@import "https://fonts.googleapis.com/css2?family=Manrope:wght@400;500;600;700;800&family=Roboto+Mono:wght@400;500;600&display=swap";:root{--bg:#f7f8fc;--surface:#fff;--surface-2:#f0f2f8;--surface-3:#e8ebf4;--text:#1e2235;--muted:#6b7087;--line:#e3e5ed;--accent:#5d54d9;--accent-soft:#eeedff;--accent-dark:#4439bd;--yellow:#f7df1e;--code:#161822;--code-top:#20232f;--shadow:0 18px 50px #191c3614;--lightningcss-light:initial;--lightningcss-dark: ;color-scheme:light}[data-theme=dark]{--bg:#111218;--surface:#181a22;--surface-2:#20222c;--surface-3:#292c38;--text:#f2f2f6;--muted:#a3a7b8;--line:#2c2f3b;--accent:#8c83ff;--accent-soft:#292547;--accent-dark:#aaa3ff;--code:#0d0e13;--code-top:#171820;--shadow:0 18px 50px #00000047;--lightningcss-light: ;--lightningcss-dark:initial;color-scheme:dark}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:92px}body{background:var(--bg);min-width:320px;color:var(--text);-webkit-font-smoothing:antialiased;margin:0;font-family:Manrope,system-ui,sans-serif;font-size:16px;line-height:1.72;transition:background .25s,color .25s}button,a{-webkit-tap-highlight-color:transparent}button{font:inherit}a{color:inherit}code{font-family:Roboto Mono,monospace;font-size:.9em}p code,h3 code{color:var(--accent-dark);background:var(--accent-soft);border-radius:5px;padding:.15em .38em}:focus-visible{outline-offset:3px;outline:3px solid #5d54d966}.reading-progress{z-index:100;transform-origin:0;background:linear-gradient(90deg, var(--accent), #9c69e8);height:3px;position:fixed;top:0;left:0;right:0}.app-header{z-index:50;border-bottom:1px solid var(--line);background:color-mix(in srgb, var(--bg) 88%, transparent);-webkit-backdrop-filter:blur(16px);backdrop-filter:blur(16px);height:72px;position:sticky;top:0}.header-inner{justify-content:space-between;align-items:center;height:100%;padding:0 28px;display:flex}.brand{align-items:center;gap:12px;line-height:1.25;text-decoration:none;display:flex}.brand-mark{background:var(--yellow);color:#151515;letter-spacing:-.04em;border-radius:9px;place-items:center;width:38px;height:38px;font-size:14px;font-weight:800;display:grid;box-shadow:inset 0 -2px #0000001f}.brand-copy{flex-direction:column;gap:3px;display:flex}.brand-copy strong{font-size:14px}.brand-copy small{color:var(--muted);align-items:center;gap:6px;font-size:11px;font-weight:600;display:flex}.brand-copy i,.next-lesson i{background:currentColor;border-radius:50%;width:3px;height:3px}.header-actions{gap:8px;display:flex}.icon-button{border:1px solid var(--line);background:var(--surface);width:38px;height:38px;color:var(--text);cursor:pointer;border-radius:10px;place-items:center;transition:all .2s;display:grid}.icon-button:hover{border-color:var(--accent);color:var(--accent);transform:translateY(-1px)}.menu-button{display:none}.app-shell{grid-template-columns:260px minmax(0,1fr);display:grid}.sidebar{border-right:1px solid var(--line);background:var(--bg);height:calc(100vh - 72px);padding:34px 22px 24px;position:sticky;top:72px;overflow-y:auto}.sidebar-label{color:var(--muted);letter-spacing:.08em;text-transform:uppercase;align-items:center;gap:8px;margin:0 8px 16px;font-size:11px;font-weight:800;display:flex}.sidebar nav{flex-direction:column;gap:2px;display:flex}.sidebar nav a{color:var(--muted);border-radius:9px;align-items:center;gap:10px;padding:8px 10px;font-size:12.5px;font-weight:600;line-height:1.35;text-decoration:none;transition:all .18s;display:flex}.sidebar nav a:hover{color:var(--text);background:var(--surface-2)}.sidebar nav a.active{color:var(--accent-dark);background:var(--accent-soft)}.nav-number{border:1px solid var(--line);background:var(--surface);border-radius:7px;flex:0 0 24px;place-items:center;height:24px;font-size:9px;display:grid}.active .nav-number{background:var(--accent);color:#fff;border-color:#0000}.sidebar-progress{color:var(--muted);margin:26px 9px 0;font-size:10px;font-weight:700}.sidebar-progress>div{background:var(--surface-3);border-radius:10px;height:3px;margin-top:8px;overflow:hidden}.sidebar-progress