.shell {
  display: grid;
  min-height: 100vh;
  grid-template-columns: 272px minmax(0, 1fr);
  transition: grid-template-columns 180ms ease;
}

.shell.sidebar-collapsed {
  grid-template-columns: 0 minmax(0, 1fr);
}

.sidebar {
  position: sticky;
  top: 0;
  height: 100vh;
  padding: 1.1rem;
  border-right: 1px solid var(--line);
  background: #1e2426;
  color: #ffffff;
}

.sidebar-brand {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  padding: 0.8rem 0.75rem 1rem;
}

.sidebar-brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  flex: 0 0 auto;
  border-radius: var(--radius-sm);
  color: var(--accent);
  background: #2b2f31;
  border: 1px solid #44494b;
}

.sidebar-brand h1 {
  font-size: 1rem;
}

.sidebar-nav {
  display: grid;
  gap: 0.45rem;
  margin-top: 1rem;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  padding: 0.85rem 0.9rem;
  border-radius: var(--radius-md);
  color: var(--text-muted);
  transition: background 160ms ease, color 160ms ease, transform 160ms ease;
}

.nav-link:hover {
  background: rgba(255, 255, 255, 0.03);
  color: var(--text);
  transform: translateX(2px);
}

.nav-link.active {
  color: #1e2426;
  background: var(--accent);
}

.nav-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.05);
  font-size: 0.84rem;
  letter-spacing: 0.08em;
}

.shell.sidebar-collapsed .sidebar-brand-copy,
.shell.sidebar-collapsed .nav-label,
.shell.sidebar-collapsed .sidebar-footer-copy {
  display: none;
}

.shell.sidebar-collapsed .sidebar {
  width: 0;
  min-width: 0;
  padding: 0;
  overflow: hidden;
  border-right: 0;
}

.sidebar-footer {
  position: absolute;
  right: 1.1rem;
  bottom: 1.1rem;
  left: 1.1rem;
  padding: 0.9rem;
  border-radius: var(--radius-md);
  border: 1px solid #44494b;
  background: #2b2f31;
}

.main {
  min-width: 0;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem 1.6rem;
  border-bottom: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(16px);
}

.topbar-left,
.topbar-right {
  display: flex;
  align-items: center;
  gap: 0.8rem;
}

.topbar-title h2 {
  font-size: 1.15rem;
}

.topbar-title p {
  margin: 0.15rem 0 0;
  color: var(--text-muted);
  font-size: 0.88rem;
}

.content {
  padding: 1.6rem;
}

.content-stack {
  display: grid;
  gap: 1.2rem;
}

.home-hero {
  padding: 1.6rem;
  overflow: hidden;
  background:
    radial-gradient(circle at top right, rgba(231, 255, 0, 0.24), transparent 32%),
    linear-gradient(135deg, #ffffff, #f7f7f4);
}

.home-hero h2 {
  font-size: clamp(1.8rem, 4vw, 2.8rem);
  margin-bottom: 0.7rem;
}

.module-card {
  display: grid;
  gap: 0.8rem;
  padding: 1.3rem;
  border-radius: var(--radius-lg);
  border: 1px solid var(--line);
  background: var(--surface);
}

.module-card p {
  margin: 0;
  color: var(--text-muted);
}

.module-card footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 0.7rem;
}

@media (max-width: 1080px) {
  .shell,
  .shell.sidebar-collapsed {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: relative;
    height: auto;
    border-right: none;
    border-bottom: 1px solid var(--line);
  }

  .sidebar-footer {
    position: static;
    margin-top: 1rem;
  }

  .shell.sidebar-collapsed .sidebar-brand-copy,
  .shell.sidebar-collapsed .nav-label,
  .shell.sidebar-collapsed .sidebar-footer-copy {
    display: initial;
  }
}

@media (max-width: 720px) {
  .topbar,
  .content {
    padding: 1rem;
  }

  .topbar {
    align-items: flex-start;
    flex-direction: column;
  }
}