/* Shared homepage/course introduction. Preserve the original animation rules. */

      /* ===== Khối Giới thiệu 3D (#gioi-thieu) ===== */
      .intro3d{position:relative;background:var(--ink);color:#fff;padding:clamp(88px,9vw,132px) 0 clamp(72px,8vw,112px);overflow:hidden;scroll-margin-top:92px}
      .intro3d:before{content:"";position:absolute;inset:0;pointer-events:none;background:radial-gradient(ellipse 70% 55% at 50% 48%,rgba(216,24,32,.09) 0%,transparent 62%),radial-gradient(circle at 82% 22%,rgba(255,255,255,.05) 0%,transparent 45%)}
      .intro3d-inner{position:relative;z-index:1}
      .intro3d-head{display:grid;grid-template-columns:minmax(0,1.05fr) minmax(300px,.82fr);align-items:start;gap:clamp(36px,6vw,110px)}.intro3d-head .eyebrow{grid-column:1/-1}
      .intro3d-head h2{max-width:20ch;text-wrap:balance;margin:0;font-size:clamp(38px,5.4vw,74px);font-weight:700;letter-spacing:-.045em;line-height:1.02}
      .intro3d-head h2 span{color:var(--red)}
      .intro3d-lead{max-width:46ch;margin:0 0 22px;color:#fff;font-size:clamp(18px,1.6vw,23px);font-weight:700;letter-spacing:-.02em;line-height:1.35}.intro3d-body{max-width:62ch;margin:0 0 18px;color:#b4b4b4;font-size:clamp(14px,1.15vw,17px);line-height:1.75}.intro3d-body:last-of-type{margin-bottom:0}
      .intro3d .service-list{display:flex;flex-wrap:wrap;gap:10px;margin:26px 0 0;padding:0;border:0}
      .intro3d .service-list span{padding:9px 15px;border:1px solid rgba(255,255,255,.24);border-radius:999px;color:#d7d7d7;font-size:11px;font-weight:700;letter-spacing:.13em;text-transform:uppercase}
      .intro3d-stage-wrap{position:relative;width:100%;height:62vh;min-height:620px;margin-top:clamp(44px,5vw,72px);perspective:1800px;perspective-origin:50% 45%}
      .intro3d-stage{position:absolute;inset:0;transform-style:preserve-3d;transform:rotateX(8deg)}
      .intro3d-dust{position:absolute;inset:0;pointer-events:none}
      .intro3d-dust span{position:absolute;width:2px;height:2px;border-radius:50%;background:var(--red);opacity:.4;box-shadow:0 0 6px var(--red);animation:intro3dDrift 12s infinite ease-in-out}
      @keyframes intro3dDrift{0%,100%{opacity:.18}50%{opacity:.6}}
      .intro3d-card{position:absolute;left:50%;top:50%;width:344px;height:230px;border-radius:14px;overflow:hidden;background:linear-gradient(180deg,#151515 0%,#0b0b0b 100%);border:1px solid rgba(255,255,255,.08);box-shadow:0 30px 60px -20px rgba(0,0,0,.75),0 12px 30px -10px rgba(216,24,32,.18),0 0 0 1px rgba(255,255,255,.04) inset;transform-style:preserve-3d;will-change:transform;transition:box-shadow .3s ease}
      .intro3d-card:not(.is-placeholder){cursor:pointer}
      .intro3d-stage-wrap.has-shots{cursor:pointer}
      .intro3d-card:not(.is-placeholder):hover{box-shadow:0 40px 80px -20px rgba(0,0,0,.85),0 20px 40px -10px rgba(216,24,32,.3),0 0 0 1px rgba(216,24,32,.4) inset,0 0 30px -5px rgba(216,24,32,.35)}
      .intro3d-chrome{height:28px;display:flex;align-items:center;gap:6px;padding:0 12px;background:linear-gradient(180deg,#1d1d1d 0%,#151515 100%);border-bottom:1px solid rgba(255,255,255,.05)}
