:root {
  --bg: #ffffff;
  --sidebar-bg: #f6f8fa;
  --border: #d0d7de;
  --text: #24292f;
  --link: #0969da;
  --code-bg: #f6f8fa;
}

* {
  box-sizing: border-box;
}

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

a {
  color: var(--link);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}

.layout {
  display: flex;
  min-height: 100vh;
}

.lang-toggle {
  background: var(--sidebar-bg);
  border-bottom: 1px solid var(--border);
  padding: 0.75rem 1rem;
  display: flex;
  gap: 1rem;
  align-items: center;
}

.lang-toggle a {
  font-weight: 600;
  padding: 0.5rem 1rem;
  border-radius: 6px;
  transition: background 0.2s;
}

.lang-toggle a:hover {
  background: rgba(0,0,0,0.05);
  text-decoration: none;
}

.lang-toggle a.active {
  background: var(--link);
  color: white;
}

.sidebar {
  width: 390px;
  background: var(--sidebar-bg);
  border-right: 1px solid var(--border);
  padding: 1rem;
}

.sidebar h2 {
  font-size: 1rem;
  margin-top: 0;
}

.sidebar ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.sidebar li {
  margin: 0.4rem 0;
}

.content {
  flex: 1;
  padding: 2rem;
  max-width: 900px;
}

pre, code {
  background: var(--code-bg);
  border-radius: 6px;
}

pre {
  padding: 1rem;
  overflow-x: auto;
}

code {
  padding: 0.2em 0.4em;
}

h1, h2, h3 {
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.3em;
}

@media (max-width: 800px) {
  .layout {
    flex-direction: column;
  }
  .sidebar {
    width: 100%;
    border-right: none;
    border-bottom: 1px solid var(--border);
  }
}