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

:root {
  --bg: #0a0a0f;
  --surface: #12121a;
  --surface-hover: #1a1a26;
  --border: #2a2a3a;
  --text: #e4e4ed;
  --text-dim: #8888a0;
  --accent: #6366f1;
  --accent-hover: #818cf8;
  --green: #22c55e;
  --yellow: #eab308;
  --red: #ef4444;
  --radius: 8px;
  --font: 'Segoe UI', system-ui, -apple-system, sans-serif;
  --mono: 'Cascadia Code', 'Fira Code', 'Consolas', monospace;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  line-height: 1.5;
  min-height: 100vh;
}

.container {
  max-width: 640px;
  margin: 0 auto;
  padding: 2rem 1rem;
}

header {
  text-align: center;
  margin-bottom: 1.5rem;
}

/* Navigation */
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.5rem;
}

.nav-brand {
  text-decoration: none;
  display: flex;
  align-items: center;
}

.nav-logo {
  height: 32px;
  width: auto;
}

.nav-brand:hover .nav-logo {
  filter: brightness(1.15);
}

.nav-links {
  display: flex;
  gap: 0.25rem;
}

.nav-link {
  font-size: 0.8rem;
  color: var(--text-dim);
  text-decoration: none;
  padding: 0.35rem 0.65rem;
  border-radius: 6px;
  transition: all 0.15s;
}

.nav-link:hover,
.nav-link.active {
  color: var(--text);
  background: var(--surface);
}

.nav-link.active {
  color: var(--accent);
}

.subtitle {
  color: var(--text-dim);
  font-size: 0.85rem;
  font-weight: 400;
  margin-top: 0.25rem;
}

/* Cards */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  margin-bottom: 1rem;
}

.card h2 {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-dim);
  margin-bottom: 0.75rem;
}

/* Server select */
.server-select {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.server-select select {
  width: 100%;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.5rem 0.75rem;
  font-size: 0.9rem;
  font-family: var(--font);
  cursor: pointer;
}

.server-select select:focus {
  outline: none;
  border-color: var(--accent);
}

.server-status {
  font-size: 0.75rem;
  color: var(--text-dim);
  word-break: break-word;
  overflow-wrap: break-word;
  line-height: 1.4;
}

.server-status.connected {
  color: var(--green);
}

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

/* Settings grid */
.settings-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
}

.settings-grid label {
  display: flex;
  flex-direction: column;
  font-size: 0.8rem;
  color: var(--text-dim);
  gap: 0.25rem;
}

.settings-grid input {
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.5rem 0.75rem;
  font-size: 0.9rem;
  font-family: var(--mono);
  width: 100%;
}

.settings-grid input:focus {
  outline: none;
  border-color: var(--accent);
}

/* Presets */
.presets {
  margin-top: 0.75rem;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.4rem;
}

.presets-label {
  font-size: 0.75rem;
  color: var(--text-dim);
  margin-right: 0.25rem;
}

.preset-btn {
  background: var(--bg);
  color: var(--text-dim);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.25rem 0.65rem;
  font-size: 0.72rem;
  cursor: pointer;
  transition: all 0.15s;
  font-family: var(--font);
}

.preset-btn:hover {
  color: var(--text);
  border-color: var(--accent);
}

/* Controls */
.controls {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.btn-primary, .btn-secondary {
  flex: 1;
  padding: 0.7rem 1.5rem;
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s;
  font-family: var(--font);
  border: none;
}

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

.btn-primary:hover:not(:disabled) {
  background: var(--accent-hover);
}

.btn-primary:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

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

.btn-secondary:hover:not(:disabled) {
  background: var(--surface-hover);
}

.btn-secondary:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

/* Tunnel visualization */
.tunnel-wrapper {
  margin-bottom: 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.75rem 1rem 0.5rem;
  overflow: hidden;
}

.tunnel-labels {
  display: flex;
  justify-content: space-between;
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-dim);
  margin-bottom: 0.35rem;
}

#tunnel-canvas {
  width: 100%;
  height: 140px;
  display: block;
  border-radius: 6px;
}

/* Progress bar */
.progress-bar {
  position: relative;
  height: 28px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 1rem;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--accent);
  transition: width 0.3s ease;
  width: 0%;
}

.progress-label {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 0.75rem;
  font-weight: 600;
  color: #fff;
  text-shadow: 0 1px 2px rgba(0,0,0,0.5);
}

/* Results */
.results h2 {
  margin-bottom: 1rem;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.75rem;
}

.stat {
  text-align: center;
  padding: 0.75rem 0.5rem;
  background: var(--bg);
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.stat-value {
  display: block;
  font-size: 1.4rem;
  font-weight: 700;
  font-family: var(--mono);
  line-height: 1.2;
}

.stat-label {
  display: block;
  font-size: 0.7rem;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-top: 0.25rem;
}

/* Color coding for loss values */
.loss-good { color: var(--green); }
.loss-warn { color: var(--yellow); }
.loss-bad { color: var(--red); }

/* Timeline */
.timeline-container {
  margin-top: 1rem;
}

.timeline-container h3 {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-dim);
  margin-bottom: 0.5rem;
}

#timeline-canvas {
  width: 100%;
  background: var(--bg);
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.timeline-legend {
  display: flex;
  gap: 1rem;
  margin-top: 0.4rem;
  font-size: 0.7rem;
  color: var(--text-dim);
}

.legend-ok { color: var(--green); }
.legend-late { color: var(--yellow); }
.legend-lost { color: var(--red); }

/* Footer */
/* Page sections (About, FAQ) */
.page-section {
  margin-top: 2rem;
  scroll-margin-top: 1rem;
}

.page-section h2 {
  font-size: 1rem;
  text-transform: none;
  letter-spacing: -0.01em;
  color: var(--text);
  margin-bottom: 1rem;
}

.prose {
  font-size: 0.88rem;
  line-height: 1.7;
  color: var(--text-dim);
}

.prose p {
  margin-bottom: 0.75rem;
}

.prose strong {
  color: var(--text);
  font-weight: 600;
}

.prose h3 {
  font-size: 0.82rem;
  color: var(--text);
  margin: 1.25rem 0 0.5rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.prose ul {
  margin: 0.5rem 0 0.75rem 1.25rem;
}

.prose li {
  margin-bottom: 0.35rem;
}

/* FAQ accordion */
.faq-item {
  border-bottom: 1px solid var(--border);
  padding: 0.75rem 0;
}

.faq-item:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.faq-item summary {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text);
  cursor: pointer;
  padding: 0.25rem 0;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: '+';
  font-size: 1.1rem;
  font-weight: 400;
  color: var(--text-dim);
  flex-shrink: 0;
  transition: transform 0.2s;
}

.faq-item[open] summary::after {
  content: '−';
}

.faq-item p,
.faq-item ul {
  margin-top: 0.5rem;
}

/* Footer */
footer {
  text-align: center;
  margin-top: 2rem;
  font-size: 0.75rem;
  color: var(--text-dim);
}

/* Responsive */
@media (max-width: 480px) {
  .container { padding: 1rem 0.75rem; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .settings-grid { grid-template-columns: 1fr; }
  .nav { flex-direction: column; gap: 0.5rem; }
  .nav-links { gap: 0.1rem; }
}