      .intro3d-chrome i{width:9px;height:9px;border-radius:50%;background:rgba(255,255,255,.2)}
      .intro3d-chrome i.on{background:var(--red)}
      .intro3d-chrome b{margin-left:8px;color:#8b8b8b;font-size:9px;font-weight:700;letter-spacing:.16em;text-transform:uppercase}
      .intro3d-img{position:relative;width:100%;height:calc(100% - 28px);background-size:cover;background-position:center}
      .intro3d-img:after{content:"";position:absolute;inset:0;pointer-events:none;box-shadow:inset 0 -20px 40px -10px rgba(0,0,0,.45)}
      .intro3d-card.is-placeholder .intro3d-img{display:flex;align-items:center;justify-content:center;background:repeating-linear-gradient(135deg,#1a1a1a 0 12px,#161616 12px 24px)}
      .intro3d-card.is-placeholder .intro3d-img em{position:relative;z-index:1;color:#6d6d6d;font-style:normal;font-size:12px;font-weight:700;letter-spacing:.14em;text-transform:uppercase;text-align:center;padding:0 14px}
      /* Lightbox */
      .intro3d-modal{position:fixed;inset:0;z-index:2147483647;display:flex;align-items:center;justify-content:center;padding:40px;opacity:0;pointer-events:none;transition:opacity .3s ease}
      .intro3d-modal.open{opacity:1;pointer-events:auto}
      .intro3d-modal-backdrop{position:absolute;inset:0;background:rgba(4,4,4,.86);cursor:pointer}
      .intro3d-modal-stage{position:relative;max-width:100%;transform:scale(.94) translateY(20px);transition:transform .35s cubic-bezier(.2,.8,.2,1)}
      .intro3d-modal.open .intro3d-modal-stage{transform:none}
      .intro3d-modal-content{position:relative;width:70vw;max-width:840px;max-height:72vh;border-radius:16px;overflow:hidden;background:#0b0b0b;border:1px solid rgba(255,255,255,.1)}
      .intro3d-modal-body{height:72vh;max-height:72vh;background:#000 center/contain no-repeat}
      .intro3d-modal button{position:absolute;z-index:2;display:flex;align-items:center;justify-content:center;border-radius:50%;background:rgba(255,255,255,.09);border:1px solid rgba(255,255,255,.18);color:#fff;cursor:pointer;transition:.2s}
      .intro3d-modal button:hover{background:var(--red);border-color:var(--red)}
      .intro3d-close{top:-52px;right:-6px;width:42px;height:42px;font-size:20px;line-height:1}
      .intro3d-nav{top:50%;width:48px;height:48px;transform:translateY(-50%);font-size:20px;line-height:1}
      .intro3d-nav.prev{left:-64px}
      .intro3d-nav.next{right:-64px}
      .intro3d-counter{position:absolute;bottom:-34px;left:50%;transform:translateX(-50%);color:#8b8b8b;font-size:11px;font-weight:700;letter-spacing:.24em;white-space:nowrap}
      @media(max-width:1100px){.intro3d-nav.prev{left:8px}.intro3d-nav.next{right:8px}.intro3d-close{top:8px;right:8px}}
      @media(max-width:900px){
        .intro3d{scroll-margin-top:78px}
        .intro3d-head{grid-template-columns:1fr}.intro3d-head h2{max-width:none}
        .intro3d-modal{padding:16px}
        .intro3d-modal-content{width:94vw}
      }
      @media(prefers-reduced-motion:reduce){.intro3d-dust span{animation:none}.intro3d-card,.intro3d-modal,.intro3d-modal-stage{transition:none}}

