:root {
  --primary-blue: #2a6f97;
  --primary-blue-light: #3b9ac9;
  --primary-green: #2d8a6c;
  --primary-green-light: #4db68f;
  --light-bg: #f8fbfe;
  --card-bg: #ffffff;
  --border-color: #d0e2f0;
  --text-color: #2c3e50;
  --text-muted: #6c757d;
  --box-shadow: 0 4px 16px rgba(42, 111, 151, 0.08);
}

body {
  background-color: var(--light-bg);
  font-family: 'Nunito', -apple-system, BlinkMacSystemFont, sans-serif;
  min-height: 100vh;
  padding: 20px 0 60px;
  color: var(--text-color);
}

/* Navbar */
.navbar {
  background: rgba(255, 255, 255, 0.95);
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  position: fixed;
  top: 0;
  width: 100%;
  z-index: 1000;
}
.logo {
  font-weight: 800;
  color: var(--primary-blue);
}

/* Header Section */
.header-section {
  background: linear-gradient(to bottom, #f0f9ff, #e6f4ff);
  border-radius: 16px;
  margin-bottom: 2.5rem;
  padding: 3rem 1.5rem 2rem;
  box-shadow: var(--box-shadow);
  text-align: center;
}
.header-section h1 {
  font-weight: 700;
  color: var(--primary-blue);
  margin-bottom: 0.5rem;
  font-size: 2.3rem;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
}
.header-section h1 i {
  color: var(--primary-green);
}
.header-section p {
  color: var(--text-muted);
  font-size: 1.1rem;
  max-width: 800px;
  margin: 0 auto;
  font-weight: 500;
}

/* Cards */
.card {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 14px;
  box-shadow: var(--box-shadow);
  margin-bottom: 1.5rem;
  transition: transform 0.25s ease;
  color: var(--text-color);
}
.card:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.1);
}
.card-header {
  border-radius: 14px 14px 0 0 !important;
  padding: 1.25rem 1.5rem;
  font-weight: 600;
  font-size: 1.1rem;
  border-bottom: 1px solid var(--border-color);
  color: inherit;
}
.primary-card .card-header {
  background: linear-gradient(135deg, var(--primary-blue), var(--primary-blue-light));
  color: white;
}
.instruction-card .card-header {
  background: linear-gradient(135deg, var(--primary-green), var(--primary-green-light));
  color: white;
}

/* Form Controls */
.form-control,
.form-select {
  border-radius: 10px;
  border: 1px solid #cbd5e1;
  padding: 0.75rem 1rem;
  font-size: 0.95rem;
  background-color: var(--card-bg);
  color: var(--text-color);
  transition: border-color 0.3s ease;
}
.form-control:focus,
.form-select:focus {
  border-color: var(--primary-blue);
  box-shadow: 0 0 0 3px rgba(42, 111, 151, 0.15);
}
textarea.form-control {
  font-family: 'Consolas', monospace;
  min-height: 180px;
  resize: vertical;
}

/* Buttons */
.btn-primary {
  background: linear-gradient(135deg, var(--primary-blue), var(--primary-blue-light));
  border: none;
  padding: 0.75rem 1.5rem;
  font-weight: 600;
  border-radius: 10px;
  transition: all 0.3s ease;
  color: white;
}
.btn-primary:hover {
  opacity: 0.95;
  transform: translateY(-1px);
  box-shadow: 0 4px 10px rgba(42, 111, 151, 0.3);
}
.btn-primary:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}
.btn-outline-secondary {
  border: 1px solid var(--border-color);
  border-radius: 10px;
  padding: 0.5rem 1rem;
  font-size: 0.85rem;
  color: var(--text-muted);
}
.btn-outline-secondary:hover {
  background-color: #f1f5f9;
  color: var(--primary-blue);
}
.btn-export {
  background: linear-gradient(135deg, var(--primary-green), var(--primary-green-light));
  border: none;
  padding: 0.75rem 1.5rem;
  font-weight: 600;
  border-radius: 10px;
  color: white;
  transition: all 0.3s ease;
}
.btn-export:hover {
  opacity: 0.95;
  transform: translateY(-1px);
  box-shadow: 0 4px 10px rgba(46, 139, 87, 0.3);
}

/* Tables */
.data-table th {
  background-color: #f0f7ff;
  color: var(--primary-blue);
  font-weight: 600;
  padding: 0.75rem;
}
.data-table td {
  padding: 0.75rem;
  vertical-align: middle;
  color: var(--text-color);
}
.results-container {
  max-height: 400px;
  overflow-y: auto;
  border: 1px solid var(--border-color);
  border-radius: 10px;
}
.empty-state {
  opacity: 0.85;
}
.empty-icon i {
  color: #a8dadc;
}

/* Layouts */
.sampling-method-select {
  max-width: 250px;
}
.textarea-section {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  margin-top: 1rem;
}
.textarea-group { margin-bottom: 0; }
.textarea-label {
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--primary-blue);
  display: block;
}
.dummy-data-btn {
  font-size: 0.75rem;
  padding: 0.25rem 0.5rem;
}
.audit-inputs-row {
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem;
  align-items: end;
}
.audit-input-group {
  flex: 1;
  min-width: 240px;
}

/* Tabs */
.nav-tabs {
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 1.5rem;
}
.nav-tabs .nav-link {
  border: none;
  padding: 0.75rem 1.25rem;
  font-weight: 600;
  color: var(--text-muted);
  margin-bottom: -1px;
}
.nav-tabs .nav-link:hover,
.nav-tabs .nav-link.active {
  color: var(--primary-blue);
}
.nav-tabs .nav-link.active {
  border-bottom: 2px solid var(--primary-blue);
}
.tab-content {
  padding: 1.5rem;
  background: var(--card-bg);
  border-top: 1px solid var(--border-color);
  border-radius: 0 0 14px 14px;
  color: var(--text-color);
}
.summary-detail-item {
  display: flex;
  justify-content: space-between;
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--border-color);
}
.summary-detail-item:last-child {
  border-bottom: none;
}
.summary-detail-label {
  font-weight: 600;
  color: var(--text-muted);
}
.summary-detail-value {
  color: var(--primary-blue);
  font-weight: 600;
}

/* Modals */
.modal-content {
  border-radius: 14px;
  border: none;
  box-shadow: var(--box-shadow);
  color: var(--text-color);
}
.modal-header {
  border-radius: 14px 14px 0 0 !important;
  padding: 1.25rem 1.5rem;
}
.error-modal .modal-header {
  background: linear-gradient(135deg, #e53e3e, #c53030);
  color: white;
}
.error-details {
  background: #fff5f5;
  border-left: 4px solid #e53e3e;
  padding: 1rem;
  border-radius: 8px;
  margin: 1rem 0;
  color: var(--text-color);
}

/* Responsive */
@media (max-width: 992px) {
  .audit-inputs-row { flex-direction: column; }
  .audit-input-group { min-width: auto; }
}
@media (max-width: 768px) {
  .textarea-section { grid-template-columns: 1fr; }
  textarea.form-control { min-height: 150px; }
  .header-section h1 { font-size: 1.8rem; }
}