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

body {
  background: #f2f5f9;
  margin: 0;
  padding: 20px;
}

.container {
  max-width: 420px;
  margin: auto;
  background: #ffffff;
  padding: 25px;
  border-radius: 15px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

h1 {
  text-align: center;
  margin-bottom: 20px;
  font-size: 2rem;
  color: #000;
}

label {
  display: block;
  margin-top: 15px;
  font-weight: bold;
  font-size: 0.9rem;
}

select {
  width: 100%;
  padding: 12px;
  margin-top: 6px;
  font-size: 16px;
  border-radius: 6px;
  border: 1px solid #ccc;
  background-color: #fff;
}

/* Input Group with Units inside */
.input-group {
  position: relative;
  display: flex;
  align-items: center;
  margin-top: 6px;
}

.input-group input {
  width: 100%;
  padding: 12px 60px 12px 12px;
  font-size: 16px;
  border-radius: 6px;
  border: 1px solid #ccc;
  outline: none;
}

.input-group input:focus {
  border-color: #007bff;
}

/* Standard Unit style inside the input field */
.unit-label {
  position: absolute;
  right: 15px;
  color: #777;
  font-size: 1rem;
  font-weight: normal;
  pointer-events: none;
  user-select: none;
}

/* Button Group Layout */
.button-group {
  display: flex;
  gap: 10px;
  margin-top: 20px;
}

button {
  flex: 1;
  padding: 14px;
  font-size: 1rem;
  font-weight: bold;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: opacity 0.2s;
}

button:active {
  opacity: 0.8;
}

.btn-calc {
  background: #007bff;
  color: #ffffff;
  flex: 2; /* Calculate button slightly wider for importance */
}

.btn-reset {
  background: #6c757d;
  color: #ffffff;
}

.btn-save {
  background: #198754;
  color: #ffffff;
  width: 100%;
}

.result-actions {
  display: none;
  margin-top: 15px;
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.7;
}

/* Result Box Layout */
.result {
  margin-top: 25px;
  padding: 25px 20px;
  border-radius: 15px;
  display: none;
  text-align: center;
}

.result-header {
  font-size: 1.6rem;
  font-weight: 800;
  margin-bottom: 5px;
  text-transform: uppercase;
}

.result-comparison {
  font-size: 1.1rem;
  opacity: 0.8;
  margin-bottom: 10px;
}

.result-big-number {
  font-size: 6rem;
  font-weight: 900;
  line-height: 1;
  margin: 10px 0;
}

.result-footer {
  font-size: 1rem;
  margin-top: 10px;
  font-weight: 500;
  line-height: 1.4;
}

/* Status Colors */
.underweight {
  background: #e3f2fd;
  color: #0d47a1;
}
.normal {
  background: #e8f5e9;
  color: #1b5e20;
}
.overweight {
  background: #fff9c4;
  color: #827717;
}
.obese {
  background: #ffebee;
  color: #b71c1c;
}

.error {
  margin-top: 15px;
  color: #dc3545;
  font-weight: bold;
  text-align: center;
  min-height: 1.2em;
}

@media (max-width: 480px) {
  .container {
    padding: 20px;
  }
  .result-big-number {
    font-size: 4.5rem;
  }
}