i{background:var(--accent);width:8.3%;height:100%;display:block}main{min-width:0}.hero{border-bottom:1px solid var(--line);background:radial-gradient(circle at 87% 50%, color-mix(in srgb, var(--accent) 10%, transparent), transparent 33%), var(--surface);min-height:460px;padding:86px clamp(32px,7vw,110px) 72px;position:relative;overflow:hidden}.hero:before{content:"";opacity:.35;background-image:radial-gradient(var(--line) 1px, transparent 1px);background-size:24px 24px;position:absolute;inset:0;-webkit-mask-image:linear-gradient(90deg,#0000 30%,#000);mask-image:linear-gradient(90deg,#0000 30%,#000)}.hero>:not(.hero-decoration){z-index:1;max-width:850px;position:relative}.eyebrow{border:1px solid var(--line);color:var(--accent-dark);background:var(--bg);letter-spacing:.08em;text-transform:uppercase;border-radius:99px;align-items:center;gap:9px;padding:5px 11px 5px 6px;font-size:11px;font-weight:800;display:inline-flex}.eyebrow span{background:var(--accent);color:#fff;border-radius:50%;place-items:center;width:23px;height:23px;font-size:9px;display:grid}.hero h1{letter-spacing:-.055em;max-width:830px;margin:24px 0 20px;font-size:clamp(38px,5.5vw,68px);line-height:1.08}.hero h1 em{color:var(--accent);font-style:normal}.hero-lead{max-width:680px;color:var(--muted);margin:0;font-size:clamp(16px,1.5vw,19px);line-height:1.65}.hero-meta{flex-wrap:wrap;gap:12px 28px;margin-top:32px;display:flex}.hero-meta span{color:var(--muted);align-items:center;gap:8px;font-size:12px;font-weight:700;display:flex}.hero-meta svg{color:var(--accent)}.hero-decoration{color:var(--line);letter-spacing:-.09em;-webkit-user-select:none;user-select:none;align-items:baseline;font-family:Roboto Mono;font-size:clamp(50px,8vw,120px);font-weight:600;display:flex;position:absolute;bottom:-30px;right:-18px;transform:rotate(-5deg)}.hero-decoration strong{color:color-mix(in srgb, var(--accent) 25%, var(--line))}.hero-decoration i{color:var(--yellow);opacity:.55;font-style:normal}.lesson-body{width:min(100% - 48px,850px);margin-inline:auto}.intro-note{border:1px solid var(--line);background:var(--surface);box-shadow:var(--shadow);border-radius:14px;gap:16px;margin:46px 0 80px;padding:20px 22px;display:flex}.intro-note svg{color:var(--accent);flex:none;margin-top:3px}.intro-note p{color:var(--muted);margin:0;font-size:14px}.intro-note strong{color:var(--text)}.lesson-section{margin-bottom:105px}.section-heading{align-items:flex-start;gap:18px;margin-bottom:32px;display:flex}.section-number{width:38px;height:38px;color:var(--accent-dark);background:var(--accent-soft);border-radius:10px;flex:none;place-items:center;font-size:11px;font-weight:800;display:grid}.section-heading h2{letter-spacing:-.035em;margin:0;font-size:clamp(26px,3vw,34px);line-height:1.2}.section-heading small{color:var(--accent);letter-spacing:.12em;margin-bottom:5px;font-size:10px;font-weight:800;display:block}.section-content>p{color:var(--muted)}.section-content>.lead{color:var(--text);font-size:19px;line-height:1.7}.section-content h3{margin:36px 0 12px;font-size:18px}.section-content hr{background:var(--line);border:0;height:1px;margin:44px 0}.muted{color:var(--muted);font-size:13px}.steps-card{border:1px solid var(--line);background:var(--surface);border-radius:16px;margin:28px 0;padding:26px 30px}.steps-card h3{margin:0 0 18px;font-size:15px}.steps-card h3 span{margin-right:8px}.steps-card ol{counter-reset:steps;margin:0;padding:0;list-style:none}.steps-card li{color:var(--muted);counter-increment:steps;padding:8px 0 8px 38px;position:relative}.steps-card li:before{content:counter(steps);background:var(--surface-2);width:23px;height:23px;color:var(--accent);border-radius:50%;place-items:center;font-size:10px;font-weight:800;display:grid;position:absolute;top:8px;left:0}.info-block{border:1px solid color-mix(in srgb, var(--accent) 25%, var(--line));background:var(--accent-soft);border-radius:13px;gap:14px;margin:28px 