:root{--ink:#edf6f7;--muted:#98abb1;--bg:#071014;--paper:#0b1519;--soft:#0f1c21;--line:#23343a;--cyan:#15c5e3;--cyan-soft:#83e6f2;--warm:#edc373;--red:#f08b8b;--shadow:0 24px 70px rgba(0,0,0,.22);font-family:"Segoe UI",Inter,Arial,sans-serif;color-scheme:dark}[data-theme=light]{--ink:#132529;--muted:#5b7076;--bg:#f3f7f7;--paper:#fff;--soft:#e9f0f1;--line:#ccdadd;--shadow:0 22px 60px rgba(29,62,69,.1);color-scheme:light}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:86px}body{margin:0;background:var(--bg);color:var(--ink);line-height:1.65}body:before{content:"";position:fixed;inset:0;z-index:-1;pointer-events:none;background:radial-gradient(circle at 85% 0,rgba(21,197,227,.08),transparent 34%)}a{color:inherit;text-decoration:none}button{font:inherit}.frame{width:min(1160px,calc(100% - 40px));margin:auto}.topbar{position:sticky;top:0;z-index:50;border-bottom:1px solid var(--line);background:color-mix(in srgb,var(--bg) 90%,transparent);backdrop-filter:blur(18px)}.topbar-inner{height:76px;display:flex;align-items:center;justify-content:space-between}.identity{display:flex;align-items:center;gap:11px;font-weight:800;letter-spacing:-.02em}.identity img{width:31px;height:31px;object-fit:contain}.identity i{color:var(--cyan);font-style:normal}.nav-wrap{display:flex;align-items:center;gap:24px}.nav-wrap nav{display:flex;gap:26px;font-size:13px}.nav-wrap nav a{color:var(--muted)}.nav-wrap nav a:hover,.nav-wrap nav a.active{color:var(--ink)}.round-button{width:38px;height:38px;border-radius:50%;border:1px solid var(--line);background:transparent;color:var(--ink);cursor:pointer}.nav-button{display:none;border:1px solid var(--line);background:transparent;color:var(--ink);padding:8px 12px}.kicker{font:700 10px ui-monospace,SFMono-Regular,Consolas,monospace;text-transform:uppercase;letter-spacing:.17em;color:var(--cyan)}h1,h2,h3{margin-top:0;line-height:1.06;letter-spacing:-.045em}h1{font-size:clamp(49px,7.5vw,92px)}h2{font-size:clamp(32px,4.4vw,54px)}h3{font-size:24px}.intro{font-size:clamp(18px,2vw,22px);color:var(--muted);max-width:690px}.link-arrow{display:inline-flex;align-items:center;gap:12px;font-weight:750;border-bottom:1px solid var(--ink);padding-bottom:5px}.link-arrow span{color:var(--cyan)}.primary{display:inline-flex;padding:13px 18px;background:var(--cyan);color:#041114;font-weight:800}.home-hero{min-height:670px;display:grid;grid-template-columns:minmax(0,1fr) 330px;gap:95px;align-items:center;padding-block:85px}.home-hero h1{margin:18px 0 25px}.hero-links{display:flex;gap:26px;align-items:center;flex-wrap:wrap;margin-top:38px}.logo-stage{position:relative;display:grid;place-items:center;aspect-ratio:1}.logo-stage:before{content:"";position:absolute;inset:1px;border:1px solid var(--line);border-radius:50%}.logo-stage:after{content:"MB";position:absolute;right:-12px;bottom:27px;font:800 12px ui-monospace,monospace;letter-spacing:.2em;color:var(--muted)}.logo-stage img{width:58%;filter:drop-shadow(0 0 26px rgba(21,197,227,.24))}.home-strip{border-block:1px solid var(--line)}.strip-inner{display:grid;grid-template-columns:repeat(3,1fr)}.strip-inner div{padding:26px 28px;border-right:1px solid var(--line)}.strip-inner div:last-child{border:0}.strip-inner b{display:block;color:var(--cyan);font:700 10px ui-monospace,monospace;text-transform:uppercase;letter-spacing:.12em}.strip-inner span{display:block;margin-top:7px;color:var(--muted);font-size:14px}.home-section{padding-block:115px}.section-title{display:grid;grid-template-columns:1fr 380px;gap:70px;align-items:end;margin-bottom:54px}.section-title h2{margin:12px 0 0}.section-title>p{color:var(--muted);margin:0}.story{display:grid;grid-template-columns:1.15fr .85fr;border-top:1px solid var(--line)}.story-main{padding:50px 70px 50px 0;border-right:1px solid var(--line)}.story-main p{font-size:19px;color:var(--muted);max-width:680px}.story-main strong{color:var(--ink)}.story-side{padding:50px 