.course-section-subnav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.65rem 2rem 0.65rem 0.75rem;
  background: var(--section-color, #1f8ba3);
  color: var(--section-on-color, #ffffff);
}

.course-section-subnav-left {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  min-width: 0;
}

.course-section-back {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
  color: inherit;
  text-decoration: none;
  border-radius: 4px;
  flex-shrink: 0;
}

.course-section-back:hover {
  background: rgba(255, 255, 255, 0.15);
}

.course-section-back svg {
  width: 1.25rem;
  height: 1.25rem;
}

.course-section-subnav-title {
  font-size: 0.95rem;
  font-weight: 600;
  line-height: 1.3;
}

.course-section-subnav-right {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  flex-shrink: 0;
}

.course-section-subnav-print[hidden] {
  display: none !important;
}

.course-section-subnav-menu,
.course-section-subnav-print {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
  border: none;
  background: transparent;
  color: inherit;
  cursor: pointer;
  border-radius: 4px;
  flex-shrink: 0;
}

.course-section-subnav-menu:hover,
.course-section-subnav-print:hover {
  background: rgba(255, 255, 255, 0.15);
}

.course-section-subnav-print:disabled {
  opacity: 0.45;
  cursor: default;
}

.course-section-subnav-print:disabled:hover {
  background: transparent;
}

.course-section-subnav-menu svg,
.course-section-subnav-print svg {
  width: 1.1rem;
  height: 1.1rem;
}

.course-section-main {
  background: var(--white);
  min-height: calc(100vh - 7.5rem);
  padding: 2rem 1.5rem 3rem;
}

.course-section-placeholder {
  max-width: 42rem;
  margin: 0 auto;
  color: #666;
  font-size: 1rem;
  line-height: 1.55;
}

.course-section-placeholder a {
  color: inherit;
  text-decoration: underline;
  text-underline-offset: 0.15em;
}

.course-section-placeholder a:hover {
  color: var(--navy);
}

.course-section-placeholder b {
  font-weight: 700;
}

.course-coming-soon {
  max-width: 42rem;
  margin: 0 auto;
}

.course-coming-soon-item-title {
  margin: 0 0 0.75rem;
  font-size: 1.05rem;
  font-weight: 700;
  line-height: 1.4;
  color: var(--navy);
}

.worksheets-layout {
  max-width: 56rem;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.worksheet-lesson-toggle,
.worksheet-unit-toggle {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  width: 100%;
  padding: 0.75rem 0.9rem;
  border: none;
  font: inherit;
  font-size: 0.9rem;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
}

.worksheet-lesson-toggle {
  background: #d9eef3;
  color: var(--navy);
}

.worksheet-lesson-toggle:hover:not(:disabled) {
  background: #c7e4eb;
}

.worksheet-lesson-toggle:disabled {
  cursor: default;
}

.worksheet-lesson-title {
  flex: 1 1 auto;
  min-width: 0;
}

.worksheet-lesson-chevron,
.worksheet-unit-chevron {
  width: 1rem;
  height: 1rem;
  flex-shrink: 0;
}

.worksheet-lesson.is-open .worksheet-lesson-chevron,
.worksheet-unit.is-open .worksheet-unit-chevron {
  transform: rotate(180deg);
}

.worksheet-lesson-panel {
  padding: 0.85rem 0.9rem 1rem;
  background: var(--white);
  border-bottom: 1px solid #c7e4eb;
}

.worksheet-card-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.85rem;
}

.worksheet-card {
  border: 1px solid #c7e4eb;
  background: var(--white);
}

.worksheet-card.is-target {
  border-color: #1f8ba3;
  box-shadow: 0 0 0 2px rgba(31, 139, 163, 0.25);
}

.worksheet-card.is-selected {
  border-color: #1f8ba3;
  box-shadow: 0 0 0 2px rgba(31, 139, 163, 0.18);
}

.worksheet-card-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  padding: 0.45rem 0.55rem;
  background: #d9eef3;
}

.worksheet-card-label {
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--navy);
}

.worksheet-card-thumb {
  display: block;
  min-height: 8.5rem;
  padding: 0;
  background: #f0f0f0;
  overflow: hidden;
}

.worksheet-card-thumb-title {
  font-size: 0.78rem;
  font-weight: 700;
  color: #1f8ba3;
  text-align: center;
}

.worksheet-unit-toggle {
  background: var(--section-color, #1f8ba3);
  color: var(--section-on-color, #ffffff);
}

.worksheet-unit-actions {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  flex-shrink: 0;
}

.worksheet-unit-toggle:hover {
  filter: brightness(1.05);
}

.worksheet-unit-panel {
  background: var(--white);
}

.worksheet-unit-nested-lessons {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  padding: 0.85rem 0.9rem 1rem;
}

.worksheet-unit-nested-lessons .worksheet-lesson-panel {
  border-bottom: none;
}

@media (max-width: 768px) {
  .worksheet-card-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .course-section-subnav {
    padding: 0.5rem 0.85rem 0.5rem 0.5rem;
    gap: 0.65rem;
  }

  .course-section-subnav-title {
    font-size: 0.85rem;
  }

  .course-section-subnav-right {
    gap: 0.2rem;
  }

  .course-section-subnav-menu,
  .course-section-subnav-print {
    width: 1.6rem;
    height: 1.6rem;
  }

  .course-section-subnav-menu svg,
  .course-section-subnav-print svg {
    width: 0.95rem;
    height: 0.95rem;
  }
}