body {
  background: #0a0a0a;
  color: #e0ffff;
  font-family: 'Poppins', sans-serif;
  height: 100vh;
  margin: 0;

  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.title {
  color: #00ffff;
  text-shadow: 0 0 18px #00ffff;
  margin-bottom: 20px;
  font-size: 28px;
}

.calculator {
  background: #0f0f0f;
  border: 1px solid #00ffff33;
  border-radius: 18px;
  padding: 30px 25px;
  width: 340px;
  box-shadow:
    0 0 15px #00ffff44,
    inset 0 0 10px #00ffff22;
}

.field {
  margin-bottom: 14px;
}

label {
  font-size: 13px;
  color: #bfffff;
  display: block;
  margin-bottom: 4px;
}

input {
  width: 100%;
  padding: 10px;
  background: #0b0b0b;
  border: 1px solid #00ffff22;
  border-radius: 12px;
  color: #00ffff;
  text-align: right;
}

.rule-title {
  margin-top: 10px;
  font-size: 14px;
  color: #00ffff;
  text-shadow: 0 0 6px #00ffff;
}

/* Visible rule buttons */
.rule-options {
  display: flex;
  justify-content: space-between;
  margin: 12px 0;
  gap: 10px;
}

.rule-btn {
  flex: 1;
  padding: 10px 0;
  border-radius: 12px;
  border: 1px solid #00ffff55;
  background: #020c0c;
  color: #00ffff;
  font-weight: bold;
  font-size: 14px;
  cursor: pointer;
  box-shadow: 0 0 8px #00ffff44;
  transition: 0.2s ease-in-out;
}

.rule-btn:hover {
  box-shadow: 0 0 15px #00ffffaa;
  transform: translateY(-2px);
}

/* Active state */
.rule-btn.active {
  background: linear-gradient(135deg, #00ffff, #00ffaa);
  color: #002020;
  box-shadow: 0 0 20px #00ffffcc;
}

/* Calculate button */
.calc-btn {
  width: 100%;
  margin-top: 8px;
  padding: 14px;
  border-radius: 14px;
  border: none;
  background: #00ffff;
  color: #001414;
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  box-shadow: 0 0 25px #00ffff99;
  transition: 0.2s ease;
}

.calc-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 35px #00ffffcc;
}

.results {
  text-align: center;
  margin-top: 18px;
}

.pass {
  color: #00ff88;
  text-shadow: 0 0 10px #00ff88;
  font-weight: bold;
}

.fail {
  color: #ff004c;
  text-shadow: 0 0 10px #ff004c;
  font-weight: bold;
}