      @media(max-width:767px){
        .about-grid{display:flex;flex-direction:column;align-items:flex-start}
        .about-grid .intro3d-head{display:contents}
        .about-grid .intro3d-head .eyebrow{order:1}
        .about-grid .intro3d-head h2{order:2}
        .about-role{order:3;margin-bottom:0}
        .about-portrait-wrap{order:4;margin:24px 0 28px}
        .about-portrait{margin:0}
        .intro3d-copy{order:5}
      }
      /* ===== Khu rang cua o canh bo goc khi co transform (Safari iOS) ===== */
      .about-portrait,.intro3d-card,.intro3d-img,.intro3d-modal-content{-webkit-backface-visibility:hidden;backface-visibility:hidden;-webkit-mask-image:-webkit-radial-gradient(#fff,#000);isolation:isolate}
      .about-portrait img{border-radius:inherit}
      .intro3d-card{transform-style:flat}

      /* ===== Chan dung: dung dua nhe + nghieng theo chuot + troi theo cuon ===== */
      .about-portrait-wrap{width:300px;perspective:1000px;will-change:transform;transition:transform .12s linear}
      .about-portrait{animation:portraitFloat 7.5s ease-in-out infinite;transform-origin:50% 60%;will-change:transform}
      @keyframes portraitFloat{0%,100%{transform:translate3d(0,0,0) rotate(0deg)}50%{transform:translate3d(0,-11px,0) rotate(.7deg)}}
      @media(max-width:1280px){.about-portrait-wrap{width:250px}}
      @media(max-width:1100px){.about-portrait-wrap{width:200px}}
      @media(max-width:767px){.about-portrait-wrap{width:190px;margin:26px 0 30px}.about-portrait{margin:0}}
      @media(prefers-reduced-motion:reduce){.about-portrait{animation:none}.about-portrait-wrap{transform:none!important;transition:none}}

      /* ===== The 3D: tu khop ti le anh, thu nho theo be ngang ===== */
      .intro3d-stage-wrap{height:auto;min-height:0;aspect-ratio:auto}
      .intro3d-stage-scaler{position:relative;left:50%;width:980px;height:620px;margin:0;transform-origin:top center;transform:translateX(-50%) translateY(var(--stage-shift,0px)) scale(var(--stage-scale,1));transform-style:preserve-3d}
      .intro3d-stage{position:absolute;inset:0}
      .intro3d-card{height:auto}
      .intro3d-card .intro3d-img{height:auto;aspect-ratio:var(--card-ar,3/2)}
      .intro3d-card.is-placeholder .intro3d-img{aspect-ratio:3/2}
      .intro3d-card:focus-visible{outline:2px solid var(--red);outline-offset:4px}
      .intro3d-modal-body{height:72vh;width:auto;max-width:min(86vw,1100px);aspect-ratio:var(--modal-ar,3/2);background:#000 center/contain no-repeat}
      .intro3d-modal-caption{margin:0;padding:14px 20px;color:#c9c9c9;font-size:14px;line-height:1.6;background:#0b0b0b;border-top:1px solid rgba(255,255,255,.08)}
      .intro3d-modal-content{width:auto;max-width:min(90vw,1120px);max-height:none}
      @media(max-width:900px){
        .intro3d-card{width:344px}
        .intro3d-modal-caption{font-size:13px;padding:12px 16px}
        .intro3d-modal-body{height:auto;width:86vw;max-width:86vw}
      }

      /* ===== Lop nen rieng + hoa tron voi hero dau trang ===== */
      .intro3d-hero{background:none!important}
      .intro3d-bg{position:absolute;inset:0;z-index:0;background-size:cover;background-position:72% center;background-repeat:no-repeat;filter:brightness(1.1) grayscale(.12) blur(2.5px);opacity:.55;-webkit-mask-image:linear-gradient(180deg,rgba(0,0,0,0) 0px,#000 130px,#000 calc(100svh - 260px),rgba(0,0,0,.55) calc(100svh - 90px),rgba(0,0,0,.22) calc(100svh + 40px),rgba(0,0,0,0) calc(100svh + 190px));mask-image:linear-gradient(180deg,rgba(0,0,0,0) 0px,#000 130px,#000 calc(100svh - 260px),rgba(0,0,0,.55) calc(100svh - 90px),rgba(0,0,0,.22) calc(100svh + 40px),rgba(0,0,0,0) calc(100svh + 190px))}
      /* Nen chi ve khi khoi Gioi thieu toi gan khung nhin — xem js/lazy-media.js */
      .intro3d-bg.is-lazy-ready{background-image:url('/assets/cover-studio.jpg')}
      .intro3d-hero:before{display:none}
      .intro3d:before{display:block;content:"";position:absolute;inset:0;z-index:1;pointer-events:none;background:linear-gradient(90deg,#080808 0%,rgba(8,8,8,.98) 18%,rgba(8,8,8,.94) 32%,rgba(8,8,8,.78) 52%,rgba(8,8,8,.4) 74%,rgba(8,8,8,.08) 100%),linear-gradient(180deg,rgba(8,8,8,.5) 0%,rgba(8,8,8,.22) 26%,rgba(8,8,8,.1) 70%,rgba(8,8,8,0) 100%);-webkit-mask-image:linear-gradient(180deg,#000 0px,#000 calc(100svh - 110px),rgba(0,0,0,.82) calc(100svh + 20px),rgba(0,0,0,.4) calc(100svh + 150px),rgba(0,0,0,0) calc(100svh + 320px));mask-image:linear-gradient(180deg,#000 0px,#000 calc(100svh - 110px),rgba(0,0,0,.82) calc(100svh + 20px),rgba(0,0,0,.4) calc(100svh + 150px),rgba(0,0,0,0) calc(100svh + 320px))}

