:root{--ink:#17283b;--muted:#4e6075;--line:#e5ebf2;--brand:#233d57;--blue:#356fc2;--surface:#fff;--bg:#f6f8fb;--radius:16px}*{box-sizing:border-box}html{scroll-behavior:smooth}body{background:var(--bg);color:var(--ink);margin:0;font-family:Arial,Helvetica,sans-serif;font-size:15px;line-height:1.55}button,textarea{font:inherit}a{color:inherit;text-decoration:none}button{cursor:pointer}:is(a:focus-visible,button:focus-visible,summary:focus-visible,textarea:focus-visible){outline-offset:4px;outline:3px solid #2469d4}a:hover{text-decoration:none}.skip-link{z-index:100;background:#fff;border-radius:8px;padding:12px 18px;position:fixed;top:-100px;left:20px}.skip-link:focus{top:12px}.app-shell{min-height:100vh}.sidebar{border-right:1px solid var(--line);z-index:21;background:#fff;flex-direction:column;width:256px;padding:29px 18px 20px;display:flex;position:fixed;top:0;bottom:0;left:0}.brand{align-items:center;gap:10px;margin:1px 3px 64px;display:flex}.brand-logo{border:1px solid var(--line);border-radius:13px;flex-shrink:0;place-items:center;width:55px;height:55px;display:grid;overflow:hidden}.brand-logo img{object-fit:contain}.brand-name{letter-spacing:-.45px;font-size:14px;font-weight:850;line-height:1.25}.brand-name span{font-size:12px}.brand-name small{color:#60738c;letter-spacing:1.55px;margin-top:5px;font-size:10px;font-weight:750;display:block}.nav-label{letter-spacing:1.5px;color:#4c6179;margin:0 14px 17px;font-size:10px;font-weight:800}.nav-links ul{margin:0;padding:0;list-style:none}.nav-links li{margin-bottom:6px}.nav-item{color:#516279;border-radius:10px;align-items:center;gap:14px;padding:12px 14px;font-weight:650;transition:background .15s;display:flex}.nav-item:hover{color:#193b68;background:#f5f8fd}.nav-item.active{color:#205ba8;background:#eaf1fc}.nav-item svg{flex-shrink:0}.sidebar-bottom{margin-top:auto}.support-note{border:1px solid var(--line);background:#f4f7fb;border-radius:12px;flex-direction:column;gap:5px;padding:16px;display:flex}.support-note svg{color:#3a76bd}.support-note strong{font-size:13px}.support-note span{color:var(--muted);font-size:12px}.brand-link{color:#526b83;justify-content:center;align-items:center;gap:5px;margin-top:20px;font-size:12px;display:flex}.brand-link:hover,.text-link:hover{color:#0c54aa}.app-content{flex-direction:column;min-height:100vh;margin-left:256px;display:flex}.topbar{border-bottom:1px solid var(--line);background:#fff;justify-content:space-between;align-items:center;height:74px;padding:0 clamp(22px,4vw,56px);display:flex}.breadcrumbs,.topbar-right{color:#4b6077;align-items:center;gap:11px;font-size:13px;display:flex}.breadcrumbs span{color:#bac4d2}.topbar-right{gap:16px}.preview-chip{letter-spacing:.7px;color:#385f8d;background:#eff4fb;border:1px solid #e0ebf7;border-radius:99px;padding:7px 12px;font-size:10px;font-weight:800}.avatar{color:#43526b;background:#e9ecf2;border-radius:50%;place-items:center;width:34px;height:34px;font-weight:800;display:grid}.main-content{flex:1;width:100%;max-width:1480px;margin:0 auto;padding:44px clamp(20px,4vw,56px) 50px}.page-intro{justify-content:space-between;align-items:center;gap:16px;margin-bottom:29px;display:flex}.eyebrow{letter-spacing:1.5px;color:#245b93;margin:0 0 10px;font-size:11px;font-weight:850}.page-intro h1,.lesson-header h1,.detail-hero h1{letter-spacing:-1.5px;margin:0 