._skipLink_7qyzj_3{z-index:10;background:var(--canvas);border:1px solid var(--border);border-radius:6px;padding:8px 12px;position:absolute;top:-48px;left:8px}._skipLink_7qyzj_3:focus{top:8px}._page_7qyzj_18{flex-direction:column;min-height:100dvh;display:flex}._main_7qyzj_24{flex-direction:column;flex:1;min-height:0;display:flex}._main_7qyzj_24:focus,._main_7qyzj_24:focus-visible{outline:none}._header_7qyzj_37{background:var(--canvas-subtle);border-bottom:1px solid var(--border);flex:0 0 48px;align-items:center;gap:16px;padding:0 16px;display:flex}._brand_7qyzj_47{color:var(--text);flex:none;align-items:center;gap:8px;font-size:14px;font-weight:600;display:inline-flex}._brand_7qyzj_47:hover{text-decoration:none}._mark_7qyzj_61{color:var(--accent)}._headerNav_7qyzj_65{gap:4px;display:flex}._headerLink_7qyzj_70{color:var(--text);border-radius:6px;padding:4px 8px}._headerLink_7qyzj_70:hover{background:var(--border-muted);text-decoration:none}._headerLinkActive_7qyzj_81{box-shadow:inset 0 -2px 0 var(--accent);border-radius:6px 6px 0 0;font-weight:600}._headerCount_7qyzj_87{color:var(--text-muted);white-space:nowrap;margin-left:auto;font-size:13px}._notice_7qyzj_94{background:var(--attention-tint);border-bottom:1px solid var(--border);color:var(--text);padding:8px 16px;font-size:13px}._button_7qyzj_104{border:1px solid var(--border-control);background:var(--canvas-subtle);min-height:32px;color:var(--text);cursor:pointer;font:inherit;white-space:nowrap;border-radius:6px;justify-content:center;align-items:center;gap:8px;padding:4px 12px;font-weight:600;display:inline-flex}._button_7qyzj_104:hover:not(:disabled){background:var(--border-muted);text-decoration:none}._button_7qyzj_104:disabled{border-color:var(--border);color:var(--text-muted);cursor:not-allowed}._primary_7qyzj_132{background:var(--primary);border-color:var(--primary);color:#fff}._primary_7qyzj_132:hover:not(:disabled){background:var(--primary-hover);border-color:var(--primary-hover)}._primary_7qyzj_132:disabled{background:var(--canvas-subtle)}._quiet_7qyzj_147{min-height:24px;color:var(--accent);background:0 0;border-color:#0000;padding:0 8px;font-weight:400}._quiet_7qyzj_147:disabled{background:0 0;border-color:#0000}._iconButton_7qyzj_161{width:32px;padding:0}._keyHint_7qyzj_166{color:inherit;opacity:.8;font-size:12px;font-weight:400}@media (pointer:coarse){._button_7qyzj_104{min-height:40px}._iconButton_7qyzj_161{width:40px}._keyHint_7qyzj_166{display:none}}._bar_7qyzj_189{background:var(--bar-track);border-radius:999px;display:flex;overflow:hidden}._barLarge_7qyzj_196{height:8px}._barSmall_7qyzj_200{height:6px}._barDone_7qyzj_204{background:var(--bar-done);min-width:2px}._tableBox_7qyzj_211{max-width:100%;overflow-x:auto}._table_7qyzj_211{border-collapse:collapse;width:100%;font-size:13px}._table_7qyzj_211 th,._table_7qyzj_211 td{border-bottom:1px solid var(--border-muted);text-align:left;white-space:nowrap;padding:4px 8px}._table_7qyzj_211 tr:last-child td{border-bottom:0}._table_7qyzj_211 th{background:var(--canvas-subtle);border-bottom:1px solid var(--border);font-weight:600}._columnType_7qyzj_240{color:var(--text-muted);font-size:12px;font-weight:400;display:block}._null_7qyzj_247{color:var(--text-muted);font-style:italic}._emptyRows_7qyzj_252{color:var(--text-muted);padding:8px 12px;font-size:13px}._editorBox_7qyzj_260{flex-direction:column;flex:1;min-height:0;display:flex}._editorBox_7qyzj_260:focus-within ._editorHeader_7qyzj_268{box-shadow:inset 