:root {
  --primary: #8B1A1A;
  --primary-light: #A52A2A;
  --primary-dark: #6B0F0F;
  --accent: #C41E3A;
  --bg: #FAFAFA;
  --card-bg: #FFFFFF;
  --text: #1A1A2E;
  --text-muted: #6B7280;
  --border: #E5E7EB;
  --success: #059669;
  --success-bg: #ECFDF5;
  --warning: #D97706;
  --warning-bg: #FFFBEB;
  --danger: #DC2626;
  --danger-bg: #FEF2F2;
  --info: #2563EB;
  --info-bg: #EFF6FF;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
  --radius: 12px;
  --radius-sm: 8px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  min-height: 100vh;
}

/* ---- NAV ---- */
.nav {
  background: var(--card-bg);
  border-bottom: 1px solid var(--border);
  padding: 0 24px;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}

.nav-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--text);
}

.nav-brand img {
  height: 40px;
  width: 40px;
}

.nav-brand span {
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.nav-brand .brand-sub {
  font-size: 0.75rem;
  font-weight: 400;
  color: var(--text-muted);
  display: block;
  line-height: 1.2;
}

.nav-links {
  display: flex;
  gap: 8px;
  list-style: none;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-muted);
  font-size: 0.9rem;
  font-weight: 500;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  transition: all 0.15s ease;
}

.nav-links a:hover {
  color: var(--primary);
  background: rgba(139, 26, 26, 0.05);
}

.nav-links a.active {
  color: var(--primary);
  background: rgba(139, 26, 26, 0.08);
}

/* ---- LAYOUT ---- */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 32px 24px 80px;
}

.page-header {
  margin-bottom: 32px;
}

.page-header h1 {
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text);
}

.page-header p {
  color: var(--text-muted);
  margin-top: 4px;
  font-size: 0.95rem;
}

/* ---- CARDS ---- */
.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 24px;
  margin-bottom: 24px;
}

.card-header {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 20px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 8px;
}

.card-header .icon {
  width: 20px;
  height: 20px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--primary);
}

/* ---- FORM ---- */
.form-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 16px;
}

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

.form-group label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 4px;
}

.form-group .unit {
  font-size: 0.7rem;
  font-weight: 400;
  color: var(--text-muted);
  text-transform: none;
  letter-spacing: 0;
}

.form-group input {
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-family: inherit;
  color: var(--text);
  background: var(--bg);
  transition: border-color 0.15s, box-shadow 0.15s;
  -moz-appearance: textfield;
}

.form-group input::-webkit-outer-spin-button,
.form-group input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.form-group input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(139, 26, 26, 0.1);
}

.form-group input.invalid {
  border-color: var(--danger);
  box-shadow: 0 0 0 3px rgba(220, 38, 38, 0.1);
}

.form-section-title {
  grid-column: 1 / -1;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--primary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-top: 8px;
  padding-bottom: 4px;
  border-bottom: 2px solid rgba(139, 26, 26, 0.15);
}

/* ---- ACCURACY BAR ---- */
.accuracy-card {
  position: sticky;
  top: 64px;
  z-index: 50;
}

.accuracy-desc {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 12px;
}

.accuracy-bar-wrap {
  width: 100%;
  height: 24px;
  background: var(--bg);
  border-radius: 12px;
  border: 1px solid var(--border);
  overflow: hidden;
}

.accuracy-fill {
  height: 100%;
  border-radius: 12px;
  transition: width 0.4s ease, background 0.4s ease;
  min-width: 0;
}

.accuracy-fill.low {
  background: linear-gradient(90deg, var(--danger), #ef4444);
}

.accuracy-fill.medium {
  background: linear-gradient(90deg, var(--warning), #f59e0b);
}

.accuracy-fill.high {
  background: linear-gradient(90deg, var(--success), #10b981);
}

.accuracy-label-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: 8px;
}

.accuracy-label {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text);
}

.accuracy-hint {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* ---- IMPORTANCE INDICATORS ---- */
.importance-indicator {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-top: 4px;
}

.importance-bar-mini {
  height: 3px;
  background: var(--primary);
  border-radius: 2px;
  opacity: 0.4;
  min-width: 2px;
}

.importance-value {
  font-size: 0.65rem;
  color: var(--text-muted);
  white-space: nowrap;
}

