/* Lesson page (lesson.php). Every rule is scoped to .lp so global/legacy styles cannot collide.
   Loaded last via $pageStyles, after the shared stylesheets. */
.lp{
  --lp-ink:#13284b;--lp-text:#33465f;--lp-muted:#617089;--lp-line:#e1e8f2;--lp-soft:#f4f7fc;
  --lp-blue:#2563eb;--lp-blue-soft:#eaf1ff;--lp-green:#14996b;--lp-green-soft:#e8f7f0;--lp-amber:#b45309;--lp-amber-soft:#fff6e6;
  --lp-radius:18px;--lp-gap:24px;--lp-header:80px;
  width:min(1400px,100% - 64px);margin:0 auto;padding:20px 0 56px;color:var(--lp-text);font-size:16px;line-height:1.65;
}
.lp *,.lp *::before,.lp *::after{box-sizing:border-box}
.lp :where(h1,h2,h3,h4){color:var(--lp-ink);letter-spacing:-.02em;line-height:1.3;margin:0}
.lp :where(p,ul,ol,figure,blockquote){margin:0}
.lp :where(img){display:block;max-width:100%;height:auto}
.lp :where(svg.lucide){width:18px;height:18px;flex:none}
.lp :where(a){color:inherit;text-decoration:none}
.lp [hidden]{display:none!important}

/* Breadcrumb */
.lp-crumbs{display:flex;flex-wrap:wrap;align-items:center;gap:6px 8px;font-size:13px;color:var(--lp-muted);margin-bottom:18px}
.lp-crumbs a{color:var(--lp-blue)}
.lp-crumbs a:hover{text-decoration:underline}
.lp-crumbs strong{color:var(--lp-ink);font-weight:600;overflow-wrap:anywhere}

/* Shell */
.lp-shell{display:grid;grid-template-columns:minmax(0,1fr);gap:var(--lp-gap);align-items:start}
.lp-main{display:flex;flex-direction:column;gap:var(--lp-gap);min-width:0}
.lp-aside{display:flex;flex-direction:column;gap:16px;min-width:0}

.lp-card{background:#fff;border:1px solid var(--lp-line);border-radius:var(--lp-radius);padding:24px;box-shadow:0 4px 18px #1d35570a;min-width:0}
.lp-section{display:flex;flex-direction:column;gap:16px;min-width:0;scroll-margin-top:calc(var(--lp-header) + 72px)}
.lp-card[id]{scroll-margin-top:calc(var(--lp-header) + 72px)}
.lp-section-head{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:12px}
.lp-section-title{display:flex;align-items:center;gap:12px;font-size:clamp(20px,2.2vw,24px)}
.lp-card>.lp-section-title{margin-bottom:16px}
.lp-badge{display:inline-grid;place-items:center;flex:none;width:32px;height:32px;border-radius:10px;background:var(--lp-blue);color:#fff;font-size:15px;font-weight:700}
.lp-muted{color:var(--lp-muted)}
.lp-small{font-size:14px}
.lp-credit{font-size:12px;color:var(--lp-muted);margin-top:8px}

/* Hero */
.lp-hero{display:grid;grid-template-columns:minmax(0,1fr);gap:20px;align-items:start}
.lp-kicker{font-size:13px;font-weight:700;text-transform:uppercase;letter-spacing:.06em;color:var(--lp-blue);margin-bottom:8px}
.lp-title{font-size:clamp(28px,4vw,44px);line-height:1.15;margin-bottom:12px;overflow-wrap:anywhere}
.lp-lead{font-size:17px;color:var(--lp-text);max-width:62ch;margin-bottom:16px}
.lp-chips{list-style:none;padding:0;display:flex;flex-wrap:wrap;gap:8px}
.lp-chips li{display:inline-flex;align-items:center;gap:6px;padding:6px 12px;border-radius:999px;background:var(--lp-soft);border:1px solid var(--lp-line);font-size:13px;font-weight:600;color:var(--lp-ink)}
.lp-chips li.is-done{background:var(--lp-green-soft);border-color:#bfe8d5;color:var(--lp-green)}
.lp-player{min-width:0}
.lp-frame{position:relative;width:100%;aspect-ratio:16/9;border-radius:var(--lp-radius);overflow:hidden;background:#0b1730;box-shadow:0 14px 34px #0b173026}
.lp-frame iframe{position:absolute;inset:0;width:100%;height:100%;border:0;display:block}
.lp-player-note{display:flex;flex-wrap:wrap;align-items:center;gap:6px 10px;margin-top:10px;font-size:13px;color:var(--lp-muted)}
.lp-player-note span{flex:1 1 220px}
.lp-player-note a{color:var(--lp-blue);font-weight:600}
.lp-player-note svg.lucide{color:#e11d48}
.lp-empty-video{aspect-ratio:16/9;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:8px;padding:24px;text-align:center;border-radius:var(--lp-radius);background:linear-gradient(135deg,#eef5ff,#f8fbff);border:1px dashed #b8cdee;color:var(--lp-muted)}
.lp-empty-video svg.lucide{width:40px;height:40px;color:var(--lp-blue)}
.lp-empty-video strong{color:var(--lp-ink);font-size:18px}

