:root{--lightningcss-light:initial;--lightningcss-dark: ;color-scheme:light;--ink:#122d35;--paper:#f7fbf6;--white:#fff;--green:#2b834f;--green-dark:#17653c;--green-badge:#2b834f;--coral:#f0644b;--coral-deep:#c9452f;--coral-deeper:#a93a26;--yellow:#f6c746;--blue:#2878c8;--line:#c8d9cf;--muted:#4c696f;--shadow:0 14px 34px #163d361a;--btn:#122d35;--btn-text:#fff;--btn-hover:#17653c;--tab-hover:#e8f2e9;--trailbar-bg:#fff;--figure-bg:#dcefed;--playground-bg:#dcefed;--lab-bg:#eaf4ec;--lab-text:#315a4a;--tip-bg:#e5f2e6;--tip-text:#30564a;--key-bg:#fff2bc;--note-bg:#fff8d8;--note-border:#e4c76b;--note-text:#4c5a48;--hint-text:#375c52;--foot-text:#4e6c64;--details-text:#4f5f4d;--summary-text:#604b08;--quiz-border:#b6d0bd;--quiz-opt-bg:#ffffffb8;--takehome-bg:#ffffff9e;--playlink-hover:#fff7cf;--divider:#2f8f5859;--badge-text:#122d35;--cheat-badge-bg:#e5f2e6;--cheat-badge-text:#17653c;--good-bg:#cbe8d3;--good-text:#155a34;--try-bg:#fff0bd;--try-text:#664c00;--focus-ring:#f0644b33;--focus-ring-strong:#f0644b47;--code-bg:#102e35;--code-deep:#0a252b;--code-text:#f5faf6;--code-head:#b9d6cc;--code-head2:#9fc2b5;--code-border:#5d7c75;--code-card-border:transparent;--copy-border:#456962;--copy-text:#d9ece5;--copy-hover-bg:#173b42;--copy-hover-border:#71948c;--dot-green:#63be7b}[data-theme=dark]{--lightningcss-light: 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#00000080;--btn:#23434d;--btn-text:#fff;--btn-hover:#2e5560;--tab-hover:#1a2f35;--trailbar-bg:#15262c;--figure-bg:#dcefed;--playground-bg:#15262c;--lab-bg:#12241c;--lab-text:#a9cdb8;--tip-bg:#14251d;--tip-text:#a9cdb8;--key-bg:#4a3d12;--note-bg:#26260f;--note-border:#7d6c2e;--note-text:#d6d2b4;--hint-text:#a9c9bb;--foot-text:#9fb8ae;--details-text:#c3c9bb;--summary-text:#f0d488;--quiz-border:#2f4a43;--quiz-opt-bg:#ffffff0d;--takehome-bg:#ffffff0a;--playlink-hover:#22333a;--divider:#6ec89161;--badge-text:#122d35;--cheat-badge-bg:#e5f2e6;--cheat-badge-text:#17653c;--good-bg:#cbe8d3;--good-text:#155a34;--try-bg:#fff0bd;--try-text:#664c00;--focus-ring:#f0644b59;--focus-ring-strong:#f0644b73;--code-bg:#102e35;--code-deep:#0a252b;--code-text:#f5faf6;--code-head:#b9d6cc;--code-head2:#9fc2b5;--code-border:#5d7c75;--code-card-border:#2b4a53;--copy-border:#456962;--copy-text:#d9ece5;--copy-hover-bg:#173b42;--copy-hover-border:#71948c;--dot-green:#63be7b}@media (prefers-color-scheme:dark){:root:not([data-theme=light]){--lightningcss-light: ;--lightningcss-dark:initial;color-scheme:dark;--ink:#edf5f0;--paper:#0d1b20;--white:#15262c;--green:#57b87f;--green-dark:#93dcb2;--green-badge:#2b834f;--coral:#f0644b;--coral-deep:#c9452f;--coral-deeper:#a93a26;--yellow:#f6c746;--blue:#6aa5dc;--line:#2b434b;--muted:#a4c3bc;--shadow:0 14px 34px #00000080;--btn:#23434d;--btn-text:#fff;--btn-hover:#2e5560;--tab-hover:#1a2f35;--trailbar-bg:#15262c;--figure-bg:#dcefed;--playground-bg:#15262c;--lab-bg:#12241c;--lab-text:#a9cdb8;--tip-bg:#14251d;--tip-text:#a9cdb8;--key-bg:#4a3d12;--note-bg:#26260f;--note-border:#7d6c2e;--note-text:#d6d2b4;--hint-text:#a9c9bb;--foot-text:#9fb8ae;--details-text:#c3c9bb;--summary-text:#f0d488;--quiz-border:#2f4a43;--quiz-opt-bg:#ffffff0d;--takehome-bg:#ffffff0a;--playlink-hover:#22333a;--divider:#6ec89161;--badge-text:#122d35;--cheat-badge-bg:#e5f2e6;--cheat-badge-text:#17653c;--good-bg:#cbe8d3;--good-text:#155a34;--try-bg:#fff0bd;--try-text:#664c00;--focus-ring:#f0644b59;--focus-ring-strong:#f0644b73;--code-bg:#102e35;--code-deep:#0a252b;--code-text:#f5faf6;--code-head:#b9d6cc;--code-head2:#9fc2b5;--code-border:#5d7c75;--code-card-border:#2b4a53;--copy-border:#456962;--copy-text:#d9ece5;--copy-hover-bg:#173b42;--copy-hover-border:#71948c;--dot-green:#63be7b}}*{box-sizing:border-box}html{scroll-behavior:smooth}body{background:var(--paper);color:var(--ink);margin:0;font-family:DM 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10px;display:flex}.track-btn strong{font-size:.9rem;line-height:1.2}.track-btn small{opacity:.72;font-size:.74rem}.track-btn.active{border-color:var(--green-badge);background:var(--btn);color:var(--btn-text)}.track-btn.active small{opacity:.85}@media (width<=360px){.track-switch{flex-direction:column}.track-btn{min-height:44px}}.lesson-nav{flex-direction:column;gap:8px;display:flex}.lesson-tab{width:100%;color:var(--ink);text-align:left;background:0 0;border:0;border-radius:10px;grid-template-columns:40px 1fr;align-items:center;gap:11px;padding:12px 10px;display:grid;position:relative}.lesson-tab:hover{background:var(--tab-hover)}.lesson-tab[aria-selected=true]{background:var(--btn);color:var(--btn-text)}.lesson-tab .num{border:1.5px solid;border-radius:50%;place-items:center;width:36px;height:36px;font-family:IBM Plex 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p{color:var(--muted);max-width:54ch;margin:0;font-size:1.05rem}.lesson-figure{aspect-ratio:1;background:var(--figure-bg);border-radius:30px 8px;min-height:245px;margin:0;overflow:hidden}.lesson-figure img{object-fit:cover;width:100%;height:100%;display:block}.concept{grid-template-columns:minmax(0,1fr) minmax(300px,.88fr);gap:22px;margin-bottom:24px;display:grid}.explain{background:var(--white);border:1.5px solid var(--line);border-radius:10px;padding:26px}.explain h3,.lab h3{letter-spacing:-.02em;margin:0 0 14px;font-size:1.35rem}.explain p{margin:0 0 14px}.explain p:last-child{margin-bottom:0}.key{background:var(--key-bg);border-radius:4px;padding:2px 6px;font-family:IBM Plex Mono,monospace;font-size:.88em}.when-why{background:var(--note-bg);border:1.5px dashed var(--note-border);border-radius:8px;margin-top:18px;padding:16px 18px}.when-why h3{margin:0 0 8px;font-size:1.05rem}.when-why p{color:var(--note-text);margin:0 0 10px;font-size:.94rem}.when-why p:last-child{margin-bottom:0}.code-card{background:var(--code-bg);color:var(--code-text);border:1px solid var(--code-card-border);box-shadow:var(--shadow);border-radius:10px;align-self:start;overflow:hidden}.code-top{background:var(--code-deep);color:var(--code-head2);align-items:center;gap:10px;padding:8px 12px 8px 14px;font-family:IBM Plex Mono,monospace;font-size:.76rem;display:flex}.dots{gap:5px;margin-left:2px;display:flex}.dots i{background:var(--coral);border-radius:50%;width:8px;height:8px}.dots i:nth-child(2){background:var(--yellow)}.dots i:nth-child(3){background:var(--dot-green)}.copy-example{border:1px solid