/* ===== CSS Variables & Reset ===== */
:root {
  --bg-primary: #1a1410;
  --bg-secondary: #231e18;
  --bg-card: #2a231c;
  --bg-card-hover: #332b22;
  --border-color: #3d3428;
  --border-accent: #E8602C;
  --text-primary: #f0e6d6;
  --text-secondary: #b8a890;
  --text-muted: #8a7d6e;
  --accent-orange: #E8602C;
  --accent-orange-dim: rgba(232, 96, 44, 0.15);
  --accent-gold: #D4A76A;
  --accent-gold-dim: rgba(212, 167, 106, 0.15);
  --success: #4CAF50;
  --success-dim: rgba(76, 175, 80, 0.12);
  --warning: #FFC107;
  --warning-dim: rgba(255, 193, 7, 0.12);
  --error: #E8602C;
  --error-dim: rgba(232, 96, 44, 0.12);
  --info: #5ba8c8;
  --info-dim: rgba(91, 168, 200, 0.12);
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --shadow: 0 2px 12px rgba(0, 0, 0, 0.3);
}

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

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

/* ===== Header ===== */
header {
  background: var(--bg-secondary);
  border-bottom: 2px solid var(--border-accent);
  padding: 1rem 1.5rem;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow);
}

.header-content {
  max-width: 900px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
}

.logo-area {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.mesh-icon {
  flex-shrink: 0;
}

header h1 {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.2;
}

.tagline {
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-top: 2px;
}

.header-links {
  display: flex;
  gap: 1rem;
}

.header-links a {
  color: var(--accent-gold);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 500;
  transition: color 0.2s;
}

.header-links a:hover {
  color: var(--accent-orange);
}

/* ===== Main ===== */
main {
  max-width: 900px;
  margin: 0 auto;
  padding: 1.5rem;
}

/* ===== Privacy Notice ===== */
.privacy-notice {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  background: var(--accent-gold-dim);
  border: 1px solid var(--accent-gold);
  border-radius: var(--radius-md);
  padding: 0.75rem 1rem;
  margin-bottom: 1.5rem;
  font-size: 0.85rem;
  color: var(--accent-gold);
}

.privacy-notice svg {
  flex-shrink: 0;
}

/* ===== Config Section ===== */
.config-section {
  margin-bottom: 2rem;
}

.step-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.step-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--accent-orange);
  color: #fff;
  font-weight: 700;
  font-size: 0.9rem;
  flex-shrink: 0;
}

.step-header h2 {
  font-size: 1.1rem;
  font-weight: 600;
}

/* ===== Region Selector ===== */
.region-selector, .node-type-selector {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
}

.region-option input, .node-type-option input {
  display: none;
}

.region-card, .node-type-card {
  display: flex;
  flex-direction: column;
  padding: 1rem;
  border: 2px solid var(--border-color);
  border-radius: var(--radius-md);
  background: var(--bg-card);
  cursor: pointer;
  transition: all 0.2s;
}

.region-card:hover, .node-type-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--text-muted);
}

.region-option input:checked + .region-card,
.node-type-option input:checked + .node-type-card {
  border-color: var(--accent-orange);
  background: var(--accent-orange-dim);
}

.region-card strong, .node-type-card strong {
  font-size: 0.95rem;
  margin-bottom: 0.25rem;
}

.region-card span, .node-type-card span {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

/* ===== Upload Area ===== */
.upload-area {
  border: 2px dashed var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2.5rem 1.5rem;
  text-align: center;
  cursor: pointer;
  transition: all 0.2s;
  background: var(--bg-card);
}

.upload-area:hover, .upload-area.dragover {
  border-color: var(--accent-orange);
  background: var(--accent-orange-dim);
}

.upload-primary {
  font-size: 1.05rem;
  font-weight: 600;
  margin-top: 0.75rem;
}

.upload-secondary {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-top: 0.25rem;
}

.upload-formats {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 0.75rem;
}

.file-info {
  margin-top: 0.75rem;
  padding: 0.75rem 1rem;
  background: var(--bg-card);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  font-size: 0.85rem;
  color: var(--text-secondary);
}

/* ===== Results Section ===== */
.results-section {
  margin-top: 2rem;
  animation: fadeIn 0.3s ease;
}

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

/* ===== Health Score ===== */
.health-score-container {
  text-align: center;
  padding: 2rem;
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  margin-bottom: 1.5rem;
  border: 1px solid var(--border-color);
}

.health-ring {
  display: inline-block;
  position: relative;
  width: 140px;
  height: 140px;
}

.health-ring svg {
  transform: rotate(-90deg);
}

.health-ring-bg {
  fill: none;
  stroke: var(--border-color);
  stroke-width: 10;
}

.health-ring-fill {
  fill: none;
  stroke-width: 10;
  stroke-linecap: round;
  transition: stroke-dashoffset 1s ease, stroke 0.3s;
}

.health-score-text {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 2rem;
  font-weight: 800;
}

.health-label {
  display: block;
  margin-top: 0.75rem;
  font-size: 1.1rem;
  font-weight: 600;
}

.health-summary {
  margin-top: 0.5rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

/* ===== Result Categories ===== */
.result-category {
  margin-bottom: 1rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--bg-card);
}

.category-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.85rem 1rem;
  cursor: pointer;
  user-select: none;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  transition: background 0.2s;
}

.category-header:hover {
  background: var(--bg-card-hover);
}

.category-header-left {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.category-icon {
  font-size: 1.1rem;
}

.category-title {
  font-weight: 600;
  font-size: 0.95rem;
}

.category-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.2rem 0.6rem;
  border-radius: 12px;
  font-size: 0.75rem;
  font-weight: 600;
}