0;padding:18px 20px;display:flex}.info-block>svg{color:var(--accent);flex:none;margin-top:2px}.info-block strong{margin-bottom:4px;font-size:13px;display:block}.info-block p{color:var(--muted);margin:0;font-size:13px}.info-warning{border-color:color-mix(in srgb, #e29c3b 35%, var(--line));background:color-mix(in srgb, #e29c3b 10%, var(--surface))}.info-warning>svg{color:#d18524}.info-tip{border-color:color-mix(in srgb, #2aaa72 30%, var(--line));background:color-mix(in srgb, #2aaa72 9%, var(--surface))}.info-tip>svg{color:#249463}.flow-diagram{grid-template-columns:1fr auto 1fr auto 1fr;align-items:center;gap:14px;margin:32px 0;display:grid}.flow-diagram>div{border:1px solid var(--line);background:var(--surface);border-radius:14px;flex-direction:column;justify-content:center;min-height:130px;padding:20px;display:flex}.flow-diagram .accent{border-color:var(--accent);box-shadow:0 8px 30px color-mix(in srgb, var(--accent) 15%, transparent)}.flow-diagram small{color:var(--accent);font-weight:800}.flow-diagram strong{margin:5px 0;font-size:14px}.flow-diagram span{color:var(--muted);font-size:11px}.flow-diagram>svg{color:var(--accent)}.code-block{background:var(--code);border:1px solid #292c39;border-radius:13px;margin:18px 0;overflow:hidden;box-shadow:0 10px 28px #0000001c}.code-header{background:var(--code-top);color:#8e93a8;letter-spacing:.04em;text-transform:uppercase;border-bottom:1px solid #ffffff0f;justify-content:space-between;align-items:center;min-height:40px;padding:0 10px 0 15px;font-size:10px;font-weight:700;display:flex}.code-header>span{align-items:center;gap:5px;display:flex}.code-header i{background:#4c5060;border-radius:50%;width:7px;height:7px}.code-header i:nth-child(3){margin-right:8px}.code-header button{color:#abb0c1;text-transform:none;cursor:pointer;background:0 0;border:0;border-radius:6px;align-items:center;gap:6px;padding:5px 8px;font-size:10px;display:flex}.code-header button:hover{color:#fff;background:#ffffff12}.code-block pre{color:#e4e6ef;tab-size:2;margin:0;padding:20px 22px;font:13px/1.75 Roboto Mono,monospace;overflow-x:auto}.code-block code{font:inherit;white-space:pre}.hljs-keyword,.hljs-literal{color:#c792ea}.hljs-string{color:#a8d986}.hljs-number{color:#f7c46c}.hljs-title,.hljs-built_in{color:#82aaff}.hljs-comment{color:#676e85;font-style:italic}.hljs-params{color:#f1f1f3}.code-pair{grid-template-columns:1fr 1fr;gap:16px;margin:30px 0;display:grid}.code-pair>div>span{color:var(--muted);text-transform:uppercase;font-size:10px;font-weight:800}.code-pair .code-block{margin-top:7px}.use-grid{grid-template-columns:repeat(3,1fr);gap:12px;margin:30px 0;display:grid}.use-grid article{border:1px solid var(--line);background:var(--surface);border-radius:13px;align-items:center;gap:13px;padding:18px;display:flex}.use-grid svg{color:var(--accent);flex:none}.use-grid strong,.use-grid span{display:block}.use-grid strong{font-size:13px}.use-grid span{color:var(--muted);margin-top:2px;font-size:10px}.formula{border:1px solid var(--line);background:var(--surface);border-radius:16px;justify-content:center;align-items:center;gap:22px;margin:32px 0;padding:28px;display:flex}.formula>div{align-items:center;gap:12px;display:flex}.formula svg{color:var(--accent)}.formula strong,.formula small{display:block}.formula small{color:var(--muted);font-size:10px}.formula>span{color:var(--muted);font-size:24px}.tree-diagram{flex-direction:column;align-items:center;margin:32px 0;display:flex}.tree-diagram>strong{background:var(--accent);color:#fff;border-radius:10px;padding:10px 22px;font-size:13px}.tree-diagram>i{background:var(--line);width:1px;height:24px}.tree-diagram>div{gap:50px;display:flex;position:relative}.tree-diagram>div:before{content:"";background:var(--line);height:1px;position:absolute;top:-1px;left:25%;right:25%}.tree-diagram span{border:1px solid