.learn-scope{--learn-accent:var(--color-brand);--learn-accent-tint:color-mix(in oklab, var(--color-brand) 9%, transparent);--learn-accent-line:color-mix(in oklab, var(--color-brand) 28%, transparent);--learn-wrong:#c00;--learn-wrong-tint:#cc000012;--learn-surface:#fff;--learn-surface-sunken:#f3f5f5;--learn-page:#f7f8f8;--learn-border:#11181c17;--learn-border-strong:#11181c29;--learn-text:#14181b;--learn-text-dim:#5d666d;--learn-veil:#f3f5f5b8;--learn-hero-fade:#fbfcfc;--learn-callout-bg:#f3f5f7;--learn-hero-grid:#11181c12;--learn-header-offset:var(--site-nav-h);--learn-spine-empty:#11181c17;--learn-shadow:0 1px 2px #11181c0a, 0 14px 32px -18px #11181c38;--learn-shadow-soft:0 1px 2px #11181c0a;color:var(--learn-text);background:var(--learn-page);font-family:-apple-system,blinkmacsystemfont,PingFang SC,Hiragino Sans GB,Microsoft YaHei,Noto Sans SC,sans-serif}[data-theme=dark] .learn-scope{--learn-accent:var(--color-brand);--learn-accent-tint:color-mix(in oklab, var(--color-brand) 16%, transparent);--learn-accent-line:color-mix(in oklab, var(--color-brand) 36%, transparent);--learn-wrong:#ff6b6b;--learn-wrong-tint:#ff6b6b1a;--learn-surface:#171a1d;--learn-surface-sunken:#1e2225;--learn-page:#101315;--learn-border:#ffffff17;--learn-border-strong:#ffffff2b;--learn-text:#ffffffe0;--learn-text-dim:#ffffff8c;--learn-veil:#1e2225c7;--learn-hero-fade:#14171a;--learn-callout-bg:#ffffff0d;--learn-hero-grid:#ffffff12;--learn-spine-empty:#ffffff1c;--learn-shadow:0 1px 2px #0000004d, 0 16px 34px -20px #0009;--learn-shadow-soft:0 1px 2px #0000004d}.learn-num{font-variant-numeric:tabular-nums;font-family:ui-monospace,JetBrains Mono,sfmono-regular,menlo,monospace}.learn-eyebrow{letter-spacing:.16em;color:var(--learn-text-dim);text-transform:uppercase;margin:0;font-size:11px;font-weight:600}.learn-hero{background:radial-gradient(120% 150% at 100% 0%, var(--learn-accent-tint) 0%, transparent 58%), linear-gradient(180deg, var(--learn-surface) 0%, var(--learn-hero-fade) 100%);border-bottom:1px solid var(--learn-border-strong);position:relative;overflow:hidden}.learn-hero:before{background-image:linear-gradient(to right, var(--learn-hero-grid) 1px, transparent 1px), linear-gradient(to bottom, var(--learn-hero-grid) 1px, transparent 1px);content:"";background-size:32px 32px;position:absolute;inset:0;-webkit-mask-image:linear-gradient(#000 0%,#00000073 55%,#0000 100%);mask-image:linear-gradient(#000 0%,#00000073 55%,#0000 100%)}.learn-hero-inner{padding-top:calc(var(--learn-header-offset) + 24px);padding-bottom:40px}@media (min-width:640px){.learn-hero-inner{padding-top:calc(var(--learn-header-offset) + 40px);padding-bottom:48px}}.learn-heat-scroll{padding-bottom:2px;overflow-x:auto}.learn-skeleton{background:var(--learn-spine-empty)!important}.learn-timeline-item{padding-left:24px;position:relative}.learn-timeline-item:before{background:var(--learn-border);content:"";width:2px;position:absolute;top:16px;bottom:-14px;left:5px}.learn-timeline-item:last-child:before{display:none}.learn-timeline-item:after{background:var(--learn-surface);border:2px solid var(--learn-accent);content:"";border-radius:50%;width:12px;height:12px;position:absolute;top:4px;left:0}.learn-heat-cell{background:var(--learn-spine-empty);border-radius:2px;width:11px;height:11px}.learn-heat-cell[data-level="1"]{background:color-mix(in