/* Basic, modern UI for EFS */
.efs-shell{max-width:900px;margin:24px auto;padding:16px}
.efs-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:12px}
.efs-title{font-weight:700;font-size:1.25rem}
.efs-stage{perspective:1600px;height:360px;display:flex;justify-content:center;align-items:center}
.efs-card{position:relative;width:min(680px,92vw);height:320px;transform-style:preserve-3d;transition:transform .6s cubic-bezier(.2,.8,.2,1)}
.efs-card.efs-flipped{transform:rotateY(180deg)}
.efs-face{position:absolute;inset:0;border-radius:18px;box-shadow:0 10px 35px rgba(0,0,0,.12);padding:24px;background:#fff;backface-visibility:hidden;display:flex;justify-content:center;align-items:center;text-align:center;overflow:hidden}
.efs-face h1,.efs-face h2,.efs-face h3{margin-top:0}
.efs-back{transform:rotateY(180deg)}
.efs-controls{margin-top:16px;display:grid;gap:10px}
.efs-btn{padding:10px 14px;border-radius:12px;border:1px solid #d0d6dd;background:#f7f9fc;cursor:pointer}
.efs-btn:hover{background:#eef3f9}
.efs-btn:active{transform:translateY(1px)}
.efs-primary{background:#1d7cf2;color:#fff;border-color:#1d7cf2}
.efs-input{display:flex;gap:8px;justify-content:center}
#efs-answer{padding:10px 12px;border-radius:10px;border:1px solid #c8ced6;min-width:300px}
.efs-img{max-width:100%;max-height:100%;object-fit:contain;border-radius:12px}
.efs-stats{opacity:.8;font-size:.9rem}
.efs-hint{min-height:24px;color:#4b5563}
@media (prefers-color-scheme: dark){
  .efs-face{background:#121318;color:#e5e7eb;border:1px solid #262a33}
  .efs-btn{background:#181b22;border-color:#2a2f3a;color:#e5e7eb}
  .efs-btn:hover{background:#1e2430}
  #efs-answer{background:#0f1218;color:#e5e7eb;border-color:#303644}
}