:root{
  /* Overall page width */
  --shell-width:1500px;

  /* Distance from browser edge to page frame */
  --site-frame:clamp(20px,4.2vw,120px);

  /* Shared frame colour */
  --frame:rgba(224,233,246,0.15);
}

/* Main page shell */
.shell{
  position:relative;
  width:calc(100vw - (var(--site-frame) * 2));
  max-width:var(--shell-width);
  margin:0 auto;
  border-left:1px solid var(--frame);
  border-right:1px solid var(--frame);
}

/* Fixed vertical frame lines */
.shell-frame{
  position:fixed;
  inset:0;
  z-index:600;
  pointer-events:none;
  width:calc(100vw - (var(--site-frame) * 2));
  max-width:var(--shell-width);
  margin:0 auto;
  border-left:1px solid var(--frame);
  border-right:1px solid var(--frame);
}

/* Inner shell helper */
.shell-inner{
  width:calc(100vw - (var(--site-frame) * 2));
  max-width:var(--shell-width);
  margin:0 auto;
}

/* Desktop refinement */
@media (min-width:901px){
  .wrap{
    max-width:1440px;
  }

  .nav{
    height:64px;
  }

  .logo-full{
    height:30px;
  }

  .nav-right .lnk{
    font-size:14px;
  }

  .nav-cta{
    height:40px;
    min-width:138px;
    padding:0 16px;
    font-size:13px;
  }

  .btn{
    min-width:190px;
    padding:15px 22px;
    font-size:14px;
  }

  .btn-lg{
    padding:15px 22px;
    font-size:14px;
  }
}

/* Mobile */
@media(max-width:600px){
  .shell{
    width:100%;
    border-left:none;
    border-right:none;
  }

  .shell-frame{
    display:none;
  }

  .shell-inner{
    width:100%;
  }
}