@media (max-width:960px){
  .m3-nav{display:none}
  .m3-burger{display:flex}
  .m3-navtog:checked~.m3-mnav{display:block}
  .m3-mnav{
    background:#0C1219;
    border-bottom:1px solid var(--m3-line);
    padding:1rem 1.2rem 1.4rem;
  }
  .m3-mgrp{margin-bottom:1rem}
  .m3-mgrp h3{color:var(--m3-ac);font-size:1.05rem;margin-bottom:.25rem}
  .m3-mgrp a{display:block;color:var(--m3-dim);padding:.22rem 0;font-size:.96rem}
}
@media (max-width:700px){
  .m3-list li{grid-template-columns:1fr}
  .m3-num{width:100%;height:48px;font-size:1.5rem}
  .m3-whylist{grid-template-columns:1fr}
  .m3-steps2 li{grid-template-columns:1fr}
  .m3-steps2 .m3-num{width:100%;height:44px;font-size:1.4rem}
  .m3-fgrid{grid-template-columns:1fr 1fr}
  .m3-floatin{flex-wrap:wrap;border-radius:12px}
  .m3-hact{margin-left:auto}
  .m3-word{font-size:1.25rem}
}
@media (max-width:460px){
  .m3-fgrid{grid-template-columns:1fr}
  .m3-cta{flex-direction:column;align-items:flex-start}
}