body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: #f4f6f8;
  color: #1f2933;
}

.app-container {
  display: flex;
  min-height: 100vh;
}

.sidebar {
  width: 240px;
  background: #2c3e50;
  color: white;
  padding: 20px;
  box-sizing: border-box;
}

.sidebar-brand {
  text-align: center;
  margin-bottom: 28px;
}

.sidebar-brand img {
  width: 110px;
  margin-bottom: 10px;
}

.sidebar-brand h1 {
  font-size: 1.35rem;
  margin: 0;
}

.sidebar-nav {
  display: grid;
  gap: 10px;
}

.nav-button {
  width: 100%;
  padding: 12px;
  border: none;
  border-radius: 8px;
  background: #34495e;
  color: white;
  cursor: pointer;
  text-align: left;
}

.nav-button:hover:not(:disabled),
.nav-button.active {
  background: #0a9bb0;
}

.nav-button:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.main-content {
  flex: 1;
  overflow-y: auto;
}

.patient-header {
  background: white;
  padding: 18px;
  border-bottom: 1px solid #ddd;
}

.patient-header h2 {
  margin-top: 0;
}

.patient-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(140px, 1fr));
  gap: 16px;
  align-items: end;
}

.weight-field {
  max-width: 140px;
}

.procedure-field {
  grid-column: span 2;
}

label {
  font-weight: 600;
  font-size: 0.9rem;
}

input,
select {
  display: block;
  width: 100%;
  margin-top: 6px;
  padding: 7px;
  box-sizing: border-box;
}

.button-row {
  display: flex;
  justify-content: space-between;
  margin-top: 22px;
}

button {
  padding: 10px 18px;
  border: none;
  border-radius: 7px;
  cursor: pointer;
}

.page {
  padding: 18px 0;
}

.content-card {
  background: white;
  padding: 24px;
  border-radius: 12px;
}

.calculator-page {
  display: grid;
  gap: 20px;
  padding: 0 18px;
}

.calculator-header {
  background: white;
  padding: 24px;
  border-radius: 12px;
}

.calculator-header h2 {
  margin: 0 0 8px;
}

.calculator-header p {
  margin: 0;
  color: #52616b;
}

.calculator-grid {
  display: grid;
  grid-template-columns: minmax(280px, 1fr) minmax(280px, 1fr);
  gap: 20px;
}

.calculator-card {
  background: white;
  padding: 18px;
  border-radius: 12px;
}

.calculator-card h3 {
  margin-top: 0;
}

.form-grid {
  display: grid;
  gap: 12px;
}

.results-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(140px, 1fr));
  gap: 12px;
}

.result-tile {
  background: #f4f6f8;
  padding: 16px;
  border-radius: 10px;
}

.result-label,
.result-unit {
  display: block;
  color: #52616b;
  font-size: 0.85rem;
}

.result-tile strong {
  display: block;
  font-size: 1.8rem;
  margin: 8px 0 4px;
}

.form-row {
  display: grid;
  gap: 12px;
}

.form-row-compact {
  grid-template-columns: repeat(2, minmax(120px, 1fr));
}

@media (max-width: 520px) {
  .form-row-compact {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 900px) {
  .calculator-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 520px) {
  .results-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 900px) {
  .patient-grid {
    grid-template-columns: repeat(2, minmax(140px, 1fr));
  }

  .procedure-field {
    grid-column: span 2;
  }
}

@media (max-width: 520px) {
  .patient-grid {
    grid-template-columns: 1fr;
  }

  .weight-field {
    max-width: none;
  }

  .procedure-field {
    grid-column: span 1;
  }
}