:root{--ink:#101820;--muted:#66717d;--paper:#f4f6f7;--white:#fff;--red:#c92a32;--line:#dfe4e7;--shadow:0 18px 50px rgba(16,24,32,.12)}
*{box-sizing:border-box;margin:0;padding:0}html{scroll-behavior:smooth}body{font-family:Arial,"Helvetica Neue",sans-serif;color:var(--ink);background:var(--white);line-height:1.65}img{display:block;width:100%}a{color:inherit;text-decoration:none}.container{width:min(1180px,calc(100% - 40px));margin:auto}.eyebrow{font-size:.76rem;font-weight:800;letter-spacing:.16em;text-transform:uppercase;color:var(--red);margin-bottom:14px}.section{padding:96px 0}.section.alt{background:var(--paper)}.section-head{display:flex;align-items:end;justify-content:space-between;gap:30px;margin-bottom:42px}.section-head h2,.split-copy h2{font-size:clamp(2rem,4vw,3.5rem);line-height:1.08;max-width:720px}.section-head p{max-width:520px;color:var(--muted)}
.navbar{height:78px;background:rgba(255,255,255,.96);border-bottom:1px solid rgba(16,24,32,.08);position:sticky;top:0;z-index:20;backdrop-filter:blur(14px)}.nav-container{width:min(1240px,calc(100% - 40px));height:100%;margin:auto;display:flex;align-items:center;justify-content:space-between}.brand{display:flex;align-items:center;gap:12px;font-weight:900;font-size:1.22rem}.brand img{width:47px;height:47px;object-fit:contain}.brand span{letter-spacing:.02em}.nav-menu{display:flex;list-style:none;gap:8px}.nav-link{display:block;padding:10px 15px;font-size:.92rem;font-weight:700;color:#4c5661}.nav-link:hover,.nav-link.active{color:var(--red)}.nav-cta{background:var(--ink);color:white!important;margin-left:8px}.hamburger{display:none;border:0;background:none;width:42px;height:42px;cursor:pointer}.hamburger span{display:block;width:23px;height:2px;background:var(--ink);margin:5px auto}
.hero{min-height:calc(100vh - 78px);display:grid;align-items:end;color:white;position:relative;background:linear-gradient(90deg,rgba(8,15,20,.9) 0%,rgba(8,15,20,.62) 47%,rgba(8,15,20,.12) 100%),url('../产品图片/disc/brake-disc (36).jpg') center/cover no-repeat}.hero-content{padding:110px 0 80px;max-width:780px}.hero .eyebrow{color:#ff6269}.hero h1{font-size:clamp(3rem,7vw,6.7rem);line-height:.94;margin-bottom:28px}.hero p{max-width:680px;font-size:1.15rem;color:#e4e8ea}.actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:34px}.btn{display:inline-flex;align-items:center;justify-content:center;min-height:52px;padding:0 24px;font-weight:800;font-size:.9rem;border:1px solid transparent;cursor:pointer}.btn-primary{background:var(--red);color:white}.btn-secondary{border-color:rgba(255,255,255,.5);color:white;background:rgba(255,255,255,.08)}.hero-metrics{display:grid;grid-template-columns:repeat(3,1fr);border-top:1px solid rgba(255,255,255,.25);margin-top:72px}.hero-metrics div{padding:20px 30px 0 0}.hero-metrics strong{font-size:1.6rem;display:block}.hero-metrics span{color:#bdc5ca;font-size:.82rem}
.product-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:18px}.product-card{position:relative;overflow:hidden;background:#111;min-height:440px;color:white}.product-card img{height:100%;position:absolute;inset:0;object-fit:cover;transition:transform .6s}.product-card:after{content:"";position:absolute;inset:0;background:linear-gradient(180deg,transparent 25%,rgba(7,12,16,.9) 100%)}.product-card:hover img{transform:scale(1.035)}.product-copy{position:absolute;z-index:2;left:30px;right:30px;bottom:28px}.product-copy small{font-weight:800;color:#ff6c73;text-transform:uppercase}.product-copy h3{font-size:2rem;margin:4px 0}.product-copy p{color:#d5dade}.feature-row{display:grid;grid-template-columns:repeat(4,1fr);border-top:1px solid var(--line);border-left:1px solid var(--line)}.feature{padding:34px;border-right:1px solid var(--line);border-bottom:1px solid var(--line)}.feature b{display:block;font-size:1.05rem;margin:12px 0 8px}.feature p{color:var(--muted);font-size:.92rem}.num{color:var(--red);font-weight:900}