0 9px;font-size:clamp(28px,3vw,38px);line-height:1.2}.page-intro p:not(.eyebrow){color:var(--muted);margin:0}.wave{color:#eaa94d}.date-tag{border:1px solid var(--line);white-space:nowrap;color:#4d6177;background:#fff;border-radius:30px;padding:9px 16px;font-size:12px}.hero{color:#fff;background:linear-gradient(110deg,#203449,#294e6b);border-radius:19px;grid-template-columns:1fr .9fr;min-height:307px;display:grid;position:relative;overflow:hidden}.hero-copy{z-index:1;padding:41px clamp(27px,4vw,55px);position:relative}.hero-eyebrow{letter-spacing:1.25px;color:#badbff;align-items:center;gap:8px;font-size:11px;font-weight:800;display:inline-flex}.hero-copy h2{letter-spacing:-1.5px;margin:17px 0;font-size:clamp(31px,3.5vw,45px);line-height:1.12}.hero-copy h2 em{color:#a7d2ff;font-style:normal}.hero-copy p{color:#dfebf7;max-width:465px;margin:0 0 23px;font-size:14px}.button{border:1px solid #0000;border-radius:9px;justify-content:center;align-items:center;gap:10px;padding:12px 17px;font-size:13px;font-weight:750;display:inline-flex}.light-button{color:#1c3857;background:#fff}.light-button:hover{background:#eaf4ff}.primary-button{color:#fff;background:#254f7c}.primary-button:hover{background:#183c65}.secondary-button{color:#264b76;background:#fff;border-color:#cfdbe9}.secondary-button:disabled{opacity:.45;cursor:not-allowed}.hero-visual{justify-content:center;align-items:center;min-width:0;display:flex;position:relative}.orbit{opacity:.5;border:1px solid #52718c;border-radius:50%;position:absolute}.orbit-one{width:270px;height:270px}.orbit-two{width:420px;height:420px}.hero-code{color:#d1dfec;background:#152638;border:1px solid #5e7790;border-radius:14px;width:min(90%,360px);padding:19px 24px 25px;position:relative;transform:rotate(-5deg);box-shadow:0 18px 50px #122b3d8a}.code-dots{gap:5px;margin-bottom:24px;display:flex}.code-dots i{background:#53718a;border-radius:50%;width:8px;height:8px}.code-dots i:first-child{background:#e6a7a7}.code-dots i:nth-child(2){background:#e0cf92}.hero-code code{font:12px/2 Consolas,Monaco,monospace}.hero-code code span{color:#96c5ff}.hero-code code b{color:#a8ddb1;font-weight:400}.hero-check{color:#255173;background:#fff;border-radius:10px;align-items:center;gap:7px;padding:10px 13px;font-size:11px;font-weight:750;display:flex;position:absolute;bottom:28px;right:13%;box-shadow:0 6px 22px #152a3c40}.hero-check svg{color:#2f9a70}.stat-grid{grid-template-columns:repeat(4,minmax(0,1fr));gap:16px;margin:21px 0 42px;display:grid}.stat-card{border:1px solid var(--line);background:#fff;border-radius:13px;align-items:center;gap:15px;min-height:103px;padding:18px;display:flex}.stat-icon{border-radius:12px;flex-shrink:0;place-items:center;width:48px;height:48px;display:grid}.soft-blue{color:#3979b4;background:#eaf3ff}.soft-purple{color:#775fc0;background:#f0eefe}.soft-teal{color:#159984;background:#e9f8f5}.soft-orange{color:#c18a43;background:#fff3e5}.stat-card div{flex-direction:column;display:flex}.stat-card strong{letter-spacing:-.6px;font-size:22px;line-height:1.3}.stat-card span:last-child{color:var(--muted);font-size:12px}.section-heading{justify-content:space-between;align-items:flex-end;gap:15px;margin:0 0 20px;display:flex}.section-heading h2{letter-spacing:-.8px;margin:0 0 5px;font-size:24px}.section-heading