0 -2px 0 var(--accent)}._editorHeader_7qyzj_268{background:var(--canvas-subtle);border-bottom:1px solid var(--border);min-height:32px;color:var(--text-muted);font-family:var(--font-mono);flex:none;justify-content:space-between;align-items:center;gap:8px;padding:0 8px 0 16px;font-size:12px;display:flex}._editorHeaderActions_7qyzj_287{font-family:var(--font-sans);align-items:center;gap:4px;display:flex}._editor_7qyzj_260{resize:none;background:var(--canvas);width:100%;min-height:120px;color:var(--text);font-family:var(--font-mono);border:0;outline:none;flex:1;padding:12px 16px;font-size:14px;line-height:1.5;display:block}._editor_7qyzj_260:focus,._editor_7qyzj_260:focus-visible{outline:none}._errorBox_7qyzj_318{background:var(--danger-tint);border-left:2px solid var(--danger);color:var(--danger);font-family:var(--font-mono);white-space:pre-wrap;overflow-wrap:anywhere;margin-top:8px;padding:8px 12px;font-size:13px}._muted_7qyzj_330{color:var(--text-muted)}._srOnly_7qyzj_334{clip-path:inset(50%);white-space:nowrap;width:1px;height:1px;position:absolute;overflow:hidden}._notFound_7qyzj_343{max-width:640px;margin:48px auto;padding:0 16px}._notFound_7qyzj_343 h1{margin-bottom:8px;font-size:20px;font-weight:600}@media (width<=1023px){._editor_7qyzj_260{font-size:16px}}@media (forced-colors:active){._barDone_7qyzj_204{background:highlight}}._topBar_1eaoh_3{border-bottom:1px solid var(--border);flex-wrap:wrap;justify-content:space-between;align-items:center;gap:8px 16px;min-height:48px;padding:8px 16px;display:flex}._crumbs_1eaoh_14{flex-wrap:wrap;gap:4px;min-width:0;font-size:13px;display:flex}._crumbSeparator_1eaoh_22{color:var(--text-muted)}._crumbCurrent_1eaoh_26{font-weight:600}._topBarRight_1eaoh_30{align-items:center;gap:8px;min-width:0;max-width:100%;display:flex}._strip_1eaoh_38{align-items:center;gap:4px;min-width:0;padding:2px;display:flex;overflow-x:auto}._stepCell_1eaoh_47{border:1px solid var(--border);width:28px;height:28px;color:var(--text);border-radius:6px;flex:none;justify-content:center;align-items:center;font-size:12px;display:inline-flex}._stepCell_1eaoh_47:hover{background:var(--canvas-subtle);text-decoration:none}._stepDone_1eaoh_65{background:var(--success-tint);border-color:var(--success);color:var(--success)}._stepAttempted_1eaoh_71{border-color:var(--attention);color:var(--attention)}._stepCurrent_1eaoh_76{border-color:var(--accent);box-shadow:0 0 0 1px var(--accent);font-weight:600}._stripDivider_1eaoh_82{background:var(--border-control);flex:none;width:1px;height:20px;margin:0 4px}._split_1eaoh_92{flex-direction:column;flex:1;min-height:0;display:flex}._left_1eaoh_99,._right_1eaoh_100{min-width:0}._left_1eaoh_99{padding:16px}._right_1eaoh_100{flex-direction:column;display:flex}@media (width>=1024px) and (height>=640px){._desktopFrame_1eaoh_115{height:100dvh;overflow:hidden}._split_1eaoh_92{grid-template-columns:minmax(0,1fr) minmax(0,1fr);display:grid;overflow:hidden}._left_1eaoh_99{border-right:1px solid var(--border);overflow-y:auto}._right_1eaoh_100{min-height:0;overflow:hidden}}._title_1eaoh_139{font-size:20px;font-weight:600;line-height:1.3}._stepLine_1eaoh_145{color:var(--text-muted);flex-wrap:wrap;align-items:center;gap:8px;margin:4px 0 12px;font-size:13px;display:flex}._extraTag_1eaoh_155{border:1px solid var(--border);border-radius:999px;padding:0 8px;font-size:12px}._prompt_1eaoh_162{margin-bottom:24px;font-size:16px}._sectionLabel_1eaoh_167{border-bottom:1px solid