.back-vw-shell{min-height:100dvh;background:radial-gradient(circle at 78% 4%,rgba(255,192,112,.3),transparent 32%),linear-gradient(145deg,#fff9ef 0%,#effaf5 58%,#e9f6fb 100%);color:#263a3b}.back-vw-experience{min-height:100dvh;display:flex;flex-direction:column}.back-vw-topbar{height:76px;padding:0 clamp(20px,4vw,64px);display:grid;grid-template-columns:auto 1fr auto;align-items:center;gap:20px;border-bottom:1px solid rgba(49,97,92,.12);background:rgba(255,255,255,.72);backdrop-filter:blur(18px);position:relative;z-index:5}.back-vw-topbar button,.back-vw-controls button{appearance:none;border:0;border-radius:15px;padding:12px 20px;background:#fff;color:#315a57;font:inherit;font-weight:800;box-shadow:0 8px 24px rgba(47,86,82,.1);cursor:pointer}.back-vw-topbar div{display:flex;align-items:baseline;gap:12px}.back-vw-topbar span{color:#df704c;font-size:13px;font-weight:800;letter-spacing:.08em}.back-vw-topbar strong{font-size:20px}.back-vw-topbar em{font-style:normal;font-weight:800;color:#51716f}.back-vw-body{flex:1;padding:clamp(20px,3vw,42px) clamp(20px,4vw,68px) 36px}.back-vw-intro{max-width:1440px;margin:auto}.back-vw-hero{display:grid;grid-template-columns:minmax(420px,1.35fr) minmax(310px,.65fr);gap:34px;align-items:center}.back-vw-hero>img{width:100%;max-height:46vh;object-fit:cover;border-radius:30px;box-shadow:0 24px 60px rgba(47,86,82,.16)}.back-vw-hero>div>span,.back-vw-complete>span{display:inline-flex;padding:7px 12px;border-radius:999px;background:#fff0e8;color:#cf623f;font-weight:900}.back-vw-hero h1,.back-vw-stage-copy h1,.back-vw-complete h1{font-size:clamp(34px,4vw,62px);line-height:1.05;margin:14px 0;color:#213c3c}.back-vw-hero>div>p{font-size:18px;line-height:1.8;color:#53716f}.back-vw-safety{padding:18px 20px;border-radius:20px;background:rgba(255,255,255,.78);border:1px solid rgba(49,97,92,.12)}.back-vw-safety strong{color:#d06342}.back-vw-safety p{margin:8px 0 0;line-height:1.65}.back-vw-guide-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:16px;margin-top:24px}.back-vw-guide-grid article{position:relative;overflow:hidden;border-radius:24px;background:rgba(255,255,255,.82);box-shadow:0 10px 30px rgba(47,86,82,.09)}.back-vw-guide-grid article>em{position:absolute;top:12px;left:12px;width:32px;height:32px;display:grid;place-items:center;border-radius:50%;background:#df704c;color:#fff;font-style:normal;font-weight:900;z-index:1}.back-vw-guide-grid img{width:100%;aspect-ratio:16/9;object-fit:cover}.back-vw-guide-grid article div{padding:14px 16px 18px}.back-vw-guide-grid strong{font-size:17px}.back-vw-guide-grid p{margin:7px 0 0;color:#617775;line-height:1.55}.back-vw-primary{display:block;margin:24px auto 0;min-width:260px;border:0;border-radius:20px;padding:17px 30px;background:linear-gradient(135deg,#df704c,#ef9a55);color:#fff;font:inherit;font-size:18px;font-weight:900;box-shadow:0 16px 32px rgba(223,112,76,.25);cursor:pointer}.back-vw-runtime{height:calc(100dvh - 154px);max-width:1500px;margin:auto;display:flex;flex-direction:column;gap:20px}.back-vw-progress{display:grid;grid-template-columns:auto 1fr auto;align-items:center;gap:20px;font-weight:900}.back-vw-progress>div{height:12px;border-radius:999px;background:rgba(49,97,92,.12);overflow:hidden}.back-vw-progress i{display:block;height:100%;border-radius:inherit;background:linear-gradient(90deg,#40b9a6,#f3a653);transition:width .3s}.back-vw-stage{flex:1;min-height:0;display:grid;grid-template-columns:minmax(0,1.35fr) minmax(300px,.65fr);gap:28px;padding:26px;border:1px solid rgba(49,97,92,.12);border-radius:36px;background:rgba(255,255,255,.72);box-shadow:0 26px 80px rgba(47,86,82,.13)}.back-vw-stage-art{position:relative;min-height:0;overflow:hidden;border-radius:28px;background:#eaf6f0}.back-vw-stage-art img{width:100%;height:100%;object-fit:contain}.back-vw-stage-art span{position:absolute;left:20px;bottom:20px;padding:9px 15px;border-radius:999px;background:rgba(26,55,54,.84);color:#fff;font-weight:900}.back-vw-stage-copy{display:flex;flex-direction:column;justify-content:center;padding:20px}.back-vw-stage-copy>span{color:#df704c;font-weight:900}.back-vw-stage-copy p{font-size:clamp(18px,2vw,26px);line-height:1.65;color:#4f6e6c}.back-vw-stage-copy>strong{font-size:clamp(56px,8vw,112px);line-height:1;color:#3aa995;margin-top:16px}.back-vw-controls{display:flex;justify-content:center;gap:14px}.back-vw-controls .danger{color:#b74f42;background:#fff2ef}.back-vw-complete{min-height:calc(100dvh - 170px);display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center}.back-vw-complete>img{width:min(640px,65vw);max-height:42vh;object-fit:contain;border-radius:32px}.back-vw-complete p{font-size:20px;color:#55726f}.back-vw-complete>div{display:grid;grid-template-columns:repeat(3,auto auto);align-items:center;gap:8px 12px;padding:16px 24px;border-radius:22px;background:#fff}.back-vw-complete>div strong{font-size:26px;color:#df704c}.back-vw-complete>div span{color:#67807e}.back-vw-runtime[data-back-vw-phase="rest"] .back-vw-stage,.back-vw-runtime[data-back-vw-phase="paused"] .back-vw-stage{background:rgba(242,250,247,.92)}
@media(max-width:900px){.back-vw-topbar{height:64px;padding:0 14px;gap:10px}.back-vw-topbar div{display:block}.back-vw-topbar span{display:none}.back-vw-topbar strong{font-size:16px}.back-vw-topbar button{padding:9px 13px}.back-vw-body{padding:14px}.back-vw-hero,.back-vw-stage{grid-template-columns:1fr}.back-vw-hero>img{max-height:none}.back-vw-guide-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.back-vw-runtime{height:auto;min-height:calc(100dvh - 92px)}.back-vw-stage-art{min-height:42vh}.back-vw-stage-copy{padding:4px}.back-vw-stage-copy h1{font-size:34px}.back-vw-stage-copy>strong{font-size:58px}.back-vw-controls{position:sticky;bottom:8px;z-index:4}.back-vw-controls button{padding:11px 14px}.back-vw-complete>div{grid-template-columns:repeat(2,auto)}}
@media(max-width:560px){.back-vw-guide-grid{grid-template-columns:1fr}.back-vw-hero h1{font-size:38px}.back-vw-progress{gap:9px;font-size:13px}.back-vw-stage{padding:12px;border-radius:24px}.back-vw-stage-art{min-height:36vh}.back-vw-controls{gap:8px}.back-vw-controls button{font-size:13px;padding:10px}.back-vw-topbar em{font-size:12px}}
@media(prefers-reduced-motion:reduce){.back-vw-progress i{transition:none}}
.back-vw-intro>.back-vw-primary{position:sticky;bottom:14px;z-index:6}

/* v2：导读语音与训练节奏解耦，动作使用横向滚轮展示。 */
.back-vw-intro-actions{position:sticky;bottom:14px;z-index:6;display:flex;align-items:center;justify-content:center;gap:14px;margin-top:24px}.back-vw-intro-actions .back-vw-primary{margin:0}.back-vw-secondary{min-width:210px;border:1px solid rgba(49,97,92,.18);border-radius:20px;padding:16px 24px;background:rgba(255,255,255,.92);color:#315a57;font:inherit;font-size:17px;font-weight:900;box-shadow:0 12px 30px rgba(47,86,82,.12);cursor:pointer}.back-vw-secondary:focus-visible,.back-vw-primary:focus-visible,.back-vw-controls button:focus-visible{outline:4px solid rgba(64,185,166,.28);outline-offset:3px}