0 50px 55px}.portrait-line{display:flex;align-items:center;gap:18px;margin-bottom:34px}.portrait-line img{width:72px;height:72px;border-radius:50%;object-fit:cover;filter:saturate(.72)}.portrait-line strong,.portrait-line span{display:block}.portrait-line span{font-size:13px;color:var(--muted)}.stack-list{list-style:none;margin:0;padding:0}.stack-list li{display:flex;justify-content:space-between;padding:12px 0;border-top:1px solid var(--line);font-size:13px;color:var(--muted)}.stack-list i{font-style:normal;color:var(--cyan)}.work-list{border-top:1px solid var(--line)}.work-row{display:grid;grid-template-columns:70px 1fr 180px 30px;gap:28px;align-items:center;padding:30px 12px;border-bottom:1px solid var(--line);transition:.2s}.work-row:hover{padding-left:20px;background:var(--paper)}.work-row>span{font:700 10px ui-monospace,monospace;color:var(--cyan)}.work-row h3{margin:0 0 6px}.work-row p{margin:0;color:var(--muted)}.work-row small{text-transform:uppercase;letter-spacing:.1em;color:var(--muted)}.work-row b{color:var(--cyan)}.contact-block{display:grid;grid-template-columns:1fr auto;gap:50px;align-items:end;border-top:1px solid var(--line);padding-top:55px}.contact-block h2{max-width:760px;margin-bottom:0}.footer{border-top:1px solid var(--line);padding:28px 0;color:var(--muted);font-size:12px}.footer-inner{display:flex;justify-content:space-between}.footer nav{display:flex;gap:20px}
/* learning hub */.learn-hero{padding-block:90px 72px}.learn-hero h1{max-width:1000px;margin:17px 0 25px}.learn-promise{display:grid;grid-template-columns:repeat(3,1fr);border-block:1px solid var(--line)}.learn-promise article{padding:26px;border-right:1px solid var(--line)}.learn-promise article:last-child{border:0}.learn-promise b{font-size:13px}.learn-promise p{margin:7px 0 0;color:var(--muted);font-size:13px}.curriculum{padding-block:80px 120px}.curriculum-head{display:flex;justify-content:space-between;gap:40px;align-items:end;margin-bottom:35px}.curriculum-head p{max-width:430px;color:var(--muted)}.track-list{counter-reset:track;border-top:1px solid var(--line)}.track{counter-increment:track;display:grid;grid-template-columns:70px minmax(0,1fr) 150px 30px;gap:28px;align-items:center;padding:32px 10px;border-bottom:1px solid var(--line)}.track:before{content:counter(track,decimal-leading-zero);color:var(--cyan);font:700 11px ui-monospace,monospace}.track:hover{background:var(--paper)}.track h3{margin:0 0 7px}.track p{margin:0;color:var(--muted);max-width:670px}.track small{text-transform:uppercase;letter-spacing:.1em;color:var(--muted)}.track>span{color:var(--cyan)}
/* lesson – book-like, no sidebar */.lesson-progress{height:2px;position:fixed;top:76px;left:0;right:0;z-index:51}.lesson-progress span{display:block;width:0;height:100%;background:var(--cyan)}.lesson-top{max-width:800px;padding:58px 0 45px}.lesson-top>a{font-size:12px;color:var(--muted)}.lesson-top h1{font-size:clamp(46px,6.5vw,74px);margin:50px 0 21px}.lesson-meta{display:flex;gap:18px;flex-wrap:wrap;margin-top:26px;color:var(--muted);font-size:12px}.lesson-meta span+span{border-left:1px solid var(--line);padding-left:18px}.lesson-outline{max-width:800px;margin:0 auto 30px;padding:24px 28px;background:var(--paper);border:1px solid var(--line)}.lesson-outline strong{font-size:13px}.lesson-outline ol{columns:2;column-gap:40px;margin:14px 0 0;padding-left:20px;color:var(--muted);font-size:13px}.reading{max-width:800px;margin:auto;padding-bottom:110px}.chapter{padding-block:50px;border-top:1px solid var(--line);scroll-margin-top:95px}.chapter-number{font:700 10px ui-monospace,monospace;color:var(--cyan);text-transform:uppercase;letter-spacing:.13em}.chapter h2{font-size:clamp(29px,4vw,40px);margin:10px 0 18px}.chapter>p{color:var(--muted);font-size:17px}.duo{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-top:24px}.callout{padding:18px;border:1px solid