/* ================================
   Layout
================================ */
header {
  background-color: #ffffff;
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 4px rgba(0,0,0,0.04);
}

nav {
  max-width: 1100px;
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  gap: 2rem;
  font-weight: 600;
}

main {
  max-width: 1100px;
  margin: 2rem auto;
  padding: 0 1rem;
}

/* ================================
   Buttons
================================ */
button,
.btn {
  display: inline-block;
  background-color: #2563eb;
  color: #ffffff;
  border: none;
  border-radius: 6px;
  padding: 0.5rem 1rem;
  font-size: 0.95rem;
  cursor: pointer;
}

button:hover,
.btn:hover {
  background-color: #1d4ed8;
}

/* ================================
   Utilities
================================ */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1rem;
}

.text-center {
  text-align: center;
}

.mt-2 { margin-top: 0.5rem; }
.mt-4 { margin-top: 1rem; }
.mt-6 { margin-top: 1.5rem; }