:root {
  --primary: #1a73e8;
  --primary-hover: #1557b0;
  --secondary: #5f6368;
  --bg: #f8f9fa;
  --surface: #ffffff;
  --border: #dadce0;
  --text: #202124;
  --text-secondary: #5f6368;
  --success: #137333;
  --error: #c5221f;
  --warning: #f29900;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 4px 12px rgba(0,0,0,0.04);
}

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

html, body {
  height: 100%;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang TC",
               "Microsoft JhengHei", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
}

.container {
  max-width: 720px;
  margin: 0 auto;
  padding: 32px 20px 80px;
}

.header {
  text-align: center;
  margin-bottom: 24px;
}

.header h1 {
  font-size: 28px;
  font-weight: 600;
  margin-bottom: 8px;
}

.subtitle {
  color: var(--text-secondary);
  font-size: 14px;
}

.card {
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 24px;
  margin-bottom: 16px;
}

.hint {
  color: var(--text-secondary);
  margin-bottom: 16px;
  font-size: 14px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px;
  font-size: 14px;
  font-weight: 500;
  border: 1px solid transparent;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.15s ease;
  font-family: inherit;
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--primary);
  color: white;
}

.btn-primary:hover:not(:disabled) {
  background: var(--primary-hover);
}

.btn-secondary {
  background: var(--surface);
  color: var(--text);
  border-color: var(--border);
}

.btn-secondary:hover:not(:disabled) {
  background: var(--bg);
}

.btn-sm {
  padding: 6px 14px;
  font-size: 13px;
}

.google-icon {
  width: 18px;
  height: 18px;
}

.hidden {
  display: none !important;
}

.user-info {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.user-email {
  font-size: 14px;
  color: var(--text-secondary);
  word-break: break-all;
}

.results-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}

.results-header h2 {
  font-size: 18px;
  font-weight: 600;
}

.status-bar {
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 12px;
  min-height: 20px;
}

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

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

.results-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.empty-state {
  text-align: center;
  color: var(--text-secondary);
  padding: 32px 0;
  font-size: 14px;
}

.code-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 16px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  transition: all 0.15s;
}

.code-item:hover {
  border-color: var(--primary);
  background: #f0f6ff;
}

.code-meta {
  display: flex;
  flex-direction: column;
  gap: 4px;
  flex: 1;
  min-width: 0;
}

.code-value {
  font-family: "SF Mono", Menlo, Consolas, monospace;
  font-size: 22px;
  font-weight: 600;
  color: var(--primary);
  letter-spacing: 2px;
}

.code-date {
  font-size: 12px;
  color: var(--text-secondary);
}

.copy-btn {
  flex-shrink: 0;
  padding: 6px 12px;
  font-size: 12px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  cursor: pointer;
  color: var(--text);
  transition: all 0.15s;
}

.copy-btn:hover {
  background: var(--primary);
  color: white;
  border-color: var(--primary);
}

.copy-btn.copied {
  background: var(--success);
  color: white;
  border-color: var(--success);
}

.spinner {
  display: inline-block;
  width: 14px;
  height: 14px;
  border: 2px solid rgba(255,255,255,0.4);
  border-top-color: white;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.footer {
  text-align: center;
  margin-top: 32px;
  font-size: 12px;
  color: var(--text-secondary);
}

@media (max-width: 480px) {
  .container {
    padding: 20px 12px 60px;
  }
  .header h1 {
    font-size: 22px;
  }
  .card {
    padding: 16px;
  }
  .code-value {
    font-size: 18px;
  }
}