:root {
  --bg: #ffffff;
  --bg-secondary: #f5f5f7;
  --text: #1d1d1f;
  --text-secondary: #6e6e73;
  --border: #d2d2d7;
  --accent: #0066cc;
  --accent-hover: #0055aa;
  --code-bg: #f5f5f7;
  --success: #248a3d;
  --error: #d70015;
  --shadow: rgba(0, 0, 0, 0.08);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #1d1d1f;
    --bg-secondary: #2c2c2e;
    --text: #f5f5f7;
    --text-secondary: #98989d;
    --border: #48484a;
    --accent: #4da3ff;
    --accent-hover: #6db5ff;
    --code-bg: #2c2c2e;
    --success: #30d158;
    --error: #ff453a;
    --shadow: rgba(0, 0, 0, 0.3);
  }
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

.container {
  max-width: 640px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

header {
  text-align: center;
  margin-bottom: 2.5rem;
}

header h1 {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
}

header p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.section {
  display: none;
}

.section.active {
  display: block;
}

.card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
  margin-bottom: 1.25rem;
}

.card h2 {
  font-size: 1.1rem;
  margin-bottom: 0.75rem;
}

.card h3 {
  font-size: 0.95rem;
  margin-bottom: 0.5rem;
  color: var(--text-secondary);
}

.signin-buttons {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.signin-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.25rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg);
  color: var(--text);
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
  text-decoration: none;
  transition: background 0.15s, box-shadow 0.15s;
}

.signin-btn:hover {
  box-shadow: 0 2px 8px var(--shadow);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.6rem 1.25rem;
  border: none;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.15s;
}

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

.btn-primary:hover {
  background: var(--accent-hover);
}

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

.btn-secondary:hover {
  background: var(--border);
}

.btn-danger {
  background: var(--error);
  color: #fff;
}

.user-info {
  margin-bottom: 0.75rem;
}

.user-info strong {
  display: block;
  font-size: 1.1rem;
}

.user-info span {
  color: var(--text-secondary);
  font-size: 0.85rem;
}

.token-display {
  margin-top: 0.75rem;
}

.token-display summary {
  cursor: pointer;
  color: var(--accent);
  font-size: 0.85rem;
  margin-bottom: 0.5rem;
}

pre {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1rem;
  overflow-x: auto;
  font-size: 0.8rem;
  line-height: 1.5;
  white-space: pre-wrap;
  word-break: break-all;
}

.actions {
  display: flex;
  gap: 0.75rem;
  margin-top: 1rem;
  flex-wrap: wrap;
}

.exchange-result {
  margin-top: 1rem;
}

.exchange-result .label {
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-bottom: 0.25rem;
}

.status-ok {
  color: var(--success);
}

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

.explainer {
  margin-top: 0.75rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.loading {
  text-align: center;
  padding: 2rem;
  color: var(--text-secondary);
}

.no-issuers {
  text-align: center;
  padding: 1rem;
  color: var(--text-secondary);
  font-size: 0.9rem;
}