var(--line);background:var(--paper)}.callout b{display:block;font:700 10px ui-monospace,monospace;text-transform:uppercase;letter-spacing:.1em;color:var(--cyan);margin-bottom:8px}.callout p{margin:0;color:var(--muted);font-size:14px}.callout.memory{border-color:color-mix(in srgb,var(--warm) 44%,var(--line))}.callout.memory b{color:var(--warm)}.code{margin:25px 0 0;border:1px solid #27383e;background:#080e11;box-shadow:var(--shadow);min-width:0}.code-head{display:flex;align-items:center;gap:6px;padding:10px 13px;border-bottom:1px solid #27383e;color:#82979e;font:600 9px ui-monospace,monospace;text-transform:uppercase;letter-spacing:.08em}.code-head i{width:7px;height:7px;border-radius:50%;background:#40545a}.code-head span{margin-left:7px}.code-head button{margin-left:auto;border:0;background:transparent;color:#82979e;font:inherit;cursor:pointer}.code pre{margin:0;padding:20px;overflow:auto;max-width:100%;color:#dae7e9;font:13px/1.75 ui-monospace,SFMono-Regular,Consolas,monospace}.kw{color:#db91d9}.str{color:#b6d78d}.num{color:#efbd78}.comment{color:#657b82}.mistake-list{display:grid;gap:9px;margin-top:24px}.mistake{display:grid;grid-template-columns:34px 1fr;gap:14px;padding:16px 18px;background:var(--paper);border:1px solid var(--line)}.mistake b{color:var(--red);font:700 10px ui-monospace,monospace}.mistake p{margin:0;color:var(--muted);font-size:14px}.exercise{padding:30px!important;background:var(--paper);border:1px solid var(--line)!important}.exercise-actions{display:flex;gap:9px;flex-wrap:wrap;margin-top:20px}.exercise-actions button{border:1px solid var(--line);background:var(--bg);color:var(--ink);padding:9px 13px;cursor:pointer}.exercise-actions button.is-active{border-color:var(--cyan);color:var(--cyan)}.answer{margin-top:12px;padding:17px;border-left:3px solid var(--cyan);background:var(--bg);overflow:hidden}.answer[hidden]{display:none}.answer pre{margin:10px 0 0;overflow:auto;color:#dae7e9;font:13px/1.7 ui-monospace,monospace}.next-lesson{display:flex;justify-content:space-between;gap:30px;padding-top:38px;border-top:1px solid var(--line)}.next-lesson small{display:block;color:var(--muted)}.legal{max-width:800px;padding-block:70px 110px}.legal h1{font-size:64px;margin-top:45px}.legal article h2{font-size:24px;margin-top:42px}.legal article p{color:var(--muted)}.legal article a{color:var(--cyan)}
@media(max-width:850px){.home-hero{grid-template-columns:1fr;min-height:auto}.logo-stage{display:none}.section-title,.story,.contact-block{grid-template-columns:1fr}.story-main{border-right:0;padding-right:0}.story-side{padding-left:0}.work-row,.track{grid-template-columns:45px 1fr 28px}.work-row small,.track small{display:none}.learn-promise{grid-template-columns:1fr}.learn-promise article{border-right:0;border-bottom:1px solid var(--line)}}@media(max-width:650px){.frame{width:min(100% - 26px,1160px)}.topbar-inner{height:67px}.nav-wrap{gap:8px}.nav-wrap nav{display:none;position:absolute;left:13px;right:13px;top:67px;background:var(--paper);border:1px solid var(--line);padding:18px;flex-direction:column;gap:13px}.menu-open .nav-wrap nav{display:flex}.nav-button{display:block}.home-hero{padding-block:65px}.home-section{padding-block:78px}.strip-inner{grid-template-columns:1fr}.strip-inner div{border-right:0;border-bottom:1px solid var(--line)}.section-title{gap:20px}.story-main,.story-side{padding-block:32px}.curriculum-head{align-items:start;flex-direction:column}.track{grid-template-columns:32px 1fr 20px;padding:25px 5px;gap:12px}.lesson-progress{top:67px}.lesson-top{padding-top:35px}.lesson-top h1{margin-top:35px}.lesson-outline ol{columns:1}.duo{grid-template-columns:1fr}.chapter{padding-block:38px}.exercise{padding:21px!important}.footer-inner{flex-direction:column;gap:12px}}
/* enhanced learning presentation */
.learn-hero--visual{display:grid;grid-template-columns:minmax(0,1fr) 430px;gap:75px;align-items:center}