.page-hero{padding:105px 0 78px;background:var(--ink);color:white;position:relative;overflow:hidden}.page-hero:after{content:"";position:absolute;width:42%;height:5px;right:0;bottom:0;background:var(--red)}.page-hero h1{font-size:clamp(3rem,6vw,5.5rem);line-height:1}.page-hero p{color:#c7ced2;max-width:700px;margin-top:20px;font-size:1.08rem}.split{display:grid;grid-template-columns:1.05fr .95fr;gap:72px;align-items:center}.split-image{height:570px;object-fit:cover}.split-copy p{color:var(--muted);margin-top:20px}.stats{display:grid;grid-template-columns:repeat(4,1fr);margin-top:52px}.stat{border-left:3px solid var(--red);padding-left:18px}.stat strong{font-size:2rem;display:block}.stat span{font-size:.82rem;color:var(--muted)}.values{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}.value{padding:34px;background:white;border-top:4px solid var(--red);box-shadow:0 8px 24px rgba(16,24,32,.06)}.value h3{margin-bottom:12px}.value p{color:var(--muted)}
.product-detail{display:grid;grid-template-columns:1fr 1fr;gap:64px;align-items:center;padding:74px 0;border-bottom:1px solid var(--line)}.product-detail:nth-child(even) .detail-gallery{order:2}.detail-gallery{display:grid;grid-template-columns:1fr 1fr;gap:10px}.detail-gallery img{height:210px;object-fit:cover}.detail-gallery img:first-child{grid-column:1/-1;height:330px}.detail-copy h2{font-size:clamp(2rem,4vw,3.4rem);line-height:1.05;margin-bottom:18px}.detail-copy>p{color:var(--muted)}.checks{list-style:none;margin:26px 0}.checks li{padding:9px 0 9px 24px;position:relative;border-bottom:1px solid var(--line)}.checks li:before{content:"+";position:absolute;left:0;color:var(--red);font-weight:900}.tags{display:flex;flex-wrap:wrap;gap:8px}.tag{padding:7px 12px;background:var(--paper);font-size:.78rem;font-weight:800;text-transform:uppercase}
.contact-grid{max-width:820px}.contact-list{margin-top:35px}.contact-item{padding:22px 0;border-top:1px solid var(--line)}.contact-item small{display:block;color:var(--red);font-weight:800;text-transform:uppercase}.contact-item a,.contact-item p{font-size:1.08rem}
.cta-band{background:var(--red);color:white;padding:58px 0}.cta-inner{display:flex;align-items:center;justify-content:space-between;gap:30px}.cta-inner h2{font-size:clamp(1.8rem,4vw,3rem);line-height:1.1}.cta-inner .btn{background:white;color:var(--ink)}.footer{background:#0b1116;color:white;padding:68px 0 24px}.footer-grid{display:grid;grid-template-columns:1.7fr 1fr 1.2fr;gap:60px}.footer h3{font-size:1.25rem;margin-bottom:14px}.footer p,.footer a{color:#aeb8be;font-size:.9rem}.footer a:hover{color:white}.footer-links{list-style:none}.footer-links li{margin-bottom:8px}.footer-bottom{border-top:1px solid #2b343b;margin-top:48px;padding-top:22px;display:flex;justify-content:space-between;color:#7f8b92;font-size:.78rem}
@media(max-width:820px){.nav-menu{display:none;position:absolute;top:78px;left:0;right:0;background:white;padding:14px 20px 22px;box-shadow:var(--shadow)}.nav-menu.active{display:block}.nav-link{padding:13px}.nav-cta{margin:5px 0 0}.hamburger{display:block}.hero{min-height:760px;background-position:62% center}.hero-content{padding-top:80px}.hero-metrics{grid-template-columns:1fr}.hero-metrics div{border-bottom:1px solid rgba(255,255,255,.16);padding:12px 0}.section{padding:70px 0}.section-head,.cta-inner{align-items:flex-start;flex-direction:column}.product-grid,.split,.product-detail,.contact-grid{grid-template-columns:1fr}.feature-row,.stats{grid-template-columns:repeat(2,1fr)}.values{grid-template-columns:1fr}.product-detail:nth-child(even) .detail-gallery{order:0}.split-image{height:420px}.footer-grid{grid-template-columns:1fr 1fr}.footer-grid>div:first-child{grid-column:1/-1}}