p:not(.eyebrow){color:var(--muted);margin:0;font-size:13px}.text-link{color:#2f67a9;white-space:nowrap;align-items:center;gap:7px;font-size:13px;font-weight:750;display:inline-flex}.course-grid{grid-template-columns:repeat(3,minmax(0,1fr));gap:18px;display:grid}.course-card{border:1px solid var(--line);background:#fff;border-radius:14px;flex-direction:column;min-width:0;padding:24px;transition:border-color .15s,box-shadow .15s;display:flex}.course-card:hover{border-color:#c7d7eb;box-shadow:0 9px 28px #263c5610}.course-card-top{justify-content:space-between;align-items:flex-start;gap:8px;display:flex}.course-illustration{letter-spacing:-1px;border-radius:14px;place-items:center;width:59px;height:59px;font-size:19px;font-weight:850;display:grid}.course-illustration.blue{color:#2e70b2;background:#e9f2ff}.course-illustration.purple{color:#725bc2;background:#efedff}.course-illustration.teal{color:#1d967e;background:#e6f8f4}.course-illustration.orange{color:#b77c36;background:#fff2e4}.course-illustration.big{flex-shrink:0;width:95px;height:95px;font-size:30px}.level-pill{color:#5c7286;text-align:center;background:#f5f7fa;border-radius:30px;padding:5px 9px;font-size:10px;font-weight:750}.course-category{text-transform:uppercase;letter-spacing:.9px;color:#425e7c;margin:22px 0 7px;font-size:10px;font-weight:800}.course-card h3{letter-spacing:-.4px;margin:0 0 9px;font-size:18px;line-height:1.4}.course-card h3 a:hover{text-decoration:underline}.course-description{color:var(--muted);flex:1;margin:0 0 22px;font-size:13px}.course-card-meta{border-bottom:1px solid var(--line);color:#506177;align-items:center;gap:18px;padding-bottom:17px;font-size:12px;display:flex}.course-card-meta span,.detail-meta span{align-items:center;gap:6px;display:flex}.course-card-link{color:#2967a6;justify-content:space-between;align-items:center;padding-top:16px;font-size:13px;font-weight:800;display:flex}.bottom-grid{grid-template-columns:1.2fr 1fr;gap:18px;margin-top:23px;display:grid}.next-step-panel,.playground-panel{background:#eef5fc;border:1px solid #d9e5f1;border-radius:14px;gap:18px;padding:24px;display:flex}.playground-panel{border-color:var(--line);background:#fff}.panel-icon{color:#245b93;background:#fff;border-radius:10px;flex-shrink:0;place-items:center;width:42px;height:42px;display:grid}.bottom-grid h3{margin:0 0 7px;font-size:18px}.bottom-grid p:not(.eyebrow){color:var(--muted);margin:0 0 16px;font-size:13px}.preview-disclaimer{color:#4c6177;margin:26px 0 0;font-size:12px}.site-footer{border-top:1px solid var(--line);color:#506176;background:#fff;flex-wrap:wrap;justify-content:space-between;gap:14px;padding:20px clamp(20px,4vw,56px);font-size:11px;display:flex}.site-footer a{color:#2e67ac;align-items:center;gap:3px;display:flex}.back-link{color:#396b9a;align-items:center;gap:8px;margin-bottom:27px;font-size:13px;font-weight:700;display:inline-flex}.detail-hero{border:1px solid var(--line);background:#fff;border-radius:17px;align-items:center;gap:26px;padding:34px;display:flex}.detail-hero h1{margin:4px 0 10px}.detail-hero p:not(.eyebrow){color:var(--muted);max-width:760px;margin:0 0 20px}.detail-meta{color:#4e6177;flex-wrap:wrap;gap:24px;font-size:13px;display:flex}.detail-hero+.section-heading{margin-top:39px}.lesson-list{gap:11px;margin:0;padding:0;list-style:none;display:grid}.lesson-row{border:1px solid