      .intro3d-hero:after{display:none}
      .intro3d-hero:before,.intro3d-hero:after{z-index:1}
      .intro3d-hero .intro3d-inner{z-index:2}
      /* ===== Bo cuc portrait + text ===== */
      .intro3d-hero .intro3d-inner{padding-left:clamp(0px,3.4vw,64px)}
      .about-grid{display:grid;grid-template-columns:300px minmax(380px,608px) 1fr;gap:clamp(28px,3.2vw,48px);align-items:center}
      .about-portrait{position:relative;width:300px;aspect-ratio:2/3;margin:0;border-radius:16px;overflow:hidden;border:1px solid rgba(255,255,255,.14);box-shadow:0 30px 60px -24px rgba(0,0,0,.8),0 0 0 1px rgba(216,24,32,.18)}
      .about-portrait img{display:block;width:100%;height:100%;object-fit:cover;object-position:center top}
      .about-portrait:after{content:"";position:absolute;inset:55% 0 0;pointer-events:none;background:linear-gradient(to bottom,transparent,rgba(0,0,0,.55))}
      .intro3d-head{max-width:608px}
      .intro3d-head .eyebrow{margin-bottom:18px;padding-bottom:13px}
      .intro3d-head .eyebrow:after{width:48px}
      .intro3d-head h2{margin:0 0 10px;font-size:clamp(44px,4.6vw,70px);line-height:.98;letter-spacing:-.04em;color:#fff}
      .about-role{margin:0 0 34px;color:var(--red);font-size:14px;font-weight:700;letter-spacing:.24em;text-transform:uppercase}
      .intro3d-lead{font-size:clamp(17px,1.35vw,20px);margin-bottom:20px}
      .intro3d-body{max-width:none;font-size:clamp(14px,1.05vw,16px);line-height:1.8}
      .intro3d .service-list{margin-top:30px;width:calc(100% + 40px);max-width:none}
      @media(max-width:1280px){
        .about-grid{grid-template-columns:250px minmax(340px,1fr);gap:36px}
        .about-portrait{width:250px}
      }
      @media(max-width:1100px){
        .intro3d-hero .intro3d-inner{padding-left:0}
        .about-grid{grid-template-columns:200px 1fr;gap:32px;align-items:start}
        .about-portrait{width:200px}
        .intro3d-bg{opacity:.42}
      }
      @media(max-width:767px){
        .about-grid{display:flex;flex-direction:column;align-items:flex-start;gap:0}
        .about-grid .intro3d-head{display:contents}
        .about-grid .intro3d-head .eyebrow{order:1}
        .about-grid .intro3d-head h2{order:2;font-size:clamp(44px,11vw,64px)}
        .about-role{order:3;margin:0;font-size:12px;letter-spacing:.2em}
        .about-portrait-wrap{order:4;width:190px;margin:24px auto 28px}
        .about-grid{align-items:center}
        .about-grid .intro3d-head .eyebrow{text-align:center;align-self:stretch}
        .about-grid .intro3d-head .eyebrow:after{left:50%;transform:translateX(-50%)}
        .about-grid .intro3d-head h2,.about-role,.intro3d-lead,.intro3d-body{text-align:center;align-self:stretch}
        .intro3d-copy{align-self:stretch}
        .intro3d .service-list{justify-content:center;width:100%}
        .about-portrait{width:auto;margin:0}
        .intro3d-copy{order:5}
        .intro3d-bg{opacity:.24;background-position:72% center}
      }

