/* ===== 乘用车知识科普站 · 全站样式 ===== */
:root{
  /* 主色 · 专业工程蓝 */
  --brand:#2459c4; --brand-d:#142d4a; --brand-l:#e8efff;
  /* 能量编码色（色盲友好：颜色 + 图标双维度） */
  --e-fuel:#d96c3d;   --e-fuel-bg:#fff0e8;   /* 燃油 / 化学能 */
  --e-elec:#2f6fed;   --e-elec-bg:#eaf1ff;   /* 电能 */
  --e-mech:#36846b;   --e-mech-bg:#eaf5f0;   /* 机械能 */
  --e-loss:#737b86;   --e-loss-bg:#eef0f3;   /* 热损耗 */
  --e-hydro:#247d84;  --e-hydro-bg:#e7f4f5;  /* 氢 */
  /* 中性 */
  --bg:#f6f8fb; --surface-muted:#edf2f7; --ink:#152131; --ink-soft:#4f5f70; --ink-mute:#788697;
  --card:#ffffff; --line:#dce3eb; --line-d:#c4ced9;
  --shadow:0 1px 2px rgba(20,45,74,.05),0 10px 28px rgba(20,45,74,.06);
  --shadow-hover:0 2px 4px rgba(20,45,74,.06),0 16px 40px rgba(20,45,74,.10);
  --focus:0 0 0 3px rgba(47,111,237,.22);
  --ease-out:cubic-bezier(.23,1,.32,1);
  --radius:14px; --radius-sm:9px;
  --maxw:1180px;
  --font-sans:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
  --font-display:"Songti SC","STSong","Noto Serif CJK SC","Source Han Serif SC",serif;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  font-family:var(--font-sans);
  background:var(--bg);color:var(--ink);line-height:1.72;-webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
a{color:inherit;text-decoration:none}
img,svg{display:block;max-width:100%}
button,input,select{font:inherit}
.wrap{max-width:var(--maxw);margin:0 auto;padding-inline:clamp(20px,4vw,32px)}
.serif{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif}

/* ===== 顶部导航 ===== */
header.nav{position:sticky;top:0;z-index:50;background:rgba(245,247,251,.88);
  backdrop-filter:saturate(160%) blur(10px);border-bottom:1px solid var(--line)}
.nav-in{display:flex;align-items:center;gap:26px;height:62px}
.logo{display:flex;align-items:center;gap:10px;font-weight:700;font-size:18px;color:var(--brand)}
.logo svg{width:34px;height:34px;flex:none}
.nav-links{display:flex;gap:20px;margin-left:auto;flex-wrap:wrap}
.nav-links a{color:var(--ink-soft);font-size:15px;font-weight:500;padding:6px 2px;border-bottom:2px solid transparent;transition:color 180ms ease,border-color 180ms ease}
.nav-links a:hover,.nav-links a.active{color:var(--brand);border-color:var(--brand)}
.nav-cta{font-size:13px;background:var(--brand);color:#fff;padding:7px 14px;border-radius:999px;font-weight:600}
@media(max-width:760px){
  .nav-in{height:auto;min-height:62px;flex-wrap:wrap;padding:9px 0;gap:8px 14px}
  .logo{flex:1}
  .nav-cta{order:2}
  .nav-links{order:3;width:100%;margin-left:0;gap:18px;overflow-x:auto;padding-bottom:3px}
  .nav-links a{white-space:nowrap;padding:4px 0;border-bottom-width:0}
}

/* ===== 通用区块 ===== */
section{padding:54px 0}
.eyebrow{display:inline-block;font-size:13px;letter-spacing:.05em;color:var(--brand);
  background:var(--brand-l);padding:5px 12px;border-radius:999px;font-weight:600;margin-bottom:16px}
h1.page{font-size:clamp(28px,4.5vw,42px);line-height:1.18;letter-spacing:-.01em;color:var(--brand-d)}
h2.sec{font-size:26px;color:var(--brand-d);letter-spacing:-.01em;margin-bottom:6px}
h2.sec .n{font-family:Georgia,serif;color:var(--e-fuel);margin-right:10px}
.sec-sub{color:var(--ink-soft);max-width:680px;margin-bottom:26px}
.lead{font-size:17px;color:var(--ink-soft);max-width:640px}

/* ===== 首页 hero ===== */
.hero{padding:64px 0 30px;border-bottom:1px solid var(--line)}
.hero h1{margin-bottom:16px}
.hero h1 em{font-style:normal;color:var(--e-elec)}
.hero .cta{margin-top:26px;display:flex;gap:14px;flex-wrap:wrap}
.btn{display:inline-flex;align-items:center;gap:8px;padding:12px 22px;border-radius:10px;font-weight:600;font-size:15px;transition:transform 150ms var(--ease-out),box-shadow 180ms ease;cursor:pointer;border:0}
.btn-primary{background:var(--brand);color:#fff;box-shadow:var(--shadow)}
.btn-primary:hover{transform:translateY(-2px)}
.btn-ghost{background:var(--card);color:var(--brand);border:1px solid var(--line-d)}
.btn-ghost:hover{border-color:var(--brand)}

/* ===== 卡片网格 ===== */
.grid{display:grid;gap:18px}
.grid.c3{grid-template-columns:repeat(auto-fill,minmax(300px,1fr))}
.grid.c4{grid-template-columns:repeat(auto-fill,minmax(230px,1fr))}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:22px;box-shadow:var(--shadow);transition:transform 160ms var(--ease-out),border-color 180ms ease;display:block}
.card:hover{transform:translateY(-3px);border-color:var(--brand)}
.card h3{font-size:18px;color:var(--brand-d);margin-bottom:6px;display:flex;align-items:center;gap:9px}
.card p{font-size:14.5px;color:var(--ink-soft)}
.card .tag{display:inline-block;font-size:12px;font-weight:600;padding:3px 9px;border-radius:6px;margin-top:12px}
.dot{width:11px;height:11px;border-radius:3px;flex:none}