/* Section tabs */
.lp-tabs{position:sticky;top:var(--lp-header);z-index:20;display:flex;gap:4px;overflow-x:auto;scrollbar-width:none;padding:6px;margin:0;background:#ffffffeb;backdrop-filter:blur(10px);border:1px solid var(--lp-line);border-radius:14px;box-shadow:0 6px 18px #1d355710}
.lp-tabs::-webkit-scrollbar{display:none}
.lp-tabs a{flex:none;padding:9px 16px;border-radius:10px;font-size:14px;font-weight:600;color:var(--lp-muted);white-space:nowrap}
.lp-tabs a:hover,.lp-tabs a.is-active{background:var(--lp-blue-soft);color:var(--lp-blue)}

/* Goals */
.lp-goals{display:grid;grid-template-columns:minmax(0,1fr);gap:20px;align-items:center;background:linear-gradient(135deg,#ffffff 60%,#f1f6ff)}
.lp-goals h2{display:flex;align-items:center;gap:10px;font-size:20px;margin-bottom:14px}
.lp-goals h2 svg.lucide{color:var(--lp-blue);width:22px;height:22px}
.lp-goal-list{list-style:none;padding:0;display:grid;gap:10px;counter-reset:goal}
.lp-goal-list li{counter-increment:goal;display:grid;grid-template-columns:28px minmax(0,1fr);gap:10px;align-items:start}
.lp-goal-list li::before{content:counter(goal);display:grid;place-items:center;width:28px;height:28px;border-radius:50%;background:var(--lp-green-soft);color:var(--lp-green);font-weight:700;font-size:13px}
.lp-goals-photo img{width:100%;aspect-ratio:4/3;object-fit:cover;border-radius:14px}

/* Rich text (Markdown + KaTeX) */
.lp-prose{color:var(--lp-text);overflow-wrap:break-word;min-width:0}
.lp-prose>*+*{margin-top:12px}
.lp-prose h2{font-size:20px;margin-top:26px;padding-top:4px}
.lp-prose h2:first-child,.lp-prose h3:first-child{margin-top:0}
.lp-prose h3{font-size:17px;margin-top:20px}
.lp-prose p{margin:0}
.lp-prose ul,.lp-prose ol{padding-left:22px;margin:0;display:grid;gap:6px}
.lp-prose ul{list-style:disc}
.lp-prose ol{list-style:decimal}
.lp-prose li::marker{color:var(--lp-blue)}
.lp-prose strong{color:var(--lp-ink)}
.lp-prose blockquote{border-left:4px solid var(--lp-blue);background:var(--lp-blue-soft);padding:10px 14px;border-radius:0 10px 10px 0}
.lp-prose .math-block{display:block;overflow-x:auto;overflow-y:hidden;padding:14px 12px;margin:4px 0;background:var(--lp-blue-soft);border-radius:12px;text-align:center;color:var(--lp-ink)}
.lp-prose .math-inline{white-space:nowrap}
.lp-prose .math-fallback{font-family:Consolas,monospace;background:#fff4f4;padding:0 4px;border-radius:4px}
.lp-prose .katex{font-size:1.08em}
.lp-prose .katex-display{margin:0}
.lp-prose .rich-table{overflow-x:auto;border:1px solid var(--lp-line);border-radius:12px}
.lp-prose table{width:100%;border-collapse:collapse;font-size:15px;min-width:420px}
.lp-prose th,.lp-prose td{padding:10px 12px;text-align:left;border-bottom:1px solid var(--lp-line);vertical-align:top}
.lp-prose th{background:var(--lp-soft);color:var(--lp-ink);font-weight:700}
.lp-prose tr:last-child td{border-bottom:0}
.lp-prose img{border-radius:12px;margin:8px auto}
.lp-prose-text{color:var(--lp-text)}
.lp-subblock{margin-top:24px;padding-top:20px;border-top:1px solid var(--lp-line)}
.lp-subblock h3{font-size:18px;margin-bottom:10px}