/* ---- OPTIONAL TAG ---- */
.optional-tag {
  display: inline-block;
  font-size: 0.6rem;
  font-weight: 500;
  color: var(--text-muted);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1px 5px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-left: 4px;
  vertical-align: middle;
}

.header-hint {
  font-size: 0.75rem;
  font-weight: 400;
  color: var(--text-muted);
  margin-left: auto;
}

/* ---- OPTIONAL FIELDS ---- */
.optional-fields {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 16px;
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
}

.optional-fields .form-group input,
.optional-fields .form-group textarea {
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-family: inherit;
  color: var(--text);
  background: var(--bg);
  transition: border-color 0.15s, box-shadow 0.15s;
}

.optional-fields .form-group textarea {
  resize: vertical;
  min-height: 42px;
}

.optional-fields .form-group input:focus,
.optional-fields .form-group textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(139, 26, 26, 0.1);
}

/* ---- BUTTONS ---- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: all 0.15s ease;
}

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

.btn-primary:hover {
  background: var(--primary-dark);
  box-shadow: var(--shadow-md);
}

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

.btn-primary:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

.btn-secondary {
  background: var(--bg);
  color: var(--text-muted);
  border: 1px solid var(--border);
}

.btn-secondary:hover {
  color: var(--text);
  border-color: var(--text-muted);
}

.btn-row {
  display: flex;
  gap: 12px;
  margin-top: 24px;
  align-items: center;
}

/* ---- SPINNER ---- */
.spinner {
  width: 18px;
  height: 18px;
  border: 2px solid rgba(255,255,255,0.3);
  border-top-color: white;
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ---- RESULTS ---- */
.results-panel {
  display: none;
}

.results-panel.visible {
  display: block;
  animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.result-hero {
  text-align: center;
  padding: 32px 24px;
}

.result-usg {
  font-size: 3.5rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1;
  margin-bottom: 8px;
}

.result-usg.adequate {
  color: var(--success);
}

.result-usg.impaired {
  color: var(--danger);
}

.result-classification {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 16px;
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.result-classification.adequate {
  background: var(--success-bg);
  color: var(--success);
}

.result-classification.impaired {
  background: var(--danger-bg);
  color: var(--danger);
}

.result-details {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
  margin-top: 24px;
}

.result-detail {
  text-align: center;
  padding: 16px;
  background: var(--bg);
  border-radius: var(--radius-sm);
}

.result-detail .label {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.result-detail .value {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text);
  margin-top: 4px;
}

.risk-banner {
  padding: 16px 20px;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 500;
  margin-top: 20px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.risk-banner.low { background: var(--success-bg); color: var(--success); }
.risk-banner.moderate_low { background: var(--info-bg); color: var(--info); }
.risk-banner.moderate_high { background: var(--warning-bg); color: var(--warning); }
.risk-banner.high { background: var(--danger-bg); color: var(--danger); }

.disclaimer {
  margin-top: 20px;
  padding: 12px 16px;
  background: var(--bg);
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  color: var(--text-muted);
  border-left: 3px solid var(--border);
}

/* ---- SHAP EXPLANATION CHART ---- */
.explanation-section {
  margin-top: 24px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
}

.explanation-header {
  margin-bottom: 16px;
}

.explanation-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text);
  display: block;
}

.explanation-subtitle {
  font-size: 0.8rem;
  color: var(--text-muted);
  display: block;
  margin-top: 2px;
}

.explanation-legend {
  display: flex;
  gap: 20px;
  margin-bottom: 16px;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--text-muted);
}

.legend-swatch {
  display: inline-block;
  width: 14px;
  height: 14px;
  border-radius: 3px;
}

.legend-adequate .legend-swatch {
  background: var(--success);
}

.legend-impaired .legend-swatch {
  background: var(--danger);
}

.shap-row {
  display: flex;
  align-items: center;
  gap: 0;
  margin-bottom: 8px;
  height: 36px;
}

.shap-label {
  width: 130px;
  min-width: 130px;
  text-align: right;
  padding-right: 12px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text);
  line-height: 1.2;
}

.shap-label-sub {
  display: block;
  font-size: 0.7rem;
  font-weight: 400;
  color: var(--text-muted);
}

.shap-bar-area {
  flex: 1;
  position: relative;
  height: 100%;
  display: flex;
  align-items: center;
}

.shap-center-line {
  position: absolute;
  left: 50%;
  top: 0;
  bottom: 0;
  width: 1px;
  background: var(--border);
  z-index: 1;
}