/* 能量徽标小图标（颜色+形状） */
.ebadge{display:inline-flex;align-items:center;gap:6px;font-size:13px;font-weight:600;padding:4px 10px;border-radius:999px}
.ebadge i{width:10px;height:10px;border-radius:2px;flex:none}
.e-fuel{background:var(--e-fuel-bg);color:#a9531c} .e-fuel i{background:var(--e-fuel)}
.e-elec{background:var(--e-elec-bg);color:#1f568f} .e-elec i{background:var(--e-elec);border-radius:50%}
.e-mech{background:var(--e-mech-bg);color:#1d6b45} .e-mech i{background:var(--e-mech);clip-path:polygon(50% 0,100% 100%,0 100%)}
.e-loss{background:var(--e-loss-bg);color:#5f6875} .e-loss i{background:var(--e-loss)}
.e-hydro{background:var(--e-hydro-bg);color:#1f6f6a} .e-hydro i{background:var(--e-hydro);border-radius:50%}

/* ===== 双层切换 L1/L2 ===== */
.layers{margin:22px 0}
.layer-tabs{display:flex;gap:8px;margin-bottom:16px}
.layer-tab{flex:1;text-align:center;padding:12px 14px;border-radius:11px;border:1px solid var(--line-d);background:var(--card);cursor:pointer;transition:background-color 180ms ease,border-color 180ms ease,color 180ms ease}
.layer-tab .t1{font-size:15px;font-weight:700;color:var(--ink)}
.layer-tab .t2{font-size:12.5px;color:var(--ink-mute)}
.layer-tab.on{background:var(--brand);border-color:var(--brand)}
.layer-tab.on .t1,.layer-tab.on .t2{color:#fff;opacity:1}
.layer-tab.on .t2{opacity:.85}
.layer-panel{display:none;animation:fade 140ms ease}
.layer-panel.on{display:block}
@keyframes fade{from{opacity:0}to{opacity:1}}
.analogy{background:var(--e-elec-bg);border-left:4px solid var(--e-elec);border-radius:0 11px 11px 0;padding:14px 18px;margin:14px 0;font-size:15.5px;color:#1f568f}
.formula{font-family:"Cambria Math",Georgia,serif;font-size:22px;text-align:center;background:linear-gradient(180deg,#fbfcfe,#eef3f9);border:1px solid var(--line);border-radius:11px;padding:16px;margin:14px 0;color:var(--ink)}

/* 关键参数卡（横排） */
.params{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:12px;margin:18px 0}
.param{background:var(--card);border:1px solid var(--line);border-radius:11px;padding:14px 16px}
.param b{display:block;font-size:12px;color:var(--ink-mute);font-weight:600}
.param .v{font-size:20px;font-weight:700;color:var(--brand-d);font-family:Georgia,serif}
.param .u{font-size:12px;color:var(--ink-soft)}

/* 误区 / FAQ */
.note{border-radius:11px;padding:14px 18px;margin:12px 0;font-size:14.5px}
.note.warn{background:#fdf3e7;border-left:4px solid var(--e-fuel);color:#8a4a14}
.note.tip{background:var(--e-mech-bg);border-left:4px solid var(--e-mech);color:#1d6b45}

/* ===== 能量流图组件（招牌） ===== */
.flowwrap{background:var(--card);border:1px solid var(--line);border-radius:16px;box-shadow:var(--shadow);overflow:hidden}
.flow-top{display:flex;flex-wrap:wrap;gap:12px;align-items:center;justify-content:space-between;padding:16px 20px;border-bottom:1px solid var(--line);background:#fbfcfe}
.flow-pick{display:flex;gap:8px;flex-wrap:wrap}
.flow-pick button{padding:7px 14px;border-radius:999px;border:1px solid var(--line-d);background:#fff;font-size:13.5px;font-weight:600;color:var(--ink-soft);cursor:pointer;transition:background-color 160ms ease,border-color 160ms ease,color 160ms ease}
.flow-pick button.on{background:var(--brand);color:#fff;border-color:var(--brand)}
.conds{display:flex;gap:7px;flex-wrap:wrap;padding:14px 20px;border-bottom:1px solid var(--line)}
.conds button{padding:8px 15px;border-radius:9px;border:1px solid var(--line-d);background:#fff;font-size:13.5px;font-weight:600;color:var(--ink-soft);cursor:pointer;transition:background-color 160ms ease,border-color 160ms ease,color 160ms ease}
.conds button.on{background:var(--e-elec);color:#fff;border-color:var(--e-elec)}
.flow-stage{position:relative;padding:10px}
.flow-stage svg{width:100%;height:auto}
.flow-note{padding:14px 20px;background:#fbfcfe;border-top:1px solid var(--line);font-size:14.5px;color:var(--ink-soft);min-height:54px}
.flow-note b{color:var(--brand-d)}
.legend{display:flex;flex-wrap:wrap;gap:14px;padding:14px 20px;border-top:1px solid var(--line)}
.legend .ebadge{cursor:default}
.legend .shape{display:inline-flex;align-items:center;gap:7px;font-size:12.5px;color:var(--ink-soft)}
.legend .shape svg{width:20px;height:20px}

/* 能量流 SVG 元素 class（JS 控制 active/dim） */
.flow-eff{padding:12px 20px;background:#fbfcfe;border-top:1px solid var(--line);font-size:13px;color:var(--ink-soft)}
.flow-eff b{color:var(--brand-d)}
.flow-next{margin-top:18px}
.flow-next-card{box-shadow:none}
.flow-next-card h3{margin-bottom:0}
.etrack{fill:none;stroke:#e6ebf2;stroke-linecap:round}
.elink{fill:none;stroke-linecap:round;transition:opacity .3s,stroke-width .3s}
.elink.dim{opacity:.18}
.enode{cursor:pointer}
.enode .nlabel{font-size:13px;font-weight:600;fill:var(--ink)}
.enode .nsub{font-size:10.5px;fill:var(--ink-mute)}
.enode.dim{opacity:.32}
.particle{pointer-events:none}