var(--line);background:#fff;border-radius:12px;align-items:center;gap:18px;padding:19px 22px;display:flex}.lesson-row:hover{border-color:#9ebce1}.lesson-index{color:#245d95;font-size:18px;font-weight:850}.lesson-row-title{flex-direction:column;flex:1;display:flex}.lesson-row-title strong{font-size:15px}.lesson-row-title small{color:var(--muted);margin-top:3px;font-size:12px}.lesson-minutes{color:var(--muted);align-items:center;gap:7px;font-size:12px;display:flex}.content-note{color:#46647d;background:#eef4fb;border:1px solid #dbe8f6;border-radius:10px;align-items:center;gap:10px;margin:23px 0;padding:15px 18px;font-size:13px;display:flex}.lesson-layout{grid-template-columns:minmax(0,1fr) 272px;gap:26px;display:grid}.lesson-main{min-width:0}.lesson-header{border-bottom:1px solid var(--line);padding-bottom:25px}.lesson-header h1{margin:5px 0 12px}.lesson-time{color:var(--muted);align-items:center;gap:7px;font-size:13px;display:inline-flex}.lesson-objectives,.lesson-section,.practice-task,.notes-panel{border:1px solid var(--line);background:#fff;border-radius:13px;margin-top:18px;padding:26px 30px}.lesson-main h2{letter-spacing:-.5px;margin:0 0 12px;font-size:20px}.lesson-main h3{font-size:14px}.lesson-main p{color:#5b6e83;margin:0 0 12px}.lesson-objectives ul,.practice-task ul{gap:11px;margin:0;padding:0;list-style:none;display:grid}.lesson-objectives li,.practice-task li{align-items:flex-start;gap:11px;font-size:14px;display:flex}.lesson-objectives li svg,.practice-task li svg{color:#26947a;flex-shrink:0;margin-top:2px}.code-example{color:#e3effa;tab-size:2;background:#152738;border-radius:10px;margin:20px 0 0;padding:20px;font-size:13px;line-height:1.65;overflow:auto}.practice-task{background:#eff6ff;border-color:#d8e8f8}.practice-label{color:#225b94;letter-spacing:1px;align-items:center;gap:8px;margin-bottom:10px;font-size:11px;font-weight:800;display:flex}.practice-task details{background:#fff;border-radius:9px;margin-top:19px;padding:13px 16px}.practice-task summary{cursor:pointer;color:#315e87;align-items:center;gap:8px;font-weight:750;display:flex}.practice-task details p{margin:9px 0 0}.notes-panel h2{align-items:center;gap:9px;display:flex}.notes-panel label{margin:18px 0 8px;font-weight:700;display:block}.notes-panel textarea{resize:vertical;width:100%;min-height:130px;color:var(--ink);border:1px solid #bfcddd;border-radius:9px;padding:14px}.notes-footer{justify-content:space-between;align-items:center;gap:15px;margin-top:12px;display:flex}.notes-footer span{color:var(--muted);align-items:center;gap:6px;font-size:12px;display:flex}.lesson-next{justify-content:flex-end;margin-top:19px;display:flex}.side-info{border:1px solid var(--line);background:#fff;border-radius:13px;margin-bottom:16px;padding:22px}.side-info h2{margin:0 0 14px;font-size:16px}.side-info ol{margin:0;padding:0;list-style:none}.side-info li a{color:#52687d;border-radius:7px;align-items:flex-start;gap:8px;padding:11px 8px;font-size:13px;display:flex}.side-info li a.selected{color:#215f9d;background:#ecf4ff;font-weight:750}.side-info li a span{color:#405a75}.side-info p{color:var(--muted);font-size:13px}.resource-grid{grid-template-columns:repeat(3,minmax(0,1fr));gap:18px;margin-top:25px;display:grid}.resource-card{border:1px solid