body {
  font-family: system-ui, Arial, sans-serif;
  background: #0b1220;
  color: #eaf0ff;
  display: grid;
  place-items: center;
  height: 100vh;
  margin: 0;
}

.card {
  width: min(420px, 92vw);
  background: #121b2f;
  border: 1px solid #223154;
  border-radius: 16px;
  padding: 22px;
  box-shadow: 0 12px 30px rgba(0,0,0,0.35);
}

h1 { margin: 0 0 14px; font-size: 22px; }
.row { margin: 12px 0; }
label { display: block; margin-bottom: 6px; opacity: 0.9; }

input {
  width: 100%;
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid #2a3a62;
  background: #0f172a;
  color: #eaf0ff;
  outline: none;
}

button {
  width: 100%;
  margin-top: 14px;
  padding: 10px 12px;
  border: 0;
  border-radius: 10px;
  background: #3b82f6;
  color: white;
  font-weight: 600;
  cursor: pointer;
}

button:hover { filter: brightness(1.05); }
.msg { margin-top: 10px; color: #ffb4b4; min-height: 1.2em; }

.result {
  margin-top: 12px;
  padding: 12px;
  border-radius: 12px;
  border: 1px solid #2a3a62;
  background: #0f172a;
}

.hidden { display: none; }
.k { opacity: 0.8; margin-right: 6px; }