var(--line);background:var(--surface);text-align:center;border-radius:9px;min-width:145px;padding:12px;font-size:12px}.run-flow{justify-content:space-between;align-items:center;margin-top:34px;display:flex}.run-flow span{color:var(--muted);align-items:center;gap:7px;font-size:10px;font-weight:700;display:flex}.run-flow span svg{color:var(--accent)}.run-flow>svg{width:14px;color:var(--line);transform:rotate(-90deg)}.operator-grid{flex-wrap:wrap;gap:8px;margin:22px 0;display:flex}.operator-grid span{border:1px solid var(--line);color:var(--muted);background:var(--surface);border-radius:8px;padding:7px 12px;font-size:11px}.operator-grid b{color:var(--accent);margin-right:5px;font:600 14px Roboto Mono}.challenge{color:#fff;background:linear-gradient(135deg,#554bc8,#7469e4);border-radius:17px;margin:36px 0;padding:28px;box-shadow:0 18px 40px #5348c733}.challenge>small{color:#d4d0ff;letter-spacing:.12em;font-size:9px;font-weight:800}.challenge h3{margin:5px 0 20px}.challenge>div{align-items:center;gap:12px;display:flex}.challenge code{color:#fff;background:#00000038;border-radius:8px;padding:9px 13px}.challenge details{border-top:1px solid #ffffff2e;margin-top:20px}.challenge summary{cursor:pointer;align-items:center;gap:5px;width:max-content;padding-top:14px;font-size:11px;font-weight:700;display:flex}.challenge details[open] summary svg{transform:rotate(90deg)}.challenge details p{color:#e4e2ff;margin:12px 0 0;font-size:12px}.comparison{grid-template-columns:repeat(3,1fr);gap:12px;display:grid}.comparison>div{border:1px solid var(--line);background:var(--surface);text-align:center;border-radius:14px;min-width:0;padding-bottom:18px;overflow:hidden}.comparison .code-block{box-shadow:none;text-align:left;border:0;border-radius:0;margin:0 0 16px}.comparison .code-header{display:none}.comparison .code-block pre{padding:16px 13px;font-size:10px}.comparison>div>strong{color:var(--accent);font:600 22px Roboto Mono;display:block}.comparison>div>small{color:var(--muted);font-size:10px}.practice-section{color:#f3f3f7;background:#181924;padding:88px 0 100px}.practice-kicker{color:#9d96ff;letter-spacing:.15em;font-size:10px;font-weight:800}.practice-section h2{letter-spacing:-.04em;margin:8px 0 12px;font-size:38px}.practice-lead{color:#9da1b2;max-width:650px;margin-bottom:38px}.practice-lead code{color:#bcb7ff;background:#28253e}.tasks-grid{grid-template-columns:1fr 1fr;gap:14px;display:grid}.task-card{background:#20212c;border:1px solid #303240;border-radius:15px;padding:24px}.task-top{justify-content:space-between;align-items:center;display:flex}.task-index{color:#6f6af0;font:600 11px Roboto Mono}.difficulty{color:#74ce9c;text-transform:uppercase;align-items:center;gap:6px;font-size:9px;font-weight:700;display:flex}.task-card h3{margin:15px 0 8px;font-size:16px}.task-card p{color:#aeb1c0;margin:0;font-size:12px}.task-card .code-block{box-shadow:none}.task-tags{gap:7px;margin-top:18px;display:flex}.task-tags span{color:#858a9e;text-transform:uppercase;background:#292b37;border-radius:5px;align-items:center;gap:4px;padding:4px 7px;font-size:8px;font-weight:700;display:flex}.bonus{background:linear-gradient(145deg,#22212d,#1d1e28);border:1px solid #3a374d;border-radius:18px;margin-top:46px;padding:30px}.bonus-heading{align-items:center;gap:13px;margin-bottom:20px;display:flex}.bonus-heading>svg{color:var(--yellow)}.bonus-heading small{color:#7f8192;letter-spacing:.1em;font-size:8px;font-weight:800}.bonus-heading h3{margin:2px 0 0}.bonus article{border-top:1px solid #30313d;gap:12px;padding:15px 0;display:flex}.bonus article>span{color:#7771ed}.bonus article strong{font-size:12px}.bonus article p{color:#999dac;margin:2px 0 0;font-size:11px}.homework-section{background:var(--surface);padding:100px 0 80px}.homework-header{gap:18px;margin-bottom:36px;display:flex}.homework-header>span{background:var(--accent);color:#fff;border-radius:14px;flex:none;place-items:center;width:52px;height:52px;display:grid}.homework-header small{color:var(--accent);letter-spacing:.15em;font-size:9px;font-weight:800}.homework-header