:root {
  --bg-main: #f9fafb;
  --bg-secondary: #ffffff;
  --text-main: #111827;
  --text-secondary: #6b7280;
  --accent: #3b82f6;
  --accent-hover: #2563eb;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
}

body {
  background-color: var(--bg-main);
  display: flex;
  min-height: 100vh;
  color: var(--text-main);
}

header {
  background: var(--accent);
  color: white;
  padding: 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 10;
}

header h1 {
  font-size: 1.2rem;
}

header input[type="text"] {
  padding: 0.5rem;
  border-radius: 5px;
  border: none;
  width: 250px;
}

.sidebar {
  width: 220px;
  background: var(--bg-secondary);
  padding-top: 80px;
  box-shadow: 2px 0 5px rgba(0,0,0,0.1);
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;

  /* make scrollable if content overflows */
  overflow-y: auto;
  overscroll-behavior: contain;
}

/* Optional: smooth scrollbar */
.sidebar::-webkit-scrollbar {
  width: 6px;
}

.sidebar::-webkit-scrollbar-thumb {
  background-color: rgba(59, 130, 246, 0.4);
  border-radius: 3px;
}

.sidebar::-webkit-scrollbar-track {
  background: transparent;
}

.sidebar ul {
  list-style: none;
  padding: 0 0 20px 0; /* bottom padding so last item isn't flush */
}

.sidebar ul li {
  margin: 10px 0;
}

.sidebar ul li a {
  display: block;
  padding: 12px 20px;
  color: var(--text-main);
  text-decoration: none;
  font-weight: 500;
  transition: background 0.2s ease;
}

.sidebar ul li a:hover {
  background: rgba(59, 130, 246, 0.1);
  color: var(--accent);
}

.sidebar ul li a.active {
  background: rgba(59, 130, 246, 0.2);
  color: var(--accent-hover);
  font-weight: 600;
}

main {
  margin-left: 240px;
  margin-top: 80px;
  padding: 20px;
  flex: 1;
}

.card {
  background: var(--bg-secondary);
  padding: 20px;
  border-radius: 10px;
  box-shadow: 0 4px 8px rgba(0,0,0,0.05);
}