.back-vw-carousel-viewport{position:relative;min-width:0;min-height:0;overflow:hidden;border-radius:28px;background:linear-gradient(145deg,#eaf6f0,#f8fbf5);isolation:isolate}.back-vw-carousel-track{height:100%;display:flex;align-items:center;gap:18px;will-change:transform;transition-property:transform;transition-timing-function:cubic-bezier(.22,1,.36,1)}.back-vw-carousel-card{flex-grow:0;flex-shrink:0;flex-basis:min(52vw,680px);height:min(52vh,570px);min-height:340px;display:grid;grid-template-rows:minmax(0,1fr) auto;overflow:hidden;border:1px solid rgba(49,97,92,.12);border-radius:30px;background:rgba(255,255,255,.96);box-shadow:0 12px 34px rgba(47,86,82,.1);opacity:.34;filter:saturate(.65) blur(.35px);transform:scale(.84);transition:opacity .48s cubic-bezier(.22,1,.36,1),transform .48s cubic-bezier(.22,1,.36,1),filter .48s ease,box-shadow .48s ease}.back-vw-carousel-card.is-active{opacity:1;filter:none;transform:scale(1);box-shadow:0 25px 70px rgba(47,86,82,.2),0 0 0 5px rgba(64,185,166,.13)}.back-vw-carousel-card.is-far{opacity:.12;transform:scale(.72)}.back-vw-carousel-card img{width:100%;height:100%;min-height:0;object-fit:contain;background:#eef8f3}.back-vw-carousel-card>div{display:grid;grid-template-columns:auto 1fr;grid-template-areas:"step title" "copy copy";align-items:center;gap:4px 12px;padding:14px 18px 17px}.back-vw-carousel-card span{grid-area:step;padding:5px 9px;border-radius:999px;background:#ebf7f3;color:#3d8f82;font-size:12px;font-weight:900}.back-vw-carousel-card strong{grid-area:title;font-size:20px;color:#294745}.back-vw-carousel-card p{grid-area:copy;margin:3px 0 0;color:#5f7976;line-height:1.5}.back-vw-carousel-shade{position:absolute;z-index:3;top:0;bottom:0;width:12%;pointer-events:none}.back-vw-carousel-shade.left{left:0;background:linear-gradient(90deg,#edf7f2,transparent)}.back-vw-carousel-shade.right{right:0;background:linear-gradient(-90deg,#f5faf4,transparent)}
@media(max-width:900px){.back-vw-intro-actions{flex-wrap:wrap}.back-vw-intro-actions .back-vw-primary,.back-vw-secondary{min-width:min(100%,260px)}.back-vw-stage{min-height:650px}.back-vw-carousel-viewport{min-height:430px}.back-vw-carousel-card{flex-basis:min(72vw,560px);height:410px;min-height:0}.back-vw-stage-copy{align-items:center;text-align:center}.back-vw-stage-copy p{max-width:720px}.back-vw-stage-copy>strong{margin-top:2px}}
@media(max-width:560px){.back-vw-intro-actions{position:static}.back-vw-intro-actions .back-vw-primary,.back-vw-secondary{width:100%}.back-vw-stage{min-height:560px}.back-vw-carousel-viewport{min-height:330px}.back-vw-carousel-card{flex-basis:76vw;height:320px;border-radius:22px}.back-vw-carousel-card>div{padding:10px 12px}.back-vw-carousel-card strong{font-size:17px}.back-vw-carousel-card p{font-size:13px}.back-vw-stage-copy p{font-size:16px}.back-vw-stage-copy h1{margin:8px 0}.back-vw-controls button{min-height:44px}}
@media(prefers-reduced-motion:reduce){.back-vw-carousel-track,.back-vw-carousel-card{transition:none!important}}

/* v3：训练态采用无外框全屏舞台，图片为主，信息缩进角落。 */
