/* Maths-Gauss uses the shared learning foundation with a 35/65 subject layout. */
.maths_app { --accent: #235e63; --accent_soft: #e7f2f1; --danger: #a63232; }
.maths_app .learning_app { grid-template-columns: minmax(0, 35fr) minmax(0, 65fr); }
.maths_app .learning_menu { background: #f0f4f4; }
.maths_app .menu_header { background: #f0f4f4; }
.maths_app .learning_content { padding: 32px clamp(24px, 4vw, 60px) 56px; }
.maths_app .detail_heading { display: block; }
.maths_app h2 { margin: 0 0 16px; font-size: clamp(25px, 2.6vw, 35px); line-height: 1.35; color: #194d52; }
.maths_app h3 { color: #235e63; }
.course_eyebrow { margin: 0 0 9px; color: #547479; font-size: 11px; letter-spacing: .08em; font-weight: 750; }
.search_label { display: block; font-size: 12px; margin-bottom: 5px; color: var(--muted); }
.math_filters { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 10px; }
.math_filters label { flex: 1 1 100px; min-width: 0; color: var(--muted); font-size: 11px; }
.math_filters select { display: block; margin-top: 4px; font-size: 12px; }
.text_button { background: transparent; border: 0; color: var(--accent); padding: 9px 0 0; font-size: 12px; text-decoration: underline; cursor: pointer; }
.quiet, .classification_path { color: var(--muted); font-size: 12px; line-height: 1.6; }
.classification_path { margin: 0 0 20px; }
.math_category { border-top: 1px solid #d5e0df; margin-top: 9px; }
.math_category > summary { display: flex; align-items: center; gap: 8px; cursor: pointer; color: #294e53; font-weight: 700; font-size: 13px; padding: 10px 2px; list-style: none; }
.math_category > summary::before { content: "›"; font-size: 18px; width: 12px; }
.math_category[open] > summary::before { content: "⌄"; }
.category_count { margin-left: auto; color: #6b8285; font-weight: 500; font-size: 11px; }
.math_category_children { margin-left: 11px; padding-left: 9px; border-left: 1px solid #d9e4e3; }
.math_category_children .math_category { border-top: 0; margin-top: 0; }
.math_menu_item { display: grid; gap: 5px; padding: 10px; margin: 4px 0; border: 1px solid transparent; border-radius: 7px; text-decoration: none; color: #213d42; overflow-wrap: anywhere; }
.math_menu_item strong { font-size: 13px; line-height: 1.5; }
.math_menu_item:hover { background: #e6efee; }
.math_menu_item.is_active { border-color: #91b8b7; background: #e0edeb; }
.math_menu_item > .quiet { font-size: 11px; }
.overview_link { font-weight: 700; }
.status_badge { font-size: 11px; color: #6d7e80; }
.status_badge.has_errors { color: #a63232; font-weight: 700; }
.overview_intro { color: #55696e; line-height: 1.8; max-width: 52em; }
.related_list { display: grid; gap: 10px; margin: 12px 0 25px; }
.related_card { display: grid; gap: 5px; padding: 15px 17px; border: 1px solid #dce5e4; border-radius: 9px; color: #244c51; text-decoration: none; background: #fbfcfc; }
.related_card:hover { border-color: #7ea9a7; background: #f1f7f6; }
.related_card strong { font-size: 14px; line-height: 1.6; }
.related_card > span { color: #6b7b7d; font-size: 12px; line-height: 1.6; }
.related_card > .has_errors { color: #a63232; }
.course_links { display: flex; flex-wrap: wrap; gap: 8px; margin: 22px 0; }
.course_link, .link_chips a { background: #eaf3f1; color: #235e63; border: 1px solid #d4e5e1; border-radius: 6px; padding: 7px 10px; text-decoration: none; font-size: 12px; }
.link_chips { display: flex; flex-wrap: wrap; gap: 7px; margin: 14px 0; }
.problem_statement { margin: 25px 0 16px; font-size: 17px; font-family: "STIX Two Text", "Times New Roman", "PingFang SC", "Microsoft YaHei", serif; }
.problem_statement p { margin: 0 0 10px; line-height: 1.9; }
.problem_figure { margin: 20px 0; background: #fff; padding: 15px; border: 1px solid #e0e7e6; border-radius: 9px; text-align: center; }
.problem_figure img { display: block; width: 100%; max-width: 550px; height: auto; margin: 0 auto; }
.problem_figure figcaption { color: #788786; font-size: 11px; margin-top: 10px; }