/* 节点信息卡（点击弹出） */
.infocard{position:absolute;max-width:240px;background:var(--card);border:1px solid var(--line-d);border-radius:12px;box-shadow:0 12px 36px rgba(0,0,0,.16);padding:14px 16px;font-size:13.5px;z-index:9;display:none}
.infocard.show{display:block;animation:fade .2s ease}
.infocard h4{font-size:15px;color:var(--brand-d);margin-bottom:5px}
.infocard p{color:var(--ink-soft);margin:3px 0}
.infocard .eff{font-weight:700;color:var(--e-mech)}
.infocard .close{position:absolute;top:8px;right:10px;cursor:pointer;color:var(--ink-mute);font-size:18px;line-height:1}

/* ===== 计算器 ===== */
.calc{background:var(--card);border:1px solid var(--line);border-radius:16px;box-shadow:var(--shadow);padding:24px;margin:18px 0}
.calc h3{font-size:18px;color:var(--brand-d);margin-bottom:4px}
.calc .desc{font-size:14px;color:var(--ink-soft);margin-bottom:18px}
.field{margin-bottom:16px}
.field label{display:block;font-size:13.5px;font-weight:600;color:var(--ink);margin-bottom:6px}
.field .hint{font-weight:400;color:var(--ink-mute);font-size:12.5px}
.field input,.field select{width:100%;padding:11px 13px;border:1px solid var(--line-d);border-radius:10px;font-size:15px;background:#fff;color:var(--ink)}
.field input:focus,.field select:focus{outline:0;border-color:var(--brand);box-shadow:0 0 0 3px var(--brand-l)}
.calc-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.result{background:var(--brand-l);border:1px solid #cfe0f3;border-radius:12px;padding:18px;margin-top:8px}
.result .big{font-size:32px;font-weight:700;color:var(--brand-d);font-family:Georgia,serif;line-height:1.1}
.result .big small{font-size:16px;color:var(--ink-soft);font-weight:400}
.result .row{display:flex;justify-content:space-between;padding:6px 0;border-bottom:1px dashed #cfe0f3;font-size:14px}
.result .row:last-child{border:0}
.result .row span:last-child{font-weight:600;color:var(--brand-d)}
@media(max-width:560px){.calc-grid{grid-template-columns:1fr}}

/* ===== 面包屑 / 上下篇 ===== */
.crumb{font-size:13.5px;color:var(--ink-mute);margin:24px 0 10px}
.crumb a:hover{color:var(--brand)}
.pager{display:flex;justify-content:space-between;gap:12px;margin-top:30px;border-top:1px solid var(--line);padding-top:18px;font-size:14px}
.xref{display:flex;gap:12px;flex-wrap:wrap;margin:18px 0}
.xref a{display:inline-flex;align-items:center;gap:7px;font-size:14px;font-weight:600;color:var(--brand);background:var(--brand-l);padding:9px 15px;border-radius:10px;transition:background-color 160ms ease,border-color 160ms ease,color 160ms ease}
.xref a:hover{background:#d8e6f6}
.xref.compact{margin:14px 0 0}
.xref.compact a{font-size:12.5px;padding:6px 10px;border-radius:8px}
.toc{display:flex;gap:8px;flex-wrap:wrap;margin:20px 0 4px}
.toc a{display:inline-flex;align-items:center;padding:7px 12px;border:1px solid var(--line-d);border-radius:999px;background:#fff;color:var(--brand);font-size:13px;font-weight:600}
.toc a:hover{border-color:var(--brand);background:var(--brand-l)}
.vehicle-card:target{border-color:var(--brand);box-shadow:0 0 0 3px var(--brand-l),var(--shadow)}

/* ===== 页脚 ===== */
footer{background:#13243d;color:#9fb0c8;padding:44px 0 28px;margin-top:40px}
footer .cols{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:28px}
footer h4{color:#fff;font-size:14px;margin-bottom:11px}
footer a{display:block;color:#9fb0c8;font-size:13.5px;padding:3px 0}
footer a:hover{color:#fff}
footer .brand{color:#fff;font-weight:700;font-size:17px;margin-bottom:9px}
footer p{font-size:13px;color:#7e90aa;line-height:1.7}
.copy{border-top:1px solid #28415f;margin-top:26px;padding-top:16px;font-size:12.5px;color:#6f82a0;display:flex;justify-content:space-between;flex-wrap:wrap;gap:10px}
@media(max-width:760px){footer .cols{grid-template-columns:1fr 1fr}}
@media(max-width:460px){footer .cols{grid-template-columns:1fr}}

/* ===== 对比矩阵表 ===== */
.matrix{width:100%;border-collapse:collapse;background:var(--card);border-radius:12px;overflow:hidden;box-shadow:var(--shadow);font-size:14px}
.matrix th,.matrix td{padding:12px 14px;text-align:left;border-bottom:1px solid var(--line)}
.matrix th{background:var(--brand);color:#fff;font-weight:600;font-size:13.5px}
.matrix tr:last-child td{border-bottom:0}
.matrix td:first-child{font-weight:600;color:var(--brand-d)}
.matrix .y{color:var(--e-mech);font-weight:700}
.matrix .n{color:var(--ink-mute)}

/* ===== 内容补强组件 ===== */
.mini-list{display:grid;gap:10px;margin-top:14px}
.mini-list li{list-style:none;background:#fbfcfe;border:1px solid var(--line);border-radius:10px;padding:11px 13px;color:var(--ink-soft);font-size:14px}
.mini-list b{color:var(--brand-d)}
.scenario{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:14px;margin-top:18px}
.scenario .card{box-shadow:none}
.glossary{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:12px;margin-top:18px}
.term{background:var(--card);border:1px solid var(--line);border-radius:11px;padding:14px}
.term b{display:block;color:var(--brand-d);font-size:15px;margin-bottom:4px}
.term span{display:block;color:var(--ink-soft);font-size:13.5px;line-height:1.55}
.callout-grid{display:grid;grid-template-columns:1.2fr .8fr;gap:18px;align-items:start}
@media(max-width:820px){.callout-grid{grid-template-columns:1fr}}

