html.learn-page,html.learn-page body{overflow:hidden}.learn-app{--learn-sidebar-width:308px;--learn-topbar-height:64px;--scrollbar-thumb:#0f172a2e;--scrollbar-thumb-hover:#0f172a52;--scrollbar-thumb-active:#0f172a75;background:var(--canvas);flex-direction:column;height:100dvh;min-height:0;display:flex;overflow:hidden}@media (prefers-color-scheme:dark){:root:not([data-theme=light]) .learn-app{--scrollbar-thumb:#fff3;--scrollbar-thumb-hover:#ffffff59;--scrollbar-thumb-active:#ffffff80}}[data-theme=dark] .learn-app,.dark .learn-app{--scrollbar-thumb:#fff3;--scrollbar-thumb-hover:#ffffff59;--scrollbar-thumb-active:#ffffff80}.learn-topbar{z-index:20;flex:0 0 var(--learn-topbar-height);height:var(--learn-topbar-height);min-height:var(--learn-topbar-height);border-bottom:1px solid var(--topbar-border);background:var(--topbar-bg);backdrop-filter:blur(14px);align-items:center;gap:10px;padding:0 clamp(14px,2.5vw,30px);display:flex;position:sticky;top:0}.brand--learn{flex:0 auto;min-width:0}.sidebar-collapse-toggle{display:inline-flex}.sidebar-collapse-toggle:active{transform:scale(.96)}.sidebar-collapse-toggle__icon{flex-shrink:0;width:18px;height:18px}.sidebar-collapse-toggle__icon--expand,.learn-app.is-sidebar-collapsed .sidebar-collapse-toggle__icon--collapse{display:none}.learn-app.is-sidebar-collapsed .sidebar-collapse-toggle__icon--expand{display:block}.brand--learn .brand__mark{width:28px;height:28px;padding:5px 4px}.brand--learn .brand__mark i{width:18px;height:2px}.brand--learn .brand__mark i:first-child{width:11px}.brand--learn .brand__mark i:last-child{width:14px}.brand--learn .brand__text{min-width:0}.brand--learn .brand__text strong{text-overflow:ellipsis;white-space:nowrap;overflow:hidden}.learn-topbar__progress{pointer-events:auto;flex-direction:column;justify-content:center;align-items:center;gap:4px;width:min(420px,100vw - 430px);min-width:220px;margin:0;display:flex;position:absolute;top:50%;left:50%;transform:translate(-50%,-50%)}.learn-topbar__nav{justify-content:center;align-items:center;width:100%;min-width:0;line-height:1.25;display:flex}.learn-topbar__chapter{text-overflow:ellipsis;white-space:nowrap;min-width:0;max-width:40%;color:var(--ink-muted);letter-spacing:-.01em;flex:0 auto;font-size:12px;font-weight:500;overflow:hidden}.learn-topbar__separator{color:var(--line-strong,#c5d2e0);opacity:.6;user-select:none;flex:none;margin:0 6px;font-size:11px}.learn-topbar__lesson{text-overflow:ellipsis;white-space:nowrap;min-width:0;color:var(--ink);letter-spacing:-.01em;flex:0 auto;font-size:12.5px;font-weight:600;overflow:hidden}.progress-indicator{width:100%;min-width:0}.progress-indicator__topline{color:var(--ink-muted);justify-content:space-between;align-items:center;margin-bottom:6px;font-size:10px;display:flex}.progress-indicator__topline strong{color:var(--ink);font-family:SFMono-Regular,Consolas,monospace;font-size:12px}.progress-indicator__topline small{color:var(--ink-muted);font-size:10px;font-weight:500}.progress-indicator__track{background:var(--progress-track);border-radius:100px;height:3px;overflow:hidden}.progress-indicator__track span{border-radius:inherit;background:var(--teal);height:100%;transition:width .25s;display:block}.progress-indicator--compact{flex-wrap:nowrap;align-items:center;gap:8px;width:100%;min-width:0;display:flex}.progress-indicator--compact .progress-indicator__topline{margin:0;display:contents}.progress-indicator--compact .progress-indicator__topline>span{display:none}.progress-indicator--compact .progress-indicator__topline strong{font-variant-numeric:tabular-nums;letter-spacing:.02em;white-space:nowrap;flex:none;order:2;font-size:11px}.progress-indicator--compact .progress-indicator__track{flex:auto;min-width:0}.sidebar-toggle{display:none}.sidebar-toggle__icon{flex:none;width:18px;height:18px}.learn-layout{grid-template-columns:var(--learn-sidebar-width,308px) minmax(0, 1fr);flex:1 1 0;width:100%;max-width:none;height:100%;min-height:0;margin:0;transition:grid-template-columns .3s cubic-bezier(.4,0,.2,1);display:grid}.course-sidebar{overscroll-behavior:contain;border-right:1px solid var(--line);box-sizing:border-box;align-self:stretch;width:auto;min-width:0;height:auto;min-height:0;padding:24px 12px 36px 14px;transition:transform .3s cubic-bezier(.4,0,.2,1),opacity .25s,border-color .3s cubic-bezier(.4,0,.2,1),visibility .3s cubic-bezier(.4,0,.2,1);position:relative;overflow:hidden auto}@media (width>=901px){.learn-app.is-sidebar-collapsed .learn-layout{grid-template-columns:0 minmax(0,1fr)}.learn-app.is-sidebar-collapsed .course-sidebar{opacity:0;visibility:hidden;pointer-events:none;border-right-color:#0000;transform:translate(-100%)}}.course-sidebar__intro{border-bottom:1px solid var(--line);padding:0 8px 18px}.course-sidebar__intro h2{letter-spacing:-.02em;margin:7px 0 5px;font-size:16px}.course-sidebar__intro p{color:var(--ink-muted);margin:0;font-size:11px;line-height:1.6}.course-sidebar__search{display:none}.course-nav{padding-top:14px}.course-chapter{margin-top:10px}.course-chapter:first-child{margin-top:0}.course-chapter__heading{width:100%;min-height:34px;color:var(--ink);cursor:pointer;text-align:left;background:0 0;border:0;border-radius:8px;align-items:center;gap:7px;padding:6px 8px;font-size:13.5px;font-weight:700;line-height:1.35;transition:background-color .16s;display:flex}.course-chapter__heading:hover{background:var(--surface-muted)}.course-chapter__heading strong{min-width:0;color:var(--ink);text-overflow:ellipsis;white-space:nowrap;flex:1;font-weight:700;overflow:hidden}.course-chapter__chevron{width:16px;height:16px;color:var(--ink-muted);flex:0 0 16px;place-items:center;transition:transform .16s;display:grid}.course-chapter__chevron svg{fill:none;stroke:currentColor;stroke-linecap:round;stroke-linejoin:round;stroke-width:1.8px;width:13px;height:13px}.course-chapter__heading[aria-expanded=false] .course-chapter__chevron{transform:rotate(-90deg)}.course-chapter__progress{background:var(--surface-muted);color:var(--ink-muted);white-space:nowrap;border:1px solid #0000;border-radius:999px;flex:none;padding:2px 7px;font-size:10.5px;font-weight:650;line-height:1.2}.course-chapter__progress.is-complete{background:var(--surface-blue);color:var(--blue-deep);border-color:#2d6cdf29}.course-chapter>ul{margin-top:3px;padding:2px 0 3px 6px;list-style:none}.course-lesson{width:100%;min-height:36px;color:var(--ink-muted);box-sizing:border-box;border:1px solid #0000;border-radius:8px;align-items:flex-start;gap:8px;margin:2px 0;padding:7px 9px 7px 8px;font-size:13px;font-weight:450;line-height:1.4;text-decoration:none;transition:background-color .13s,color .13s;display:flex}.course-lesson:hover{background:var(--surface-muted);color:var(--ink-soft)}.course-lesson.is-active{background:var(--surface-blue);color:var(--ink);box-shadow:inset 2.5px 0 0 var(--blue);font-weight:600}.course-lesson__title{-webkit-line-clamp:2;line-clamp:2;text-overflow:ellipsis;white-space:normal;word-break:break-word;-webkit-box-orient:vertical;flex:1;min-width:0;line-height:1.4;display:-webkit-box;overflow:hidden}.course-lesson__status{border:1.5px solid var(--line-strong);width:17px;height:17px;color:var(--blue-deep);border-radius:50%;flex:0 0 17px;place-items:center;margin-top:1.5px;display:grid}.course-lesson__status.is-active:not(.is-completed){border-color:var(--blue);box-shadow:0 0 0 3px #2d6cdf1a}.course-lesson__status.is-active:not(.is-completed):after{background:var(--blue);content:"";border-radius:50%;width:6px;height:6px}.course-lesson__status.is-completed{border-color:var(--blue);background:var(--surface-blue)}.course-lesson__status svg{fill:none;stroke:currentColor;stroke-linecap:round;stroke-linejoin:round;stroke-width:1.8px;width:11px;height:11px}.sidebar-backdrop{display:none}.learn-main{flex-direction:column;width:100%;min-width:0;max-width:none;height:100%;min-height:0;margin:0;display:flex;overflow:hidden}.learn-main__scroll{overscroll-behavior:contain;scrollbar-gutter:stable;flex:auto;min-width:0;min-height:0;padding:30px clamp(24px,3.5vw,44px) 32px;overflow:hidden auto}.course-sidebar::-webkit-scrollbar,.learn-main__scroll::-webkit-scrollbar{width:6px;height:6px}.course-sidebar::-webkit-scrollbar-track,.learn-main__scroll::-webkit-scrollbar-track{background:0 0}.course-sidebar::-webkit-scrollbar-thumb,.learn-main__scroll::-webkit-scrollbar-thumb{background-color:var(--scrollbar-thumb);border-radius:999px;transition:background-color .15s}.course-sidebar::-webkit-scrollbar-thumb:hover,.learn-main__scroll::-webkit-scrollbar-thumb:hover{background-color:var(--scrollbar-thumb-hover)}.course-sidebar::-webkit-scrollbar-thumb:active,.learn-main__scroll::-webkit-scrollbar-thumb:active{background-color:var(--scrollbar-thumb-active)}.course-sidebar::-webkit-scrollbar-button,.learn-main__scroll::-webkit-scrollbar-button{width:0;height:0;display:none}.course-sidebar::-webkit-scrollbar-corner,.learn-main__scroll::-webkit-scrollbar-corner{background:0 0}@supports not selector(::-webkit-scrollbar){.course-sidebar,.learn-main__scroll{scrollbar-width:thin;scrollbar-color:var(--scrollbar-thumb) transparent}.course-sidebar:hover,.learn-main__scroll:hover{scrollbar-color:var(--scrollbar-thumb-hover) transparent}}.learn-main>.lesson-nav{z-index:1;border-top:1px solid var(--line);background:var(--canvas);flex:none;width:100%;min-width:0;padding:12px clamp(24px,3.5vw,44px) 14px}.learn-main__crumbs{color:var(--ink-muted);white-space:nowrap;align-items:center;gap:9px;margin-bottom:38px;font-size:11px;display:flex;overflow:hidden}.learn-main__crumbs a:hover{color:var(--blue)}.learn-main__crumbs>span:last-child{text-overflow:ellipsis;overflow:hidden}.lesson-header{border-bottom:1px solid var(--line);padding-bottom:42px}.lesson-header__meta{color:var(--ink-muted);align-items:center;gap:9px;margin-bottom:17px;font-size:11px;display:flex}.lesson-number{background:var(--navy);width:35px;min-width:35px;height:25px;color:var(--on-primary);border-radius:7px;place-items:center;font-family:SFMono-Regular,Consolas,monospace;font-size:10px;display:inline-grid}.meta-separator{color:var(--line-strong)}.lesson-header