* {
  box-sizing: border-box;
  font-family: Arial, sans-serif;
}

body {
  margin: 0;
  background: #f6f7fb;
  color: #111;
}

.container {
  max-width: 560px;
  margin: 48px auto;
  padding: 18px;
}

.header h1 {
  margin: 0 0 6px;
}

.subtitle {
  margin: 0;
  color: #555;
}

.card {
  background: #fff;
  padding: 18px;
  margin-top: 18px;
  border-radius: 14px;
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.08);
}

.field {
  margin-bottom: 14px;
}

label {
  display: block;
  margin-bottom: 6px;
  font-weight: 700;
}

input {
  width: 100%;
  padding: 12px;
  border-radius: 12px;
  border: 1px solid #cfcfcf;
  font-size: 16px;
  outline: none;
}

input:focus {
  border-color: #2f6fed;
}

.btn {
  width: 100%;
  padding: 12px;
  border: none;
  border-radius: 12px;
  margin-top: 10px;
  background: #2f6fed;
  color: #fff;
  font-size: 16px;
  cursor: pointer;
}

.btn.secondary {
  background: #e7e7e7;
  color: #222;
}

.btn:hover {
  opacity: 0.95;
}

.error {
  margin-top: 14px;
  padding: 12px;
  border-radius: 12px;
  background: #ffe8ec;
  color: #b00020;
}

.result {
  margin-top: 18px;
  background: #fff;
  padding: 18px;
  border-radius: 14px;
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.08);
}

.result-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 6px;
}

.tip {
  margin-top: 12px;
  color: #444;
}

.hidden {
  display: none;
}

/* BMI COLOR INDICATOR BAR */
.bmi-bar {
  margin-top: 16px;
}

.bmi-scale {
  position: relative;
  height: 14px;
  border-radius: 10px;
  overflow: hidden;

  /* Underweight (blue) | Normal (green) | Overweight (orange) | Obese (red) */
  background: linear-gradient(
    to right,
    #3b82f6 0%,
    #3b82f6 25%,
    #22c55e 25%,
    #22c55e 50%,
    #f59e0b 50%,
    #f59e0b 75%,
    #ef4444 75%,
    #ef4444 100%
  );
}

.bmi-indicator {
  position: absolute;
  top: -6px;
  left: 0%;
  width: 4px;
  height: 26px;
  background: #111;
  border-radius: 4px;
  transition: left 0.35s ease;
}

.label {
  position: absolute;
  top: 18px;
  font-size: 11px;
  color: #444;
  white-space: nowrap;
}

.label.left {
  left: 0%;
}

.label.mid-left {
  left: 25%;
  transform: translateX(-50%);
}

.label.mid-right {
  left: 50%;
  transform: translateX(-50%);
}

.label.right {
  left: 75%;
  transform: translateX(-50%);
}

.footer {
  margin-top: 32px;
  padding: 16px;
  text-align: center;
  color: #666;
  font-size: 14px;
}

.footer p {
  margin: 0;
}