:root {
  --bg: #07100f; --panel: #0c1715; --panel-2: #101e1b; --line: #20322e;
  --text: #e7eee9; --muted: #8da19b; --green: #6ef0b2; --green-dim: #163c2e;
  --amber: #f0ba6e; --red: #ff7f7f; --blue: #75baff; --sidebar: 310px;
  --sans: Inter, system-ui, sans-serif; --mono: "IBM Plex Mono", Consolas, monospace;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--bg); color: var(--text); font-family: var(--sans); line-height: 1.65; }
button, input { font: inherit; }
button { color: inherit; }
.app-shell { min-height: 100vh; display: grid; grid-template-columns: var(--sidebar) 1fr; }
.sidebar { position: sticky; top: 0; height: 100vh; overflow: auto; background: #091311; border-right: 1px solid var(--line); padding: 20px 14px; z-index: 20; }
.brand { display: flex; align-items: center; gap: 12px; padding: 0 8px 21px; border-bottom: 1px solid var(--line); }
.brand-mark { display: grid; place-items: center; flex: 0 0 42px; width: 42px; height: 42px; text-decoration: none; }
.brand-mark img { display: block; width: 42px; height: 42px; }
.brand strong, .brand small { display: block; }
.brand strong { font: 600 14px var(--mono); letter-spacing: -.02em; }
.brand small { color: var(--muted); font-size: 11px; }
.dashboard-link { width: 100%; margin: 18px 0 6px; border: 0; border-radius: 5px; display: flex; align-items: center; gap: 10px; padding: 11px 12px; background: transparent; cursor: pointer; color: var(--muted); text-align: left; }
.dashboard-link:hover, .dashboard-link.active { background: var(--green-dim); color: var(--green); }
.nav-icon { font-family: var(--mono); font-size: 18px; }
.nav-shortcut { margin-left: auto; font: 10px var(--mono); color: var(--muted); }
.sidebar-label { margin: 20px 10px 8px; color: #62756f; text-transform: uppercase; letter-spacing: .13em; font: 10px var(--mono); }
.nav-view-switch { display: grid; grid-template-columns: 1fr 1fr; gap: 3px; margin: 0 6px 12px; padding: 3px; border: 1px solid var(--line); background: var(--bg); }
.nav-view-switch button { border: 0; padding: 7px 4px; background: transparent; color: var(--muted); cursor: pointer; font: 500 9px var(--mono); }
.nav-view-switch button:hover { color: var(--text); }
.nav-view-switch button.active { background: var(--green-dim); color: var(--green); }
.sequence-label { margin: 16px 10px 6px; color: #62756f; text-transform: uppercase; letter-spacing: .08em; font: 9px var(--mono); }
.sequence-lessons { padding: 0 7px; }
.module-group { margin-bottom: 4px; }
.module-toggle { width: 100%; border: 0; background: transparent; padding: 10px; display: flex; align-items: center; gap: 9px; cursor: pointer; border-radius: 4px; }
.module-toggle:hover { background: var(--panel); }
.module-code { width: 26px; height: 26px; display: grid; place-items: center; background: var(--panel-2); border: 1px solid var(--line); color: var(--green); font: 600 11px var(--mono); }
.module-name { font-size: 12px; font-weight: 600; text-align: left; flex: 1; }
.module-count { color: var(--muted); font: 10px var(--mono); }
.module-chevron { color: var(--muted); font-size: 10px; transition: transform .2s; }
.module-group.open .module-chevron { transform: rotate(90deg); }
.module-lessons { display: none; margin: 2px 0 9px 22px; padding-left: 12px; border-left: 1px solid var(--line); }
.module-group.open .module-lessons { display: block; }
.lesson-link { border: 0; background: transparent; width: 100%; color: var(--muted); display: grid; grid-template-columns: 24px 1fr 12px; gap: 6px; padding: 8px 4px; text-align: left; cursor: pointer; font-size: 11px; line-height: 1.35; }
.lesson-link:hover, .lesson-link.active { color: var(--text); }
.lesson-link.active .lesson-order { color: var(--green); }
.lesson-order { font: 10px var(--mono); color: #60736d; }
.lesson-link-title { min-width: 0; }
.lesson-link-title small { display: block; margin-top: 2px; color: #60736d; font: 8px var(--mono); text-transform: uppercase; letter-spacing: .06em; }