oklab, var(--learn-accent) 26%, transparent)}.learn-heat-cell[data-level="2"]{background:color-mix(in oklab, var(--learn-accent) 48%, transparent)}.learn-heat-cell[data-level="3"]{background:color-mix(in oklab, var(--learn-accent) 72%, transparent)}.learn-heat-cell[data-level="4"]{background:var(--learn-accent)}.learn-heat-cell[data-today="1"]{box-shadow:0 0 0 1.5px var(--learn-accent)}.learn-node-list{padding-left:0;list-style:none}.learn-page-top{padding-top:calc(var(--learn-header-offset) + 24px)}.learn-title-mark{padding-left:16px;position:relative}.learn-title-mark:before{background:linear-gradient(180deg, var(--learn-accent) 0%, var(--learn-accent-line) 100%);content:"";border-radius:2px;width:4px;position:absolute;top:.18em;bottom:.18em;left:0}.learn-hero>*{position:relative}.learn-chip{color:var(--learn-text-dim);white-space:nowrap;border:1px solid var(--learn-border-strong);border-radius:999px;align-items:center;gap:5px;padding:3px 9px;font-size:11.5px;font-weight:500;display:inline-flex}.learn-chip-accent{color:var(--learn-accent);background:var(--learn-accent-tint);border-color:var(--learn-accent-line)}.learn-chip-wrong{color:var(--learn-wrong);background:var(--learn-wrong-tint);border-color:color-mix(in oklab, var(--learn-wrong) 32%, transparent)}.learn-card-surface{background:var(--learn-surface);border:1px solid var(--learn-border);box-shadow:var(--learn-shadow-soft);border-radius:14px}.learn-card-main{background:var(--learn-surface);border:1px solid var(--learn-border);box-shadow:var(--learn-shadow);border-radius:18px;position:relative;overflow:hidden}.learn-prompt{border-left:3px solid var(--learn-accent);padding-left:16px}.learn-actionbar{background:var(--learn-surface-sunken);border-radius:14px;flex-wrap:wrap;align-items:center;gap:10px;padding:14px 16px;display:flex}.learn-callout{background-color:var(--learn-callout-bg);border-left:.5rem solid var(--color-brand);padding:.75rem 1.25rem}.learn-quote{color:var(--learn-text-dim);border-left:.2rem solid var(--learn-border-strong);padding:.25rem 0 .25rem 1rem}.learn-spine{flex-direction:column-reverse;gap:2px;width:4px;display:flex}.learn-spine-row{flex-direction:row;width:auto;height:5px}.learn-spine-seg{background:var(--learn-spine-empty);border-radius:2px;flex:auto;min-height:6px;transition:background .32s cubic-bezier(.22,1,.36,1)}.learn-spine-row .learn-spine-seg{min-width:7px;min-height:0}.learn-spine-seg[data-on="1"]{background:color-mix(in oklab, var(--learn-accent) 32%, transparent)}.learn-spine-seg[data-on="2"]{background:color-mix(in oklab, var(--learn-accent) 54%, transparent)}.learn-spine-seg[data-on="3"]{background:color-mix(in oklab, var(--learn-accent) 76%, transparent)}.learn-spine-seg[data-on="4"]{background:var(--learn-accent)}.learn-steps{align-items:center;gap:3px;display:flex}.learn-steps-seg{background:var(--learn-spine-empty);border-radius:2px;width:14px;height:4px;transition:background .2s,width .2s}.learn-steps-seg[data-state=done]{background:var(--learn-accent)}.learn-steps-seg[data-state=current]{background:var(--learn-accent-tint);width:24px;box-shadow:inset 0 0 0 1.5px var(--learn-accent)}.learn-veil-wrap{position:relative}.learn-veil{background:var(--learn-veil);-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);box-shadow:inset 0 1px 0 #ffffff4d, inset 0 0 0 1px