.class-body {
  min-height: 100vh;
  margin: 0;
  background: var(--bg);
  color: var(--ink);
}

.class-shell {
  min-height: 100vh;
  display: grid;
  grid-template-columns: 240px minmax(0, 1fr) minmax(280px, 340px);
}

.class-nav,
.class-mentor {
  position: sticky;
  top: 0;
  height: 100vh;
  overflow: auto;
  background: color-mix(in srgb, var(--panel) 92%, transparent);
}

.class-nav {
  display: flex;
  flex-direction: column;
  gap: 16px;
  padding: 18px;
  border-right: 1px solid var(--line);
}

.class-mentor {
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: 18px;
  border-left: 1px solid var(--line);
}

.class-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: inherit;
  text-decoration: none;
}

.class-brand span {
  display: grid;
  gap: 2px;
}

.class-user,
.class-mentor-head small,
.class-mentor-note,
.class-check-out,
.class-practice-head span,
.class-head p {
  color: var(--muted);
}

.class-lessons {
  display: grid;
  gap: 6px;
  flex: 1;
}

.class-lessons button {
  display: grid;
  gap: 2px;
  text-align: left;
  padding: 10px 12px;
  border: 1px solid transparent;
  border-radius: 12px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font: 700 0.88rem/1.25 Inter, sans-serif;
}

.class-lessons button small {
  font-weight: 600;
  color: var(--soft);
}

.class-lessons button.is-active,
.class-lessons button:hover {
  color: var(--ink);
  border-color: var(--line);
  background: color-mix(in srgb, var(--blue) 12%, transparent);
}

.class-lessons button.is-done {
  border-color: color-mix(in srgb, var(--green) 35%, var(--line));
}

.class-nav-foot {
  display: grid;
  gap: 8px;
}

.class-nav-foot a {
  color: var(--muted);
  font-weight: 700;
  font-size: 0.88rem;
}

.class-main {
  display: grid;
  gap: 16px;
  padding: 22px;
  align-content: start;
}

.class-head {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: start;
}

.class-head-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

.class-head h1 {
  margin: 6px 0;
  font-family: Manrope, Inter, sans-serif;
  font-size: clamp(1.4rem, 2.4vw, 1.9rem);
}

.class-progress {
  display: grid;
  justify-items: end;
}

.class-progress strong {
  font-size: 1.6rem;
  line-height: 1;
}

.class-theory {
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: color-mix(in srgb, var(--panel) 88%, transparent);
}

.class-theory h3 {
  margin-top: 0;
  font-family: Manrope, Inter, sans-serif;
}

.class-theory code {
  font-family: "JetBrains Mono", monospace;
  font-size: 0.9em;
}

.class-practice {
  display: grid;
  gap: 12px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: color-mix(in srgb, var(--panel-2) 80%, transparent);
}

.class-practice-head {
  display: flex;
  justify-content: space-between;
  gap: 12px;
}

.class-editor {
  width: 100%;
  min-height: 220px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 12px;
  resize: vertical;
  background: #0b1522;
  color: #e8f1ff;
  font: 500 0.92rem/1.45 "JetBrains Mono", monospace;
}

.class-practice-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.beta-button {
  min-height: 42px;
  padding: 0 14px;
  border-radius: 12px;
  border: 1px solid var(--line);
  background: transparent;
  color: var(--ink);
  font: 800 0.9rem/1 Inter, sans-serif;
  cursor: pointer;
}

.beta-button.primary {
  border-color: transparent;
  background: linear-gradient(135deg, var(--green), var(--blue));
  color: #04111e;
}

.beta-button.ghost:hover {
  background: color-mix(in srgb, var(--blue) 12%, transparent);
}

.class-mentor-head {
  display: grid;
  gap: 4px;
}

.class-mentor-thread {
  flex: 1;
  display: grid;
  gap: 10px;
  align-content: start;
  overflow: auto;
  padding-right: 4px;
}

.class-bubble {
  padding: 12px 14px;
  border-radius: 14px;
  border: 1px solid var(--line);
  background: color-mix(in srgb, var(--panel-2) 85%, transparent);
  font-size: 0.92rem;
  line-height: 1.45;
  white-space: pre-wrap;
}

.class-bubble.mentor {
  border-color: color-mix(in srgb, var(--blue) 35%, var(--line));
}

.class-mentor-actions {
  display: grid;
  grid-template-columns: 1fr;
  gap: 8px;
}

.class-mentor-note {
  margin: 0;
  font-size: 0.82rem;
}

@media (max-width: 1100px) {
  .class-shell {
    grid-template-columns: 220px minmax(0, 1fr);
  }

  .class-mentor {
    position: static;
    height: auto;
    grid-column: 1 / -1;
    border-left: 0;
    border-top: 1px solid var(--line);
  }
}

@media (max-width: 760px) {
  .class-shell {
    grid-template-columns: 1fr;
  }

  .class-nav {
    position: static;
    height: auto;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }
}