var(--border-muted);color:var(--text-muted);letter-spacing:.04em;text-transform:uppercase;margin-bottom:8px;padding-bottom:4px;font-size:12px;font-weight:600}._story_1eaoh_178{color:var(--text-muted);margin-bottom:12px}._tableName_1eaoh_183{font-family:var(--font-mono);margin:12px 0 4px;font-size:13px;font-weight:600}._actions_1eaoh_192{border-top:1px solid var(--border);flex-wrap:wrap;flex:none;align-items:center;gap:8px;padding:8px 16px;display:flex}._caption_1eaoh_202{color:var(--text-muted);font-size:12px}._running_1eaoh_207{color:var(--text-muted);font-size:13px}._nextLink_1eaoh_212{text-overflow:ellipsis;max-width:100%;margin-left:auto;overflow:hidden}._spacerActions_1eaoh_219{flex-wrap:wrap;gap:8px;min-width:0;margin-left:auto;display:flex}._panel_1eaoh_229{border-top:1px solid var(--border);flex-direction:column;flex:none;min-height:0;display:flex}._panelOpen_1eaoh_237{flex:50%}._tabBar_1eaoh_241{background:var(--canvas-subtle);border-bottom:1px solid var(--border);flex:none;align-items:stretch;display:flex}._tabs_1eaoh_249{flex:1;min-width:0;display:flex;overflow-x:auto}._tab_1eaoh_183{min-height:40px;color:var(--text-muted);cursor:pointer;font:inherit;background:0 0;border:0;flex:none;align-items:center;gap:6px;padding:0 12px;display:inline-flex}._tab_1eaoh_183:hover{color:var(--text)}._tab_1eaoh_183:focus-visible{outline-offset:-2px}._tabActive_1eaoh_278{color:var(--text);box-shadow:inset 0 -2px 0 var(--accent);font-weight:600}._tabBadge_1eaoh_284{background:var(--border-muted);color:var(--text-muted);border-radius:999px;padding:0 6px;font-size:12px;font-weight:400}._badgePass_1eaoh_293{background:var(--success-tint);color:var(--success)}._badgeFail_1eaoh_298{background:var(--danger-tint);color:var(--danger)}._collapse_1eaoh_303{width:40px;color:var(--text-muted);cursor:pointer;background:0 0;border:0;flex:none}._collapse_1eaoh_303:hover{color:var(--text)}._collapse_1eaoh_303:focus-visible{outline-offset:-2px}._collapseIcon_1eaoh_320{transition:transform .1s;display:inline-block}._collapseIconOpen_1eaoh_325{transform:rotate(180deg)}._tabPanel_1eaoh_329{flex:1;min-height:0;padding:12px 16px 16px;overflow-y:auto}._tabPanel_1eaoh_329:focus-visible{outline-offset:-2px}._empty_1eaoh_342{color:var(--text-muted)}._stale_1eaoh_346{color:var(--text-muted);margin-bottom:8px;font-size:13px;font-style:italic}._resultBlock_1eaoh_353{margin-bottom:12px}._resultLabel_1eaoh_357{margin-bottom:4px;font-size:13px;font-weight:600}._meta_1eaoh_363{color:var(--text-muted);margin-top:4px;font-size:13px}._verdict_1eaoh_369{align-items:center;gap:8px;margin-bottom:8px;font-size:16px;font-weight:600;display:flex}._verdictPass_1eaoh_378{color:var(--success)}._verdictFail_1eaoh_382{color:var(--danger)}._milestone_1eaoh_386{margin-bottom:8px}._caseRow_1eaoh_390{border-top:1px solid var(--border-muted);padding:8px 0}._caseLine_1eaoh_395{align-items:center;gap:8px;display:flex}._casePass_1eaoh_401{color:var(--success);flex:none}._caseFail_1eaoh_406{color:var(--danger);flex:none}._caseHidden_1eaoh_411{color:var(--text-muted);flex:none}._compare_1eaoh_416{flex-wrap:wrap;gap:16px;margin-top:8px;display:flex}._compare_1eaoh_416>div{flex:200px;min-width:0}._compareTitle_1eaoh_428{margin-bottom:4px;font-size:13px;font-weight:600}._hiddenCount_1eaoh_434{border-top:1px solid var(--border-muted);color:var(--text-muted);align-items:center;gap:8px;padding:8px 0;display:flex}._hintList_1eaoh_443{margin-bottom:12px}._hintItem_1eaoh_447{border-bottom:1px solid