var(--line);background:#fff;border-radius:13px;flex-direction:column;gap:14px;padding:24px;display:flex}.resource-card:hover{border-color:#a6c3e4}.resource-icon{color:#3c76ac;background:#eaf2ff;border-radius:10px;place-items:center;width:48px;height:48px;display:grid}.resource-card>span:last-child{color:#2d68ab;align-items:center;gap:5px;font-size:13px;font-weight:750;display:flex}.settings-stack{gap:14px;display:grid}.settings-item{border:1px solid var(--line);background:#fff;border-radius:13px;align-items:center;gap:18px;padding:22px;display:flex}.settings-item>div{flex:1}.settings-item h2{margin:0 0 5px;font-size:17px}.settings-item p{color:var(--muted);margin:0;font-size:13px}.status-pill{white-space:nowrap;border:1px solid var(--line);color:#4d6074;background:#f6f7f9;border-radius:30px;padding:6px 10px;font-size:11px}.mobile-bar,.mobile-scrim{display:none}@media (max-width:1100px){.course-grid,.stat-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.hero-visual{opacity:.8}.hero-check{right:5%}.resource-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}@media (max-width:900px){.sidebar{transition:transform .2s;transform:translate(-100%)}.sidebar.sidebar-open{transform:translate(0)}.app-content{margin-left:0}.mobile-bar{border-bottom:1px solid var(--line);z-index:20;background:#fff;justify-content:space-between;align-items:center;height:63px;padding:0 20px;display:flex;position:sticky;top:0}.mobile-brand{letter-spacing:-.3px;align-items:center;gap:9px;font-size:14px;display:flex}.mobile-brand img{object-fit:contain}.icon-button{color:var(--ink);background:0 0;border:0;padding:10px}.mobile-scrim{z-index:20;background:#14283980;border:0;display:block;position:fixed;inset:0}.topbar{height:55px}.lesson-layout{grid-template-columns:minmax(0,1fr)}.lesson-sidebar{display:none}}@media (max-width:620px){.main-content{padding:28px 18px 38px}.topbar{padding:0 18px}.topbar-right{gap:7px}.preview-chip{padding:5px 7px;font-size:9px}.breadcrumbs{font-size:11px}.page-intro{align-items:start}.date-tag{display:none}.hero{grid-template-columns:1fr}.hero-copy{padding:30px 26px}.hero-visual{min-height:198px}.hero-code{width:75%;max-width:310px;padding:12px 15px;transform:rotate(-3deg)}.hero-check{bottom:10px;right:7%}.hero-copy h2{font-size:32px}.stat-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:10px;margin:13px 0 32px}.stat-card{gap:9px;min-height:95px;padding:12px}.stat-icon{width:39px;height:39px}.stat-icon svg{width:19px}.stat-card strong{font-size:16px}.stat-card span:last-child{font-size:10px}.course-grid,.bottom-grid,.resource-grid{grid-template-columns:1fr}.section-heading{align-items:flex-start}.section-heading h2{font-size:22px}.text-link{font-size:12px}.detail-hero{flex-direction:column;align-items:flex-start;gap:16px;padding:23px}.detail-meta{gap:12px}.lesson-row{gap:11px;padding:13px}.lesson-minutes{display:none}.lesson-objectives,.lesson-section,.practice-task,.notes-panel{padding:21px 18px}.settings-item{flex-wrap:wrap;align-items:flex-start;padding:18px}.settings-item .status-pill{margin-left:65px}.site-footer{padding:18px}.notes-footer{flex-direction:column;align-items:flex-start}}@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,:before,:after{transition:none!important;animation:none!important}}.auth-wrap{background:linear-gradient(135deg,#e8eff7,#f9fbfe);place-items:center;min-height:100vh;padding:24px;display:grid}.auth-card{background:#fff;border:1px solid #d9e3ee;border-radius:18px;width:min(100%,450px);padding:32px;box-shadow:0 15px 45px #20344912}.auth-brand{align-items:center;gap:12px;margin-bottom:25px;font-size:14px;font-weight:850;display:flex}.auth-brand img{object-fit:contain;border-radius:10px}.auth-brand small{color:#58708b;letter-spacing:1.4px;font-size:10px;display:block}.auth-card h1{letter-spacing:-.7px;margin:0 0 5px;font-size:29px}.auth-card>p{color:#55697e;margin:0 0 18px}.auth-form{gap:10px;display:grid}.auth-form label{margin-top:5px;font-size:13px;font-weight:700}.auth-form input{width:100%;font:inherit;border:1px solid #9fadc0;border-radius:9px;padding:12px 13px}.auth-form input:focus-visible{outline-offset:3px;outline:3px solid #2469d4}.auth-form button:focus-visible{outline-offset:3px;outline:3px solid #2469d4}.signout-button:focus-visible{outline-offset:3px;outline:3px solid #2469d4}.auth-form button{margin-top:14px}.auth-links{font-size:13px;margin-top:17px!important}.auth-links a,.auth-footer a{color:#215e9f;text-decoration:underline}.auth-footer{color:#60768b;border-top:1px solid #e1e7ed;margin-top:25px;padding-top:16px;font-size:11px}.auth-message,.auth-error{border-radius:8px;padding:13px;margin:15px 0!important;font-size:13px!important}.auth-message{color:#185d3e;background:#e9f7ef}.auth-error{color:#8a2521;background:#fff0ef}.account-email{text-overflow:ellipsis;white-space:nowrap;color:#385777;max-width:200px;overflow:hidden}.signout-button{color:#264e79;background:#fff;border:1px solid #cbd8e5;border-radius:8px;padding:7px 12px;font-size:12px;font-weight:700}.signout-button:hover{background:#eff4fb}@media (max-width:620px){.auth-card{padding:22px}.account-email{max-width:100px}.topbar-right{gap:6px}}.tutor-panel{background:#fff;border:1px solid #d7e3ef;border-radius:20px;gap:20px;max-width:1000px;padding:clamp(16px,3vw,32px);display:grid}.tutor-heading{flex-wrap:wrap;justify-content:space-between;align-items:flex-start;gap:12px;display:flex}.tutor-heading h2{margin:4px 0 8px;font-size:clamp(1.4rem,3vw,2rem)}.tutor-caution{background:#fff7e7;border:1px solid #e8c78b;border-radius:12px;padding:14px;line-height:1.6}.tutor-panel label,.tutor-mode legend{margin-bottom:8px;font-weight:700;display:block}.tutor-panel input[type=password],.tutor-panel textarea{color:#172c40;width:100%;min-width:0;font:inherit;background:#fff;border:1px solid #879db6;border-radius:10px;padding:12px}.tutor-panel :is(input,textarea,button,a):focus-visible{outline-offset:3px;outline:3px solid #2161a8}.tutor-key-row{align-items:center;gap:10px;display:flex}.tutor-key-row input{flex:1}.tutor-mode{border:0;margin:0;padding:0}.tutor-mode-options{flex-wrap:wrap;gap:14px;display:flex}.tutor-mode-options label{align-items:center;gap:7px;margin:0;font-weight:500;display:flex}.tutor-transcript{white-space:pre-wrap;overflow-wrap:anywhere;background:#f2f7fc;border-radius:12px;min-height:130px;max-height:420px;padding:18px;overflow:auto}.tutor-entry{border-bottom:1px solid #d6e3ee;padding:12px}.tutor-entry:last-child{border:0}.tutor-entry p{margin:7px 0 0;line-height:1.6}.tutor-actions{flex-wrap:wrap;gap:10px;margin-top:12px;display:flex}.tutor-notice{color:#9b3030;font-weight:700}.tutor-footnote{color:#52647a;font-size:.88rem}@media (max-width:580px){.tutor-key-row{flex-direction:column;align-items:stretch}.tutor-panel{border-radius:12px}}
