:root {
  color-scheme: light;
  --paper:#f7f6ef; --white:#fffefa; --ink:#263128; --muted:#667067;
  --forest:#4d6747; --leaf:#809665; --sage:#dce6cc;
  --berry:#c84d5e; --berry-dark:#973744; --sun:#f0c96f; --peach:#f3b9a3;
  --line:rgba(38,49,40,.13); --header-height:82px;
}
*{box-sizing:border-box} html{scroll-behavior:smooth} body{margin:0;overflow-x:hidden;color:var(--ink);background:var(--paper);font-family:"SF Pro Rounded","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;-webkit-font-smoothing:antialiased} body.dialog-open{overflow:hidden} img{display:block;max-width:100%} a{color:inherit;text-decoration:none} button,a{-webkit-tap-highlight-color:transparent} button{font:inherit}

.site-header{position:fixed;inset:0 0 auto;z-index:20;height:var(--header-height);padding:0 clamp(22px,5vw,80px);display:grid;grid-template-columns:1fr auto 1fr;align-items:center;transition:background-color .35s,border-color .35s,backdrop-filter .35s}.site-header.scrolled{background:rgba(247,246,239,.86);border-bottom:1px solid var(--line);backdrop-filter:blur(18px)}.brand{display:inline-flex;align-items:center;gap:10px;width:max-content;font-size:20px;font-weight:850}.brand-egg{width:23px;height:29px;border:2px solid var(--ink);border-radius:48% 48% 47% 47%/58% 58% 42% 42%;background:var(--white);transform:rotate(-8deg);box-shadow:inset 5px -4px 0 var(--sage)}.desktop-nav{display:flex;gap:36px;color:#465047;font-size:14px;font-weight:700}.desktop-nav a{transition:color .2s}.desktop-nav a:hover{color:var(--berry)}.header-download{justify-self:end;padding:11px 18px;border:1px solid var(--ink);border-radius:6px;font-size:14px;font-weight:800;transition:color .2s,background .2s,transform .2s}.header-download:hover{color:var(--white);background:var(--ink);transform:translateY(-2px)}

.hero{position:relative;min-height:100svh;padding:calc(var(--header-height) + 56px) clamp(22px,7vw,120px) 56px;display:grid;grid-template-columns:minmax(280px,.78fr) minmax(480px,1.22fr);align-items:center;gap:3vw;overflow:hidden;background:#edf1e3}.hero-copy{position:relative;z-index:3;max-width:580px}.kicker{margin:0 0 18px;color:var(--berry-dark);font-size:13px;font-weight:850;letter-spacing:0;text-transform:uppercase}.hero h1{margin:0;font-size:clamp(76px,9vw,150px);line-height:.82;letter-spacing:0;font-weight:900}.hero-line{margin:28px 0 0;font-size:clamp(28px,3vw,48px);line-height:1.18;font-weight:850}.hero-description{max-width:530px;margin:24px 0 0;color:#576159;font-size:17px;line-height:1.85}.hero-actions{margin-top:34px;display:flex;align-items:center;gap:26px;flex-wrap:wrap}.primary-button{min-height:52px;padding:0 24px;display:inline-flex;align-items:center;justify-content:center;border:0;border-radius:6px;color:var(--white);background:var(--berry);box-shadow:0 12px 24px rgba(151,55,68,.16);font-weight:850;transition:transform .25s,background .25s}.primary-button:hover{transform:translateY(-3px);background:var(--berry-dark)}.text-link{padding:12px 0;font-weight:760;border-bottom:1px solid rgba(38,49,40,.36)}