var(--border-muted);padding:8px 0}._hintNumber_1eaoh_452{color:var(--text-muted);margin-right:8px;font-size:13px}._alsoUses_1eaoh_458{color:var(--text-muted);margin-top:12px;font-size:13px}._locked_1eaoh_464{color:var(--text-muted);align-items:center;gap:8px;display:flex}._answerNote_1eaoh_471{margin-bottom:12px}._solution_1eaoh_475{background:var(--canvas-subtle);font-family:var(--font-mono);white-space:pre-wrap;margin:0 0 12px;padding:12px;font-size:13px;overflow-x:auto}._answerHeading_1eaoh_485{margin:12px 0 4px;font-size:13px;font-weight:600}._mistake_1eaoh_491{border-top:1px solid var(--border-muted);padding:4px 0}._playgroundResults_1eaoh_498{border-top:1px solid var(--border);flex:50%;min-height:0;padding:12px 16px 16px;overflow-y:auto}@media (width<=1023px),(height<=639px){._left_1eaoh_99{border-bottom:1px solid var(--border)}._editorSlot_1eaoh_511{flex-direction:column;min-height:200px;display:flex}._tabPanel_1eaoh_329,._playgroundResults_1eaoh_498{overflow:visible}._nextLink_1eaoh_212,._spacerActions_1eaoh_219{margin-left:0}}@media (width>=1024px) and (height>=640px){._editorSlot_1eaoh_511{flex-direction:column;flex:50%;min-height:120px;display:flex}}@media (pointer:coarse){._stepCell_1eaoh_47{width:32px;height:32px}._tab_1eaoh_183{min-height:44px}}._page_10p7t_1{width:100%;max-width:760px;margin:0 auto;padding:32px 16px 48px}._intro_10p7t_8{flex-wrap:wrap;justify-content:space-between;align-items:center;gap:16px;margin-bottom:24px;display:flex}._title_10p7t_17{font-size:24px;font-weight:600;line-height:1.25}._subtitle_10p7t_23{color:var(--text-muted);margin-top:4px}._continue_10p7t_28{text-overflow:ellipsis;max-width:100%;overflow:hidden}._progressLabel_10p7t_34{flex-wrap:wrap;justify-content:space-between;gap:4px 8px;margin-bottom:8px;display:flex}._progressName_10p7t_42{font-weight:600}._overall_10p7t_46{border-bottom:1px solid var(--border);padding-bottom:24px}._chapterRow_10p7t_53{border-bottom:1px solid var(--border-muted);min-height:56px;color:var(--text);grid-template-columns:96px minmax(0,1fr) 160px 72px 16px;align-items:center;gap:12px;padding:8px;display:grid}._chapterRow_10p7t_53:hover{background:var(--canvas-subtle);text-decoration:none}._chapterNumber_10p7t_69{color:var(--text-muted)}._chapterName_10p7t_73{font-size:16px;font-weight:600}._count_10p7t_78{color:var(--text-muted);text-align:right;white-space:nowrap;font-size:13px}._rowArrow_10p7t_85{color:var(--text-muted);display:inline-flex}._back_10p7t_92{align-items:center;gap:4px;margin-bottom:16px;font-size:13px;display:inline-flex}._chapterEyebrow_10p7t_100{color:var(--text-muted);font-size:13px}._chapterProgress_10p7t_105{padding-bottom:24px}._groupHeading_10p7t_109{border-bottom:1px solid var(--border);justify-content:space-between;align-items:baseline;gap:16px;padding:24px 8px 8px;display:flex}._groupTitle_10p7t_118{font-size:16px;font-weight:600}._groupOutcome_10p7t_123{color:var(--text-muted);font-size:13px}._assignmentRow_10p7t_128{border-bottom:1px solid var(--border-muted);min-height:40px;color:var(--text);grid-template-columns:16px 24px minmax(0,1fr) 150px 44px;align-items:center;gap:8px;padding:4px 8px;display:grid}._assignmentRow_10p7t_128:hover{background:var(--canvas-subtle);text-decoration:none}._assignmentNumber_10p7t_144{color:var(--text-muted);text-align:right;font-size:13px}._assignmentTitle_10p7t_150{text-overflow:ellipsis;white-space:nowrap;overflow:hidden}._assignmentType_10p7t_156{color:var(--text-muted);font-size:13px}._extraTag_10p7t_161{color:var(--text-muted);text-align:right;font-size:12px}._verifySection_10p7t_167{padding-top:32px}._verifyHeading_10p7t_171{padding:0 