.badge-pass {
  background: var(--success-dim);
  color: var(--success);
}

.badge-fail {
  background: var(--error-dim);
  color: var(--error);
}

.badge-warn {
  background: var(--warning-dim);
  color: var(--warning);
}

.badge-info {
  background: var(--info-dim);
  color: var(--info);
}

.category-chevron {
  font-size: 0.85rem;
  color: var(--text-muted);
  transition: transform 0.2s;
}

.category-header.expanded .category-chevron {
  transform: rotate(180deg);
}

.category-body {
  display: none;
  padding: 0.5rem;
}

.category-body.visible {
  display: block;
}

/* ===== Check Items ===== */
.check-item {
  display: flex;
  gap: 0.75rem;
  padding: 0.75rem;
  border-radius: var(--radius-sm);
  margin-bottom: 0.25rem;
}

.check-item:last-child {
  margin-bottom: 0;
}

.check-icon {
  flex-shrink: 0;
  width: 22px;
  height: 22px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  font-size: 0.75rem;
  font-weight: 700;
  margin-top: 1px;
}

.check-icon.pass {
  background: var(--success-dim);
  color: var(--success);
}

.check-icon.fail {
  background: var(--error-dim);
  color: var(--error);
}

.check-icon.warn {
  background: var(--warning-dim);
  color: var(--warning);
}

.check-icon.info {
  background: var(--info-dim);
  color: var(--info);
}

.check-content {
  flex: 1;
  min-width: 0;
}

.check-title {
  font-weight: 600;
  font-size: 0.9rem;
}

.check-detail {
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-top: 0.15rem;
}

.check-values {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.4rem;
  font-size: 0.8rem;
}

.check-value-current, .check-value-expected {
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  font-family: 'SF Mono', 'Fira Code', monospace;
}

.check-value-current {
  background: var(--error-dim);
  color: var(--error);
}

.check-value-current.match {
  background: var(--success-dim);
  color: var(--success);
}

.check-value-expected {
  background: var(--bg-secondary);
  color: var(--text-secondary);
}

/* ===== Fix Details ===== */
.fix-details {
  margin-top: 0.5rem;
  padding: 0.65rem 0.85rem;
  background: var(--bg-secondary);
  border-radius: var(--radius-sm);
  border-left: 3px solid var(--accent-orange);
}

.fix-details summary {
  cursor: pointer;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--accent-orange);
  user-select: none;
}

.fix-details summary:hover {
  color: var(--accent-gold);
}

.fix-why {
  margin-top: 0.4rem;
  font-size: 0.78rem;
  color: var(--text-secondary);
  font-style: italic;
}

.fix-steps {
  margin-top: 0.5rem;
  padding-left: 1.2rem;
  font-size: 0.78rem;
  color: var(--text-primary);
}

.fix-steps li {
  margin-bottom: 0.25rem;
}

.fix-steps code {
  background: rgba(255,255,255,0.07);
  padding: 0.1rem 0.3rem;
  border-radius: 3px;
  font-size: 0.76rem;
}

/* ===== Node Info ===== */
.node-info-banner {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  padding: 1rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  margin-bottom: 1.5rem;
  font-size: 0.85rem;
}

.node-info-item {
  display: flex;
  flex-direction: column;
}

.node-info-item .label {
  font-size: 0.7rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.node-info-item .value {
  font-weight: 600;
  color: var(--text-primary);
}

/* ===== Action Bar ===== */
.action-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
  padding: 1rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
}

.action-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 1.2rem;
  border: 2px solid transparent;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  font-family: inherit;
}

.action-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.action-btn-primary {
  background: var(--accent-orange);
  color: #fff;
  border-color: var(--accent-orange);
}

.action-btn-primary:hover:not(:disabled) {
  background: #d4541f;
  border-color: #d4541f;
}

.action-btn-secondary {
  background: var(--bg-secondary);
  color: var(--text-primary);
  border-color: var(--border-color);
}

.action-btn-secondary:hover:not(:disabled) {
  border-color: var(--accent-gold);
  background: var(--bg-card-hover);
}

/* ===== Web Serial Section ===== */
.web-serial-section {
  margin-top: 2rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
}

.serial-description {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

.serial-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: center;
}

.serial-status {
  font-size: 0.8rem;
  color: var(--text-secondary);
  width: 100%;
  min-height: 1.2rem;
  margin-top: 0.25rem;
}

.serial-status.connected {
  color: var(--success);
}

.serial-status.error {
  color: var(--error);
}

.serial-not-supported {
  padding: 1rem;
  background: var(--warning-dim);
  border: 1px solid var(--warning);
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  color: var(--warning);
}

.serial-not-supported a {
  color: var(--accent-gold);
}

/* ===== Footer ===== */
footer {
  text-align: center;
  padding: 2rem 1.5rem;
  border-top: 1px solid var(--border-color);
  margin-top: 3rem;
}

footer p {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

footer a {
  color: var(--accent-gold);
  text-decoration: none;
}

footer a:hover {
  color: var(--accent-orange);
}

.footer-sub {
  margin-top: 0.25rem;
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* ===== Responsive ===== */
@media (max-width: 640px) {
  header h1 {
    font-size: 1.05rem;
  }

  .header-links {
    gap: 0.6rem;
    font-size: 0.8rem;
  }

  .region-selector, .node-type-selector {
    grid-template-columns: 1fr;
  }

  .upload-area {
    padding: 1.5rem 1rem;
  }

  .health-ring {
    width: 110px;
    height: 110px;
  }

  .health-score-text {
    font-size: 1.6rem;
  }

  .node-info-banner {
    gap: 0.5rem;
  }
}