h1{color:var(--ink);letter-spacing:-.055em;margin-bottom:10px;font-size:clamp(28px,4vw,43px);font-weight:720;line-height:1.2}.lesson-header__subtitle{color:var(--ink-soft);margin-bottom:16px;font-size:15px}.lesson-header__tags{flex-wrap:wrap;gap:7px;margin-bottom:28px;display:flex}.lesson-header__tags span{border:1px solid var(--line);color:var(--ink-muted);border-radius:4px;padding:3px 8px;font-size:10px}.quick-summary{border:1px solid var(--success-border);border-radius:var(--radius-sm);background:var(--success-bg);padding:17px 19px;display:block}.quick-summary p{color:var(--ink-soft);margin:5px 0 0;font-size:13px;line-height:1.65}.lesson-content{padding-top:37px}.lesson-opening{border:1px solid var(--warning-border);border-radius:var(--radius-md);background:var(--warning-bg);margin-bottom:28px;padding:22px 24px 20px}.lesson-opening__heading h2{color:var(--ink);letter-spacing:-.04em;margin:8px 0 6px;font-size:24px;line-height:1.3}.lesson-opening__heading p{color:var(--ink-soft);margin:0;font-size:13px}.lesson-opening__cards{grid-template-columns:repeat(3,minmax(0,1fr));gap:9px;margin-top:18px;display:grid}.lesson-opening__card{border:1px solid var(--warning-border);background:var(--surface-1);border-radius:9px;flex-direction:column;min-width:0;padding:13px 14px;display:flex}.lesson-opening__card>span{color:var(--ink-muted);font-size:10px;font-weight:700}.lesson-opening__card strong{overflow-wrap:anywhere;color:var(--navy);margin:5px 0 2px;font-family:SFMono-Regular,Consolas,monospace;font-size:20px;line-height:1.2}.lesson-opening__card small{color:var(--ink-muted);font-size:10px;line-height:1.5}.lesson-opening__question{border-top:1px solid var(--warning-border);color:var(--amber);margin:16px 0 0;padding-top:13px;font-size:12px;font-weight:650}.concept-card{border:1px solid var(--info-border);border-radius:var(--radius-md);background:var(--info-bg);grid-template-columns:150px minmax(0,1fr);align-items:center;gap:30px;padding:23px 25px;display:grid}.concept-card__label{color:var(--blue-deep);align-items:center;gap:8px;font-size:11px;font-weight:700;display:inline-flex}.dot{border-radius:50%;width:7px;height:7px}.dot--teal{background:var(--teal)}.concept-card h2{margin:0;font-size:19px}.concept-card p{color:var(--ink-soft);margin:7px 0 0;font-size:13px}.lesson-sections{padding:38px 0 18px}.lesson-section{padding:0 0 30px;display:block}.lesson-section h2{letter-spacing:-.03em;margin-bottom:11px;font-size:21px}.lesson-section p{margin-bottom:12px;font-size:14px;line-height:1.9}.check-list{gap:7px;margin-top:15px;display:grid}.check-list li{color:var(--ink-soft);align-items:flex-start;gap:9px;font-size:13px;display:flex}.check-list li:before{background:var(--teal-soft);width:16px;height:16px;color:var(--teal);content:"✓";text-align:center;border-radius:50%;flex:none;margin-top:3px;font-size:10px;line-height:16px;display:inline-block}@media (width<=1120px){.learn-main__scroll{padding-inline:36px}}@media (width<=900px){.learn-topbar{padding-inline:20px}.learn-topbar__progress{flex:1 1 0;width:auto;min-width:0;max-width:420px;margin:0 auto;position:static;transform:none}.sidebar-collapse-toggle{display:none}.sidebar-toggle{display:inline-flex}.learn-layout{display:block}.course-sidebar{z-index:30;top:var(--learn-topbar-height);border-right:1px