var(--learn-border);border-radius:12px;justify-content:center;align-items:center;display:flex;position:absolute;inset:0}.learn-reveal{animation:.24s cubic-bezier(.22,1,.36,1) both learn-wipe}@keyframes learn-wipe{0%{clip-path:inset(0 0 100%)}to{clip-path:inset(0)}}.learn-card-enter{animation:.16s cubic-bezier(.22,1,.36,1) both learn-slide}@keyframes learn-slide{0%{opacity:0;transform:translate(12px)}to{opacity:1;transform:translate(0)}}.learn-btn{border-radius:11px;justify-content:center;align-items:center;gap:8px;min-height:46px;padding:0 20px;font-size:14.5px;font-weight:600;transition:transform .14s,opacity .14s,background .14s;display:inline-flex}.learn-btn:active{transform:translateY(1px)}.learn-btn-primary{background:var(--color-brand);box-shadow:0 8px 18px -10px color-mix(in oklab, var(--color-brand) 70%, transparent);color:#fff!important}.learn-btn-primary:hover{opacity:.92;color:#fff!important}.learn-btn-ghost{color:var(--learn-text-dim);background:var(--learn-surface);border:1px solid var(--learn-border-strong)}.learn-btn-ghost:hover{color:var(--learn-text);background:var(--learn-surface-sunken)}.learn-btn:disabled{cursor:not-allowed;opacity:.4}.learn-grade{text-align:left;border:1px solid var(--learn-border-strong);border-radius:12px;flex-direction:column;align-items:flex-start;gap:2px;min-height:62px;padding:10px 14px;transition:border-color .14s,background .14s;display:flex}.learn-grade:hover:not(:disabled){background:var(--learn-accent-tint);border-color:var(--learn-accent-line)}.learn-scope :focus-visible{outline:2px solid var(--learn-accent);outline-offset:2px;box-shadow:0 0 0 4px var(--learn-accent-tint);border-radius:8px}.learn-inline :where(code),.learn-prose :where(code:not(pre.hljs>code)){color:var(--code-text-color);background-color:var(--code-bg);border-radius:5px;margin:auto 3px;padding:.2em .4em;font-family:source-code-pro,ui-monospace,sfmono-regular,menlo,monaco,consolas,monospace;font-size:.9em}.learn-prose :where(p,ul,ol,pre){margin-bottom:.75rem;line-height:1.7}.learn-prose :where(ul,ol){padding-left:1.15rem;list-style:outside}.learn-prose :where(ol){list-style:decimal}.learn-prose :where(pre){border-radius:10px;padding-bottom:14px;padding-left:16px;padding-right:16px;font-size:13px;line-height:1.75;overflow-x:auto}.learn-prose :where(pre code){background:0 0;border:0;margin:0;padding:0;font-size:13px}.learn-digest{background:var(--learn-surface);border:1px solid var(--learn-border);box-shadow:var(--learn-shadow-soft);border-radius:14px;overflow:hidden}.learn-digest>summary{color:var(--learn-text);cursor:pointer;align-items:center;gap:10px;padding:13px 16px;font-size:13.5px;font-weight:600;list-style:none;transition:background .16s;display:flex}.learn-digest>summary::-webkit-details-marker{display:none}.learn-digest>summary:hover{background:var(--learn-surface-sunken)}.learn-digest[open]>summary{border-bottom:1px solid var(--learn-border)}.learn-digest-caret{color:var(--learn-text-dim);flex:none;transition:transform .2s cubic-bezier(.22,1,.36,1)}.learn-digest[open] .learn-digest-caret{transform:rotate(90deg)}.learn-digest-list{margin:0;padding:8px;list-style:none}.learn-digest-item{border-radius:12px;padding:11px 12px 12px;transition:background .16s;position:relative}.learn-digest-item:hover{background:var(--learn-surface-sunken)}.learn-digest-q{border:0;margin:0;padding:0;font-size:14.5px;font-weight:600;line-height:1.7}.learn-digest-jump{width:100%;font:inherit;color:inherit;text-align:left;cursor:pointer;background:0 0;border:0;grid-template-columns:24px minmax(0,1fr) 16px;align-items:start;gap:0 10px;padding:0;display:grid}.learn-digest-jump:after{content:"";border-radius:12px;position:absolute;inset:0}.learn-digest-index{font-variant-numeric:tabular-nums;height:22px;color:var(--learn-text-dim);background:var(--learn-surface-sunken);border-radius:7px;justify-content:center;align-items:center;margin-top:2px;font-family:ui-monospace,JetBrains Mono,sfmono-regular,menlo,monospace;font-size:11.5px;font-weight:600;transition:color .16s,background .16s;display:flex}.learn-digest-item:hover .learn-digest-index{color:var(--learn-accent);background:var(--learn-accent-tint)}.learn-digest-go{color:var(--learn-text-dim);opacity:0;margin-top:5px;transition:opacity .16s,transform .16s;transform:translate(-3px)}.learn-digest-item:hover .learn-digest-go,.learn-digest-jump:focus-visible .learn-digest-go{color:var(--learn-accent);opacity:1;transform:none}@media (hover:none){.learn-digest-go{opacity:.45;transform:none}}.learn-digest-a{color:var(--learn-text-dim);border-left:2px solid var(--learn-border);margin:7px 0 0 34px;padding-left:11px;font-size:13px;line-height:1.75;transition:border-color .16s}.learn-digest-item:hover .learn-digest-a{border-left-color:var(--learn-accent-line)}.learn-digest .learn-inline :where(code){color:inherit;background-color:var(--learn-surface-sunken);border:1px solid var(--learn-border);margin:0 2px;padding:.1em .35em;font-size:.88em}@media (min-width:640px){.learn-digest-list{padding:10px}.learn-digest-item{padding:12px 14px 13px}.learn-digest-jump{gap:0 12px}.learn-digest-a{margin-left:36px}.learn-digest-item+.learn-digest-item{margin-top:2px}}@media (prefers-reduced-motion:reduce){.learn-reveal,.learn-card-enter{animation:none}.learn-digest-caret,.learn-digest-index,.learn-digest-go,.learn-spine-seg,.learn-btn,.learn-grade{transition:none}}.learn-scroll-slim{scrollbar-width:thin;scrollbar-color:transparent transparent}.learn-scroll-slim:hover{scrollbar-color:var(--learn-border-strong) transparent}.learn-scroll-slim::-webkit-scrollbar{width:6px}.learn-scroll-slim::-webkit-scrollbar-track{background:0 0}.learn-scroll-slim::-webkit-scrollbar-thumb{background:0 0;border-radius:999px;transition:background .2s}.learn-scroll-slim:hover::-webkit-scrollbar-thumb{background:var(--learn-border-strong)}.learn-scroll-slim::-webkit-scrollbar-thumb:hover{background:var(--learn-text-dim)}.learn-input{background:var(--learn-surface-sunken);border:1px solid var(--learn-border)}.learn-search{border-radius:12px}:root[data-theme=dark] .learn-card-main.wi-glass,:root[data-theme=dark] .learn-card-surface.wi-glass,:root[data-theme=dark] .learn-chip.wi-glass:not(.learn-chip-accent),:root[data-theme=dark] .learn-search.wi-glass .learn-input,:root[data-theme=dark] .learn-search.wi-glass:focus-within .learn-input{border-color:#0000}.learn-veil-wrap.wi-glass{border-radius:12px}:root[data-theme=dark] .learn-btn-ghost.wi-glass,:root[data-theme=dark] .learn-card-main.wi-glass,:root[data-theme=dark] .learn-card-surface.wi-glass,:root[data-theme=dark] .learn-digest.wi-glass{border-color:#0000}.learn-plain-list{padding-left:0;list-style:none}