.shap-bar {
  position: absolute;
  height: 24px;
  border-radius: 4px;
  z-index: 2;
  transition: width 0.5s ease, left 0.5s ease;
  min-width: 2px;
}

.shap-bar.adequate {
  background: linear-gradient(90deg, var(--success), #34d399);
}

.shap-bar.impaired {
  background: linear-gradient(90deg, #f87171, var(--danger));
}

.shap-impact {
  position: absolute;
  z-index: 3;
  font-size: 0.72rem;
  font-weight: 600;
  white-space: nowrap;
  line-height: 24px;
}

.shap-impact.adequate {
  color: var(--success);
}

.shap-impact.impaired {
  color: var(--danger);
}

/* Axis labels below the chart */
.shap-axis {
  display: flex;
  align-items: center;
  margin-top: 4px;
  padding-left: 130px;
}

.shap-axis-bar {
  flex: 1;
  position: relative;
  height: 20px;
}

.shap-axis-label {
  position: absolute;
  font-size: 0.7rem;
  font-weight: 500;
  color: var(--text-muted);
  top: 0;
}

.shap-axis-label.left {
  left: 0;
}

.shap-axis-label.center {
  left: 50%;
  transform: translateX(-50%);
}

.shap-axis-label.right {
  right: 0;
}

@media (max-width: 768px) {
  .shap-label {
    width: 90px;
    min-width: 90px;
    font-size: 0.72rem;
    padding-right: 8px;
  }
  .shap-label-sub {
    display: none;
  }
  .shap-axis {
    padding-left: 90px;
  }
  .explanation-legend {
    gap: 12px;
  }
}

/* ---- PREDICTION LOG TABLE ---- */
.log-table-wrap {
  overflow-x: auto;
}

.log-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
}

.log-table th {
  text-align: left;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  font-size: 0.7rem;
  padding: 10px 12px;
  border-bottom: 2px solid var(--border);
}

.log-table td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  color: var(--text);
}

.log-table tbody tr:hover {
  background: rgba(139, 26, 26, 0.02);
}

.badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 10px;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.02em;
}

.badge.adequate { background: var(--success-bg); color: var(--success); }
.badge.impaired { background: var(--danger-bg); color: var(--danger); }

/* ---- REPORT IFRAME ---- */
.report-frame {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  min-height: calc(100vh - 180px);
  background: white;
}

/* ---- ERROR ---- */
.error-msg {
  display: none;
  padding: 12px 16px;
  background: var(--danger-bg);
  color: var(--danger);
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  margin-top: 16px;
}

.error-msg.visible {
  display: block;
}

/* ---- INPUT HINTS (validation) ---- */
.input-hint {
  font-size: 0.78rem;
  padding: 4px 0 0;
  line-height: 1.3;
}
.input-hint-warn {
  color: var(--warning);
}
.input-hint-error {
  color: var(--danger);
}

/* ---- RESULT WARNINGS ---- */
.result-warnings {
  background: var(--warning-bg);
  border: 1px solid var(--warning);
  border-radius: 8px;
  padding: 12px 16px;
  margin-bottom: 12px;
}
.result-warnings .warning-item {
  font-size: 0.85rem;
  color: var(--warning);
  padding: 2px 0;
}
.result-warnings .warning-item::before {
  content: "\26A0\FE0F ";
}

/* ---- RESPONSIVE ---- */
@media (max-width: 768px) {
  .nav-inner { height: 56px; }
  .nav-brand span { font-size: 0.95rem; }
  .nav-brand .brand-sub { display: none; }
  .container { padding: 20px 16px 60px; }
  .form-grid { grid-template-columns: 1fr 1fr; gap: 12px; }
  .result-usg { font-size: 2.5rem; }
  .page-header h1 { font-size: 1.35rem; }
  .btn-row { flex-direction: column; }
  .btn-row .btn { width: 100%; }
}

@media (max-width: 480px) {
  .form-grid { grid-template-columns: 1fr; }
}

/* ---- EMPTY STATE ---- */
.empty-state {
  text-align: center;
  padding: 48px 24px;
  color: var(--text-muted);
}

.empty-state .icon {
  font-size: 2rem;
  margin-bottom: 12px;
  opacity: 0.4;
}

.empty-state p {
  font-size: 0.95rem;
}