.solution_block { margin: 24px 0; border: 1px solid #c9dcd8; border-radius: 9px; padding: 15px 18px; background: #f6faf9; }
.solution_block > summary, .knowledge_example > summary { color: #235e63; font-weight: 700; cursor: pointer; line-height: 1.6; }
.solution_block li { padding: 4px 0; line-height: 1.85; overflow-wrap: anywhere; }
.answer_line { font-size: 18px; font-weight: 700; color: #194d52; }
.diagram_notes { margin: 12px 0; font-size: 13px; color: #637776; }
.diagram_notes > summary { cursor: pointer; }
.knowledge_example { margin: 12px 0; padding: 15px 18px; border: 1px solid #d6e2df; border-radius: 9px; }
.maths_app .detail_section { margin: 28px 0; }
.maths_app .detail_section p { margin: 8px 0; line-height: 1.9; }
.source_section { border-top: 1px solid #dce5e4; padding-top: 20px; }
.source_link { display: block; margin: 9px 0; font-size: 12px; line-height: 1.75; overflow-wrap: anywhere; }
.confirmation_notice { margin: 22px 0; padding: 17px 20px; border-left: 4px solid #b78428; background: #fffaee; border-radius: 0 8px 8px 0; color: #73511b; }
.empty_review { padding: 22px 24px; border: 1px dashed #abc5c1; background: #f5faf8; border-radius: 9px; margin: 24px 0; }
.review_outcome { color: #235e63; font-size: 18px; font-weight: 700; }
.math_panel[hidden] { display: none; }
.maths_app :focus-visible { outline: 2px solid #235e63; outline-offset: 3px; }
.maths_lesson .related_card { width: 100%; box-sizing: border-box; }
@media (max-width: 820px) {
  .maths_app .learning_app { grid-template-columns: minmax(0, 1fr); }
  .maths_app .learning_content { padding: 24px 20px 40px; }
  .maths_app #math_tree { max-height: 42vh; overflow-y: auto; }
}
@media print {
  .maths_app .learning_app { display: block; }
  .maths_app .learning_content { padding: 0; }
  .math_panel[hidden] { display: none; }
}

.editorial_notes { margin: 16px 0; padding: 12px 16px; background: #fff9ed; border-left: 3px solid #c19a51; color: #755a2c; font-size: 13px; }
.editorial_notes > strong { font-weight: 650; }
.learning_connections { margin: 28px 0; padding: 18px; background: #f2f7f6; border: 1px solid #d7e4e1; border-radius: 10px; }
.knowledge_graph { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, .7fr) minmax(0, 1fr); gap: 12px; align-items: center; }
.knowledge_graph h4, .related_knowledge h4 { font-size: 13px; margin: 8px 0; color: #526e70; }
.knowledge_node { display: grid; gap: 5px; padding: 12px; margin: 8px 0; border: 1px solid #bfd6d1; border-radius: 8px; background: white; color: #235e63; text-decoration: none; overflow-wrap: anywhere; }
.knowledge_node strong { font-size: 13px; line-height: 1.65; }
.knowledge_node span { font-size: 11px; color: #718580; }
.knowledge_node:hover { border-color: #235e63; }
.current_knowledge { display: flex; flex-direction: column; gap: 9px; text-align: center; color: #194d52; font-size: 13px; line-height: 1.7; }
.current_knowledge > span { font-size: 22px; }
.related_knowledge { border-top: 1px solid #d7e4e1; margin-top: 15px; padding-top: 10px; }
.learning_objectives { margin: 20px 0; }
.learning_objectives li { line-height: 1.9; }
.teaching_group { margin: 35px 0; }
.teaching_example { padding: 18px; margin: 14px 0; border-left: 3px solid #6b9b94; background: #fafcfb; }
.teaching_example h4 { margin: 0 0 12px; font-size: 17px; }
.teaching_origin { color: #667d78; font-size: 12px; line-height: 1.7; }
.learning_hint { margin: 12px 0; color: #566e6a; line-height: 1.8; }
.learning_hint > summary, .course_origin_links > summary { cursor: pointer; }
.learning_path_steps { padding-left: 25px; }
.learning_path_steps > li { padding: 5px 0; color: #235e63; }
.learning_routes { margin: 25px 0; }
.course_origin_links { margin: 22px 0; }
.learning_route_link { color: #235e63; border-left: 3px solid #accbc5; font-size: 13px; }
@media (max-width: 1100px) {
  .knowledge_graph { grid-template-columns: minmax(0, 1fr); }
  .current_knowledge { flex-direction: row; align-items: center; justify-content: center; }
  .current_knowledge > span { transform: rotate(90deg); }
}