@font-face{font-family:InterVariable;font-style:normal;font-weight:100 900;font-display:swap;src:url(/fonts/InterVariable.woff2)format("woff2")}:root{--lightningcss-light: ;--lightningcss-dark:initial;color-scheme:dark;font-optical-sizing:auto;color:#edf2f7;font-synthesis:none;--surface:#151c25;--surface-hover:#202b36;--accent:#8fdfbd;--accent-ink:#10231d;--muted:#a3b2c2;--line:#293440;background:#0d1117;font-family:InterVariable,Segoe UI,Arial,sans-serif}*{box-sizing:border-box}body{margin:0}button{font:inherit;cursor:pointer;color:inherit;touch-action:manipulation}button:disabled{cursor:default;opacity:.5}button:focus-visible,a:focus-visible{outline:3px solid var(--accent);outline-offset:4px}h1,h2,p{margin:0}h1,h2{letter-spacing:-.035em;font-weight:700}h1{font-size:clamp(38px,4.3vw,64px);line-height:1.12}h2{font-size:34px;line-height:1.2}svg{flex-shrink:0}.site-header{border-bottom:1px solid var(--line)}.header-inner{justify-content:space-between;align-items:center;max-width:1370px;min-height:82px;margin:auto;display:flex;position:relative}.brand{letter-spacing:-.025em;background:0 0;border:0;align-items:center;gap:16px;padding:0;font-size:26px;font-weight:700;display:flex}.brand svg{color:var(--accent)}.site-header nav{gap:34px;display:flex;position:absolute;left:50%;transform:translate(-50%)}nav button{color:var(--muted);background:0 0;border:0;border-bottom:2px solid #0000;padding:10px 7px;font-size:18px}nav button[aria-current=page]{border-color:var(--accent);color:#edf2f7}.profile-mark{background:var(--surface);border:1px solid #506174;border-radius:50%;place-items:center;width:49px;height:49px;font-size:23px;font-weight:600;display:grid}.app-content{max-width:1370px;margin:56px auto 0}.discovery-layout{grid-template-columns:minmax(0,952px) minmax(0,1fr);gap:32px;display:grid}.discovery-main{min-width:0}.intro-subtitle{color:var(--muted);letter-spacing:-.02em;margin-top:8px;font-size:28px;line-height:1.4}.intro-actions{gap:18px;margin-top:29px;display:flex}.button{border:1px solid var(--line);border-radius:7px;justify-content:center;align-items:center;gap:10px;min-height:49px;padding:12px 24px;font-size:17px;font-weight:600;transition:background .15s,border-color .15s;display:inline-flex}.button.primary{background:var(--accent);border-color:var(--accent);color:var(--accent-ink)}.button.primary:hover{background:#a8e9cc;border-color:#a8e9cc}.button.secondary{background:0 0;border-color:#445363}.button.secondary:hover:not(:disabled){background:var(--surface-hover);border-color:var(--muted)}.intro-actions .button{width:255px;min-height:59px;font-size:20px}.quota{color:var(--muted);margin-top:12px;font-size:16px;line-height:1.5}.topic-tabs{gap:28px;margin-top:25px;display:flex;overflow:auto}.topic-tabs button{color:var(--muted);white-space:nowrap;background:0 0;border:0;border-bottom:2px solid #0000;padding:12px 2px 8px;font-size:18px}.topic-tabs .selected{border-color:var(--accent);color:#edf2f7;font-weight:600}.featured-lesson{background:var(--surface);border:1px solid #344353;border-radius:12px;margin-top:14px;padding:25px 27px 24px;position:relative}.feature-top{justify-content:space-between;align-items:center;height:27px;display:flex}.topic-label{color:var(--muted);font-size:16px;line-height:1.5}.featured-lesson h2{margin:9px 0 12px;font-size:36px}.feature-description{color:var(--muted);padding-right:185px;font-size:20px;line-height:1.45}.feature-bottom{justify-content:space-between;align-items:end;gap:20px;margin-top:14px;display:flex}.lesson-meta{color:var(--muted);padding-bottom:1px;font-size:16px}.read-button{min-width:164px;position:absolute;bottom:24px;right:27px}.icon-button{background:0 0;border:0;border-radius:7px;place-items:center;width:44px;height:44px;display:grid}.icon-button:hover{background:var(--surface-hover)}.icon-button[aria-pressed=true]{color:var(--accent)}.explore{margin-top:42px}.explore