.hero-world{position:relative;min-height:min(720px,70vw);align-self:end}.sun-disc{position:absolute;right:12%;top:2%;width:24%;aspect-ratio:1;border-radius:50%;background:var(--sun);opacity:.82}.hill{position:absolute;bottom:-13%;border-radius:50% 50% 0 0/100% 100% 0 0}.hill-back{left:-8%;width:115%;height:48%;background:#cddab7;transform:rotate(-4deg)}.hill-front{left:-14%;bottom:-20%;width:128%;height:44%;background:#99ad79;transform:rotate(5deg)}.hero-pet{position:absolute;z-index:2;object-fit:contain;filter:drop-shadow(0 18px 8px rgba(44,55,41,.13));will-change:transform}.hero-mouse{width:46%;left:29%;bottom:7%;animation:breathe 5.8s ease-in-out infinite}.hero-chick{width:28%;right:1%;bottom:8%;animation:breathe 6.4s .7s ease-in-out infinite}.hero-bunny{width:27%;left:1%;bottom:7%;animation:breathe 6s 1.1s ease-in-out infinite}.hero-pup{width:24%;right:6%;top:10%;animation:hoverPet 7.2s 1.4s ease-in-out infinite}.hero-note{position:absolute;z-index:4;right:4%;bottom:2%;margin:0;padding:8px 0;color:#344336;font-size:13px;font-weight:750;border-bottom:1px solid currentColor}

.manifesto{padding:150px clamp(24px,10vw,170px);background:var(--white)}.manifesto p{margin:0 0 16px;color:var(--berry);font-size:18px;font-weight:800}.manifesto h2{max-width:980px;margin:0;font-size:clamp(46px,7vw,104px);line-height:1.06;letter-spacing:0}
.growth-section{padding:130px clamp(24px,7vw,120px) 110px;background:#e4ead7}.section-copy{max-width:620px}.section-copy h2,.friends-copy h2,.download-copy h2{margin:0;font-size:clamp(38px,5vw,72px);line-height:1.12;letter-spacing:0}.section-copy>p:not(.kicker),.friends-copy>p:not(.kicker),.download-copy>p:not(.kicker){margin:24px 0 0;color:var(--muted);font-size:17px;line-height:1.85}.species-tabs{margin-top:34px;display:flex;gap:8px;flex-wrap:wrap}.species-tab{padding:10px 15px;border:1px solid rgba(38,49,40,.22);border-radius:5px;color:var(--ink);background:transparent;cursor:pointer;font-weight:750;transition:color .2s,background .2s,transform .2s}.species-tab:hover{transform:translateY(-2px)}.species-tab.active{color:var(--white);background:var(--forest);border-color:var(--forest)}.growth-stage{margin-top:72px;overflow-x:auto;scrollbar-width:none;transition:opacity .16s,transform .16s}.growth-stage.switching{opacity:.25;transform:translateY(8px)}.growth-stage::-webkit-scrollbar{display:none}.growth-track{min-width:980px;display:grid;grid-template-columns:repeat(5,1fr);align-items:end;gap:16px}.growth-step{position:relative;margin:0;min-width:0;text-align:center}.growth-step:after{content:"";position:absolute;left:calc(50% + 42px);bottom:25px;width:calc(100% - 62px);height:1px;background:rgba(38,49,40,.25)}.growth-step:last-child:after{display:none}.growth-step img{width:100%;height:260px;object-fit:contain;transition:transform .35s}.growth-step:hover img{transform:translateY(-10px) rotate(-1deg)}.growth-step figcaption{min-height:52px;display:flex;align-items:center;justify-content:center;gap:9px}.growth-step figcaption b{color:var(--berry);font-size:12px}.growth-step figcaption span{font-weight:850}

.health-section{min-height:940px;padding:130px clamp(24px,8vw,140px);display:grid;grid-template-columns:minmax(430px,1fr) minmax(330px,.86fr);align-items:center;gap:8vw;background:#f4c8b5}.phone-scene{position:relative;min-height:690px}.phone-device{position:absolute;left:4%;top:0;width:min(360px,75%);padding:12px;border-radius:52px;background:#222923;box-shadow:0 30px 60px rgba(72,47,37,.2);transform:rotate(-4deg)}.phone-island{position:absolute;z-index:2;top:23px;left:50%;width:96px;height:26px;border-radius:20px;background:#111;transform:translateX(-50%)}.phone-ui{min-height:650px;padding:48px 20px 24px;overflow:hidden;border-radius:42px;background:#fffdf7}.phone-top{display:flex;align-items:center;justify-content:space-between;font-size:19px;font-weight:850}.phone-top