:root,
[data-theme="dark"] {
  color-scheme: dark;
  --bg: #000000;
  --surface: #1c1c1e;
  --surface-elevated: #2c2c2e;
  --text: #f5f5f7;
  --text-secondary: #98989d;
  --accent: #0a84ff;
  --accent-soft: rgba(10, 132, 255, 0.18);
  --accent-glow: rgba(10, 132, 255, 0.4);
  --border: rgba(255, 255, 255, 0.08);
  --success: #30d158;
  --gauge-track: #3a3a3c;
  --shimmer-base: #2c2c2e;
  --shimmer-highlight: #3a3a3c;
  --shadow: 0 12px 40px rgba(0, 0, 0, 0.45);
  --radius: 20px;
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI", sans-serif;
}

[data-theme="light"] {
  color-scheme: light;
  --bg: #f5f5f7;
  --surface: #ffffff;
  --surface-elevated: #ffffff;
  --text: #1d1d1f;
  --text-secondary: #86868b;
  --accent: #0071e3;
  --accent-soft: rgba(0, 113, 227, 0.12);
  --accent-glow: rgba(0, 113, 227, 0.35);
  --border: rgba(0, 0, 0, 0.08);
  --success: #34c759;
  --gauge-track: #ececee;
  --shimmer-base: #ececee;
  --shimmer-highlight: #f8f8fa;
  --shadow: 0 12px 40px rgba(0, 0, 0, 0.06);
}

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

html,
body {
  margin: 0;
  min-height: 100%;
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

.bg-glow {
  position: fixed;
  inset: 0;
  pointer-events: none;
  animation: bg-shift 12s ease-in-out infinite alternate;
}

[data-theme="dark"] .bg-glow {
  background:
    radial-gradient(circle at 20% 10%, rgba(10, 132, 255, 0.12), transparent 42%),
    radial-gradient(circle at 80% 20%, rgba(48, 209, 88, 0.08), transparent 35%),
    radial-gradient(circle at 50% 100%, rgba(88, 86, 214, 0.08), transparent 45%);
}

[data-theme="light"] .bg-glow {
  background:
    radial-gradient(circle at 20% 10%, rgba(0, 113, 227, 0.08), transparent 40%),
    radial-gradient(circle at 80% 20%, rgba(52, 199, 89, 0.06), transparent 35%),
    radial-gradient(circle at 50% 100%, rgba(0, 113, 227, 0.05), transparent 45%);
}

@keyframes bg-shift {
  from { opacity: 0.85; transform: scale(1); }
  to { opacity: 1; transform: scale(1.04); }
}

.page {
  position: relative;
  max-width: 920px;
  margin: 0 auto;
  padding: 48px 24px 64px;
}

.fade-in {
  animation: fade-in 0.7s ease both;
}

.fade-in-delay-1 { animation-delay: 0.08s; }
.fade-in-delay-2 { animation-delay: 0.16s; }
.fade-in-delay-3 { animation-delay: 0.24s; }

@keyframes fade-in {
  from {
    opacity: 0;
    transform: translateY(16px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.header {
  text-align: center;
  margin-bottom: 40px;
}

.header-top {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  position: relative;
}

.theme-toggle {
  position: absolute;
  right: 0;
  appearance: none;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  width: 42px;
  height: 42px;
  border-radius: 50%;
  cursor: pointer;
  display: grid;
  place-items: center;
  font-size: 1.1rem;
  transition: transform 0.2s ease, background 0.2s ease, box-shadow 0.2s ease;
  box-shadow: var(--shadow);
}

.theme-toggle:hover {
  transform: scale(1.05);
}

.theme-icon {
  grid-area: 1 / 1;
  transition: opacity 0.25s ease, transform 0.25s ease;
}

[data-theme="dark"] .theme-icon-sun {
  opacity: 1;
  transform: rotate(0deg);
}

[data-theme="dark"] .theme-icon-moon {
  opacity: 0;
  transform: rotate(-90deg) scale(0.5);
}

[data-theme="light"] .theme-icon-sun {
  opacity: 0;
  transform: rotate(90deg) scale(0.5);
}

[data-theme="light"] .theme-icon-moon {
  opacity: 1;
  transform: rotate(0deg);
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.03em;
}

.logo-icon {
  flex-shrink: 0;
  color: var(--accent);
}

.tagline {
  margin: 8px 0 0;
  color: var(--text-secondary);
  font-size: 1.05rem;
}

.main {
  display: grid;
  gap: 24px;
}

.hero {
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 40px 32px 32px;
  text-align: center;
  transition: box-shadow 0.4s ease, transform 0.4s ease;
}

.hero:hover {
  box-shadow: 0 16px 48px rgba(0, 0, 0, 0.08);
}

.gauge-wrap {
  position: relative;
  width: 240px;
  height: 240px;
  margin: 0 auto 28px;
}

.gauge-glow {
  position: absolute;
  inset: 10%;
  border-radius: 50%;
  background: radial-gradient(circle, var(--accent-glow), transparent 70%);
  opacity: 0;
  transform: scale(0.85);
  transition: opacity 0.4s ease, transform 0.4s ease;
}

.gauge-wrap.running .gauge-glow {
  opacity: 1;
  transform: scale(1);
  animation: glow-pulse 2s ease-in-out infinite;
}

.gauge-wrap.done .gauge-glow {
  opacity: 1;
  background: radial-gradient(circle, rgba(52, 199, 89, 0.35), transparent 70%);
  animation: success-pop 0.6s ease;
}