/* Figures */
.lp-figure{min-width:0}
.lp-figure img{width:100%;border-radius:14px;background:var(--lp-soft);object-fit:cover}
.lp-figure figcaption{display:flex;flex-direction:column;gap:2px;margin-top:8px;font-size:14px;color:var(--lp-text)}
.lp-figure figcaption small{font-size:12px;color:var(--lp-muted)}
.lp-cover img{aspect-ratio:16/9}

/* Visual grid */
.lp-visual-grid{display:grid;grid-template-columns:minmax(0,1fr);gap:16px}
.lp-visual{display:flex;flex-direction:column;gap:12px;padding:20px}
.lp-visual h3{font-size:17px}
.lp-visual .lp-figure img{aspect-ratio:3/2;object-fit:contain}
.lp-visual .lp-figure img[src$=".webp"],.lp-visual .lp-figure img[src*=".webp?"]{object-fit:cover}

/* Interactive labs */
.lp-lab{display:grid;gap:14px;padding:16px;border-radius:14px;background:var(--lp-soft);border:1px solid var(--lp-line)}
.lp-lab-controls{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:12px}
.lp-lab-field{display:grid;gap:6px;font-size:13px;font-weight:600;color:var(--lp-ink)}
.lp-lab-field output{color:var(--lp-blue)}
.lp-lab-row{display:grid;grid-template-columns:minmax(0,1fr) 72px;gap:8px;align-items:center}
.lp-lab-row input[type=range]{width:100%;accent-color:var(--lp-blue);min-height:28px;padding:0;border:0;background:transparent}
.lp-lab-row input[type=number]{width:100%;min-height:36px;padding:6px 8px;border:1px solid #cbd7e8;border-radius:8px;font:inherit;font-size:14px;background:#fff;color:var(--lp-ink)}
.lp-lab-svg{display:block;width:100%;height:auto;max-height:300px;background:#fff;border-radius:12px;border:1px solid var(--lp-line)}
.lp-svg-label{font:700 15px/1 'Be Vietnam Pro',Arial,sans-serif;fill:var(--lp-ink)}
.lp-svg-area{font:700 15px/1 'Be Vietnam Pro',Arial,sans-serif}
.lp-lab-result{padding:10px 14px;border-radius:10px;background:#fff;border:1px solid var(--lp-line);font-size:15px;color:var(--lp-ink)}
.lp-lab-result[data-state=error]{background:#fff4f2;border-color:#f6c9c0;color:#b42318}
.lp-lab-result small{color:var(--lp-muted)}

/* Examples */
.lp-examples{display:grid;grid-template-columns:minmax(0,1fr);gap:16px}
.lp-example{display:flex;flex-direction:column;gap:12px;border-left:4px solid var(--lp-blue)}
.lp-example header{display:flex;flex-direction:column;gap:4px}
.lp-example-no{font-size:12px;font-weight:700;letter-spacing:.06em;text-transform:uppercase;color:var(--lp-blue)}
.lp-example h3{font-size:18px}
.lp-solution{border:1px solid var(--lp-line);border-radius:12px;background:#fbfcfe;overflow:hidden}
.lp-solution summary{cursor:pointer;list-style:none;display:flex;align-items:center;gap:8px;padding:11px 14px;font-weight:700;font-size:14px;color:var(--lp-blue);min-height:44px}
.lp-solution summary::-webkit-details-marker{display:none}
.lp-solution summary::before{content:'';width:8px;height:8px;border-right:2px solid currentColor;border-bottom:2px solid currentColor;transform:rotate(-45deg);transition:transform .15s}
.lp-solution[open] summary::before{transform:rotate(45deg)}
.lp-solution[open] summary{border-bottom:1px solid var(--lp-line)}
.lp-solution>.lp-prose{padding:14px}
.lp-cta{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:12px 20px;padding:18px 22px;border-radius:var(--lp-radius);background:linear-gradient(120deg,#1d4ed8,#2563eb 60%,#3b82f6);color:#fff}
.lp-cta div{display:flex;flex-direction:column;gap:2px}
.lp-cta strong{font-size:17px}
.lp-cta span{font-size:14px;opacity:.9}
.lp-cta .lp-btn-primary{background:#fff;color:var(--lp-blue);box-shadow:none}