.lesson-link.active .lesson-link-title small { color: #7da396; }
.lesson-check { color: var(--green); }
.sidebar-footer { position: sticky; bottom: -20px; background: #091311; padding: 16px 8px 8px; color: var(--muted); font: 10px var(--mono); }
.mini-progress { height: 3px; background: var(--line); margin-bottom: 7px; }
.mini-progress span { display: block; height: 100%; width: 0; background: var(--green); transition: width .3s; }
main { min-width: 0; }
.topbar { height: 64px; position: sticky; top: 0; z-index: 10; display: flex; align-items: center; justify-content: space-between; padding: 0 30px; background: rgba(7,16,15,.9); backdrop-filter: blur(12px); border-bottom: 1px solid var(--line); }
.breadcrumb { color: var(--muted); font: 11px var(--mono); }
.topbar-actions { display: flex; align-items: center; gap: 9px; color: var(--muted); font: 10px var(--mono); }
.status-dot { width: 6px; height: 6px; border-radius: 50%; background: var(--green); box-shadow: 0 0 8px var(--green); }
.icon-button { border: 1px solid var(--line); background: var(--panel); color: var(--muted); width: 34px; height: 34px; display: grid; place-items: center; cursor: pointer; border-radius: 4px; }
.icon-button:hover { color: var(--green); border-color: #3b665a; }
.mobile-only { display: none; }
#app { width: min(1120px, calc(100% - 48px)); margin: 0 auto; padding: 46px 0 90px; outline: none; }
.eyebrow { color: var(--green); font: 600 11px var(--mono); text-transform: uppercase; letter-spacing: .12em; }
h1, h2, h3 { line-height: 1.2; letter-spacing: -.035em; }
h1 { font-size: clamp(32px, 5vw, 60px); margin: 14px 0 18px; max-width: 900px; }
h2 { font-size: 23px; margin: 0 0 20px; }
h3 { font-size: 15px; }
p { color: #c1cec9; }
.lead { font-size: clamp(16px, 2vw, 20px); max-width: 730px; color: var(--muted); }
.dashboard-hero { display: grid; grid-template-columns: 1fr auto; gap: 30px; align-items: end; padding-bottom: 38px; border-bottom: 1px solid var(--line); }
.overall-ring { width: 132px; height: 132px; border-radius: 50%; display: grid; place-items: center; background: conic-gradient(var(--green) var(--progress), var(--line) 0); position: relative; }
.overall-ring::before { content: ""; position: absolute; inset: 8px; background: var(--bg); border-radius: 50%; }
.ring-label { position: relative; text-align: center; font: 600 24px var(--mono); }
.ring-label small { display: block; color: var(--muted); font-size: 9px; font-weight: 400; }
.stat-row { display: grid; grid-template-columns: repeat(3, 1fr); margin: 28px 0 40px; border: 1px solid var(--line); }
.stat { padding: 20px; border-right: 1px solid var(--line); }
.stat:last-child { border: 0; }
.stat strong { display: block; font: 600 22px var(--mono); color: var(--text); }
.stat span { color: var(--muted); font-size: 11px; }
.section-heading { display: flex; justify-content: space-between; align-items: end; margin: 44px 0 16px; }
.section-heading h2 { margin: 0; }
.section-heading small { color: var(--muted); font: 10px var(--mono); }
.module-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 13px; }
.module-card { border: 1px solid var(--line); background: var(--panel); padding: 21px; cursor: pointer; transition: border-color .2s, transform .2s; }
.module-card:hover { border-color: #42665c; transform: translateY(-2px); }
.module-card-header { display: flex; align-items: center; gap: 10px; }
.module-card h3 { margin: 0; flex: 1; }
.module-card .percent { color: var(--green); font: 12px var(--mono); }
.progress-track { height: 4px; background: #1c2b27; margin: 17px 0 11px; }
.progress-track span { display: block; height: 100%; background: var(--green); }
.module-card p { margin: 0; font-size: 11px; color: var(--muted); }
.next-card { background: linear-gradient(135deg, #10251f, #0c1715); border: 1px solid #305146; padding: 24px; display: grid; grid-template-columns: 1fr auto; align-items: center; gap: 20px; }