/* ===== GPT Image 2 底图 + 精确尺寸标注层 ===== */
.diagram-plate{position:relative;background:#fff;border:1px solid var(--line);border-radius:14px;overflow:hidden;box-shadow:var(--shadow);margin:18px 0}
.diagram-plate img{display:block;width:100%;height:auto}
.diagram-overlay{position:absolute;inset:0;width:100%;height:100%;pointer-events:none}
.diagram-overlay .label rect{fill:rgba(255,255,255,.92);stroke:var(--line-d);stroke-width:1.4;filter:drop-shadow(0 2px 4px rgba(20,30,50,.12))}
.diagram-overlay .label text{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;fill:var(--brand-d)}
.diagram-overlay .label .code{font-weight:800;font-size:25px}
.diagram-overlay .label .cn{font-weight:600;font-size:18px;fill:var(--ink-soft)}
.diagram-overlay .leader{fill:none;stroke:var(--brand);stroke-width:3;stroke-linecap:round;stroke-dasharray:7 6}
.diagram-overlay .leader.green{stroke:var(--e-mech)}
.diagram-overlay .leader.orange{stroke:var(--e-fuel)}
.diagram-overlay .dot{fill:var(--brand);stroke:#fff;stroke-width:4}
.diagram-overlay .dot.green{fill:var(--e-mech)}
.diagram-overlay .dot.orange{fill:var(--e-fuel)}
.diagram-caption{font-size:12.5px;color:var(--ink-mute);margin:-8px 0 18px;text-align:right}

/* ===== 2026 视觉重构 · 清晰、专业、克制 ===== */
.skip-link{
  position:fixed;left:20px;top:-64px;z-index:100;background:var(--brand-d);color:#fff;
  padding:10px 16px;border-radius:0 0 var(--radius-sm) var(--radius-sm);font-weight:700;
  transition:top 160ms var(--ease-out)
}
.skip-link:focus{top:0}
:focus-visible{outline:2px solid var(--e-elec);outline-offset:3px}

header.nav{
  position:sticky;top:0;z-index:50;background:rgba(255,255,255,.92);
  backdrop-filter:saturate(150%) blur(16px);border-bottom:1px solid rgba(196,206,217,.78)
}
.nav-in{height:72px;gap:24px}
.logo{gap:11px;color:var(--brand-d);font-size:17px;letter-spacing:.01em}
.logo svg{width:36px;height:36px}
.brand-lockup{display:grid;line-height:1.08}
.brand-lockup strong{font-size:17px;font-weight:750;letter-spacing:.01em}
.brand-lockup small{font-size:8px;font-weight:700;letter-spacing:.16em;color:var(--ink-mute);margin-top:5px}
.nav-links{gap:4px}
.nav-links a{
  position:relative;border:0;border-radius:8px;padding:8px 10px;font-size:14px;font-weight:650;color:var(--ink-soft);
  transition:color 160ms ease,background-color 160ms ease
}
.nav-links a:hover,.nav-links a.active,.nav-links a[aria-current="page"]{
  color:var(--brand-d);border:0;background:var(--surface-muted)
}
.nav-cta{
  display:inline-flex;align-items:center;gap:7px;background:var(--brand-d);color:#fff;padding:9px 13px;
  border-radius:9px;border:1px solid var(--brand-d);font-weight:700;
  transition:background-color 160ms ease,transform 140ms var(--ease-out)
}
.nav-cta span{font-size:13px;color:#a9c5ff}
.nav-cta:hover{background:#0d2238}
.nav-cta:active{transform:scale(.97)}
.nav-toggle{display:none}

section{padding:clamp(60px,7vw,88px) 0}
section[style*="background:#eef3f9"]{
  background:var(--surface-muted)!important;border-color:var(--line)!important
}
.hero:not(.home-page .hero){background:#fff}
.eyebrow{
  border:1px solid #cad8f8;border-radius:999px;background:var(--brand-l);color:var(--brand);
  padding:5px 11px;font-size:12px;font-weight:750;letter-spacing:.06em
}
h1.page{font-size:clamp(36px,5vw,60px);line-height:1.08;letter-spacing:-.04em;max-width:900px}
h2.sec{font-size:clamp(27px,3vw,36px);line-height:1.22;letter-spacing:-.03em;margin-bottom:10px}
h2.sec .n{display:inline-flex;min-width:34px;color:var(--e-elec);font-style:normal}
.sec-sub{max-width:740px;font-size:16px;line-height:1.82;margin-bottom:34px}
.lead{font-size:clamp(16px,1.6vw,18px);line-height:1.88;max-width:720px}
.crumb{margin-top:0;padding-top:4px}
.crumb a,.pager a{color:var(--brand);font-weight:650}

.home-page .hero{
  position:relative;overflow:hidden;padding:0;border-bottom:1px solid var(--line);background:#fff
}
.home-page .hero .wrap{
  position:relative;min-height:610px;padding-top:clamp(72px,8vw,104px);padding-bottom:clamp(72px,8vw,104px);
  padding-right:min(52%,620px)
}
.home-page .hero .wrap::after{
  content:"";position:absolute;right:32px;top:50%;width:44%;aspect-ratio:3/2;
  transform:translateY(-50%);border:1px solid #24415e;border-radius:18px;box-shadow:var(--shadow);
  background:#16324f url("/assets/home-energy-flow-v3.jpg") center/cover no-repeat
}
.home-page .hero h1{margin:20px 0 24px;max-width:640px}
.home-page .hero h1 em{color:var(--e-elec);text-decoration:none}
.home-page .hero .lead{max-width:620px}
.home-page .hero .cta{margin-top:32px;gap:10px}