h2{letter-spacing:-.04em;margin:3px 0;font-size:34px}.homework-header p{color:var(--muted);margin:0}.homework-parts{border-top:1px solid var(--line)}.homework-parts>article{border-bottom:1px solid var(--line);grid-template-columns:48px 1fr;gap:18px;padding:30px 0;display:grid}.homework-parts>article>span{color:var(--accent);font:600 11px Roboto Mono}.homework-parts h3{margin:0 0 8px;font-size:17px}.homework-parts p{color:var(--muted);margin:0;font-size:13px}.homework-parts .code-block{margin-bottom:0}.next-lesson{border:1px solid var(--line);background:var(--surface);box-shadow:var(--shadow);border-radius:17px;justify-content:space-between;align-items:center;margin:70px 0 45px;padding:30px 34px;text-decoration:none;transition:all .2s;display:flex}.next-lesson:hover{border-color:var(--accent);transform:translateY(-2px)}.next-lesson small{color:var(--accent);letter-spacing:.14em;font-size:9px;font-weight:800}.next-lesson h2{margin:5px 0 3px;font-size:22px}.next-lesson p{color:var(--muted);align-items:center;gap:8px;margin:0;font:10px Roboto Mono;display:flex}.next-lesson>span{background:var(--accent);color:#fff;border-radius:50%;place-items:center;width:43px;height:43px;display:grid}footer{color:var(--muted);align-items:center;gap:12px;padding:20px 0 38px;font-size:11px;display:flex}.brand-mark.small{border-radius:6px;width:27px;height:27px;font-size:10px}footer p{flex:1}footer a{text-decoration:none}footer a:hover{color:var(--accent)}.sidebar-backdrop{display:none}@media (width<=980px){.app-shell{display:block}.menu-button{display:grid}.sidebar{z-index:45;width:290px;box-shadow:var(--shadow);transition:transform .25s;position:fixed;top:72px;left:0;transform:translate(-100%)}.sidebar.open{transform:translate(0)}.sidebar-backdrop{z-index:44;-webkit-backdrop-filter:blur(2px);backdrop-filter:blur(2px);background:#090a107a;display:block;position:fixed;inset:72px 0 0}.hero{padding-inline:max(32px,8vw)}.lesson-body{width:min(100% - 64px,850px)}}@media (width<=700px){body{font-size:15px}.header-inner{padding:0 16px}.brand-copy strong{font-size:12px}.brand-copy small{font-size:9px}.hero{min-height:450px;padding:62px 24px 52px}.hero h1{font-size:clamp(36px,11vw,53px)}.hero-decoration{display:none}.hero-meta{gap:11px 18px}.lesson-body{width:min(100% - 32px,850px)}.intro-note{margin:30px 0 68px}.lesson-section{margin-bottom:82px}.section-heading{gap:12px}.section-number{width:32px;height:32px}.section-heading h2{font-size:27px}.section-content>.lead{font-size:17px}.flow-diagram{grid-template-columns:1fr}.flow-diagram>svg{justify-self:center;transform:rotate(90deg)}.code-pair,.comparison,.tasks-grid{grid-template-columns:1fr}.use-grid{grid-template-columns:1fr 1fr}.formula{flex-direction:column;align-items:flex-start}.formula>span{padding-left:12px}.run-flow{flex-direction:column;align-items:flex-start;gap:8px;margin-left:16px}.run-flow>svg{margin-left:6px;transform:none}.practice-section,.homework-section{padding:72px 0}.practice-section h2{font-size:32px}.next-lesson{padding:23px}.next-lesson h2{font-size:18px}.next-lesson>span{flex:none;width:36px;height:36px}.homework-parts>article{grid-template-columns:35px 1fr;gap:10px}}@media (width<=430px){.brand-copy strong{white-space:nowrap;text-overflow:ellipsis;max-width:155px;overflow:hidden}.icon-button{width:35px;height:35px}.hero h1{font-size:38px}.hero-lead{font-size:15px}.hero-meta span{font-size:10px}.use-grid{grid-template-columns:1fr}.steps-card{padding:22px 18px}.tree-diagram>div{gap:10px}.tree-diagram span{min-width:132px;font-size:10px}.challenge{padding:23px 18px}.challenge>div{flex-direction:column;align-items:flex-start}.bonus{padding:23px 18px}.homework-header{align-items:flex-start}.homework-header h2{font-size:28px}.next-lesson p{display:none}footer{flex-wrap:wrap}footer p{min-width:200px}}@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,:before,:after{transition-duration:.01ms!important;animation-duration:.01ms!important}}