.card-perspective{perspective:1200px;perspective-origin:50%}.card-object{position:relative;transform-style:preserve-3d;will-change:transform;width:450px;height:630px}@media (max-width:768px){.card-object{width:250px;height:350px}}.card-face{position:absolute;inset:0;backface-visibility:hidden;-webkit-backface-visibility:hidden;overflow:hidden;transform:translateZ(1px)}.card-face:after{content:"";position:absolute;inset:0;background-image:url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.65' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.03'/%3E%3C/svg%3E");opacity:.5;pointer-events:none}.card-face-back{transform:rotateY(180deg) translateZ(1px)}.card-left-panel{width:50%;opacity:0}.card-left-panel,.card-right-panel{position:absolute;left:0;top:0;height:100%;transform-style:preserve-3d}.card-right-panel{width:100%;transform-origin:left center;will-change:transform}.card-shadow{position:absolute;bottom:-8px;left:4px;right:4px;height:20px;background:radial-gradient(ellipse at center,rgba(0,0,0,.15) 0,transparent 70%);border-radius:50%;filter:blur(8px);will-change:opacity,transform}.envelope-wrapper{position:relative;width:720px;padding:28px 20px}@media (max-width:768px){.envelope-wrapper{width:400px;padding:18px 14px}}.envelope-card-behind{position:absolute;width:80%;height:80%;left:50%;top:36%;transform:translate(-50%,-50%) rotate(-6deg);z-index:0;border-radius:4px;overflow:hidden;box-shadow:0 2px 8px rgba(0,0,0,.08)}.envelope{position:relative;transform-style:preserve-3d;will-change:transform;width:100%;height:510px;z-index:1}@media (max-width:768px){.envelope{height:283px}}.envelope-face{position:absolute;inset:0;backface-visibility:hidden;-webkit-backface-visibility:hidden;border-radius:4px;overflow:hidden}.envelope-face-back{transform:rotateY(180deg)}.envelope-flap{position:absolute;top:0;left:0;right:0;height:40%;clip-path:polygon(0 0,50% 100%,100% 0);transform-origin:top center}.envelope-stamp{position:absolute;top:24px;right:24px}.envelope-sender-address{position:absolute;top:24px;left:36px;font-size:16px;line-height:1.4}.envelope-recipient-address{position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);text-align:center;font-size:21px;line-height:1.5}@media (max-width:768px){.envelope-sender-address{font-size:10px;top:14px;left:18px}.envelope-recipient-address{font-size:13px}.envelope-stamp{top:14px;right:14px}}@media (prefers-reduced-motion:reduce){.card-object,.card-right-panel,.card-shadow,.envelope{will-change:auto;transition:opacity .15s ease!important;animation:none!important}}