/* =========================================================
   SPEED TEST - MINIMAL DESIGN SYSTEM
   One Accent Color. System Dark/Light Mode. Tabular Figures.
   ========================================================= */

:root {
  /* Default: Light Theme */
  --bg-app: #f8fafc;
  --bg-card: #ffffff;
  --border-color: #e2e8f0;
  --text-main: #0f172a;
  --text-muted: #64748b;
  --text-dim: #94a3b8;
  --gauge-track: #e2e8f0;
  --accent: #0099b8;
  --accent-light: #e0f7fa;
  --accent-glow: rgba(0, 153, 184, 0.2);
  --btn-text: #ffffff;
  --shadow-card: 0 4px 20px -2px rgba(0, 0, 0, 0.05);
  --font-stack: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg-app: #080c14;
    --bg-card: #111726;
    --border-color: #1e293b;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --text-dim: #475569;
    --gauge-track: #172033;
    --accent: #00e5ff;
    --accent-light: rgba(0, 229, 255, 0.12);
    --accent-glow: rgba(0, 229, 255, 0.35);
    --btn-text: #080c14;
    --shadow-card: 0 10px 30px -5px rgba(0, 0, 0, 0.5);
  }
}

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

body {
  background-color: var(--bg-app);
  color: var(--text-main);
  font-family: var(--font-stack);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 1.5rem 1rem;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

.app-shell {
  width: 100%;
  max-width: 640px;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

/* --- Header & Network Bar --- */
.app-header {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
  text-align: center;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

.brand-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--accent);
  box-shadow: 0 0 10px var(--accent);
}

.brand-title {
  font-size: 0.95rem;
  font-weight: 800;
  letter-spacing: 0.18em;
  color: var(--text-main);
}

.network-info {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 0.5rem 0.75rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  padding: 0.45rem 1rem;
  border-radius: 9999px;
  font-size: 0.8rem;
  box-shadow: var(--shadow-card);
  transition: border-color 0.2s ease;
}

.info-item {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

.info-label {
  font-weight: 700;
  font-size: 0.7rem;
  letter-spacing: 0.05em;
  color: var(--text-muted);
}

.info-val {
  color: var(--text-main);
  font-weight: 500;
  white-space: nowrap;
}

.info-divider {
  color: var(--text-dim);
  font-size: 0.6rem;
}

/* --- Main Stage & Gauge --- */
.main-stage {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.stage-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 1rem 0;
  position: relative;
}

.gauge-ring {
  position: relative;
  width: 280px;
  height: 280px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.gauge-svg {
  width: 100%;
  height: 100%;
  transform: rotate(-90deg);
}

.gauge-base {
  fill: none;
  stroke: var(--gauge-track);
  stroke-width: 12;
}

.gauge-meter {
  fill: none;
  stroke: var(--accent);
  stroke-width: 12;
  stroke-linecap: round;
  stroke-dasharray: 728.85; /* 2 * PI * 116 */
  stroke-dashoffset: 728.85;
  transition: stroke-dashoffset 0.08s linear;
  filter: drop-shadow(0 0 10px var(--accent-glow));
}

.gauge-core {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

/* Big Central "GO" Button */
.go-btn {
  width: 170px;
  height: 170px;
  border-radius: 50%;
  background: var(--bg-card);
  border: 2px solid var(--accent);
  box-shadow: 0 0 25px var(--accent-glow), inset 0 0 15px var(--accent-light);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform 0.2s cubic-bezier(0.34, 1.56, 0.64, 1), box-shadow 0.2s ease, background 0.2s ease;
  user-select: none;
  outline: none;
}

.go-btn:hover {
  transform: scale(1.05);
  box-shadow: 0 0 35px var(--accent-glow), inset 0 0 20px var(--accent-light);
}

.go-btn:active {
  transform: scale(0.96);
}

.go-btn:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 4px;
}

.go-text {
  font-size: 2.75rem;
  font-weight: 900;
  letter-spacing: 0.08em;
  color: var(--accent);
}

/* Running Reading Display */
.reading-group {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  pointer-events: none;
}

.reading-phase {
  font-size: 0.8rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  color: var(--accent);
  text-transform: uppercase;
  margin-bottom: 0.25rem;
}

.reading-number {
  font-size: 3.5rem;
  font-weight: 900;
  line-height: 1;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.03em;
  color: var(--text-main);
}

.reading-unit {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-muted);
  letter-spacing: 0.05em;
  margin-top: 0.25rem;
}

.status-subtext {
  margin-top: 1rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  text-align: center;
  min-height: 1.3rem;
}

.status-subtext.error {
  color: #ef4444;
}

.stage-actions {
  margin-top: 0.75rem;
}

.action-btn {
  background: var(--accent);
  color: var(--btn-text);
  border: none;
  border-radius: 9999px;
  padding: 0.65rem 2rem;
  font-size: 0.85rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  cursor: pointer;
  box-shadow: 0 4px 15px var(--accent-glow);
  transition: transform 0.15s ease, opacity 0.15s ease;
}

.action-btn:hover {
  transform: translateY(-1px);
  opacity: 0.92;
}

.action-btn:active {
  transform: translateY(1px);
}

/* --- Metrics Grid --- */
.metrics-section {
  width: 100%;
}

.metrics-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.85rem;
}

.metric-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 1rem 1.15rem;
  box-shadow: var(--shadow-card);
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.metric-card.active {
  border-color: var(--accent);
  box-shadow: 0 0 20px var(--accent-glow);
}

.metric-header {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.metric-icon {
  font-size: 1rem;
  color: var(--accent);
  font-weight: 800;
}

.metric-title {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--text-muted);
}

.metric-body {
  display: flex;
  align-items: baseline;
  gap: 0.4rem;
}

.metric-value {
  font-size: 1.85rem;
  font-weight: 800;
  color: var(--text-main);
  font-variant-numeric: tabular-nums;
  line-height: 1.1;
}

.metric-unit {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-muted);
}

.metric-sub {
  font-size: 0.75rem;
  color: var(--text-dim);
  margin-top: 0.1rem;
  font-variant-numeric: tabular-nums;
}

/* --- Results Summary Card --- */
.results-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 1.25rem;
  box-shadow: var(--shadow-card);
}

.results-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.75rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 0.5rem;
}

.results-title {
  font-size: 0.85rem;
  font-weight: 800;
  letter-spacing: 0.1em;
  color: var(--accent);
}

.results-timestamp {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.results-details {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.75rem;
  font-size: 0.8rem;
}

.result-row {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}

.result-row span {
  color: var(--text-muted);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.result-row strong {
  color: var(--text-main);
  font-weight: 600;
}

/* --- Footer --- */
.app-footer {
  text-align: center;
  padding: 0.5rem 0;
}

.footer-note {
  font-size: 0.75rem;
  color: var(--text-dim);
}

/* Utility */
.hidden {
  display: none !important;
}

/* Responsive Breakpoint */
@media (max-width: 480px) {
  .gauge-ring {
    width: 240px;
    height: 240px;
  }
  .go-btn {
    width: 145px;
    height: 145px;
  }
  .go-text {
    font-size: 2.25rem;
  }
  .reading-number {
    font-size: 2.85rem;
  }
  .metrics-grid {
    grid-template-columns: 1fr;
  }
  .results-details {
    grid-template-columns: 1fr;
  }
}