@keyframes glow-pulse {
  0%, 100% { opacity: 0.7; transform: scale(1); }
  50% { opacity: 1; transform: scale(1.06); }
}

@keyframes success-pop {
  0% { transform: scale(0.9); opacity: 0; }
  60% { transform: scale(1.08); opacity: 1; }
  100% { transform: scale(1); opacity: 1; }
}

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

.gauge-track,
.gauge-progress {
  fill: none;
  stroke-width: 10;
}

.gauge-track {
  stroke: var(--gauge-track);
}

.gauge-progress {
  stroke: var(--accent);
  stroke-linecap: round;
  stroke-dasharray: 628.32;
  stroke-dashoffset: 628.32;
  transition: stroke-dashoffset 0.35s ease, stroke 0.4s ease;
}

.gauge-wrap.running .gauge-progress {
  animation: pulse-ring 1.6s ease-in-out infinite;
}

.gauge-wrap.running.phase-ping .gauge-progress { stroke: #ff9500; }
.gauge-wrap.running.phase-download .gauge-progress { stroke: var(--accent); }
.gauge-wrap.running.phase-upload .gauge-progress { stroke: #5856d6; }
.gauge-wrap.done .gauge-progress { stroke: var(--success); }

@keyframes pulse-ring {
  0%, 100% { opacity: 1; filter: drop-shadow(0 0 0 transparent); }
  50% { opacity: 0.85; filter: drop-shadow(0 0 8px var(--accent-glow)); }
}

.gauge-center {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.phase-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 6px;
  transition: opacity 0.25s ease, transform 0.25s ease;
}

.phase-label.change {
  animation: label-flip 0.35s ease;
}

@keyframes label-flip {
  0% { opacity: 0; transform: translateY(6px); }
  100% { opacity: 1; transform: translateY(0); }
}

.speed-value {
  font-size: 3.2rem;
  font-weight: 700;
  letter-spacing: -0.04em;
  line-height: 1;
  font-variant-numeric: tabular-nums;
  transition: transform 0.2s ease, color 0.3s ease;
}

.speed-value.tick {
  animation: value-pop 0.25s ease;
}

@keyframes value-pop {
  0% { transform: scale(1); }
  50% { transform: scale(1.06); }
  100% { transform: scale(1); }
}

.speed-unit {
  margin-top: 4px;
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.start-btn {
  appearance: none;
  border: none;
  background: var(--accent);
  color: #fff;
  font: inherit;
  font-size: 1rem;
  font-weight: 600;
  padding: 14px 36px;
  border-radius: 999px;
  cursor: pointer;
  transition: transform 0.15s ease, opacity 0.15s ease, box-shadow 0.25s ease;
  box-shadow: 0 8px 24px rgba(0, 113, 227, 0.28);
}

.start-btn:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: 0 12px 32px rgba(0, 113, 227, 0.35);
}

.start-btn:active:not(:disabled) {
  transform: translateY(0);
}

.start-btn:disabled {
  opacity: 0.55;
  cursor: not-allowed;
  box-shadow: none;
}

.metrics {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-top: 32px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
}

.metric {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 12px;
  border-radius: 14px;
  transition: background 0.3s ease, transform 0.3s ease;
}

.metric.active {
  background: var(--accent-soft);
  transform: translateY(-2px);
}

.metric.flash .metric-value {
  animation: metric-flash 0.45s ease;
}

@keyframes metric-flash {
  0% { color: var(--accent); transform: scale(1.08); }
  100% { color: inherit; transform: scale(1); }
}

.metric-label {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.metric-value {
  font-size: 1.25rem;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

.info-card {
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 8px 20px;
}

.insights {
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 24px;
}

.insights-rating {
  margin: 0 0 20px;
  font-size: 1.05rem;
  font-weight: 600;
  text-align: center;
  color: var(--text);
}

.use-cases {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
}

.use-case {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 14px;
  border-radius: 14px;
  font-size: 0.9rem;
  background: var(--surface-elevated);
}

.use-case-ok {
  color: var(--text);
}

.use-case-ok .use-case-icon {
  color: var(--success);
  font-weight: 700;
}

.use-case-no {
  color: var(--text-secondary);
}

.use-case-no .use-case-icon {
  opacity: 0.45;
}

.use-case-icon {
  flex-shrink: 0;
  width: 1.25rem;
  text-align: center;
}

.info-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.95rem;
}

.info-row:last-child {
  border-bottom: none;
}

.info-row span {
  color: var(--text-secondary);
}

.info-row strong.loaded {
  animation: info-reveal 0.4s ease;
}

@keyframes info-reveal {
  from { opacity: 0; transform: translateX(8px); }
  to { opacity: 1; transform: translateX(0); }
}

.shimmer {
  color: transparent;
  background: linear-gradient(
    90deg,
    var(--shimmer-base) 25%,
    var(--shimmer-highlight) 50%,
    var(--shimmer-base) 75%
  );
  background-size: 200% 100%;
  animation: shimmer 1.2s linear infinite;
  border-radius: 6px;
  min-width: 80px;
  min-height: 1em;
  display: inline-block;
}

.shimmer.loaded {
  color: inherit;
  background: none;
  animation: none;
  min-width: 0;
}

@keyframes shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

.hidden {
  display: none;
}

@media (max-width: 640px) {
  .page {
    padding-top: 28px;
  }

  .header-top {
    flex-direction: column;
    gap: 12px;
  }

  .theme-toggle {
    position: static;
  }

  .metrics {
    grid-template-columns: 1fr;
    text-align: left;
  }

  .use-cases {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation: none !important;
    transition: none !important;
  }
}