.btn{
  min-height:44px;border-radius:10px;padding:11px 18px;border:1px solid var(--line-d);box-shadow:none;
  transition:background-color 160ms ease,border-color 160ms ease,color 160ms ease,transform 140ms var(--ease-out)
}
.btn-primary{background:var(--brand);border-color:var(--brand);color:#fff;box-shadow:none}
.btn-ghost{background:#fff;color:var(--brand-d);border-color:var(--line-d)}
.btn:hover{transform:none}
.btn:active{transform:scale(.97)}

.grid{gap:18px}
.card{
  position:relative;overflow:hidden;border-color:var(--line);border-radius:var(--radius);box-shadow:var(--shadow);
  transition:border-color 180ms ease,box-shadow 180ms ease,transform 180ms var(--ease-out)
}
.card h3{color:var(--brand-d);font-family:inherit;font-size:19px;line-height:1.4}
.card p{font-size:14.5px;line-height:1.78}
.card .tag{border-radius:6px;letter-spacing:.01em}
.card:hover{transform:none;border-color:var(--line);box-shadow:var(--shadow)}
a.card:active{transform:scale(.985)}
.ebadge{border-radius:7px;border:1px solid rgba(20,45,74,.08)}

.home-page section:nth-of-type(even):not([style]){background:rgba(255,255,255,.62)}
.home-page #energy .card{background:#fff}
.home-page #guide .scenario{counter-reset:reading-step}
.home-page #guide .scenario .card::before{
  counter-increment:reading-step;content:"0" counter(reading-step);display:block;margin-bottom:16px;
  color:var(--e-elec);font:700 12px/1 ui-monospace,SFMono-Regular,Menlo,monospace;letter-spacing:.12em
}

.flowwrap,.calc,.matrix,.diagram-plate{
  border-radius:var(--radius);border-color:var(--line);box-shadow:var(--shadow)
}
.flow-top,.flow-note,.flow-eff{background:#f8fafc}
.layer-tab,.param,.note,.result,.toc a,.xref a,.scenario .card,.term{border-radius:var(--radius-sm)}
.layer-tab,.flow-pick button,.conds button{
  transition:background-color 160ms ease,border-color 160ms ease,color 160ms ease,transform 140ms var(--ease-out)
}
.layer-tab:active,.flow-pick button:active,.conds button:active{transform:scale(.97)}
.formula{border-radius:var(--radius-sm);background:#f8fafc}
.field input,.field select{min-height:44px;background:#fff;transition:border-color 160ms ease,box-shadow 160ms ease}
.field input:focus,.field select:focus{box-shadow:var(--focus)}
.toc a,.xref a{transition:background-color 160ms ease,border-color 160ms ease,color 160ms ease}
.toc a:active,.xref a:active{transform:scale(.98)}
.matrix th{background:var(--brand-d)}
.matrix th,.matrix td{padding:14px 16px}

footer{background:#10273e;color:#b8c4cf;padding:58px 0 30px;margin-top:0;border-top:1px solid #24415e}
footer .brand{font-family:inherit;font-size:20px}
footer .brand small{display:block;margin-top:6px;font-size:8px;letter-spacing:.18em;color:#7f93a5}
footer h4{letter-spacing:.04em}
footer a{color:#b1beca;transition:color 160ms ease}
.copy{border-color:#29465f;color:#8497a8}

@media (hover:hover) and (pointer:fine){
  .btn:hover{border-color:var(--brand);background:var(--brand-l);color:var(--brand)}
  .btn-primary:hover{background:#194daf;border-color:#194daf;color:#fff}
  .card:hover{transform:translateY(-3px);border-color:#aebed0;box-shadow:var(--shadow-hover)}
  .nav-cta:hover{background:#0d2238}
  .layer-tab:hover,.flow-pick button:hover,.conds button:hover{border-color:var(--brand);color:var(--brand)}
  .toc a:hover,.xref a:hover{background:var(--brand-l);border-color:#b9cdfa}
}

@media(max-width:1040px){
  .nav-in{gap:14px}.nav-links{gap:0}.nav-links a{padding-inline:7px}.nav-cta{display:none}
  .home-page .hero .wrap{padding-right:49%;min-height:580px}
  .home-page .hero .wrap::after{width:42%}
}
@media(max-width:820px){
  .nav-in{height:64px;padding-inline:20px}
  .logo{margin-right:auto}.logo svg{width:34px;height:34px}
  .nav-toggle{
    display:inline-flex;align-items:center;gap:9px;min-height:40px;padding:8px 10px;border:1px solid var(--line);
    border-radius:9px;background:#fff;color:var(--brand-d);font:650 14px/1 inherit;cursor:pointer
  }
  .nav-toggle:active{transform:scale(.97)}
  .nav-toggle-icon{display:grid;gap:4px;width:16px}
  .nav-toggle-icon i{display:block;width:16px;height:1.5px;background:currentColor;transition:transform 140ms var(--ease-out)}
  .nav-toggle[aria-expanded="true"] .nav-toggle-icon i:first-child{transform:translateY(2.75px) rotate(45deg)}
  .nav-toggle[aria-expanded="true"] .nav-toggle-icon i:last-child{transform:translateY(-2.75px) rotate(-45deg)}
  .nav-links{
    display:none;position:absolute;left:0;right:0;top:64px;margin:0;padding:10px 20px 16px;
    grid-template-columns:1fr 1fr;gap:6px;background:#fff;border-bottom:1px solid var(--line);box-shadow:var(--shadow)
  }
  .nav-links.is-open{display:grid}
  .nav-links a{padding:11px 12px;border:1px solid transparent}
  .nav-links a.active,.nav-links a[aria-current="page"]{border-color:var(--line)}
  .home-page .hero .wrap{min-height:auto;padding:64px 20px 72px}
  .home-page .hero .wrap::after{
    position:relative;display:block;right:auto;top:auto;width:100%;height:auto;aspect-ratio:3/2;
    margin-top:42px;transform:none
  }
  section{padding:58px 0}
  .matrix{display:block;overflow-x:auto;-webkit-overflow-scrolling:touch}
  .matrix th,.matrix td{min-width:140px}
}
@media(max-width:560px){
  .brand-lockup small{display:none}
  h1.page{font-size:clamp(34px,10vw,44px)}
  h2.sec{font-size:28px}
  .home-page .hero .cta{display:grid}
  .home-page .hero .btn{justify-content:center}
  .home-page .hero .wrap::after{height:auto}
  .grid.c3,.grid.c4{grid-template-columns:1fr}
  .card{padding:20px}
  .layer-tabs{display:grid}
  footer .cols{grid-template-columns:1fr 1fr}
}
@media(max-width:400px){
  .brand-lockup strong{font-size:15px}.nav-toggle-label{display:none}.nav-links{grid-template-columns:1fr}
  footer .cols{grid-template-columns:1fr}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important}
  .btn:hover,.card:hover,.btn:active,a.card:active,.nav-cta:active,.nav-toggle:active,
  .layer-tab:active,.flow-pick button:active,.conds button:active,.toc a:active,.xref a:active{transform:none!important}
}