i{width:32px;height:32px;border-radius:50%;background:var(--sage)}.pet-room{position:relative;height:350px;margin-top:16px;display:grid;place-items:end center;overflow:hidden;border-radius:8px;background:#dfe9d1}.pet-room:after{content:"";position:absolute;inset:auto -10% -9%;height:32%;background:#a8bb88;border-radius:50% 50% 0 0}.pet-room img{position:relative;z-index:2;width:88%;height:88%;object-fit:contain;animation:breathe 5.8s ease-in-out infinite}.mood-mark{position:absolute;z-index:3;right:21px;top:24px;width:38px;height:38px;display:grid;place-items:center;border-radius:50%;color:var(--white);background:var(--berry);font-weight:900}.step-copy{margin-top:18px;display:flex;align-items:end;justify-content:space-between}.step-copy b{font-size:14px}.step-copy strong{font-size:27px}.step-track,.watch-progress{height:8px;margin-top:10px;overflow:hidden;border-radius:10px;background:#e3e4dc}.step-track span,.watch-progress span{display:block;width:80%;height:100%;background:var(--berry)}.health-signals{margin-top:20px;display:flex;gap:8px;flex-wrap:wrap}.health-signals span{padding:7px 9px;border:1px solid var(--line);border-radius:4px;font-size:11px;font-weight:750}.watch-device{position:absolute;z-index:4;right:2%;bottom:30px;width:220px;padding:20px 13px;border-radius:52px;background:#263128;box-shadow:0 24px 48px rgba(72,47,37,.23);transform:rotate(8deg)}.watch-ui{min-height:250px;padding:23px 16px 18px;display:flex;flex-direction:column;align-items:center;border-radius:39px;color:var(--white);background:#171c18}.watch-label{font-size:12px;font-weight:800}.watch-ui img{width:145px;height:140px;object-fit:contain}.watch-ui strong{font-size:24px}.watch-progress{width:100%;background:#3c463d}.watch-progress span{background:var(--sun)}.health-copy{justify-self:end}.feature-list{margin:42px 0 0;padding:0;list-style:none}.feature-list li{padding:20px 0;display:grid;grid-template-columns:38px 1fr;gap:14px;border-top:1px solid rgba(38,49,40,.18)}.feature-list li>span{color:var(--berry-dark);font-size:12px;font-weight:900}.feature-list b{font-size:17px}.feature-list p{margin:7px 0 0;color:#6b5149;line-height:1.6}

.friends-section{padding:130px clamp(24px,8vw,140px);display:grid;grid-template-columns:.78fr 1.22fr;align-items:center;gap:8vw;background:#fffdf8}.friends-copy{max-width:540px}.friend-world{position:relative;min-height:620px;display:flex;align-items:flex-end;justify-content:center;gap:0;overflow:hidden;background:#e4ead7}.friend-ground{position:absolute;inset:auto -10% -10%;height:39%;border-radius:50% 50% 0 0;background:#adc08e}.friend-world img{position:relative;z-index:2;width:45%;max-height:500px;object-fit:contain;transform-origin:50% 90%}.friend-world img:first-of-type{transform:translateX(13%) rotate(2deg)}.friend-world img:last-of-type{transform:translateX(-13%) rotate(-2deg)}.friend-heart{position:absolute;z-index:3;left:50%;top:22%;color:var(--berry);font-size:42px;animation:heartBeat 2.8s ease-in-out infinite}.friend-world p{position:absolute;z-index:3;bottom:24px;left:50%;margin:0;padding:10px 15px;color:var(--white);background:rgba(38,49,40,.84);border-radius:4px;font-size:13px;font-weight:760;transform:translateX(-50%);white-space:nowrap}