h2{margin-bottom:16px;font-size:28px}.lesson-row{border-top:1px solid var(--line);grid-template-columns:minmax(0,1fr) 215px 140px 44px 44px;align-items:center;gap:10px;min-height:68px;display:grid}.lesson-row:last-child{border-bottom:1px solid var(--line)}.row-title{text-align:left;letter-spacing:-.018em;background:0 0;border:0;align-items:center;gap:9px;padding:12px 0;font-size:22px;font-weight:600;line-height:1.3;display:flex}.row-title:hover{color:var(--accent)}.row-topic,.row-time{color:var(--muted);font-size:16px}.practice-rail{border-left:1px solid var(--line);padding:13px 0 0 40px}.practice-rail h2{margin-bottom:25px;font-size:32px}.practice-rail h2 span{display:block}.practice-rail p{color:var(--muted);font-size:22px;line-height:1.5}.practice-rail hr{border:0;border-top:1px solid var(--line);margin:37px 0}.practice-rail ul{gap:20px;margin:33px 0 0;padding:0;list-style:none;display:grid}.practice-rail li{align-items:center;gap:18px;font-size:18px;line-height:1.5;display:flex}.check-circle{background:var(--accent);width:29px;height:29px;color:var(--accent-ink);border-radius:50%;flex-shrink:0;place-items:center;display:grid}.text-link{color:var(--accent);text-align:left;background:0 0;border:0;align-items:center;gap:10px;padding:0;font-size:18px;display:inline-flex}.text-link:hover{text-decoration:underline}.practice-rail .text-link{margin-top:25px}footer{border-top:1px solid var(--line);color:var(--muted);margin-top:38px;padding:14px 0 24px;font-size:13px;line-height:1.5}.reader{max-width:800px;margin:0 auto;padding-top:4px}.reader-toolbar{justify-content:space-between;align-items:center;margin-bottom:28px;display:flex}.reader-progress{gap:7px;margin:16px 0 34px;display:flex}.reader-progress span{background:var(--line);border-radius:2px;flex:1;height:4px}.reader-progress .done{background:var(--accent)}.reader-count{color:var(--muted);margin-bottom:13px;font-size:14px}.reader h1{outline:0;font-size:46px}.reader-body{min-height:220px;margin-top:25px;font-size:25px;line-height:1.7}.reader-controls{justify-content:space-between;gap:16px;margin-top:35px;display:flex}.source-note{color:var(--muted);border-top:1px solid var(--line);margin-top:40px;padding-top:16px;font-size:13px;line-height:1.6}.exercise{background:var(--surface);border:1px solid var(--line);border-radius:10px;margin-top:25px;padding:25px}.exercise h2,.quiz h2{font-size:27px}.exercise p,.quiz-question{margin-top:13px;font-size:20px;line-height:1.6}.quiz{margin-top:28px}.quiz-options{gap:10px;margin-top:18px;display:grid}.quiz-option{background:var(--surface);text-align:left;border:1px solid #506174;border-radius:7px;justify-content:space-between;align-items:center;gap:15px;padding:16px 18px;font-size:17px;line-height:1.5;display:flex}.quiz-option.correct{border-color:var(--accent);color:#c4f0d9;background:#1a3028}.quiz-option.incorrect{color:#f5d2c3;background:#33251f;border-color:#db9b85}.quiz-option[aria-disabled=true]{cursor:default}.answer-label{flex-shrink:0;align-items:center;gap:5px;font-size:13px;display:inline-flex}.quiz-result{background:var(--surface);border-radius:7px;margin-top:16px;padding:19px 22px;font-size:17px;line-height:1.6}.quiz-result p{margin-top:4px}.plans-page,.saved-page{max-width:1000px;margin:0 auto}.plans-page>.text-link{margin-bottom:30px}.plan-columns{grid-template-columns:1fr 1fr;gap:28px;margin-top:38px;display:grid}.plan-option{border:1px solid var(--line);background:var(--surface);border-radius:12px;padding:27px}.plan-option h2{font-size:32px}.plan-price{letter-spacing:-.035em;margin:17px 0 8px;font-size:44px}.plan-price span{color:var(--muted);letter-spacing:normal;font-size:17px}.plan-option ul{gap:18px;margin:25px 0;padding:0;list-style:none;display:grid}.plan-option li{align-items:center;gap:13px;font-size:17px;line-height:1.5;display:flex}.plan-option