:root {
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  line-height: 1.45;
  color: #1a1f24;
  background: #f4f6f8;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
}

a {
  color: inherit;
  text-decoration: none;
}

.shell {
  display: grid;
  grid-template-columns: 220px 1fr;
  min-height: 100vh;
}

.shell-nav {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  padding: 1rem;
  background: #1a2330;
  color: #e8eef4;
}

.shell-brand-title {
  font-size: 1rem;
  font-weight: 600;
}

.shell-module-list {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  flex: 1;
}

.shell-module-link {
  color: #c5d0db;
  padding: 0.5rem 0.65rem;
  border-radius: 6px;
}

.shell-module-link:hover {
  background: #243041;
  color: #fff;
}

.shell-module-link.active {
  background: #2d6a8f;
  color: #fff;
}

.shell-nav-footer {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  padding-top: 0.75rem;
  border-top: 1px solid #2f3b4a;
}

.shell-main {
  min-width: 0;
  background: #fff;
}

.module-frame {
  display: block;
  width: 100%;
  height: 100vh;
  border: 0;
}

.muted {
  color: #9aa8b6;
  font-size: 0.8rem;
}

.truncate {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.btn {
  display: inline-block;
  border: 1px solid #4a5868;
  background: transparent;
  color: inherit;
  border-radius: 6px;
  padding: 0.4rem 0.7rem;
  font: inherit;
  cursor: pointer;
  text-align: center;
}

.btn:hover {
  background: #243041;
}

.btn-primary {
  border-color: #2d6a8f;
  background: #2d6a8f;
  color: #fff;
}

.auth-screen {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  padding: 2rem;
}

@media (max-width: 720px) {
  .shell {
    grid-template-columns: 1fr;
  }

  .module-frame {
    height: calc(100vh - 4.5rem);
  }
}