.learn-hero--visual .link-arrow{margin-top:32px}
.hero-code{min-width:0;background:#080e11;border:1px solid #27383e;box-shadow:0 30px 80px rgba(0,0,0,.32);transform:rotate(1deg)}
.hero-code-tabs{display:flex;gap:4px;border-bottom:1px solid #27383e;padding:0 12px}
.hero-code-tabs span{padding:11px 12px;color:#657a82;font:600 10px ui-monospace,monospace;text-transform:uppercase}
.hero-code-tabs .active{color:#dce9eb;border-bottom:2px solid var(--cyan)}
.hero-code pre{margin:0;padding:27px;overflow:auto;color:#dce9eb;font:13px/1.75 ui-monospace,monospace}
.hero-code footer{display:flex;align-items:center;gap:8px;border-top:1px solid #27383e;padding:10px 14px;color:#71868e;font:10px ui-monospace,monospace}
.hero-code footer i,.mini-result i{display:inline-block;width:7px;height:7px;border-radius:50%;background:#56d994;box-shadow:0 0 12px rgba(86,217,148,.55)}
.fn{color:#74c9ff}
.preview-gallery{display:grid;grid-template-columns:.75fr 1.25fr;gap:80px;align-items:center;padding-block:120px;border-bottom:1px solid var(--line)}
.preview-copy h2{margin:13px 0 20px}
.preview-copy>p{color:var(--muted)}
.preview-copy ul{list-style:none;padding:20px 0 0;margin:0}
.preview-copy li{border-top:1px solid var(--line);padding:10px 0;color:var(--muted);font-size:13px}
.preview-copy li:before{content:"✓";color:var(--cyan);margin-right:10px}
.preview-stage{position:relative;min-height:390px}
.mini-editor{position:absolute;left:0;top:0;width:min(100%,540px);background:#080e11;border:1px solid #27383e;box-shadow:var(--shadow)}
.mini-editor header{display:flex;border-bottom:1px solid #27383e}
.mini-editor header span{padding:10px 14px;color:#647a81;font:600 9px ui-monospace,monospace}
.mini-editor header .active{color:#dce9eb;background:#10191d;border-bottom:2px solid var(--cyan)}
.mini-editor pre{margin:0;padding:25px;overflow:auto;color:#dce9eb;font:13px/1.8 ui-monospace,monospace}
.mini-result{position:absolute;right:0;bottom:22px;width:255px;min-height:145px;padding:22px;background:var(--paper);border:1px solid var(--line);box-shadow:var(--shadow);display:flex;flex-direction:column}
.mini-result small,.mini-hint small{color:var(--cyan);font:700 9px ui-monospace,monospace;letter-spacing:.11em}
.mini-result strong{font-size:24px;margin:auto 0}
.mini-result span{font-size:11px;color:var(--muted)}
.mini-result i{margin-right:6px}
.mini-hint{position:absolute;left:25px;bottom:0;width:280px;padding:17px 19px;background:color-mix(in srgb,var(--warm) 8%,var(--paper));border-left:3px solid var(--warm)}
.mini-hint small{color:var(--warm)}
.mini-hint p{font-size:12px;color:var(--muted);margin:7px 0 0}
@media(max-width:900px){.learn-hero--visual,.preview-gallery{grid-template-columns:1fr}.hero-code{max-width:560px;transform:none}.preview-stage{max-width:620px}.preview-gallery{gap:45px;padding-block:85px}}
@media(max-width:600px){.hero-code{display:none}.preview-stage{min-height:auto;display:grid;gap:10px}.mini-editor,.mini-result,.mini-hint{position:static;width:100%}.preview-gallery{padding-block:70px}.mini-result{min-height:120px}.mini-result strong{margin:17px 0}}
/* SQL book */
.sql-book-hero{padding-block:55px 80px}.sql-book-hero>a,.book-chapter-head>a{font-size:12px;color:var(--muted)}.sql-book-hero-grid{display:grid;grid-template-columns:minmax(0,1fr) 320px;gap:90px;align-items:center;margin-top:55px}.sql-book-hero h1{margin:15px 0 24px}.book-cover{aspect-ratio:3/4;background:linear-gradient(145deg,#102229,#071014);border:1px solid #29434c;box-shadow:0 35px 80px rgba(0,0,0,.38);padding:28px;display:flex;flex-direction:column;position:relative;overflow:hidden;transform:rotate(2deg)}.book-cover:after{content:"";position:absolute;width:260px;height:260px;border:1px solid rgba(21,197,227,.25);border-radius:50%;right:-110px;bottom:30px}.book-cover span,.book-cover small{font:700 9px ui-monospace,monospace;letter-spacing:.15em;color:#7f969e}.book-cover