.back-vw-experience.is-runtime{height:100dvh;min-height:0;overflow:hidden}.back-vw-experience.is-runtime .back-vw-body{flex:1;min-height:0;padding:0;overflow:hidden}.back-vw-experience.is-runtime .back-vw-runtime{position:relative;width:100%;height:100%;max-width:none;margin:0;gap:0;overflow:hidden}.back-vw-experience.is-runtime .back-vw-progress{position:absolute;z-index:7;top:18px;left:clamp(24px,4vw,72px);right:clamp(24px,4vw,72px);height:34px;text-shadow:0 1px 0 rgba(255,255,255,.72)}.back-vw-experience.is-runtime .back-vw-stage{position:absolute;inset:0;display:block;min-height:0;padding:0;border:0;border-radius:0;background:transparent;box-shadow:none;overflow:hidden}.back-vw-experience.is-runtime .back-vw-carousel-viewport{position:absolute;inset:0;min-height:0;border-radius:0;background:transparent}.back-vw-experience.is-runtime .back-vw-carousel-track{height:100%;padding-top:30px}.back-vw-experience.is-runtime .back-vw-carousel-card{position:relative;flex-basis:min(66vw,1000px);height:calc(100% - 118px);min-height:520px;max-height:900px;display:block;border:0;border-radius:28px;background:transparent;box-shadow:none}.back-vw-experience.is-runtime .back-vw-carousel-card.is-active{box-shadow:0 28px 80px rgba(47,86,82,.16)}.back-vw-experience.is-runtime .back-vw-carousel-card img{display:block;width:100%;height:100%;object-fit:contain;border-radius:28px;background:rgba(237,248,243,.72)}.back-vw-experience.is-runtime .back-vw-carousel-card>div{position:absolute;left:14px;bottom:14px;right:auto;max-width:min(520px,calc(100% - 28px));display:grid;padding:10px 14px 12px;border-radius:16px;background:rgba(255,255,255,.82);box-shadow:0 8px 28px rgba(47,86,82,.1);backdrop-filter:blur(14px)}.back-vw-experience.is-runtime .back-vw-carousel-card p{white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.back-vw-experience.is-runtime .back-vw-carousel-shade{width:16%}.back-vw-experience.is-runtime .back-vw-stage-copy{position:absolute;z-index:8;top:76px;right:clamp(22px,3vw,56px);width:min(290px,26vw);display:block;padding:16px 18px;border:1px solid rgba(49,97,92,.1);border-radius:22px;background:rgba(255,255,255,.8);box-shadow:0 18px 48px rgba(47,86,82,.12);backdrop-filter:blur(16px)}.back-vw-experience.is-runtime .back-vw-stage-copy h1{margin:8px 0;font-size:clamp(26px,3vw,46px)}.back-vw-experience.is-runtime .back-vw-stage-copy p{margin:0;font-size:clamp(14px,1.35vw,18px);line-height:1.5}.back-vw-experience.is-runtime .back-vw-stage-copy>strong{display:block;margin-top:8px;font-size:clamp(44px,5vw,72px)}.back-vw-experience.is-runtime .back-vw-controls{position:absolute;z-index:10;left:50%;bottom:14px;transform:translateX(-50%);padding:5px;border-radius:20px;background:rgba(255,255,255,.68);box-shadow:0 12px 34px rgba(47,86,82,.1);backdrop-filter:blur(14px)}
@media(max-width:1024px){.back-vw-experience.is-runtime .back-vw-progress{top:12px;left:18px;right:18px}.back-vw-experience.is-runtime .back-vw-carousel-card{flex-basis:min(76vw,760px);height:calc(100% - 112px);min-height:440px}.back-vw-experience.is-runtime .back-vw-stage-copy{top:64px;right:16px;width:min(250px,30vw);padding:13px 15px}.back-vw-experience.is-runtime .back-vw-carousel-card>div{left:10px;bottom:10px}}
