/* --- General Styles --- */
:root {
  --primary-color: #007bff;
  --primary-light: #e6f2ff;
  --secondary-color: #4a5568;
  --background-color: #ffffff;
  --border-color: #dee2e6;
  --text-color: #212529;
  --label-color: #495057;
  --bmr-color: #ffc107;
  --activity-color: #28a745;
  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --border-radius: 8px;
  --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
}

.ruck-calculator-container {
  font-family: var(--font-family);
  background-color: var(--container-bg);
  padding: 2rem;
  border-radius: var(--border-radius);
  max-width: 800px;
  margin: 2rem auto;
  box-shadow: var(--box-shadow);
  color: var(--text-color);
}

/* --- Form Styles --- */
.ruck-form {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.form-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 1rem;
  margin-bottom: -0.5rem;
}

.form-header h2 {
  margin: 0;
  color: var(--primary-color);
  font-size: 1.75rem;
}

.unit-switcher {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.toggle-container {
  display: flex;
  border: 1px solid var(--border-color);
  border-radius: 16px;
  overflow: hidden;
}

.unit-btn {
  background-color: transparent;
  border: none;
  padding: 0.4rem 1rem;
  cursor: pointer;
  font-weight: 500;
  transition: background-color 0.2s, color 0.2s;
  color: var(--secondary-color);
}

.unit-btn.active {
  background-color: var(--primary-color);
  color: white;
}

fieldset {
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: 1.5rem;
}

legend {
  font-weight: 600;
  padding: 0 0.5rem;
  color: var(--secondary-color);
}

.form-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.25rem;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.form-group label {
  font-weight: 500;
  font-size: 0.9rem;
  color: var(--label-color);
}

.form-group input,
.form-group select {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  font-size: 1rem;
  transition: border-color 0.2s, box-shadow 0.2s;
  background-color: var(--background-color);
}

.form-group input:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px var(--primary-light);
}

.input-with-unit {
  position: relative;
}

.input-with-unit input {
  padding-right: 3.5rem; /* Space for unit */
}

.unit-label {
  position: absolute;
  right: 1rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--secondary-color);
  font-weight: 500;
}

.input-group-split {
  display: flex;
  gap: 0.5rem;
}

.imperial-only {
  display: none;
}

/* --- Tooltip --- */
.tooltip-trigger {
  display: inline-block;
  background-color: var(--secondary-color);
  color: white;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  text-align: center;
  font-size: 12px;
  line-height: 16px;
  cursor: help;
  position: relative;
  margin-left: 4px;
}

.tooltip-trigger::after {
  content: attr(data-tooltip);
  position: absolute;
  bottom: 125%;
  left: 50%;
  transform: translateX(-50%);
  background-color: var(--secondary-color);
  color: white;
  padding: 0.5rem;
  border-radius: 6px;
  width: 220px;
  text-align: left;
  font-size: 0.8rem;
  line-height: 1.4;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.2s, visibility 0.2s;
  z-index: 10;
}

.tooltip-trigger:hover::after {
  opacity: 1;
  visibility: visible;
}


/* --- Buttons --- */
.form-actions {
  display: flex;
  gap: 1rem;
  justify-content: flex-end;
}

.submit-btn, .reset-btn {
  padding: 0.75rem 1.5rem;
  font-size: 1rem;
  font-weight: 600;
  border-radius: 6px;
  border: none;
  cursor: pointer;
  transition: background-color 0.2s, transform 0.1s;
}

.submit-btn {
  background-color: var(--primary-color);
  color: white;
}

.submit-btn:hover {
  background-color: #0056b3;
}

.submit-btn:active {
  transform: scale(0.98);
}

.reset-btn {
  background-color: var(--border-color);
  color: var(--secondary-color);
}

.reset-btn:hover {
  background-color: #c8d0d8;
}

/* --- Results Section --- */
.results-container {
  margin-top: 2rem;
  padding: 2rem;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  background-color: var(--background-color);
  animation: fadeIn 0.5s ease-in-out;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

.results-container h3 {
  text-align: center;
  color: var(--primary-color);
  margin-top: 0;
  margin-bottom: 1.5rem;
  font-size: 1.5rem;
}

.results-grid {
  display: grid;
  grid-template-columns: 1fr 1.5fr;
  gap: 2rem;
  align-items: center;
  margin-bottom: 2rem;
}

.results-main {
  text-align: center;
  background-color: var(--primary-light);
  padding: 1.5rem;
  border-radius: var(--border-radius);
}

.results-main p {
  margin: 0 0 0.5rem 0;
  font-weight: 500;
  color: var(--secondary-color);
}

.total-calories {
  font-size: 3.5rem;
  font-weight: 700;
  color: var(--primary-color);
  line-height: 1;
}

.results-main span {
  font-size: 1.25rem;
  color: var(--secondary-color);
}

.results-details {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  text-align: center;
}

.detail-item h4 {
  margin: 0 0 0.5rem 0;
  font-size: 1rem;
  color: var(--label-color);
  font-weight: 500;
}

.detail-item p {
  margin: 0;
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-color);
}

/* --- Chart --- */
.chart-container {
  margin-bottom: 1.5rem;
}

.chart-container h4 {
  text-align: center;
  font-weight: 600;
  color: var(--secondary-color);
  margin-bottom: 1.5rem;
}

.chart {
  display: flex;
  justify-content: center;
  align-items: flex-end;
  gap: 2rem;
  height: 150px;
  width: 100%;
  max-width: 300px;
  margin: 0 auto;
}

.chart-bar-wrapper {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  flex: 1;
}

.chart-bar {
  width: 100%;
  border-radius: 6px 6px 0 0;
  position: relative;
  transition: height 0.5s ease-out;
}

.bmr-bar { background-color: var(--bmr-color); }
.activity-bar { background-color: var(--activity-color); }

.bar-label {
  position: absolute;
  top: -25px;
  left: 50%;
  transform: translateX(-50%);
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--text-color);
  background-color: rgba(255,255,255,0.7);
  padding: 2px 6px;
  border-radius: 4px;
}

.chart-bar-wrapper p {
  font-size: 0.9rem;
  font-weight: 500;
  margin: 0;
}

.chart-legend {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  margin-top: 1.5rem;
  font-size: 0.9rem;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
}

.bmr-dot { background-color: var(--bmr-color); }
.activity-dot { background-color: var(--activity-color); }


/* --- Insight Box --- */
.insight-box {
  background-color: var(--primary-light);
  border-left: 5px solid var(--primary-color);
  padding: 1rem 1.5rem;
  border-radius: 0 var(--border-radius) var(--border-radius) 0;
}

.insight-box h4 {
  margin: 0 0 0.5rem 0;
  color: var(--primary-color);
}

.insight-box p {
  margin: 0;
  line-height: 1.6;
}

/* --- Responsive Design --- */
@media (max-width: 768px) {
  .ruck-calculator-container {
    padding: 1.5rem;
  }
  .form-header {
    flex-direction: column;
    align-items: flex-start;
  }
  .form-grid {
    grid-template-columns: 1fr;
  }
  .results-grid {
    grid-template-columns: 1fr;
  }
  .results-details {
    grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
  }
  .total-calories {
    font-size: 3rem;
  }
}