strong{margin:auto 0;color:#e8f3f4;font:700 35px/1.28 ui-monospace,monospace;letter-spacing:-.05em}.book-features{border-block:1px solid var(--line)}.book-features>div{display:grid;grid-template-columns:repeat(4,1fr)}.book-features article{padding:25px;border-right:1px solid var(--line)}.book-features article:last-child{border:0}.book-features b{display:block;font-size:26px;color:var(--cyan)}.book-features span{font-size:11px;color:var(--muted);text-transform:uppercase;letter-spacing:.09em}.book-index{padding-block:95px}.book-index>header{display:flex;justify-content:space-between;align-items:end;gap:50px;margin-bottom:42px}.book-index h2{margin:12px 0 0}.book-progress{width:260px;color:var(--muted);font-size:11px}.book-progress i{display:block;height:3px;background:var(--line);margin-top:10px}.book-progress b{display:block;width:0;height:100%;background:var(--cyan);transition:.3s}.book-chapter{display:grid;grid-template-columns:62px minmax(0,1fr) 30px;gap:25px;align-items:center;padding:29px 10px;border-top:1px solid var(--line)}.book-chapter:last-child{border-bottom:1px solid var(--line)}.book-chapter:hover{background:var(--paper);padding-left:18px}.book-chapter>span{font:700 11px ui-monospace,monospace;color:var(--cyan)}.book-chapter small{color:var(--muted);text-transform:uppercase;letter-spacing:.09em}.book-chapter h2{font-size:25px;margin:5px 0 6px}.book-chapter p{margin:0;color:var(--muted)}.book-chapter>b{color:var(--cyan)}.book-chapter.complete>b{width:24px;height:24px;border-radius:50%;display:grid;place-items:center;background:var(--cyan);color:#041114}.book-note{display:grid;grid-template-columns:1fr 1fr;gap:80px;border-top:1px solid var(--line);padding-block:65px 110px}.book-note h2{margin:10px 0 0}.book-note>p{color:var(--muted)}
.sql-chapter{max-width:900px;padding-block:55px 110px}.book-chapter-head{padding-bottom:45px}.book-chapter-head .kicker{margin-top:52px}.book-chapter-head h1{font-size:clamp(47px,7vw,74px);margin:12px 0 20px}.book-chapter-head nav{display:grid;grid-template-columns:1fr 1fr;gap:0 25px;margin-top:35px;padding:18px 22px;border:1px solid var(--line);background:var(--paper)}.book-chapter-head nav a{padding:8px 0;border-bottom:1px solid var(--line);font-size:12px;color:var(--muted)}.book-chapter-head nav a:hover{color:var(--cyan)}.book-reading .chapter>.callout{margin-top:13px}.sql-practice{margin-top:28px;padding:30px!important;background:var(--paper);border:1px solid var(--line)!important}.practice-layout{display:grid;grid-template-columns:310px minmax(0,1fr);gap:12px;margin-top:25px}.schema-card,.sql-editor{border:1px solid var(--line);background:var(--bg);min-width:0}.schema-card header{display:flex;justify-content:space-between;padding:11px 13px;border-bottom:1px solid var(--line);font-size:11px}.schema-card header span{color:var(--muted);text-transform:uppercase}.schema-cols{display:flex;flex-wrap:wrap;gap:6px;padding:12px}.schema-cols code{font-size:10px;background:var(--soft);padding:4px 6px;color:var(--cyan)}.sample-table,.result-table{overflow:auto}.sample-table table,.result-table table{width:100%;border-collapse:collapse;font-size:11px}.sample-table td,.result-table td,.result-table th{padding:8px 10px;border-top:1px solid var(--line);text-align:left;white-space:nowrap}.sample-table td{color:var(--muted)}.result-table th{color:var(--cyan);background:var(--soft)}.sql-editor{display:grid;grid-template-rows:auto 1fr auto;background:#080e11;border-color:#27383e}.sql-editor header{display:flex;justify-content:space-between;padding:10px 12px;border-bottom:1px solid #27383e;color:#789098;font:700 9px ui-monospace,monospace}.sql-editor header button{border:0;background:none;color:#789098;font:inherit;cursor:pointer}.sql-editor textarea{width:100%;min-height:190px;resize:vertical;border:0;outline:0;background:#080e11;color:#dce9eb;padding:18px;font:13px/1.65 ui-monospace,monospace}.sql-editor