:root {
  --color-bg: #0d1117;
  --color-surface: #161b22;
  --color-border: #30363d;
  --color-text: #e6edf3;
  --color-text-muted: #7d8590;
  --color-accent: #58a6ff;
  --color-success: #3fb950;
  --color-warning: #f0883e;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-sans);
  line-height: 1.5;
}

.container {
  max-width: 640px;
  margin: 0 auto;
  padding: 40px 20px;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
  border-bottom: 1px solid var(--color-border);
}

.site-header .brand {
  color: var(--color-text);
  font-weight: 700;
  text-decoration: none;
  font-size: 18px;
}

.site-header nav a {
  color: var(--color-text-muted);
  text-decoration: none;
  margin-left: 20px;
  font-size: 14px;
}

.site-header nav a:hover {
  color: var(--color-text);
}

.site-footer {
  padding: 24px;
  text-align: center;
  color: var(--color-text-muted);
  font-size: 13px;
  border-top: 1px solid var(--color-border);
  margin-top: 60px;
}

.subtitle {
  color: var(--color-text-muted);
}

.primary-button {
  background: var(--color-accent);
  color: #0d1117;
  border: none;
  border-radius: 8px;
  padding: 12px 24px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
}

.primary-button:hover {
  opacity: 0.9;
}

.error {
  color: var(--color-warning);
}

.tool-list {
  padding-left: 20px;
}

.tool-list li {
  margin-bottom: 8px;
}

.tool-list a {
  color: var(--color-accent);
}