/* ===== 同步 / 异步电机转速关系动画 ===== */
.motor-demo-shell{
  margin:18px 0;padding:18px;background:#fff;border:1px solid var(--line);
  border-radius:var(--radius);box-shadow:var(--shadow)
}
.motor-comparison{width:100%;margin:0 auto!important;overflow:visible}
.motor-field,.motor-rotor{
  transform-box:view-box;animation-name:motor-spin;animation-timing-function:linear;
  animation-iteration-count:infinite;will-change:transform
}
.motor-field-pmsm,.motor-rotor-pmsm{transform-origin:170px 140px;animation-duration:4s}
.motor-field-im{transform-origin:510px 140px;animation-duration:4s}
.motor-rotor-im{transform-origin:510px 140px;animation-duration:4.26s}
.motor-stator{transition:stroke 180ms ease,filter 180ms ease}
.motor-stator-pmsm{stroke:#a9b9ca}
.motor-stator-im{stroke:#a9b9ca}
.motor-demo-shell:not(.is-paused) .motor-stator{
  stroke:#8da7c3;filter:drop-shadow(0 0 5px rgba(47,111,237,.16))
}
.motor-demo-shell.is-paused .motor-field,
.motor-demo-shell.is-paused .motor-rotor{animation-play-state:paused}
@keyframes motor-spin{to{transform:rotate(360deg)}}

.motor-demo-footer{display:grid;gap:14px;margin-top:8px}
.motor-speed-grid{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.motor-speed-card{
  display:grid;grid-template-columns:auto auto;align-items:center;gap:5px 14px;
  padding:12px 14px;border:1px solid var(--line);border-radius:var(--radius-sm);background:#f8fafc;
  color:var(--ink-soft);font-size:12.5px
}
.motor-speed-card b{grid-column:1/-1;color:var(--brand-d);font-size:13.5px}
.motor-speed-card span{display:inline-flex;align-items:center;gap:7px;white-space:nowrap}
.motor-speed-card i{width:9px;height:9px;border-radius:50%;flex:none}
.motor-speed-card .field-key{background:var(--e-elec)}
.motor-speed-card .rotor-key{background:var(--e-fuel)}
.motor-speed-slip{border-color:#d8e0e9;background:#fbfcfd}

.motor-demo-controls{display:flex;align-items:center;justify-content:space-between;gap:18px}
.motor-demo-controls p{max-width:560px;color:var(--ink-soft);font-size:13px;line-height:1.65}
.motor-toggle{
  display:inline-flex;align-items:center;justify-content:center;gap:7px;min-height:40px;padding:8px 13px;
  border:1px solid var(--line-d);border-radius:9px;background:#fff;color:var(--brand-d);font-weight:700;
  cursor:pointer;white-space:nowrap;transition:background-color 160ms ease,border-color 160ms ease,transform 140ms var(--ease-out)
}
.motor-toggle:active{transform:scale(.97)}
.motor-toggle:disabled{cursor:not-allowed;color:var(--ink-mute);background:var(--surface-muted)}
@media (hover:hover) and (pointer:fine){
  .motor-toggle:not(:disabled):hover{border-color:var(--brand);background:var(--brand-l);color:var(--brand)}
}
@media(max-width:680px){
  .motor-demo-shell{padding:12px;margin-inline:-4px}
  .motor-speed-grid{grid-template-columns:1fr}
  .motor-demo-controls{align-items:stretch;flex-direction:column}
  .motor-toggle{width:100%}
}
@media(prefers-reduced-motion:reduce){
  .motor-field,.motor-rotor{animation:none!important;will-change:auto}
  .motor-toggle:active{transform:none}
}

/* ===== 车语长卷 · 第 3 版首页 ===== */
.sr-only{
  position:absolute!important;width:1px!important;height:1px!important;padding:0!important;margin:-1px!important;
  overflow:hidden!important;clip:rect(0,0,0,0)!important;white-space:nowrap!important;border:0!important
}