      /* ===== Bo cuc moi 26/08: nen anh studio, chu cot trai ===== */
      .intro3d{padding:0}
      
      .intro3d-hero{position:relative;z-index:1;min-height:100svh;display:flex;align-items:center;padding:clamp(96px,11vh,150px) 0 clamp(72px,9vh,120px);background:transparent}
      .intro3d-hero:before{content:"";position:absolute;inset:0;pointer-events:none;background:linear-gradient(90deg,rgba(8,8,8,.98) 0%,rgba(8,8,8,.95) 32%,rgba(8,8,8,.8) 52%,rgba(8,8,8,.42) 74%,rgba(8,8,8,.1) 100%)}
      .intro3d-hero:after{content:"";position:absolute;inset:0;pointer-events:none;background:linear-gradient(180deg,rgba(8,8,8,.55) 0%,rgba(8,8,8,0) 24%,rgba(8,8,8,0) 72%,rgba(8,8,8,.8) 100%)}
      .intro3d-hero .intro3d-inner{position:relative;z-index:1}
      .intro3d-head{display:block;max-width:660px;gap:0}
      .intro3d-head .eyebrow{position:relative;margin:0 0 22px;padding-bottom:15px}
      .intro3d-head .eyebrow:after{content:"";position:absolute;left:0;bottom:0;width:58px;height:2px;background:var(--red)}
      .intro3d-head h2{max-width:none;margin:0 0 30px;font-size:clamp(46px,6.6vw,96px);line-height:.98;letter-spacing:-.05em}
      .intro3d-head h2 .t-line{display:block;color:#fff}
      .intro3d-head h2 .t-line span{color:var(--red)}
      .intro3d-lead{max-width:none;margin-bottom:24px}
      .intro3d-body{max-width:58ch;color:#c6c6c6}
      .intro3d{background:var(--ink)}
      .intro3d-gallery{position:relative;background:transparent;padding:clamp(80px,8vw,120px) 0 clamp(72px,8vw,112px);overflow:hidden}
      .intro3d-gallery:after{display:none}
      .intro3d-gallery:before{display:none}
      .intro3d-gallery .intro3d-inner{position:relative;z-index:1}
      .intro3d-gallery .intro3d-stage-wrap{margin-top:0}
      @media(max-width:900px){
        .intro3d-bg{-webkit-mask-image:linear-gradient(180deg,rgba(0,0,0,0) 0%,#000 12%,#000 40%,rgba(0,0,0,.35) 56%,rgba(0,0,0,0) 70%);mask-image:linear-gradient(180deg,rgba(0,0,0,0) 0%,#000 12%,#000 40%,rgba(0,0,0,.35) 56%,rgba(0,0,0,0) 70%)}
        .intro3d-bg{background-position:center top}.intro3d-bg.is-lazy-ready{background-image:url('/assets/cover-studio-mobile.jpg')}
        .intro3d-hero{padding:clamp(84px,12vh,120px) 0 clamp(64px,8vh,96px)}
        .intro3d-hero:before{background:linear-gradient(180deg,rgba(8,8,8,.7) 0%,rgba(8,8,8,.88) 42%,rgba(8,8,8,.96) 100%)}
        .intro3d-hero:after{display:none}
        .intro3d-hero{align-items:flex-end}
        .intro3d-head{max-width:none}
        .intro3d-head h2{font-size:clamp(42px,10.5vw,62px)}
        .intro3d-body{max-width:none}
      }
    
.intro3d .eyebrow { font-weight: 700; }
.intro3d .shell { width: min(100% - 48px,1380px); }
@media(max-width:760px) { .intro3d .shell { width: min(100% - 32px,1380px); } }
@media(max-width:580px) { .intro3d .shell { width: calc(100% - 28px); } }
/* Global reduced-motion rules set a tiny transition on every property.
   Geometry is measured synchronously: transforms/heights must settle immediately. */
@media(prefers-reduced-motion:reduce) {
  .intro3d-stage-wrap,.intro3d-stage-scaler,.intro3d-stage,.intro3d-card { transition: none!important; }
}