/* Applications */
.lp-filter{display:flex;flex-wrap:wrap;gap:8px}
.lp-filter button{min-height:36px;padding:6px 14px;border-radius:999px;border:1px solid var(--lp-line);background:#fff;color:var(--lp-text);font:600 13px/1.2 inherit;cursor:pointer}
.lp-filter button:hover{border-color:#b9cdf0}
.lp-filter button.is-active{background:var(--lp-ink);border-color:var(--lp-ink);color:#fff}
.lp-apps{display:grid;grid-template-columns:minmax(0,1fr);gap:16px}
.lp-app{display:flex;flex-direction:column;padding:0;overflow:hidden}
.lp-app .lp-figure img{border-radius:0;aspect-ratio:3/2;object-fit:cover}
.lp-app .lp-figure img[src$=".svg"],.lp-app .lp-figure img[src*=".svg?"]{object-fit:contain;background:#f8fafc}
.lp-app .lp-figure figcaption{padding:0 20px}
.lp-app-body{display:flex;flex-direction:column;gap:12px;padding:18px 20px 20px;flex:1}
.lp-field{align-self:flex-start;padding:4px 10px;border-radius:999px;background:var(--lp-amber-soft);color:var(--lp-amber);font-size:12px;font-weight:700;letter-spacing:.02em}
.lp-app h3{font-size:18px}
.lp-more-apps{display:flex;flex-wrap:wrap;align-items:center;gap:8px;font-size:14px;color:var(--lp-muted)}
.lp-more-apps a{color:var(--lp-blue);font-weight:700}

/* Notes */
.lp-note{background:var(--lp-amber-soft);border-color:#f7dfb5}
.lp-note h2{display:flex;align-items:center;gap:10px;font-size:19px;margin-bottom:12px;color:#7c3a06}
.lp-note h2 svg.lucide{color:var(--lp-amber)}

/* Resources */
.lp-resource-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:12px;margin-bottom:8px}
.lp-resource{display:flex;align-items:center;gap:12px;padding:14px;border:1px solid var(--lp-line);border-radius:14px;background:var(--lp-soft);min-height:64px;transition:border-color .15s,background .15s}
.lp-resource:hover{border-color:#b9cdf0;background:#fff}
.lp-resource svg.lucide{width:22px;height:22px;color:var(--lp-blue)}
.lp-resource span{display:flex;flex-direction:column;min-width:0}
.lp-resource strong{color:var(--lp-ink);font-size:15px}
.lp-resource small{color:var(--lp-muted);font-size:13px}

/* Buttons */
.lp-btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:46px;padding:11px 20px;border-radius:12px;border:1px solid transparent;font:600 15px/1.3 inherit;cursor:pointer;text-align:center;transition:background .15s,box-shadow .15s,transform .15s}
.lp-btn:hover{transform:translateY(-1px)}
.lp-btn:disabled{opacity:.6;cursor:progress;transform:none}
.lp-btn-primary{background:var(--lp-blue);color:#fff;box-shadow:0 6px 16px #2563eb30}
.lp-btn-success{background:var(--lp-green);color:#fff;box-shadow:0 6px 16px #14996b30}
.lp-btn-success[aria-pressed=true]{background:var(--lp-green-soft);color:var(--lp-green);box-shadow:none;border-color:#bfe8d5}
.lp-btn-ghost{background:#fff;border-color:var(--lp-line);color:var(--lp-ink)}
.lp-finish{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:12px;padding-top:4px}
.lp-pager{display:flex;flex-wrap:wrap;gap:10px}

