/* 第三轮：统一字体比例、留白与精细动效 */
:root{--text-large:clamp(44px,5vw,72px);--text-section:clamp(38px,4.4vw,64px);--text-card:clamp(26px,2.5vw,38px);--text-body:17px;--content-width:980px;--motion:cubic-bezier(.25,.1,.25,1)}
body{font-family:-apple-system,BlinkMacSystemFont,"SF Pro Display","SF Pro Text","PingFang SC","Helvetica Neue","Microsoft YaHei",sans-serif;font-size:var(--text-body);font-weight:400;letter-spacing:-.012em;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
.section-label,.eyebrow{font-size:12px;line-height:1.25;letter-spacing:.09em}
.hero{gap:clamp(32px,5vw,76px)}
.hero h1{max-width:760px;font-size:clamp(50px,5.35vw,82px);line-height:1.02;letter-spacing:-.055em;font-weight:720}
.hero-lead{max-width:590px;font-size:18px;line-height:1.55;letter-spacing:-.012em}
.floating-label{font-size:17px;font-weight:650;letter-spacing:-.02em;transition:translate .45s var(--motion),scale .45s var(--motion),box-shadow .45s}
.floating-label:hover{translate:0 -7px;scale:1.04;box-shadow:0 22px 50px rgba(70,55,74,.14)}
.film-section{padding-block:132px 112px}
.film-intro{max-width:1040px}
.film-intro h2{max-width:900px;font-size:clamp(34px,3.5vw,52px);line-height:1.14;font-weight:680;letter-spacing:-.043em}
.film-screen{margin-top:42px;transition:scale .7s var(--motion),box-shadow .7s var(--motion);isolation:isolate}
.film-screen::after{content:"";position:absolute;z-index:1;inset:0;pointer-events:none;background:radial-gradient(circle 320px at var(--spot-x,70%) var(--spot-y,40%),rgba(255,255,255,.13),transparent 72%);opacity:0;transition:opacity .5s}
.film-screen:hover{scale:1.008;box-shadow:0 55px 120px rgba(0,0,0,.3)}
.film-screen:hover::after{opacity:1}
.principle,.system{padding-block:150px}
.editorial-heading,.system-heading,.app-story-title{max-width:1200px}
.editorial-heading h2,.system-heading h2,.app-story-title h2{max-width:1080px;margin:24px 0 72px;font-size:var(--text-section);line-height:1.08;font-weight:700;letter-spacing:-.052em}
.principle-item{grid-template-columns:64px minmax(0,1fr) 44px;padding-block:43px}
.principle-item h3{font-size:30px;line-height:1.18;font-weight:650;letter-spacing:-.035em}
.principle-item p{max-width:700px;font-size:16px;line-height:1.55}
.promise{padding-block:150px}
.promise-sticky h2{font-size:var(--text-section);line-height:1.07;font-weight:700;letter-spacing:-.052em}
.promise-sticky>p:last-child{max-width:500px;font-size:17px;line-height:1.55}
.promise-card{min-height:300px;padding:40px}
.promise-card h3{font-size:34px;line-height:1.15;font-weight:650;letter-spacing:-.035em}
.promise-card p{font-size:16px;line-height:1.55}
.system-heading{grid-template-columns:minmax(0,1fr) 370px}
.system-heading>p{font-size:17px;line-height:1.55}
.data-loop{margin-top:26px}
.data-loop span{font-size:14px;font-weight:560}
.system-node h3{font-weight:650}.system-node p{line-height:1.5}
.app-story{padding-top:150px}
.app-story-title h2{margin-bottom:27px}
.app-story-title>p:last-child{max-width:760px;margin:0 0 80px;color:#6e6e73;font-size:19px;line-height:1.52;letter-spacing:-.018em}
.iphone{transition:transform .65s var(--motion),filter .65s var(--motion);transform:perspective(1200px) rotateX(var(--phone-rx,0deg)) rotateY(var(--phone-ry,0deg))}
.feature-step{min-height:75vh;padding-block:95px;opacity:.24;transform:translateY(20px);transition:opacity .65s var(--motion),transform .65s var(--motion)}
.feature-step.active{opacity:1;transform:none}
.feature-step>span{font-size:12px;letter-spacing:.1em}
.feature-step h3{max-width:560px;margin:25px 0 22px;font-size:clamp(38px,4.1vw,60px);line-height:1.05;font-weight:700;letter-spacing:-.052em}
.feature-step p{max-width:570px;color:#6e6e73;font-size:17px;line-height:1.58;letter-spacing:-.012em}
.download-section{background:#f5e8cf}
.download-visual{background:transparent}
.download-copy>p:first-child{font-size:12px;letter-spacing:.1em}
.download-copy h2{font-size:clamp(50px,5.5vw,82px);line-height:1.01;font-weight:700;letter-spacing:-.055em}
.download-copy>p:nth-of-type(2){max-width:480px;font-size:18px;line-height:1.55}
.site-footer{padding-top:100px}.footer-brand h2{font-weight:650}.footer-links a{font-size:14px;transition:color .25s,translate .25s}.footer-links a:hover{color:#fff;translate:5px 0}
.reveal{opacity:0;transform:translateY(44px) scale(.985);filter:blur(7px);will-change:opacity,transform,filter;transition:opacity .9s var(--motion),transform 1s var(--motion),filter .85s var(--motion)}
.reveal.visible{opacity:1;transform:none;filter:blur(0)}
.hero-product,.download-visual img{transition:translate .7s var(--motion),filter .7s var(--motion)}
.hero-product:hover,.download-visual img:hover{translate:0 -10px;filter:drop-shadow(0 45px 48px rgba(61,44,51,.2))}
.app-header,.live-card,.phone-alert,.assistant-orb,.app-chart,.moment-image,.chat-parent,.chat-ai,.boundary{transition:transform .4s var(--motion),box-shadow .4s var(--motion)}
.live-card:hover,.phone-alert:hover,.moment-image:hover,.chat-ai:hover,.boundary:hover{transform:translateY(-4px);box-shadow:0 14px 30px rgba(50,40,54,.11)}

@media(max-width:1020px){.system-heading{grid-template-columns:1fr}.app-story-title>p:last-child{margin-bottom:55px}}
@media(max-width:700px){:root{--text-body:16px}.hero h1{font-size:43px}.hero-lead{font-size:16px}.film-section,.principle,.promise,.system,.app-story{padding-top:96px}.film-intro h2{font-size:29px}.editorial-heading h2,.system-heading h2,.app-story-title h2{font-size:38px;margin-bottom:42px}.principle-item h3{font-size:23px}.app-story-title>p:last-child{font-size:16px;margin-bottom:35px}.feature-step{min-height:auto;padding-block:55px;opacity:1;transform:none}.feature-step h3{font-size:37px}.feature-step p{font-size:16px}.download-copy h2{font-size:51px}}
@media(prefers-reduced-motion:reduce){.reveal{opacity:1;transform:none;filter:none}.iphone{transform:none!important}}