li svg{color:var(--accent)}.plan-option .button{width:100%}.small-note{color:var(--muted);margin-top:12px;font-size:14px;line-height:1.6}.saved-page>.intro-subtitle{margin-bottom:33px}.empty-saved{text-align:center;color:var(--muted);padding:60px 0}.empty-saved h2{color:#edf2f7;margin-top:20px}.empty-saved p{margin:14px 0 24px}.notice{background:var(--surface);border-left:3px solid var(--accent);margin-bottom:24px;padding:16px 48px 16px 20px;line-height:1.6;position:relative}.notice .text-link{margin-top:4px;font-size:16px}.notice-close{background:0 0;border:0;padding:4px 8px;font-size:26px;position:absolute;top:9px;right:12px}@media (width>=1451px){.app-content{margin-top:48px}.intro h1{font-size:74px;line-height:1}.intro-subtitle{font-size:33px;line-height:1.3}.quota{font-size:18px}.practice-rail h2{font-size:34px}}@media (width<=1450px){.header-inner,.app-content{margin-left:4.7%;margin-right:4.7%}.discovery-layout{grid-template-columns:minmax(0,2.7fr) minmax(240px,1fr);gap:30px}.practice-rail{padding-left:28px}.practice-rail h2{font-size:27px}.practice-rail p{font-size:18px}.practice-rail li{gap:12px;font-size:16px}.lesson-row{grid-template-columns:minmax(0,1fr) 125px 75px 40px 40px;gap:8px}}@media (width<=1000px){.discovery-layout{grid-template-columns:minmax(0,1fr)}.practice-rail{display:none}.header-inner{min-height:78px}.brand{gap:10px;font-size:24px}.site-header nav{gap:12px;position:static;transform:none}.intro-subtitle{font-size:26px}.app-content{margin-top:38px}}@media (width<=600px){.header-inner{flex-wrap:wrap;gap:14px;padding:15px 0 0}.brand{font-size:23px}.brand svg{width:27px}.profile-mark{width:33px;height:33px;font-size:16px}.site-header nav{order:3;justify-content:center;gap:28px;width:100%}nav button{padding:9px 7px;font-size:15px}.app-content{margin:28px 20px 0}h1{font-size:38px}.intro-subtitle{margin-top:12px;font-size:22px;line-height:1.4}.intro-actions{gap:10px;margin-top:23px}.intro-actions .button{flex:1;width:auto;min-height:49px;padding:12px 7px;font-size:15px}.quota{font-size:14px}.topic-tabs{gap:16px;margin-top:22px}.topic-tabs button{padding:12px 1px 8px;font-size:14px}.featured-lesson{margin-top:15px;padding:20px}.featured-lesson h2{margin-top:10px;font-size:29px;line-height:1.2}.feature-description{padding-right:0;font-size:18px}.feature-bottom{flex-wrap:wrap;align-items:center;gap:14px}.lesson-meta{font-size:14px}.read-button{min-width:0;min-height:45px;padding:10px 18px;font-size:15px;position:static}.explore{margin-top:30px}.explore h2{font-size:26px}.lesson-row{grid-template-columns:minmax(0,1fr) 35px 33px;gap:4px;min-height:77px}.row-title{padding-right:5px;font-size:18px;line-height:1.35}.row-topic,.row-time{display:none}.lesson-row .icon-button{width:33px;height:44px}.reader h1{font-size:36px}.reader-body{min-height:200px;font-size:22px;line-height:1.65}.reader .topic-label{font-size:13px}.reader-controls{gap:10px}.reader-controls .button{padding:12px 13px;font-size:14px}.reader-toolbar{margin-bottom:22px}.reader-progress{margin-bottom:25px}.reader-count{font-size:13px}.reader .exercise{padding:20px}.exercise p,.quiz-question{font-size:18px}.quiz-option{padding:13px 15px;font-size:16px}.plan-columns{grid-template-columns:1fr;gap:24px;margin-top:27px}.plan-option{padding:23px}.plans-page>.text-link{margin-bottom:23px}.plan-option h2{font-size:30px}.plan-price{font-size:39px}.saved-page>.intro-subtitle{font-size:22px}.empty-saved{padding:40px 0}.empty-saved h2{font-size:27px}.notice{font-size:15px}.source-note{margin-top:30px}footer{font-size:12px}}@media (prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}.availability{color:#a3b2c2;background:#151c25;border-bottom:1px solid #293440;flex-wrap:wrap;justify-content:center;align-items:center;gap:12px 24px;padding:12px 20px;font-size:14px;display:flex}