.next-card h3 { font-size: 20px; margin: 7px 0; }
.next-card p { margin: 0; color: var(--muted); font-size: 12px; }
.course-frame { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1px; margin-top: 16px; background: var(--line); border: 1px solid var(--line); }
.course-frame article { padding: 18px; background: var(--panel); }
.course-frame article > span { color: var(--green); font: 9px var(--mono); }
.course-frame h3 { margin: 7px 0; }
.course-frame p { margin: 0; color: var(--muted); font-size: 11px; }
.primary-button, .secondary-button { border-radius: 3px; padding: 11px 17px; cursor: pointer; font: 600 11px var(--mono); }
.primary-button { border: 1px solid var(--green); background: var(--green); color: #07130f; }
.primary-button:hover { background: #95f7ca; }
.secondary-button { border: 1px solid var(--line); background: transparent; color: var(--muted); }
.secondary-button:hover { border-color: var(--green); color: var(--green); }
.lesson-header { padding-bottom: 30px; border-bottom: 1px solid var(--line); }
.lesson-meta { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.tag { border: 1px solid var(--line); padding: 4px 8px; color: var(--muted); font: 9px var(--mono); text-transform: uppercase; letter-spacing: .07em; }
.tag.green { color: var(--green); border-color: #2c5a49; }
.lesson-header h1 { font-size: clamp(30px, 4vw, 48px); }
.lesson-layout { display: grid; grid-template-columns: minmax(0, 740px) 210px; gap: 54px; margin-top: 35px; }
.lesson-layout > div { min-width: 0; }
.content-section { margin-bottom: 45px; }
.content-section h2 { display: flex; gap: 12px; align-items: center; }
.section-number { color: var(--green); font: 10px var(--mono); }
.theory p { font-size: 15px; }
.theory code, .connection-box code { font-family: var(--mono); color: var(--green); background: #10251e; padding: 1px 5px; }
.callout { border-left: 2px solid var(--amber); background: #211b12; padding: 13px 17px; margin: 22px 0; color: #d9c29d; font-size: 13px; }
.practice-box { border: 1px solid var(--line); background: var(--panel); }
.practice-head { padding: 14px 17px; border-bottom: 1px solid var(--line); display: flex; justify-content: space-between; color: var(--muted); font: 10px var(--mono); }
.practice-body { padding: 20px; }
.practice-body p { margin-top: 0; font-size: 13px; }
pre { overflow-x: auto; background: #050b0a; border: 1px solid #1b2b27; margin: 16px 0 0; padding: 18px; color: #c7dad3; font: 12px/1.65 var(--mono); tab-size: 2; }
pre .prompt { color: var(--green); user-select: none; }
.quiz { display: grid; gap: 14px; }
.question { border: 1px solid var(--line); background: var(--panel); padding: 18px; }
.question.correct { border-color: #347057; }
.question.incorrect { border-color: #724047; }
.question-title { display: flex; gap: 11px; font-size: 13px; font-weight: 600; }
.question-number { color: var(--green); font: 10px var(--mono); padding-top: 3px; }
.options { display: grid; gap: 7px; margin-top: 14px; }
.option { display: flex; align-items: flex-start; gap: 9px; border: 1px solid var(--line); background: #0a1412; padding: 10px 12px; cursor: pointer; font-size: 12px; color: #b9c7c2; }
.option:hover { border-color: #3d5d54; }
.option input { accent-color: var(--green); margin-top: 3px; }
.text-answer { width: 100%; margin-top: 14px; border: 1px solid var(--line); background: #07100e; color: var(--text); padding: 11px; font: 12px var(--mono); outline: none; }
.text-answer:focus { border-color: var(--green); }
.feedback { display: none; margin: 12px 0 0; padding: 10px 12px; font-size: 11px; }
.feedback.show { display: block; }
.correct .feedback { color: #9ee8c3; background: #10271f; }
.incorrect .feedback { color: #f2b2b2; background: #2a1718; }
.quiz-actions { display: flex; align-items: center; gap: 15px; margin-top: 18px; }
.quiz-result { color: var(--muted); font: 11px var(--mono); }
