.stdd-box{max-width:400px;margin:40px auto;padding:20px;background:#fff;border-radius:15px;box-shadow:0 10px 30px rgba(0,0,0,0.1);text-align:center;font-family:Arial}
.stdd-box input{width:100%;padding:10px;margin:8px 0;border-radius:10px;border:1px solid #ccc}
button{width:100%;padding:10px;background:#2563eb;color:#fff;border:none;border-radius:10px;cursor:pointer}
#st_result{margin-top:15px;font-size:18px;font-weight:bold}
.stdd-grid{margin-top:10px;text-align:left}