8px 4px;font-size:16px;font-weight:600}._verifyNote_10p7t_177{border-bottom:1px solid var(--border);color:var(--text-muted);padding:0 8px 8px;font-size:13px}._verifyRow_10p7t_184{border-bottom:1px solid var(--border-muted);min-height:40px;color:var(--text);grid-template-columns:minmax(0,1fr) 64px auto;align-items:center;gap:12px;padding:4px 8px;display:grid}._verifyRow_10p7t_184:hover{background:var(--canvas-subtle);text-decoration:none}._verifyPlatform_10p7t_200{color:var(--accent);align-items:center;gap:4px;font-size:13px;display:inline-flex}._lessonSummary_10p7t_208{margin:12px 0;font-size:16px}._lessonPoints_10p7t_213{padding-left:20px;list-style:outside}._lessonPoints_10p7t_213 li{padding:4px 0}._lessonHeading_10p7t_222{border-bottom:1px solid var(--border);margin-top:32px;padding-bottom:8px;font-size:16px;font-weight:600}._lessonExplain_10p7t_230{margin:12px 0}._lessonCode_10p7t_234{background:var(--canvas-subtle);font-family:var(--font-mono);white-space:pre-wrap;margin:0;padding:12px 16px;font-size:13px;overflow-x:auto}._lessonResult_10p7t_244{margin:12px 0}._lessonAction_10p7t_248{margin-top:24px}@media (width<=640px){._chapterRow_10p7t_53{grid-template-columns:minmax(0,1fr) auto 16px;gap:4px 12px}._chapterNumber_10p7t_69{grid-column:1;font-size:13px}._chapterName_10p7t_73{grid-column:1}._chapterBar_10p7t_267{grid-area:3/1/auto/-1}._count_10p7t_78{grid-area:1/2/span 2}._rowArrow_10p7t_85{grid-area:1/3/span 2}._assignmentRow_10p7t_128{grid-template-columns:16px 20px minmax(0,1fr) 36px}._assignmentType_10p7t_156{display:none}}:root{--lightningcss-light:initial;--lightningcss-dark: ;color-scheme:light;--canvas:#fff;--canvas-subtle:#f6f8fa;--text:#1f2328;--text-muted:#59636e;--border:#d1d9e0;--border-muted:#e6eaef;--border-control:#818b98;--accent:#0969da;--accent-emphasis:#0550ae;--accent-tint:#ddf4ff;--success:#1a7f37;--success-tint:#dafbe1;--danger:#cf222e;--danger-tint:#ffebe9;--attention:#9a6700;--attention-tint:#fff8c5;--primary:#1a7f37;--primary-hover:#116329;--bar-track:#e6eaef;--bar-done:#1a7f37;--font-sans:-apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans", Helvetica, Arial, sans-serif;--font-mono:ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace}@media (prefers-color-scheme:dark){:root{--lightningcss-light: ;--lightningcss-dark:initial;color-scheme:dark;--canvas:#0d1117;--canvas-subtle:#161b22;--text:#e6edf3;--text-muted:#9198a1;--border:#30363d;--border-muted:#21262d;--border-control:#6e7681;--accent:#4493f8;--accent-emphasis:#1f6feb;--accent-tint:#121d2f;--success:#3fb950;--success-tint:#12261e;--danger:#f85149;--danger-tint:#25171c;--attention:#d29922;--attention-tint:#272115;--primary:#238636;--primary-hover:#1a7f37;--bar-track:#21262d;--bar-done:#2ea043}}*{box-sizing:border-box}html,body{background:var(--canvas);color:var(--text);font-family:var(--font-sans);margin:0;font-size:14px;line-height:1.5}h1,h2,h3,h4,p,ul,ol{margin:0;padding:0}ul,ol{list-style:none}a{color:var(--accent);text-decoration:none}a:hover{text-decoration:underline}code{font-family:var(--font-mono);font-size:.93em}:focus-visible{outline:2px solid var(--accent);outline-offset:1px}details>summary{cursor:pointer;list-style:none}details>summary::-webkit-details-marker{display:none}@media (prefers-reduced-motion:no-preference){html{scroll-behavior:smooth}}