*{box-sizing:border-box;}
  body{margin:0; background:#F6E9E4; color:#5A2A33; font-family:'Literata',serif; line-height:1.7;}
  .wrap{max-width:680px; margin:0 auto;}

  /* PHONG THƯ MỞ */
  .envelope-stage{min-height:100vh; display:flex; align-items:center; justify-content:center; padding:40px 20px; background:radial-gradient(ellipse at 50% 20%, #FCEDE8, #F6E9E4);}
  .envelope{width:100%; max-width:340px; position:relative;}
  .env-body{background:#fff; border-radius:4px; box-shadow:0 20px 50px rgba(90,42,51,.2); padding:26px 24px 30px; text-align:center; position:relative; overflow:hidden;}
  .env-flap{
    position:absolute; top:0; left:0; right:0; height:0; border-left:170px solid transparent; border-right:170px solid transparent;
    border-top:110px solid #7A2E3A; transform-origin:top; transition:transform .8s ease; z-index:2;
  }
  .envelope.open .env-flap{transform:rotateX(180deg);}
  .env-seal{position:absolute; top:60px; left:50%; transform:translateX(-50%); width:44px; height:44px; border-radius:50%; background:#C9A24B; color:#5A2A33; font-family:'Cormorant Garamond',serif; font-size:12px; display:flex; align-items:center; justify-content:center; z-index:3; box-shadow:0 4px 10px rgba(0,0,0,.2); cursor:pointer;}
  .envelope.open .env-seal{display:none;}
  .env-content{opacity:0; transition:opacity .6s ease .3s;}
  .envelope.open .env-content{opacity:1;}
  .env-content .eyebrow{font-size:11px; letter-spacing:.25em; color:#C9A24B; margin-bottom:10px;}
  .env-content h1{font-family:'Cormorant Garamond',serif; font-style:italic; font-weight:600; font-size:34px; margin:0 0 8px;}
  .env-content p{font-size:14px; color:#8A5A62; margin:0 0 16px;}
  .env-hint{font-size:12px; color:#B08A80; margin-top:14px;}

  .section{padding:50px 24px 8px; max-width:680px; margin:0 auto;}
  .section h2{font-family:'Cormorant Garamond',serif; font-style:italic; font-weight:600; font-size:28px; text-align:center; margin:0 0 4px;
    background:linear-gradient(90deg,#C9A24B,#E8CE8A,#C9A24B); -webkit-background-clip:text; background-clip:text; color:transparent; background-size:200% auto; animation:shimmer 4s linear infinite;}
  @keyframes shimmer{to{background-position:200% center;}}
  .section .sub{text-align:center; font-size:13.5px; color:#8A5A62; margin:0 0 28px;}

  /* SÁCH ẢNH LẬT TRANG */
  .book{position:relative; max-width:420px; margin:0 auto;}
  .pages{display:flex; overflow-x:auto; scroll-snap-type:x mandatory; border-radius:6px; box-shadow:0 16px 40px rgba(90,42,51,.18);}
  .page{flex:0 0 100%; scroll-snap-align:center; background:#fff; padding:14px 14px 34px; position:relative;}
  .page img{width:100%; height:230px; object-fit:cover; border-radius:2px;}
  .page figcaption{text-align:center; font-family:'Cormorant Garamond',serif; font-style:italic; font-size:15px; margin-top:10px;}
  .page-num{position:absolute; bottom:10px; right:16px; font-size:11px; color:#B08A80;}
  .book-hint{text-align:center; font-size:12px; color:#B08A80; margin-top:10px;}

  .see-full{text-align:center; margin:18px 0 0;}
  .see-full a{font-family:'Cormorant Garamond',serif; font-style:italic; font-size:15px; color:#7A2E3A; text-decoration:none; border-bottom:1px solid #C9A24B;}

  .notes{max-width:480px; margin:0 auto;}
  .note{background:#fff; border-radius:4px; padding:18px 20px; margin-bottom:14px; box-shadow:0 10px 24px rgba(90,42,51,.08); position:relative;}
  .note::before{content:"❝"; position:absolute; top:8px; left:12px; font-size:24px; color:#F0DCD2; font-family:Georgia,serif;}
  .note p{margin:0 0 8px; font-size:14.5px; padding-left:14px;}
  .note cite{font-family:'Cormorant Garamond',serif; font-style:italic; font-size:13.5px; color:#C9A24B; display:block; text-align:right;}

  .share{margin:44px 24px 30px; padding:36px 24px; text-align:center; border-radius:4px; background:#7A2E3A; color:#F6E9E4; border:1px solid #C9A24B;}
  .share h2{font-family:'Cormorant Garamond',serif; font-style:italic; font-size:26px; margin:0 0 6px; color:#E8CE8A;}
  .share p{font-size:13.5px; margin:0 0 18px; color:#E4C2C8;}
  #qrcode{background:#fff; display:inline-block; padding:8px; margin-bottom:14px;}
  .link-row{display:flex; justify-content:center; gap:8px; flex-wrap:wrap; font-size:13px;}
  .link-row code{background:rgba(232,206,138,.15); padding:6px 12px; color:#E8CE8A;}
  .link-row button{background:#E8CE8A; color:#5A2A33; border:none; padding:6px 14px; font-size:12.5px; font-weight:600; cursor:pointer;}

  .foot{text-align:center; font-size:12px; color:#B08A80; padding:0 20px 40px;}