.download-section{min-height:760px;padding:100px clamp(24px,10vw,180px);display:grid;grid-template-columns:.85fr 1.15fr;align-items:center;gap:7vw;background:#506848;color:var(--white)}.download-pet img{width:min(500px,100%);margin:auto;filter:drop-shadow(0 24px 12px rgba(25,34,24,.22));animation:breathe 6.2s ease-in-out infinite}.download-copy{max-width:650px}.download-copy .kicker{color:#f3d689}.download-copy>p:not(.kicker){color:#dfe8d9}.download-actions{margin-top:34px;display:flex;gap:12px;flex-wrap:wrap}.store-button{min-height:64px;padding:8px 19px;display:flex;align-items:center;gap:13px;border-radius:6px;color:var(--ink);background:var(--white);transition:transform .25s}.store-button:hover{transform:translateY(-3px)}.apple-mark{width:28px;height:28px;display:grid;place-items:center;color:var(--ink);font-size:28px;line-height:1}.store-button span:last-child{display:flex;flex-direction:column}.store-button small{font-size:10px}.store-button b{font-size:17px}.qr-button{min-height:64px;padding:0 20px;border:1px solid rgba(255,255,255,.45);border-radius:6px;color:var(--white);background:transparent;cursor:pointer;font-weight:800}.compatibility{display:block;margin-top:18px;color:#cfdac9;line-height:1.6}

footer{padding:54px clamp(24px,7vw,120px);display:grid;grid-template-columns:1fr auto;gap:18px 40px;align-items:center;background:#222b24;color:#e8ede4}footer p{margin:0;color:#aeb9ad}footer nav{grid-column:2;grid-row:1/span 2;display:flex;gap:24px;color:#cbd4c8;font-size:13px}footer small{color:#869086}.footer-brand .brand-egg{border-color:#e8ede4;background:#fff}
[data-reveal]{opacity:0;transform:translateY(28px);transition:opacity .8s,transform .8s cubic-bezier(.2,.75,.25,1)}[data-reveal].visible{opacity:1;transform:none}
.download-dialog{width:min(440px,calc(100% - 32px));padding:40px;border:0;border-radius:8px;text-align:center;color:var(--ink);background:var(--white);box-shadow:0 30px 90px rgba(25,34,24,.3)}.download-dialog::backdrop{background:rgba(23,28,24,.58);backdrop-filter:blur(7px)}.dialog-close{position:absolute;top:12px;right:14px;width:36px;height:36px;border:0;background:transparent;cursor:pointer;font-size:27px}.download-dialog h2{margin:20px 0 10px;font-size:28px}.download-dialog p{margin:0 0 22px;color:var(--muted);line-height:1.7}.qr-placeholder{width:150px;aspect-ratio:1;margin:auto;padding:14px;display:grid;place-items:center;background:#fff;border:1px solid var(--line)}.qr-placeholder span{width:100%;height:100%;background:repeating-conic-gradient(#263128 0 25%,transparent 0 50%) 0 0/20px 20px;mask:radial-gradient(circle at center,transparent 0 18%,#000 19%)}.download-dialog .primary-button{width:100%}
.legal-page{min-height:100svh;padding:130px 24px 80px;background:var(--paper)}.legal-shell{width:min(780px,100%);margin:auto}.legal-shell .kicker{margin-bottom:14px}.legal-shell h1{margin:0 0 22px;font-size:clamp(42px,7vw,72px)}.legal-shell .lead{color:var(--muted);font-size:17px;line-height:1.8}.legal-content{margin-top:56px}.legal-content section{padding:28px 0;border-top:1px solid var(--line)}.legal-content h2{margin:0 0 12px;font-size:21px}.legal-content p,.legal-content li{color:#59635b;line-height:1.85}.legal-content ul{padding-left:20px}.back-link{display:inline-flex;margin-top:36px;color:var(--berry-dark);font-weight:800}
@keyframes breathe{0%,100%{transform:translateY(0) scale(1)}50%{transform:translateY(-7px) scale(1.012)}}@keyframes hoverPet{0%,100%{transform:translateY(0) rotate(1deg)}50%{transform:translateY(-12px) rotate(-1deg)}}@keyframes heartBeat{0%,100%{transform:translate(-50%,0) scale(1)}45%{transform:translate(-50%,-7px) scale(1.12)}}