footer{display:flex;align-items:center;gap:12px;padding:10px;border-top:1px solid #27383e}.sql-editor footer span{color:#657a82;font-size:9px}.check-sql{border:0;background:var(--cyan);color:#041114;padding:9px 13px;font-weight:800;cursor:pointer}.sql-feedback{margin-top:12px;padding:19px;border-left:3px solid var(--cyan);background:var(--bg)}.sql-feedback.error{border-color:var(--red)}.sql-feedback p{color:var(--muted)}.sql-feedback button,.hint-button{border:1px solid var(--line);background:transparent;color:var(--ink);padding:8px 11px;cursor:pointer}.result-table{margin-top:15px;border:1px solid var(--line)}.hint-button{margin-top:12px}.sql-practice .answer{margin-top:10px}
@media(max-width:800px){.sql-book-hero-grid{grid-template-columns:1fr}.book-cover{display:none}.book-features>div{grid-template-columns:1fr 1fr}.book-features article:nth-child(2){border-right:0}.book-index>header,.book-note{grid-template-columns:1fr;display:grid;align-items:start}.practice-layout{grid-template-columns:1fr}.book-chapter-head nav{grid-template-columns:1fr}}@media(max-width:540px){.book-features>div{grid-template-columns:1fr}.book-features article{border-right:0;border-bottom:1px solid var(--line)}.book-chapter{grid-template-columns:34px 1fr 20px;gap:12px}.book-chapter p{font-size:13px}.sql-practice{padding:20px!important}.sql-editor footer{align-items:flex-start;flex-direction:column}}


/* shared course system */
.course-detail{max-width:930px;padding-block:60px 110px}.course-detail-head>a{font-size:12px;color:var(--muted)}.course-detail-head .kicker{margin-top:52px}.course-detail-head h1{font-size:clamp(48px,7vw,76px);margin:12px 0 20px}.course-status{margin-top:34px;width:min(360px,100%);font-size:11px;color:var(--muted)}.course-status i{display:block;height:3px;background:var(--line);margin-top:9px}.course-status b{display:block;height:100%;background:var(--cyan)}.course-chapters{margin-top:65px}.course-chapters>a{display:grid;grid-template-columns:55px 1fr 28px;gap:22px;align-items:center;padding:27px 10px;border-top:1px solid var(--line)}.course-chapters>a:last-child{border-bottom:1px solid var(--line)}.course-chapters>a:hover{background:var(--paper);padding-left:17px}.course-chapters>a>span{font:700 11px ui-monospace,monospace;color:var(--cyan)}.course-chapters small{color:var(--muted);text-transform:uppercase;letter-spacing:.08em}.course-chapters h2{font-size:25px;margin:4px 0 6px}.course-chapters p{margin:0;color:var(--muted)}.course-chapters>a>b{color:var(--cyan)}.course-chapters .complete>b{width:23px;height:23px;border-radius:50%;background:var(--cyan);color:#041114;display:grid;place-items:center}.course-lesson{max-width:800px;padding-bottom:110px}.answer-editor{margin-top:23px;border:1px solid #27383e;background:#080e11}.answer-editor textarea{display:block;width:100%;min-height:170px;resize:vertical;border:0;background:#080e11;color:#dce9eb;padding:18px;outline:0;font:13px/1.7 ui-monospace,monospace}.answer-editor>div{display:flex;gap:8px;border-top:1px solid #27383e;padding:10px}.answer-editor button:not(.primary){border:1px solid #27383e;background:transparent;color:#dce9eb;padding:9px 12px;cursor:pointer}.course-feedback{margin-top:12px;padding:19px;border-left:3px solid var(--cyan);background:var(--bg)}.course-feedback.error{border-color:var(--red)}.course-feedback p{color:var(--muted)}.course-feedback .code{box-shadow:none}.course-feedback .code pre{white-space:pre-wrap}.course-lesson>.lesson-top,.course-lesson>.reading{width:100%}
@media(max-width:600px){.course-chapters>a{grid-template-columns:34px 1fr 20px;gap:12px}.course-chapters p{font-size:13px}.answer-editor>div{flex-wrap:wrap}}


.lesson-summary{background:var(--paper);border:1px solid var(--line)!important;padding:30px!important;margin-top:28px}.lesson-summary>p,.lesson-summary li{color:var(--muted)}.lesson-summary ul{margin:20px 0 26px;padding-left:20px}.lesson-summary li{padding:5px 0}.lesson-summary .primary:disabled{background:#56d994;cursor:default}