header.nav{background:rgba(255,255,255,.96);border-bottom:1px solid #e3e8ef}
.nav-in{max-width:none;height:100px;padding-inline:44px;gap:28px}
.logo{min-width:260px;color:#12243a}
.brand-lockup{line-height:1}
.brand-lockup strong{
  font-family:var(--font-display);font-size:36px;font-weight:600;letter-spacing:.12em
}
.brand-lockup small{font-size:9px;font-weight:600;letter-spacing:.25em;margin-top:10px;color:#657487}
.site-search{
  position:relative;display:flex;align-items:center;flex:none;width:470px;min-width:300px;margin-left:162px
}
.site-search button{
  position:absolute;left:8px;z-index:1;display:flex;align-items:center;justify-content:center;width:38px;height:38px;
  border:0;border-radius:9px;background:transparent;color:#6f7d8f;cursor:pointer
}
.site-search button:hover{background:#f2f5f9;color:var(--brand)}
.site-search button .ph{font-size:20px}
.site-search input{
  width:100%;height:48px;padding:0 18px 0 49px;border:1px solid #cfd7e1;border-radius:13px;
  background:#fff;color:var(--ink);font-size:15px;outline:0;transition:border-color 160ms ease,box-shadow 160ms ease
}
.site-search input::placeholder{color:#8a96a6}
.site-search input:focus{border-color:#6f96eb;box-shadow:var(--focus)}
.nav-links{width:425px;margin-left:26px;gap:0;justify-content:space-between;flex:none}
.nav-links a{padding:10px 0;border-radius:0;background:transparent!important;color:#152131;font-size:16px;font-weight:650}
.nav-links a:hover,.nav-links a.active,.nav-links a[aria-current="page"]{color:var(--brand);border:0}

.home-page{background:#fff}
.home-page .wrap{max-width:1487px;padding-inline:60px}
.learning-hero{padding:0;border-bottom:0;background:#fff;overflow:hidden}
.learning-hero-grid{
  display:grid;grid-template-columns:minmax(440px,.84fr) minmax(620px,1.16fr);align-items:center;
  min-height:520px
}
.learning-hero-copy{position:relative;z-index:2;max-width:540px;padding:68px 0 48px}
.learning-badge{
  display:inline-flex;align-items:center;min-height:34px;padding:6px 18px;border-radius:999px;
  background:#e9f0ff;color:#245fc8;font-size:13.5px;font-weight:600;letter-spacing:.025em
}
.learning-hero h1{
  margin:22px 0 18px;color:#102a4a;font-family:var(--font-display);
  font-size:clamp(44px,3.85vw,56px);font-weight:600;letter-spacing:.025em;line-height:1.22
}
.learning-hero-copy p{max-width:468px;color:#5a6b7f;font-size:16px;line-height:1.9;letter-spacing:.01em}
.learning-primary{
  display:inline-flex;align-items:center;justify-content:center;gap:20px;min-width:178px;min-height:54px;
  margin-top:22px;padding:12px 23px;border-radius:10px;background:#2e66dc;color:#fff;font-size:17px;font-weight:600;
  box-shadow:0 12px 28px rgba(46,102,220,.2);transition:background-color 160ms ease,transform 140ms ease
}
.learning-primary .ph{font-size:20px}
.learning-primary:hover{background:#2458c7}
.learning-primary:active{transform:scale(.98)}
.learning-hero-visual{
  align-self:stretch;display:flex;align-items:center;justify-content:flex-end;min-width:0;margin:0;
  transform:none
}
.learning-hero-visual img{
  width:108%;max-width:none;height:520px;object-fit:contain;object-position:right center;transform:translate(18px,-4px)
}

.learning-path-section{padding:10px 0 34px;background:#fff}
.learning-path{
  display:grid;grid-template-columns:repeat(4,1fr);min-height:178px;border:1px solid #cfd8e3;border-radius:16px;
  background:#fff;overflow:hidden
}
.learning-step{
  position:relative;display:grid;grid-template-columns:1fr 1fr;grid-template-rows:42px auto;gap:7px 10px;align-items:center;
  padding:25px 30px 43px;border-bottom:0;transition:background-color 160ms ease
}
.learning-step + .learning-step{border-left:1px solid #e4e9ef}
.learning-step:hover{background:#f8fbff}
.learning-step-number{grid-column:1;grid-row:1;color:var(--step-color);font-size:32px;font-weight:750;letter-spacing:-.03em}
.learning-step-icon{grid-column:2;grid-row:1;justify-self:end;color:var(--step-color);font-size:34px}
.learning-step-copy{grid-column:1/3;grid-row:2;display:block}
.learning-step-copy strong{display:block;color:#132a46;font-size:17px;font-weight:650;line-height:1.35}
.learning-step-copy small{display:block;margin-top:5px;color:#738194;font-size:12.5px;line-height:1.5}
.learning-step-arrow{position:absolute;right:20px;bottom:46px;color:#8290a1;font-size:18px}
.learning-step-progress{
  position:absolute;left:0;right:0;bottom:31px;height:3px;background:var(--step-color)
}
.tone-blue{--step-color:#356ed7}
.tone-green{--step-color:#36957e}
.tone-amber{--step-color:#dc9b33}

.question-section{padding:30px 0 48px;background:#fff}
.question-shell{position:relative;padding:35px 18px 15px;border:1px solid #d3dce6;border-radius:14px}
.question-shell h2{
  position:absolute;left:42px;top:-19px;padding:0 14px;background:#fff;color:#19304d;
  font-family:var(--font-display);font-size:22px;font-weight:600;letter-spacing:.035em
}
.question-grid{display:grid;grid-template-columns:repeat(3,1fr)}
.question-link{
  display:grid;grid-template-columns:48px 1fr 20px;align-items:center;gap:16px;min-height:78px;padding:8px 24px;
  color:#172b45;transition:background-color 160ms ease
}
.question-link + .question-link{border-left:1px solid #dfe5ec}
.question-link:hover{background:#f8fbff}
.question-icon{
  display:flex;align-items:center;justify-content:center;width:46px;height:46px;border-radius:50%;
  background:var(--step-color);color:#fff;font-size:26px
}
.question-link strong{font-size:17px;font-weight:650}
.question-arrow{color:#607084;font-size:18px}