@media(max-width:980px){.desktop-nav{display:none}.site-header{grid-template-columns:1fr auto}.hero{min-height:auto;grid-template-columns:1fr;padding-top:130px}.hero-copy{max-width:680px}.hero-world{min-height:680px}.health-section,.friends-section,.download-section{grid-template-columns:1fr}.health-copy{justify-self:start}.phone-scene{width:min(650px,100%);margin:auto}.friends-copy{max-width:680px}.friend-world{min-height:650px}.download-pet{order:2}.download-copy{order:1}}
@media(max-width:640px){:root{--header-height:68px}.site-header{padding-inline:18px}.header-download{padding:9px 12px}.hero{padding:108px 20px 28px}.hero h1{font-size:64px}.hero-line{font-size:31px}.hero-description{font-size:15px}.hero-world{min-height:440px;margin-inline:-20px}.hero-mouse{width:52%;left:25%}.hero-bunny{width:30%}.hero-chick{width:31%}.hero-pup{width:27%;right:3%;top:8%}.hero-note{right:20px;bottom:0}.manifesto,.growth-section,.health-section,.friends-section,.download-section{padding:86px 20px}.manifesto h2{font-size:48px}.section-copy h2,.friends-copy h2,.download-copy h2{font-size:40px}.growth-stage{margin-right:-20px}.growth-track{min-width:780px}.growth-step img{height:210px}.phone-scene{min-height:560px}.phone-device{width:295px;left:0}.phone-ui{min-height:535px;padding-inline:16px}.pet-room{height:280px}.watch-device{width:170px;right:0}.watch-ui{min-height:200px}.watch-ui img{width:110px;height:105px}.friend-world{min-height:430px;margin-inline:-20px}.friend-world img{width:52%}.download-section{padding-bottom:36px}.download-pet img{width:330px}footer{grid-template-columns:1fr}footer nav{grid-column:auto;grid-row:auto;flex-wrap:wrap}.download-dialog{padding:34px 24px 26px}}
:root{--paper:#f8faf8;--white:#ffffff;--ink:#283d36;--muted:#56685f;--berry:#b54560}
[hidden]{display:none!important}
button:focus-visible,a:focus-visible,select:focus-visible{outline:3px solid #b54560;outline-offset:5px}
.hero{display:block;min-height:700px;height:92svh;max-height:1000px;padding:118px 24px 0;background:#edf5f1;text-align:center}
.hero-copy{max-width:760px;margin:0 auto}.hero h1{font-size:76px;line-height:1.15}.hero-line{font-size:32px;margin-top:16px}.hero-description{margin:18px auto 0;max-width:590px;font-size:16px}.hero-actions{justify-content:center;margin-top:24px}
.hero-world{position:absolute;inset:auto 0 20px;height:40%;min-height:0;margin:0;pointer-events:none}
.hero-pet{height:100%;width:24%;bottom:0;top:auto;animation:none;filter:none}
.hero-bunny{left:4%;width:23%;height:80%}.hero-mouse{left:26%;width:24%}.hero-chick{left:52%;width:21%;height:78%}.hero-pup{left:75%;width:21%;height:86%}
.hero-note{bottom:0;right:50%;transform:translateX(50%);font-weight:500;border:0;white-space:nowrap;font-size:12px}
.manifesto{padding:80px 8%;background:#fff}.manifesto h2{font-size:52px}
.section-copy h2,.friends-copy h2,.download-copy h2{font-size:48px}.legal-shell h1{font-size:48px}
.growth-section{background:#edf2e7;padding-top:96px}.growth-stage{margin-top:40px}
.health-section{background:#e6eff3}.feature-list p{color:var(--muted)}
.friends-section{display:block;background:#fff;padding-top:96px}.friends-copy{max-width:850px;margin:auto;text-align:center}.friends-copy h2{line-height:1.25}
.demo-note{display:block;margin:22px auto;color:var(--muted);line-height:1.7;font-size:13px}
.yard-label{margin-right:12px;font-size:14px}#yard-pet{font:inherit;padding:10px 32px 10px 14px;background:#fff;border:1px solid #83988c;border-radius:6px;color:var(--ink)}
.yard-actions{display:flex;justify-content:center;gap:12px;margin:22px 0}.yard-actions button,.copy-site{padding:12px 20px;background:var(--ink);color:#fff;border:0;border-radius:6px;font-weight:700;cursor:pointer}.yard-actions button:disabled{opacity:.5}