var(--copy-border);color:var(--copy-text);background:0 0;border-radius:5px;margin-left:auto;padding:5px 8px;font:600 .7rem IBM Plex Mono,monospace}.copy-example:hover{background:var(--copy-hover-bg);border-color:var(--copy-hover-border)}.copy-example:focus-visible{outline:2px solid 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IBM Plex Mono,monospace}textarea{resize:vertical;border:2px solid var(--ink);background:var(--code-bg);width:100%;min-height:154px;color:var(--code-text);border-radius:7px;outline:none;padding:15px;font:500 .86rem/1.6 IBM Plex Mono,monospace;display:block}textarea:focus{border-color:var(--coral);box-shadow:0 0 0 3px var(--focus-ring)}.actions{flex-wrap:wrap;align-items:center;gap:10px;margin-top:12px;display:flex}.run,.check,.next{border:0;border-radius:6px;padding:10px 16px;font-weight:800}.run{background:var(--btn);color:var(--btn-text)}.run:hover{background:var(--btn-hover)}.run:disabled{cursor:wait;opacity:.68}.share-link{background:var(--btn);color:var(--btn-text);border:0;border-radius:6px;min-height:44px;padding:10px 16px;font-weight:800}.share-link:hover{background:var(--btn-hover)}.share-note{color:var(--muted);margin:10px 0 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var(--divider);margin-top:22px;padding:20px 0 2px}.take-home h4{letter-spacing:-.01em;margin:0 0 5px;font-size:1.08rem}.take-home .goal{color:var(--lab-text);margin:0 0 12px}.take-home-editor{background:var(--takehome-bg);border-radius:8px;margin:14px 0 16px;padding:16px}.take-home-editor label{justify-content:space-between;align-items:baseline;gap:10px;margin-bottom:8px;font-size:.88rem;font-weight:800;display:flex}.take-home-editor textarea{min-height:176px}.take-home details{background:var(--note-bg);border:1px solid var(--note-border);border-radius:8px;margin-top:8px;padding:10px 13px}.take-home summary{cursor:pointer;color:var(--summary-text);font-weight:800}.take-home details p{color:var(--details-text);margin:9px 0 0;font-size:.9rem}.take-home pre{border:1px solid var(--code-card-border);background:var(--code-bg);color:var(--code-text);border-radius:6px;margin-top:10px;padding:14px;font-size:.8rem}.lesson-foot{border-top:1.5px solid var(--divider);justify-content:space-between;align-items:center;gap:14px;margin-top:18px;padding-top:17px;display:flex}.lesson-foot p{color:var(--foot-text);margin:0;font-size:.84rem}.next{background:var(--btn);color:var(--btn-text);white-space:nowrap}.next:hover{background:var(--btn-hover)}.final-note{text-align:center;color:var(--green-dark);padding:20px 14px 4px;font-weight:800;display:none}.final-note.show{animation:.45s note-pop;display:block}@keyframes note-pop{0%{opacity:0;transform:translateY(10px)scale(.98)}to{opacity:1;transform:none}}.crash-note{background:var(--white);border:1.5px solid var(--line);text-align:center;border-radius:12px;max-width:560px;margin:60px auto;padding:32px}.crash-note h1{letter-spacing:-.02em;margin:0 0 12px;font-size:1.6rem}.crash-note p{color:var(--muted);margin:0 0 20px}.spark{color:var(--coral);display:inline-block}.playground-link,.cheatsheet-link{color:var(--ink);border:2px solid 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