@media(max-width:520px){.container,.nav-container{width:min(100% - 28px,1180px)}.hero h1{font-size:3.05rem}.product-grid,.feature-row,.stats,.form-row{grid-template-columns:1fr}.product-card{min-height:380px}.detail-gallery img,.detail-gallery img:first-child{height:230px}.detail-gallery{grid-template-columns:1fr}.contact-form{padding:24px}.footer-grid{grid-template-columns:1fr}.footer-grid>div:first-child{grid-column:auto}.footer-bottom{display:block}.footer-bottom span{display:block;margin-top:8px}}

/* Motion system */
.navbar{transition:height .3s ease,box-shadow .3s ease,background .3s ease}.navbar.scrolled{height:70px;box-shadow:0 10px 30px rgba(16,24,32,.09)}
.hero:before{content:"";position:absolute;inset:0;background:linear-gradient(115deg,transparent 35%,rgba(255,255,255,.12) 50%,transparent 65%);transform:translateX(-120%);animation:heroSweep 1.4s .35s cubic-bezier(.2,.8,.2,1) both;pointer-events:none}.hero-content>.eyebrow,.hero-content>h1,.hero-content>p,.hero-content>.actions,.hero-content>.hero-metrics{opacity:0;transform:translateY(28px);animation:heroEnter .75s cubic-bezier(.2,.75,.25,1) forwards}.hero-content>h1{animation-delay:.1s}.hero-content>p{animation-delay:.2s}.hero-content>.actions{animation-delay:.3s}.hero-content>.hero-metrics{animation-delay:.42s}
.page-hero .container>*{opacity:0;transform:translateY(22px);animation:heroEnter .65s cubic-bezier(.2,.75,.25,1) forwards}.page-hero .container>h1{animation-delay:.08s}.page-hero .container>p:last-child{animation-delay:.16s}.page-hero:after{transform-origin:right;animation:lineGrow .9s .15s cubic-bezier(.2,.75,.25,1) both}
.reveal{opacity:0;transform:translateY(36px);transition:opacity .7s cubic-bezier(.2,.75,.25,1),transform .7s cubic-bezier(.2,.75,.25,1);transition-delay:var(--delay,0ms)}.reveal.from-left{transform:translateX(-38px)}.reveal.from-right{transform:translateX(38px)}.reveal.is-visible{opacity:1;transform:translate(0,0)}
.btn{overflow:hidden;position:relative;transition:transform .25s ease,box-shadow .25s ease,background .25s ease}.btn:after{content:"→";width:0;opacity:0;overflow:hidden;transition:width .25s ease,opacity .25s ease,margin .25s ease}.btn:hover{transform:translateY(-3px);box-shadow:0 12px 24px rgba(16,24,32,.18)}.btn:hover:after{width:16px;opacity:1;margin-left:9px}
.product-card{transition:transform .4s cubic-bezier(.2,.75,.25,1),box-shadow .4s ease}.product-card:hover{transform:translateY(-7px);box-shadow:var(--shadow)}.product-card img{transition:transform .75s cubic-bezier(.2,.75,.25,1),filter .5s ease}.product-card:hover img{transform:scale(1.075);filter:saturate(1.08)}.product-copy{transition:transform .4s ease}.product-card:hover .product-copy{transform:translateY(-5px)}
.feature,.value,.contact-item{transition:transform .3s ease,background .3s ease,box-shadow .3s ease}.feature:hover{transform:translateY(-6px);background:white;box-shadow:0 16px 32px rgba(16,24,32,.08);position:relative;z-index:1}.value:hover{transform:translateY(-6px);box-shadow:0 18px 38px rgba(16,24,32,.11)}.contact-item:hover{transform:translateX(8px)}.detail-gallery img{transition:transform .45s ease,filter .45s ease}.detail-gallery img:hover{transform:scale(1.025);filter:contrast(1.04)}.tag{transition:color .25s ease,background .25s ease,transform .25s ease}.tag:hover{color:white;background:var(--red);transform:translateY(-2px)}
@keyframes heroEnter{to{opacity:1;transform:translateY(0)}}@keyframes heroSweep{to{transform:translateX(120%)}}@keyframes lineGrow{from{transform:scaleX(0)}to{transform:scaleX(1)}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{animation-duration:.01ms!important;animation-delay:0ms!important;transition-duration:.01ms!important}.reveal{opacity:1;transform:none}.hero-content>*{opacity:1;transform:none}}