/* contextual real-world examples */
.real-example{margin-top:28px;padding:30px!important;background:var(--paper);border:1px solid var(--line)!important}.real-example>p{color:var(--muted);font-size:16px}.debug-preview{display:grid;grid-template-columns:.75fr 1.25fr;gap:10px;margin:26px 0 18px}.debug-steps,.debug-screen{border:1px solid var(--line);background:var(--bg);min-width:0}.debug-steps{padding:13px}.debug-steps>small{display:block;margin:2px 4px 10px;color:var(--muted);font:700 9px ui-monospace,monospace;text-transform:uppercase;letter-spacing:.1em}.debug-steps>div{display:grid;grid-template-columns:27px 1fr;gap:8px;align-items:center;padding:9px 4px;border-top:1px solid var(--line)}.debug-steps span{color:var(--cyan);font:700 9px ui-monospace,monospace}.debug-steps b{font-size:12px;font-weight:600}.debug-screen{background:#080e11;border-color:#27383e}.debug-screen header{display:flex;align-items:center;gap:6px;border-bottom:1px solid #27383e;padding:10px 12px}.debug-screen header i{width:7px;height:7px;border-radius:50%;background:#40545a}.debug-screen header span{margin-left:6px;color:#71868e;font:700 9px ui-monospace,monospace;text-transform:uppercase;letter-spacing:.09em}.debug-screen>div{padding:16px}.debug-screen p{display:grid;grid-template-columns:18px minmax(0,1fr);gap:7px;margin:0;padding:7px 0;border-bottom:1px solid rgba(39,56,62,.65)}.debug-screen p:last-child{border:0}.debug-screen p>span{color:var(--cyan);font:700 11px ui-monospace,monospace}.debug-screen code{color:#bdd0d5;font:12px/1.6 ui-monospace,monospace;overflow-wrap:anywhere}.debug-preview--error .debug-screen p:first-child code{color:var(--red)}.debug-preview--security .debug-screen p:last-child code,.debug-preview--terminal .debug-screen p:last-child code{color:#72dda1}.debug-preview--browser .debug-screen{background:#f4f7f7}.debug-preview--browser .debug-screen code{color:#24383e}.example-explanation{display:grid;grid-template-columns:220px 1fr;gap:0 24px;border-top:1px solid var(--line);padding-top:18px}.example-explanation strong{grid-row:1/4;font-size:13px}.example-explanation p{margin:0 0 8px;color:var(--muted);font-size:13px}.example-explanation p:before{content:"✓";color:var(--cyan);margin-right:8px}.example-reflection{margin:18px 0 22px;padding:15px 17px;border-left:3px solid var(--warm);background:color-mix(in srgb,var(--warm) 6%,var(--bg))}.example-reflection small{color:var(--warm);font:700 9px ui-monospace,monospace;text-transform:uppercase;letter-spacing:.09em}.example-reflection p{margin:6px 0 0;color:var(--muted);font-size:13px}.real-example .primary:disabled{background:#56d994;cursor:default}@media(max-width:650px){.real-example{padding:20px!important}.debug-preview{grid-template-columns:1fr}.example-explanation{grid-template-columns:1fr}.example-explanation strong{grid-row:auto;margin-bottom:10px}}


/* tools and automation */
.logo-stage:after{display:none}.tools-head,.automation-hero{padding-block:55px 65px}.tools-head>a,.automation-hero>a{font-size:12px;color:var(--muted)}.tools-head .kicker,.automation-hero .kicker{margin-top:52px}.tools-head h1,.automation-hero h1{margin:12px 0 22px}.tool-workspace{display:grid;grid-template-columns:230px minmax(0,1fr);gap:42px;align-items:start;padding-bottom:110px}.tool-nav{position:sticky;top:105px;display:flex;flex-direction:column}.tool-nav>p{font:700 9px ui-monospace,monospace;text-transform:uppercase;letter-spacing:.12em;color:var(--muted)}.tool-nav>button{display:grid;grid-template-columns:28px 1fr;text-align:left;border:0;border-top:1px solid var(--line);background:transparent;color:var(--muted);padding:12px 5px;cursor:pointer}.tool-nav>button span{font:700 9px ui-monospace,monospace;color:var(--cyan)}.tool-nav>button.active,.tool-nav>button:hover{color:var(--ink);padding-left:10px}.tool-coming{margin-top:22px;padding:16px;border:1px