* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  background: #f5f7fb;
  color: #202124;
}

.topbar {
  min-height: 72px;
  background: #172033;
  color: white;
  display: flex;
  align-items: center;
  gap: 18px;
  padding: 0 22px;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.15);
}

.topbar h1 {
  font-size: clamp(1.2rem, 3vw, 2rem);
  margin: 0;
  letter-spacing: 0.3px;
}

.topbar h1 a {
  color: white;
  text-decoration: none;
}

.hamburger {
  width: 46px;
  height: 42px;
  border: none;
  border-radius: 10px;
  background: #ffffff;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 6px;
  padding: 9px;
  flex-shrink: 0;
}

.hamburger span {
  display: block;
  width: 100%;
  height: 3px;
  background: #172033;
  border-radius: 4px;
}

.sidebar {
  position: fixed;
  top: 0;
  left: -360px;
  width: 340px;
  max-width: 88vw;
  height: 100vh;
  background: #ffffff;
  z-index: 1000;
  transition: left 0.25s ease;
  box-shadow: 4px 0 18px rgba(0, 0, 0, 0.2);
  overflow-y: auto;
}

.sidebar.open {
  left: 0;
}

.sidebar-header {
  background: #172033;
  color: white;
  padding: 18px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.sidebar-header h2 {
  margin: 0;
}

.close-btn {
  border: none;
  background: transparent;
  color: white;
  font-size: 2rem;
  cursor: pointer;
}

.menu {
  padding: 14px;
}

.menu details {
  margin-bottom: 8px;
}

.menu summary {
  cursor: pointer;
  list-style: none;
  padding: 12px 14px;
  border-radius: 10px;
  background: #eef2f8;
  font-weight: 700;
}

.menu summary::-webkit-details-marker {
  display: none;
}

.menu summary::after {
  content: "▾";
  float: right;
  transition: transform 0.2s ease;
}

.menu details[open] > summary::after {
  transform: rotate(180deg);
}

.menu ul {
  list-style: none;
  margin: 7px 0 7px 14px;
  padding: 0 0 0 10px;
  border-left: 2px solid #d9e1ee;
}

.menu li {
  margin: 7px 0;
}

.menu a {
  color: #202124;
  text-decoration: none;
}

.menu li > a {
  display: block;
  padding: 10px 12px;
  border-radius: 9px;
  background: #fafafa;
}

.menu li > a:hover,
.menu summary:hover {
  background: #dce8ff;
}

.menu summary a {
  display: inline-block;
  width: calc(100% - 24px);
}

.overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.38);
  z-index: 900;
}

.overlay.show {
  display: block;
}

.content {
  padding: 34px 22px;
  max-width: 1100px;
  margin: 0 auto;
}

.hero {
  background: white;
  padding: 34px;
  border-radius: 18px;
  box-shadow: 0 8px 24px rgba(23, 32, 51, 0.08);
  margin-bottom: 24px;
}

.eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.78rem;
  color: #5f6673;
  font-weight: 700;
  margin-bottom: 10px;
}

.hero h2 {
  margin: 0 0 10px;
  font-size: clamp(1.8rem, 4vw, 3rem);
}

.hero p {
  margin: 0;
  color: #5f6673;
  line-height: 1.6;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 18px;
}

.card {
  display: block;
  background: white;
  padding: 24px;
  border-radius: 18px;
  box-shadow: 0 8px 24px rgba(23, 32, 51, 0.08);
  text-decoration: none;
  color: inherit;
}

.card:hover {
  transform: translateY(-2px);
}

.card h3 {
  margin-top: 0;
  color: #172033;
}

.card p {
  color: #5f6673;
  line-height: 1.5;
}

.page-panel {
  background: white;
  padding: 28px;
  border-radius: 18px;
  box-shadow: 0 8px 24px rgba(23, 32, 51, 0.08);
}

.page-panel h3 {
  margin-top: 0;
}

.starter-box {
  margin-top: 18px;
  padding: 18px;
  border-radius: 14px;
  background: #eef2f8;
}

.starter-box h4 {
  margin-top: 0;
}

.starter-box ul {
  margin-bottom: 0;
}

@media (max-width: 600px) {
  .topbar {
    min-height: 68px;
    padding: 12px 14px;
  }

  .content {
    padding: 22px 14px;
  }

  .hero,
  .page-panel {
    padding: 24px;
  }
}