@media(max-width:560px){.back-vw-experience.is-runtime .back-vw-progress{top:8px;left:12px;right:12px;height:28px}.back-vw-experience.is-runtime .back-vw-carousel-track{padding-top:22px}.back-vw-experience.is-runtime .back-vw-carousel-card{flex-basis:88vw;height:calc(100% - 170px);min-height:330px;max-height:none;border-radius:20px}.back-vw-experience.is-runtime .back-vw-carousel-card img{border-radius:20px}.back-vw-experience.is-runtime .back-vw-carousel-card>div{left:8px;right:8px;bottom:8px;max-width:none;padding:8px 10px}.back-vw-experience.is-runtime .back-vw-carousel-card p{display:none}.back-vw-experience.is-runtime .back-vw-stage-copy{top:auto;right:12px;bottom:72px;width:calc(100% - 24px);padding:10px 13px;border-radius:17px}.back-vw-experience.is-runtime .back-vw-stage-copy h1{display:inline;margin:0 10px 0 0;font-size:22px}.back-vw-experience.is-runtime .back-vw-stage-copy p{display:inline;font-size:14px}.back-vw-experience.is-runtime .back-vw-stage-copy>span{display:block;margin-bottom:3px;font-size:12px}.back-vw-experience.is-runtime .back-vw-stage-copy>strong{position:absolute;right:14px;top:50%;margin:0;font-size:40px;transform:translateY(-50%);opacity:.88}.back-vw-experience.is-runtime .back-vw-controls{bottom:8px;width:max-content;max-width:calc(100% - 16px)}}
.back-vw-experience.is-runtime .back-vw-carousel-card{height:calc(100% - 140px)}
@media(max-width:1024px){.back-vw-experience.is-runtime .back-vw-carousel-card{height:calc(100% - 136px)}}
@media(max-width:560px){.back-vw-experience.is-runtime .back-vw-carousel-card{height:calc(100% - 170px)}}

/* v4：训练过程改为“一次完整视频 = 一次动作”，视频结束后自动计数并重播。 */
.back-vw-experience.is-runtime .back-vw-video-stage{position:absolute;inset:48px 0 0;display:grid;place-items:center;overflow:hidden;background:radial-gradient(circle at 50% 46%,rgba(255,255,255,.95),rgba(239,249,244,.42) 58%,transparent 78%)}
.back-vw-experience.is-runtime .back-vw-video-stage video{display:block;width:100%;height:100%;object-fit:contain;object-position:center;border:0;background:transparent;transition:opacity .24s ease,filter .24s ease}
.back-vw-experience.is-runtime .back-vw-video-badge{position:absolute;z-index:2;left:clamp(18px,3vw,48px);bottom:78px;display:flex;align-items:center;gap:10px;padding:10px 15px;border:1px solid rgba(49,97,92,.1);border-radius:16px;background:rgba(255,255,255,.78);box-shadow:0 12px 34px rgba(47,86,82,.1);backdrop-filter:blur(14px)}
.back-vw-experience.is-runtime .back-vw-video-badge span{color:#df704c;font-size:13px;font-weight:900}.back-vw-experience.is-runtime .back-vw-video-badge strong{color:#294745;font-size:20px}
.back-vw-experience.is-runtime .back-vw-controls button:disabled{cursor:default;opacity:.62}
.back-vw-runtime[data-back-vw-phase="prepare"] .back-vw-video-stage video,.back-vw-runtime[data-back-vw-phase="rest"] .back-vw-video-stage video{opacity:.48;filter:saturate(.72)}
.back-vw-runtime[data-back-vw-phase="paused"] .back-vw-video-stage video{opacity:.62;filter:saturate(.72)}
@media(max-width:900px){.back-vw-experience.is-runtime .back-vw-video-stage{inset:42px 0 0}.back-vw-experience.is-runtime .back-vw-video-badge{left:14px;bottom:72px;padding:8px 12px}.back-vw-experience.is-runtime .back-vw-video-badge strong{font-size:17px}}
@media(max-width:900px) and (orientation:portrait){.back-vw-experience.is-runtime .back-vw-video-stage video{position:absolute;left:50%;top:50%;width:auto;height:78%;max-width:none;object-fit:contain;transform:translate(-50%,-50%)}}
@media(max-width:560px){.back-vw-experience.is-runtime .back-vw-video-stage{inset:34px 0 108px}.back-vw-experience.is-runtime .back-vw-video-badge{left:10px;bottom:8px}.back-vw-experience.is-runtime .back-vw-video-badge span{display:none}}
@media(prefers-reduced-motion:reduce){.back-vw-experience.is-runtime .back-vw-video-stage video{transition:none}}