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

:root {
  --bg: #f7f7f7;
  --card-bg: #ffffff;
  --border: #dddddd;
  --text-main: #222222;
  --text-muted: #666666;
  --accent: #005bbb;
  --accent-soft: #e4f0ff;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--bg);
  color: var(--text-main);
}

.app {
  max-width: 960px;
  margin: 0 auto;
  padding: 16px;
}

.header {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 16px 12px 8px;
}

h1 {
  margin: 0 0 4px;
  font-size: 1.5rem;
}

.subtitle {
  margin: 0;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.last-updated {
  font-size: 0.85rem;
  color: var(--text-muted);
  display: flex;
  gap: 4px;
}

.last-updated .label {
  font-weight: 500;
}

.main {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
  gap: 16px;
}

.panel {
  background: var(--card-bg);
  border-radius: 4px;
  border: 1px solid var(--border);
  padding: 16px;
}

.panel h2 {
  margin: 0 0 4px;
  font-size: 1.1rem;
}

.refresh-info {
  margin: 0 0 12px;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.price-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 12px;
}

.card {
  border-radius: 4px;
  border: 1px solid var(--border);
  padding: 12px;
  background: #fafafa;
}

.card h3 {
  margin: 0 0 6px;
  font-size: 0.95rem;
  color: var(--text-muted);
}

.price {
  margin: 0;
  font-size: 1.4rem;
  font-weight: 600;
}

.status {
  margin: 10px 0 0;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.converter-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 12px;
  margin: 10px 0 12px;
}

.converter-group {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

label {
  font-size: 0.85rem;
  color: var(--text-muted);
}

input,
select {
  padding: 6px 8px;
  border-radius: 4px;
  border: 1px solid var(--border);
  font-size: 0.95rem;
  outline: none;
}

input:focus,
select:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 1px var(--accent-soft);
}

.result {
  min-height: 34px;
  padding: 6px 8px;
  border-radius: 4px;
  border: 1px dashed var(--border);
  font-size: 1rem;
  display: flex;
  align-items: center;
}

.btn {
  display: inline-flex;
  padding: 8px 14px;
  border-radius: 4px;
  border: 1px solid var(--accent);
  background: var(--accent);
  color: #ffffff;
  font-size: 0.9rem;
  cursor: pointer;
}

.btn:hover {
  background: #004999;
  border-color: #004999;
}

.btn:disabled {
  background: #b9c9e2;
  border-color: #b9c9e2;
  cursor: default;
}

.hint {
  margin: 8px 0 0;
  font-size: 0.75rem;
  color: var(--text-muted);
}

.footer {
  margin-top: 16px;
  padding: 12px 4px 4px;
  font-size: 0.75rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border);
}

@media (max-width: 768px) {
  .main {
    grid-template-columns: 1fr;
  }

  .converter-grid {
    grid-template-columns: 1fr;
  }

  .header {
    align-items: flex-start;
  }
}