.friend-world{min-height:0;height:430px;max-width:900px;margin:20px auto 0;background:#edf5f1;padding-bottom:55px}.friend-world img{height:95%;width:40%;max-height:none}.friend-heart{animation:none;top:20%;font-size:28px}.friend-world p{white-space:normal;text-align:center;min-width:250px;max-width:90%;bottom:12px}
.copy-site{margin:18px 0}.download-dialog p{overflow-wrap:anywhere}.download-section{background:#345c51}.compatibility{color:#e0e9e4}
@media(max-width:640px){.hero{height:92svh;min-height:650px;max-height:850px;padding:104px 20px 0}.hero h1{font-size:48px}.hero-line{font-size:25px}.hero-description{font-size:15px;max-width:340px}.hero-actions{gap:16px}.hero-world{height:34%;bottom:25px}.hero-bunny{left:0;width:25%}.hero-mouse{left:23%;width:29%}.hero-chick{left:50%;width:24%}.hero-pup{left:74%;width:26%}.hero-note{font-size:11px;bottom:-6px}.manifesto{padding:60px 20px}.manifesto h2{font-size:34px}.section-copy h2,.friends-copy h2,.download-copy h2{font-size:34px}.friend-world{height:320px;margin-inline:0}.friend-world img{width:49%}.yard-actions{gap:8px}.yard-actions button{padding:12px 16px}.phone-device{width:min(295px,87%)}.legal-shell h1{font-size:36px}}
.manifesto{padding-top:30px}
@media(max-width:640px){.hero-world{height:38%;bottom:22px}.hero-mouse{left:23%;width:55%;height:100%;z-index:3}.hero-bunny{left:-2%;width:36%;height:65%}.hero-chick{left:69%;width:32%;height:60%}.hero-pup{display:none}.hero-note{bottom:-9px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important}[data-reveal]{opacity:1;transform:none}}
:root .brand-icon{width:38px;height:38px;object-fit:contain;border-radius:8px}
/* Keep the source image proportional inside its transparent-margin viewport. */
:root .brand-wordmark{display:inline-block;width:104px;height:auto;aspect-ratio:1300/352;background:transparent url("brand/bubu-english.png") 55% 50%/137.846154% 203.636364% no-repeat}
.growth-stage{padding:24px 12px 12px;scroll-padding-inline:12px}
.growth-track{padding-inline:8px}
.growth-step img{box-sizing:border-box;padding:14px;display:block}
.growth-step:hover img{transform:translateY(-5px)}
.growth-art{height:260px;display:grid;place-items:center;padding:14px;box-sizing:border-box}
.growth-source-window{width:100%;aspect-ratio:1;position:relative}
.growth-art img{height:auto;padding:0}
.growth-stage[data-species="berry-mouse"] .growth-source-window{overflow:hidden;mix-blend-mode:multiply}
.growth-stage[data-species="berry-mouse"] .growth-art img{position:static;width:100%;max-width:100%;height:auto;transform:none}
.growth-step:has(.growth-art):hover .growth-source-window{translate:0 -5px}
.growth-source-window{transition:translate .35s}
@media(max-width:640px){.growth-art{height:210px}}
@media(prefers-reduced-motion:reduce){.growth-step:hover img{transform:none}}
:root .hero-wordmark{width:204px;height:auto}
@media(min-width:641px){.hero-world{height:32%}}

/* 步步 33: native Chinese wordmark; filing remains readable on every page. */
:root .brand-wordmark{background:none;aspect-ratio:auto;width:auto;height:auto;font-size:32px;line-height:1.2;font-weight:850;letter-spacing:.1em;color:#283d36}
:root .brand-wordmark::before{content:"步步"}
:root .hero-wordmark{font-size:76px;width:auto}
.filing{font-size:13px;line-height:1.8;color:#526459}.filing a{text-decoration:none;color:inherit}.filing a:hover{text-decoration:underline}.legal-filing{text-align:center;padding:18px 24px 32px}