dashed var(--line)}.tool-coming span,.tool-coming strong,.tool-coming small{display:block}.tool-coming span{color:var(--cyan);font:700 9px ui-monospace,monospace;text-transform:uppercase}.tool-coming strong{margin:8px 0 5px}.tool-coming small{color:var(--muted);line-height:1.5}.tool-stage{min-width:0}.tool-panel{display:none;padding:34px;border:1px solid var(--line);background:var(--paper)}.tool-panel.active{display:block}.tool-title{display:grid;grid-template-columns:38px 1fr;gap:15px;margin-bottom:30px}.tool-title>span{color:var(--cyan);font:700 10px ui-monospace,monospace}.tool-title h2{font-size:31px;margin:0 0 7px}.tool-title p{margin:0;color:var(--muted)}.tool-panel label{display:block;margin:18px 0 7px;color:var(--muted);font-size:11px;text-transform:uppercase;letter-spacing:.08em}.tool-panel textarea,.tool-panel input,.tool-panel select{width:100%;border:1px solid var(--line);background:var(--bg);color:var(--ink);padding:13px;outline:0;font:13px/1.6 ui-monospace,monospace}.tool-panel textarea{min-height:190px;resize:vertical}.tool-panel input:focus,.tool-panel textarea:focus,.tool-panel select:focus{border-color:var(--cyan)}.tool-actions,.tool-inline,.tool-result{display:flex;gap:8px;align-items:center;margin-top:12px}.tool-actions button,.tool-inline button,.tool-result button{border:1px solid var(--cyan);background:var(--cyan);color:#041114;padding:10px 13px;font-weight:800;cursor:pointer}.tool-actions .secondary{background:transparent;color:var(--ink);border-color:var(--line)}.tool-inline select{width:180px}.tool-result input{flex:1}.tool-status,.tool-output{margin-top:14px;padding:14px;border-left:3px solid var(--cyan);background:var(--bg)}.tool-status:empty,.tool-output:empty{display:none}.tool-status.error,.tool-output.error{border-color:var(--red)}.tool-output strong,.tool-output span{display:block}.tool-output span{color:var(--muted);overflow-wrap:anywhere}.tool-hint{color:var(--muted);font-size:12px}.regex-row{display:grid;grid-template-columns:auto 1fr auto 70px;gap:8px;align-items:center}.automation-hero{display:grid;grid-template-columns:minmax(0,1fr) 330px;gap:80px;align-items:center}.automation-hero>a{grid-column:1/-1}.flow-demo{padding:22px;border:1px solid var(--line);background:var(--paper)}.flow-demo span,.flow-demo b,.flow-demo i{display:block}.flow-demo span{color:var(--cyan);font:700 9px ui-monospace,monospace;text-transform:uppercase;letter-spacing:.1em}.flow-demo b{font-size:13px;margin-top:5px}.flow-demo i{text-align:center;color:var(--muted);font-style:normal;padding:8px}.automation-content{padding-block:70px 100px}.automation-content>header{display:grid;grid-template-columns:1fr 380px;gap:60px;align-items:end;margin-bottom:42px}.automation-content>header p{color:var(--muted)}.automation-list{border-top:1px solid var(--line)}.automation-list article{display:grid;grid-template-columns:55px 1fr 100px;gap:25px;align-items:center;padding:28px 8px;border-bottom:1px solid var(--line)}.automation-list article>span{color:var(--cyan);font:700 10px ui-monospace,monospace}.automation-list h3{margin:0 0 6px}.automation-list p{margin:0;color:var(--muted)}.automation-list small{text-align:right;color:var(--muted);text-transform:uppercase;letter-spacing:.09em}@media(max-width:800px){.tool-workspace,.automation-hero,.automation-content>header{grid-template-columns:1fr}.tool-nav{position:static;display:grid;grid-template-columns:repeat(2,1fr)}.tool-nav>p,.tool-coming{grid-column:1/-1}.automation-hero>a{grid-column:auto}}@media(max-width:520px){.tool-workspace{gap:22px}.tool-panel{padding:21px}.tool-actions,.tool-inline,.tool-result{align-items:stretch;flex-direction:column}.tool-inline select{width:100%}.tool-actions button,.tool-inline button,.tool-result button{width:100%}.automation-list article{grid-template-columns:32px 1fr}.automation-list small{display:none}}