:root {
  --text: #1f2937;
  --muted: #6b7280;
  --accent: #2563eb;
  --border: #e5e7eb;
  --bg: #ffffff;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Inter", system-ui, sans-serif;
  color: var(--text);
  background: var(--bg);
  display: grid;
  grid-template-columns: 260px 1fr;
  min-height: 100vh;
}

/* Sidebar */
.sidebar {
  border-right: 1px solid var(--border);
  padding: 32px 24px;
}

.sidebar h1 {
  font-size: 1.25rem;
  margin-bottom: 8px;
}

.subtitle {
  font-size: 0.9rem;
  color: var(--muted);
  margin-bottom: 24px;
}

nav a {
  display: block;
  margin-bottom: 10px;
  text-decoration: none;
  color: var(--text);
  font-size: 0.95rem;
}

nav a:hover {
  color: var(--accent);
}

.sidebar-footer {
  margin-top: 32px;
  font-size: 0.85rem;
  color: var(--muted);
}

/* Main content */
.content {
  padding: 48px 56px;
  max-width: 900px;
}

section {
  margin-bottom: 56px;
}

h2 {
  font-size: 1.4rem;
  border-bottom: 1px solid var(--border);
  padding-bottom: 6px;
  margin-bottom: 20px;
}

.item {
  margin-bottom: 24px;
}

.item h3 {
  margin-bottom: 4px;
  font-size: 1.05rem;
}

.meta {
  font-size: 0.85rem;
  color: var(--muted);
  margin-bottom: 8px;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* Timeline */
.timeline {
  border-left: 2px solid var(--border);
  padding-left: 24px;
}

.timeline-item {
  position: relative;
  margin-bottom: 32px;
}

.timeline-item::before {
  content: "";
  position: absolute;
  left: -9px;
  top: 6px;
  width: 10px;
  height: 10px;
  background: var(--accent);
  border-radius: 50%;
}

/* Footer */
footer {
  font-size: 0.8rem;
  color: var(--muted);
  margin-top: 64px;
}

/* Mobile */
@media (max-width: 900px) {
  body {
    grid-template-columns: 1fr;
  }

  .sidebar {
    border-right: none;
    border-bottom: 1px solid var(--border);
  }
}