:root {
  --bg: #0b0f17;
  --panel: #131927;
  --panel-2: #1a2235;
  --border: #243047;
  --text: #e6ecf5;
  --muted: #93a3bc;
  --accent: #5fa8ff;
  --accent-hover: #7ab8ff;
  --usd-twd: #5fa8ff;
  --cad-twd: #f97316;
  --eur-twd: #22c55e;
  --eur-cad: #a78bfa;
  --eur-usd: #f43f5e;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang TC",
               "Microsoft JhengHei", Roboto, sans-serif;
  font-size: 15px;
  line-height: 1.5;
}

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 24px;
  border-bottom: 1px solid var(--border);
  background: var(--panel);
  flex-wrap: wrap;
  gap: 12px;
}

.brand h1 {
  margin: 0;
  font-size: 20px;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.brand .subtitle {
  font-size: 12px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.status {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 13px;
  color: var(--muted);
}

button {
  background: var(--panel-2);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 6px 12px;
  font: inherit;
  font-size: 13px;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
}

button:hover {
  border-color: var(--accent);
}

button:active {
  background: var(--accent);
  color: #fff;
}

main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 20px 24px 32px;
}

.controls {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 24px;
  padding: 16px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  margin-bottom: 20px;
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
  min-width: 0;
}

.control-label {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  font-weight: 600;
}

.toggles {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.toggle {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  font-size: 13px;
  user-select: none;
  transition: border-color 0.15s;
}

.toggle:hover {
  border-color: var(--accent);
}

.toggle input[type="checkbox"] {
  margin: 0;
  accent-color: var(--accent);
}

.toggle .swatch {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  display: inline-block;
}

.chart {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 12px;
  min-height: 520px;
}

.latest {
  margin-top: 24px;
}

.latest h2 {
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  margin: 0 0 12px;
  font-weight: 600;
}

.latest-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 12px;
}

.latest-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px 16px;
}

.latest-card .pair {
  font-size: 12px;
  color: var(--muted);
  letter-spacing: 0.04em;
}

.latest-card .rate {
  font-size: 22px;
  font-weight: 600;
  margin-top: 4px;
  font-variant-numeric: tabular-nums;
}

.latest-card .delta {
  font-size: 12px;
  margin-top: 2px;
  font-variant-numeric: tabular-nums;
}

.delta.up    { color: #22c55e; }
.delta.down  { color: #f43f5e; }
.delta.flat  { color: var(--muted); }

footer {
  text-align: center;
  font-size: 11px;
  color: var(--muted);
  padding: 16px;
  border-top: 1px solid var(--border);
  margin-top: 32px;
}

@media (max-width: 720px) {
  header { padding: 14px 16px; }
  main { padding: 16px; }
  .controls { grid-template-columns: 1fr; padding: 14px; }
  .chart { min-height: 420px; padding: 8px; }
  .brand h1 { font-size: 18px; }
}