.topic-section{padding:82px 0;background:#f5f8fc}
.section-kicker{display:block;color:var(--brand);font-size:13px;font-weight:800;letter-spacing:.14em}
.topic-title,.learning-value-section h2{
  margin-top:9px;color:#132a46;font-family:var(--font-display);
  font-size:clamp(30px,3.15vw,42px);font-weight:600;line-height:1.34;letter-spacing:.025em
}
.topic-intro{max-width:720px;margin-top:14px;color:#657589;font-size:16px}
.topic-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;margin-top:36px}
.topic-card{
  position:relative;display:grid;grid-template-columns:52px 1fr;gap:18px;min-height:170px;padding:27px;
  border:1px solid #dbe3ec;border-radius:15px;background:#fff;box-shadow:var(--shadow);
  transition:transform 180ms var(--ease-out),border-color 180ms ease,box-shadow 180ms ease
}
.topic-card > .ph:first-child{color:var(--brand);font-size:42px}
.topic-card h3{color:#17304d;font-size:20px}
.topic-card p{margin-top:7px;color:#66778a;font-size:14px;line-height:1.7}
.topic-card .topic-arrow{position:absolute;right:22px;top:24px;color:#8c99a8;font-size:19px}
.topic-card:hover{transform:translateY(-3px);border-color:#a8bce1;box-shadow:var(--shadow-hover)}

.learning-value-section{padding:82px 0;background:#fff}
.learning-value-grid{display:grid;grid-template-columns:.8fr 1.2fr;gap:70px;align-items:start}
.learning-value-list{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.learning-value-list article{padding:25px;border-top:3px solid #c8d9ff;background:#f7f9fc}
.learning-value-list .ph{color:var(--brand);font-size:34px}
.learning-value-list h3{margin-top:16px;color:#17304d;font-size:18px}
.learning-value-list p{margin-top:8px;color:#67778a;font-size:14px;line-height:1.7}

.suspension-photo-grid{
  display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;margin:16px 0 22px
}
.suspension-photo-card{
  margin:0;border:1px solid var(--line);border-radius:16px;background:#fff;
  box-shadow:0 10px 30px rgba(24,50,82,.08);overflow:hidden
}
.suspension-photo-card img{
  display:block;width:100%;height:auto;aspect-ratio:4/3;object-fit:contain;background:#eef2f6
}
.suspension-photo-card figcaption{padding:14px 16px 15px}
.suspension-photo-card b{display:block;color:var(--brand-d);font-size:15px}
.suspension-photo-card small{
  display:block;margin-top:5px;color:var(--ink-soft);font-size:13px;line-height:1.55
}
.suspension-photo-source{
  display:block;margin-top:8px;color:#718096;font-size:10.5px;line-height:1.45;text-decoration:none
}
.suspension-photo-source:hover{color:var(--brand);text-decoration:underline}

@media (max-width:1350px){
  .nav-in{padding-inline:30px;gap:22px}
  .logo{min-width:220px}.brand-lockup strong{font-size:29px}
  .site-search{width:min(31vw,390px);min-width:250px;margin-left:auto}
  .nav-links{width:auto;gap:18px;margin-left:4px}.nav-links a{font-size:15px}
  .home-page .wrap{padding-inline:30px}
  .learning-hero-grid{grid-template-columns:minmax(420px,.84fr) minmax(560px,1.16fr)}
  .learning-hero-visual img{width:104%;height:500px;transform:translateX(24px)}
  .learning-step{padding-inline:24px}
}

@media (max-width:980px){
  .nav-in{height:82px}
  .logo{min-width:auto;margin-right:auto}.brand-lockup strong{font-size:28px}
  .site-search{display:none}
  .learning-hero-grid{grid-template-columns:1fr 1.2fr;min-height:500px}
  .learning-hero-copy{padding-left:0}
  .learning-hero h1{font-size:44px}
  .learning-hero-visual{transform:translateX(44px)}
  .learning-path{grid-template-columns:1fr 1fr}
  .learning-step:nth-child(3){border-left:0;border-top:1px solid #e4e9ef}
  .learning-step:nth-child(4){border-top:1px solid #e4e9ef}
  .question-grid{grid-template-columns:1fr}
  .question-link + .question-link{border-left:0;border-top:1px solid #dfe5ec}
  .topic-grid{grid-template-columns:1fr 1fr}
  .learning-value-grid{grid-template-columns:1fr;gap:36px}
}

@media (max-width:820px){
  .nav-in{height:auto;min-height:72px;padding:10px 20px;gap:10px}
  .brand-lockup strong{font-size:24px}.brand-lockup small{font-size:7px;margin-top:7px}
  .nav-toggle{display:inline-flex}
  .nav-toggle-icon{font-size:20px}
  .site-search{display:flex;order:3;width:100%;min-width:0}
  .site-search input{height:44px}
  .nav-links{top:126px;padding-inline:20px}
  .learning-hero-grid{display:flex;flex-direction:column;min-height:auto}
  .learning-hero-copy{width:100%;padding:54px 0 12px}
  .learning-hero h1{font-size:clamp(40px,6.8vw,48px)}
  .learning-hero-visual{width:100%;transform:none}
  .learning-hero-visual img{width:100%;height:auto;max-height:500px;transform:none}
  .learning-path-section{padding-top:28px}
  .topic-grid{grid-template-columns:1fr}
  .learning-value-list{grid-template-columns:1fr}
}

@media (max-width:600px){
  .home-page .wrap{padding-inline:18px}
  .learning-hero-copy{padding-top:44px}
  .learning-badge{padding-inline:15px;font-size:13px}
  .learning-hero h1{margin-top:20px;font-size:36px;line-height:1.28}
  .learning-hero-copy p{font-size:15.5px}
  .learning-primary{width:100%;min-height:54px;font-size:17px}
  .learning-path{grid-template-columns:1fr}
  .learning-step,.learning-step:nth-child(3),.learning-step:nth-child(4){
    border-left:0;border-top:1px solid #e4e9ef
  }
  .learning-step:first-child{border-top:0}
  .question-section{padding-top:38px}
  .question-shell{padding-inline:10px}
  .question-shell h2{left:14px}
  .question-link{padding-inline:12px;grid-template-columns:42px 1fr 18px}
  .question-icon{width:42px;height:42px}
  .topic-section,.learning-value-section{padding:64px 0}
  .suspension-photo-grid{grid-template-columns:1fr}
}