.activity-builder {
  display: grid;
  gap: 14px;
  padding-top: 14px;
  border-top: 1px solid var(--revision-line);
}
.activity-preview {
  display: grid;
  gap: 12px;
  max-height: 560px;
  overflow: auto;
  padding: 3px;
}
.activity-preview:empty {
  display: none;
}
.activity-question {
  background: #0b1828;
  border: 1px solid #2b4154;
  border-radius: 12px;
  padding: 18px;
  min-width: 0;
}
.activity-question h3 {
  font-size: 1rem;
  line-height: 1.5;
  white-space: pre-wrap;
  margin: 8px 0 16px;
}
.activity-question p,
.activity-question li {
  font-size: 0.84rem;
  line-height: 1.65;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}
.activity-question ol {
  padding-left: 22px;
}
.activity-question summary {
  font-size: 0.8rem;
  color: var(--revision-accent);
  cursor: pointer;
}
.question-meta {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  flex-wrap: wrap;
  color: var(--revision-muted);
  font-size: 0.7rem;
}
.question-options {
  display: grid;
  gap: 9px;
  margin: 12px 0;
}
.question-options label {
  display: flex;
  align-items: center;
  gap: 12px;
  border: 1px solid var(--revision-line);
  border-radius: 10px;
  padding: 12px;
  background: #112438;
  font-size: 0.9rem;
  cursor: pointer;
}
.question-options label:has(input:checked) {
  border-color: var(--revision-accent);
  background: #143a37;
}
.question-options input {
  width: 18px;
  height: 18px;
  accent-color: var(--revision-accent);
  flex-shrink: 0;
}
.activity-answer {
  width: 100%;
  border: 1px solid var(--revision-line);
  background: #102132;
  color: var(--revision-text);
  padding: 12px;
  border-radius: 9px;
  line-height: 1.5;
}
.activity-answer-number {
  max-width: 300px;
}
.activity-unit {
  color: var(--revision-muted);
  font-size: 0.8rem;
  margin-left: 10px;
}
.activity-wrap {
  max-width: 960px;
}
.activity-topbar {
  position: sticky;
  top: 65px;
  z-index: 20;
  background: #102132f5;
  border: 1px solid var(--revision-line);
  border-radius: 14px;
  padding: 16px;
  display: flex;
  gap: 14px;
  align-items: center;
  justify-content: space-between;
  margin: 20px 0;
}
.activity-topbar p {
  margin: 0;
  font-size: 0.8rem;
}
.activity-topbar progress {
  display: block;
  width: 100%;
  height: 7px;
  margin-top: 9px;
  accent-color: var(--revision-accent);
}
.activity-topbar > div {
  flex: 1;
  min-width: 0;
}
.activity-question-list {
  display: grid;
  gap: 16px;
}
.activity-result {
  margin: 24px 0;
  padding: 24px;
  border: 1px solid #416c63;
  background: #12332f;
  border-radius: 16px;
}
.activity-result h2 {
  margin-top: 0;
}
.activity-score {
  font-size: 2rem;
  font-weight: 800;
  color: var(--revision-accent);
}
.activity-result p {
  line-height: 1.6;
  font-size: 0.88rem;
}
.question-feedback {
  padding: 12px;
  border-left: 3px solid var(--revision-accent);
  margin-top: 14px;
  background: #102d2b;
}
.question-feedback[data-correct="false"] {
  border-color: #f2c779;
  background: #2f2b20;
}
.question-feedback[data-review="true"] {
  border-color: #abbded;
  background: #202b41;
}
.activity-footer-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin: 22px 0;
}
.activity-submission {
  display: grid;
  gap: 12px;
}
.activity-review-item {
  border-top: 1px solid var(--revision-line);
  padding-top: 12px;
}
.activity-review-item h4 {
  white-space: pre-wrap;
  line-height: 1.5;
  margin: 0 0 8px;
}
.activity-review-item p {
  white-space: pre-wrap;
  line-height: 1.6;
  margin: 5px 0;
  font-size: 0.78rem;
  overflow-wrap: anywhere;
}
.activity-review-item label {
  font-size: 0.74rem;
}
.activity-review-score {
  max-width: 120px;
  margin: 6px;
}
.activity-review-item details {
  font-size: 0.76rem;
  color: #c8d5de;
}
.activity-stat-strip {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  font-size: 0.72rem;
  margin: 14px 0;
}
.activity-stat-strip span {
  border: 1px solid var(--revision-line);
  padding: 8px;
  border-radius: 8px;
}
.activity-missing {
  font-size: 0.72rem;
  color: #e8c796;
  line-height: 1.6;
}
.activity-preview-header {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: center;
}
.activity-preparation {
  padding: 16px;
  border: 1px solid var(--revision-line);
  border-radius: 12px;
  margin: 16px 0;
}
.activity-preparation p {
  line-height: 1.6;
  font-size: 0.85rem;
}
.activity-preparation a {
  display: block;
  margin: 8px 0;
  color: var(--revision-accent);
  font-size: 0.8rem;
}
.activity-toolbar {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}
.custom-question {
  padding: 12px;
  border: 1px solid var(--revision-line);
  border-radius: 10px;
}
.custom-question summary {
  cursor: pointer;
  font-size: 0.8rem;
}
.custom-question .teacher-form {
  margin-top: 14px;
}
.activity-notice {
  font-size: 0.85rem;
  line-height: 1.6;
}
.activity-status-filter {
  width: 100%;
  margin-top: 8px;
}
.question-review-error {
  outline: 2px solid #eda3af;
  outline-offset: 3px;
}
.teacher-form input[type="checkbox"] {
  width: 18px;
  height: 18px;
  padding: 0;
  accent-color: var(--revision-accent);
}
.teacher-form .checkbox-label {
  display: flex;
  align-items: center;
  gap: 10px;
}
.activity-pending {
  color: #f2c779;
}
.activity-result details {
  margin-top: 16px;
}
.activity-result summary {
  cursor: pointer;
}
.activity-recommendations {
  padding-top: 10px;
}
.activity-builder select,
.activity-builder input {
  min-width: 0;
}
.assignment-card h3,
.assignment-class-name {
  overflow-wrap: anywhere;
}
@media (max-width: 650px) {
  .activity-topbar {
    top: 105px;
    flex-wrap: wrap;
    padding: 12px;
  }
  .activity-topbar > div {
    flex-basis: 100%;
  }
  .activity-topbar button {
    flex: 1;
  }
  .activity-question {
    padding: 14px;
  }
  .activity-question h3 {
    font-size: 0.94rem;
  }
  .activity-result {
    padding: 18px;
  }
  .activity-preview {
    max-height: 430px;
  }
  .activity-stat-strip span {
    flex: 1;
  }
  .question-options label {
    font-size: 0.82rem;
  }
  .activity-footer-actions .teacher-button {
    width: 100%;
  }
}
/* Shared task figures remain legible at classroom and mobile widths. */
.homework-figure { margin: 1rem 0; }
.homework-figure img { display: block; width: 100%; max-width: 640px; height: auto; border-radius: 12px; background: #f5f9fb; }
.homework-figure figcaption { margin-top: .5rem; font-size: .9rem; }