.connection-box { border: 1px solid #315247; background: #0e211c; padding: 20px; font-size: 13px; }
.connection-box h3 { margin: 0 0 9px; color: var(--green); font: 600 11px var(--mono); text-transform: uppercase; letter-spacing: .08em; }
.connection-box p { margin: 0; }
.lesson-sources { margin: 0; padding: 0; list-style: none; border: 1px solid var(--line); background: var(--panel); }
.lesson-sources li + li { border-top: 1px solid var(--line); }
.lesson-sources a { display: block; padding: 12px 15px; color: var(--green); font: 11px var(--mono); text-decoration: none; }
.lesson-sources a:hover { background: var(--green-dim); text-decoration: underline; }
.content-loading { max-width: 620px; margin: 18vh auto 0; padding: 32px; border: 1px solid var(--line); background: var(--panel); }
.content-loading h1 { margin: 8px 0 12px; font-size: clamp(24px, 4vw, 38px); }
.content-loading p { color: var(--muted); font: 500 12px var(--mono); }
.loading-track { height: 6px; margin-top: 22px; overflow: hidden; background: var(--panel-2); }
.loading-track span { display: block; width: 0; height: 100%; background: var(--green); transition: width .18s ease; }
.lesson-aside { position: sticky; top: 98px; height: max-content; }
.toc { border-left: 1px solid var(--line); padding-left: 17px; }
.toc small { color: #60736d; font: 9px var(--mono); text-transform: uppercase; }
.toc a { display: block; color: var(--muted); text-decoration: none; font-size: 11px; margin: 10px 0; }
.toc a:hover { color: var(--green); }
.aside-score { margin-top: 25px; border: 1px solid var(--line); padding: 15px; }
.aside-score strong { display: block; font: 18px var(--mono); color: var(--green); }
.aside-score span { font-size: 10px; color: var(--muted); }
.lesson-pager { display: flex; justify-content: space-between; align-items: stretch; gap: 10px; margin-top: 38px; }
.pager-button { border: 1px solid var(--line); background: var(--panel); padding: 13px 15px; cursor: pointer; color: var(--muted); width: 48%; text-align: left; font-size: 11px; }
.pager-button:last-child { text-align: right; margin-left: auto; }
.pager-button:hover { border-color: #3d675a; color: var(--text); }
.pager-button small { display: block; color: #60736d; font: 9px var(--mono); margin-bottom: 4px; }
.empty { color: var(--muted); text-align: center; padding: 80px 0; }
body.high-contrast { --bg:#020504; --panel:#08100e; --panel-2:#0c1613; --line:#3a504a; --text:#fff; --muted:#b1c2bc; }
.sidebar-scrim { display: none; }
@media (max-width: 950px) {
  .app-shell { grid-template-columns: 1fr; }
  .sidebar { position: fixed; left: 0; transform: translateX(-102%); transition: transform .25s; width: min(340px, 88vw); }
  .sidebar.open { transform: translateX(0); }
  .sidebar-scrim.show { display: block; position: fixed; inset: 0; z-index: 15; background: rgba(0,0,0,.62); }
  .mobile-only { display: grid; }
  .brand .mobile-only { margin-left: auto; order: 3; }
  .lesson-layout { grid-template-columns: 1fr; }
  .lesson-aside { display: none; }
}
@media (max-width: 650px) {
  #app { width: min(100% - 28px, 1120px); padding-top: 30px; }
  .topbar { padding: 0 14px; }
  .status-text { display: none; }
  .dashboard-hero { grid-template-columns: 1fr; }
  .overall-ring { width: 105px; height: 105px; }
  .stat-row { grid-template-columns: 1fr; }
  .stat { border-right: 0; border-bottom: 1px solid var(--line); }
  .module-grid { grid-template-columns: 1fr; }
  .course-frame { grid-template-columns: 1fr; }
  .next-card { grid-template-columns: 1fr; }
  .lesson-header h1 { font-size: 30px; }
  .lesson-meta { gap: 6px; }
  .content-section { margin-bottom: 36px; }
  .practice-head { align-items: flex-start; gap: 8px; flex-direction: column; }
  .quiz-actions { align-items: stretch; flex-direction: column; }
  .lesson-pager { flex-direction: column; }
  .pager-button { width: 100%; }
}
@media (prefers-reduced-motion: reduce) { * { scroll-behavior: auto !important; transition: none !important; } }