solid var(--line);background:var(--canvas);width:min(320px,100vw - 42px);height:auto;position:fixed;bottom:0;left:0;transform:translate(-105%);box-shadow:12px 0 30px #1c33541f}.course-sidebar.is-open{transform:translate(0)}.course-sidebar__search{border:1px solid var(--line);background:var(--surface);width:100%;min-height:44px;color:var(--ink-soft);cursor:pointer;font:inherit;text-align:left;border-radius:9px;align-items:center;gap:10px;margin-top:12px;padding:0 11px;font-size:12px;display:flex}.course-sidebar__search:hover,.course-sidebar__search:focus-visible{border-color:var(--line-strong);background:var(--surface-muted);color:var(--ink)}.course-sidebar__search:focus-visible{outline:3px solid var(--focus-ring);outline-offset:2px}.course-sidebar__search svg{flex:none;width:17px;height:17px}.sidebar-backdrop{z-index:25;inset:var(--learn-topbar-height) 0 0;cursor:pointer;background:#15223847;border:0;display:block;position:fixed}.learn-main{width:100%;max-width:none;margin:0}.learn-main__scroll,.learn-main>.lesson-nav{padding-inline:30px}}@media (width<=768px){.learn-topbar__nav{display:none}.learn-topbar__progress{gap:0}}@media (width<=680px){.learn-app{--learn-topbar-height:60px}.learn-topbar{flex-basis:var(--learn-topbar-height);height:var(--learn-topbar-height);min-height:var(--learn-topbar-height);padding-inline:13px}.brand--learn .brand__text small{display:none}.course-sidebar{top:var(--learn-topbar-height);height:auto;padding:24px 14px 32px 16px;bottom:0}.course-nav{padding-top:12px}.course-chapter{margin-top:8px}.course-chapter__heading{gap:6px;min-height:33px;padding-inline:7px;font-size:13px}.course-chapter__progress{padding-inline:6px}.course-chapter>ul{padding-left:4px}.course-lesson{gap:8px;width:100%;min-height:34px;margin:2px 0;padding:6px 8px}.sidebar-backdrop{inset:var(--learn-topbar-height) 0 0}.learn-main__scroll{padding:21px 16px 30px}.learn-main>.lesson-nav{padding:10px 16px 14px;padding-bottom:max(14px, env(safe-area-inset-bottom))}.learn-main__crumbs{margin-bottom:27px;font-size:10px}.lesson-header{padding-bottom:29px}.lesson-header h1{font-size:31px}.lesson-header__subtitle{font-size:14px}.quick-summary{padding:14px}.quick-summary p{font-size:12px}.lesson-content{padding-top:27px}.lesson-opening{padding:17px}.lesson-opening__heading h2{font-size:21px}.lesson-opening__heading p{font-size:12px}.lesson-opening__cards{grid-template-columns:1fr;gap:7px}.lesson-opening__card{grid-template-columns:50px minmax(75px,.7fr) minmax(0,1.3fr);align-items:baseline;gap:8px;padding:10px 11px;display:grid}.lesson-opening__card strong{margin:0;font-size:17px}.lesson-opening__card small{text-align:right}.lesson-opening__question{font-size:11px}.concept-card{padding:17px;display:block}.concept-card__label{margin-bottom:10px}.concept-card h2{margin-bottom:5px;font-size:18px}.concept-card p{margin:0;font-size:12px}.lesson-sections{padding-top:29px}.lesson-section{padding-bottom:22px}.lesson-section h2{font-size:19px}.lesson-section p{font-size:13px}}@media (width<=480px){.learn-topbar{padding-inline:8px}.brand--learn .brand__text{display:none}}@media (prefers-reduced-motion:reduce){.progress-indicator__track span,.learn-layout,.course-sidebar{transition:none!important}}