/* Aside / roadmap */
.lp-roadmap-head{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-bottom:12px}
.lp-roadmap h2,.lp-quick h2{font-size:18px}
.lp-pill{padding:3px 10px;border-radius:999px;background:var(--lp-blue-soft);color:var(--lp-blue);font-size:13px;font-weight:700}
.lp-progress{display:block;width:100%;height:8px;border:0;border-radius:99px;overflow:hidden;background:#e8eef8;margin-bottom:14px;appearance:none}
.lp-progress::-webkit-progress-bar{background:#e8eef8;border-radius:99px}
.lp-progress::-webkit-progress-value{background:var(--lp-green);border-radius:99px}
.lp-progress::-moz-progress-bar{background:var(--lp-green);border-radius:99px}
.lp-steps{list-style:none;padding:0;display:grid;gap:6px}
.lp-step{display:flex;align-items:center;gap:12px;padding:10px 12px;border-radius:12px;color:var(--lp-ink);font-size:14px;font-weight:600;line-height:1.35;transition:background .15s}
.lp-step:hover{background:var(--lp-soft)}
.lp-step.is-current{background:var(--lp-blue-soft);color:var(--lp-blue)}
.lp-step-check{display:grid;place-items:center;flex:none;width:30px;height:30px;border-radius:50%;background:#eef2f8;color:var(--lp-muted);font-size:13px;font-weight:700}
.lp-step.is-current .lp-step-check{background:var(--lp-blue);color:#fff}
.lp-step.is-done .lp-step-check{background:var(--lp-green);color:#fff}
.lp-step-text{display:flex;flex-direction:column;min-width:0;overflow-wrap:anywhere}
.lp-step-text small{font-weight:500;font-size:12px;color:var(--lp-muted)}
.lp-quick ul{list-style:none;padding:0;margin-top:12px;display:grid;gap:12px;font-size:14px}
.lp-quick li{display:grid;grid-template-columns:20px minmax(0,1fr);gap:10px}
.lp-quick svg.lucide{color:var(--lp-blue);margin-top:3px}
.lp-missing{padding-top:48px}
.lp-missing .lp-card{display:grid;gap:14px;max-width:640px}

/* ---------- Responsive ---------- */
@media (min-width:640px){
  .lp-visual-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
  .lp-visual-interactive{grid-column:1/-1}
  .lp-goals{grid-template-columns:minmax(0,1.4fr) minmax(0,1fr)}
}
@media (min-width:900px){
  .lp-apps{grid-template-columns:repeat(2,minmax(0,1fr))}
  .lp-examples{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media (min-width:1024px){
  .lp-shell{grid-template-columns:minmax(0,1fr) 290px}
  .lp-aside{position:sticky;top:calc(var(--lp-header) + 16px)}
  .lp-visual-interactive{grid-column:auto}
  .lp-visual-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
  .lp-visual-interactive:first-child{grid-column:1/-1}
}
@media (min-width:1024px) and (max-width:1279px){
  .lp-apps,.lp-examples{grid-template-columns:minmax(0,1fr)}
}
@media (min-width:1280px){
  .lp-shell{grid-template-columns:minmax(0,1fr) 320px;gap:32px}
  .lp-hero{grid-template-columns:minmax(0,1fr) minmax(0,1.25fr);gap:32px;align-items:center}
  .lp-visual-grid{grid-template-columns:repeat(3,minmax(0,1fr))}
  .lp-visual-interactive:first-child{grid-column:span 2}
}
@media (min-width:1600px){
  .lp{width:min(1560px,100% - 96px)}
  .lp-apps{grid-template-columns:repeat(3,minmax(0,1fr))}
}
@media (max-width:767px){
  .lp{width:calc(100% - 32px);padding-top:14px;font-size:15px;--lp-gap:18px;--lp-header:64px}
  .lp-card{padding:18px;border-radius:16px}
  .lp-visual,.lp-app-body{padding:16px}
  .lp-lead{font-size:16px}
  .lp-tabs{margin:0 -4px}
  .lp-cta{padding:16px}
  .lp-cta .lp-btn,.lp-finish>.lp-btn{width:100%}
  .lp-pager{width:100%}
  .lp-pager .lp-btn{flex:1 1 140px}
  .lp-section-title{font-size:20px}
}
@media (max-width:359px){
  .lp{width:calc(100% - 24px)}
  .lp-card{padding:14px}
  .lp-chips li{font-size:12px;padding:5px 10px}
  .lp-tabs a{padding:8px 11px;font-size:13px}
  .lp-lab{padding:12px}
  .lp-lab-row{grid-template-columns:minmax(0,1fr) 62px}
  .lp-resource-grid{grid-template-columns:minmax(0,1fr)}
}
@media (prefers-reduced-motion:reduce){.lp *{transition:none!important}}
.lp-application-gate{background:#f0f6ff;border:1px solid #c7dbfb;border-radius:16px;padding:18px;margin-top:20px}.lp-application-gate label{display:block;font-weight:600;margin:8px 0}.lp-application-gate input[type=text]{width:100%;padding:12px 14px;border:1px solid #94b2d9;border-radius:10px;background:#fff;color:#173452;font:inherit;min-height:46px;margin-bottom:12px}.lp-application-gate fieldset{border:0;padding:0}.lp-gate-option{display:flex!important;gap:10px;align-items:center;padding:12px;background:#fff;border:1px solid #d3dfee;border-radius:10px}.lp-gate-message{font-size:14px;line-height:1.6}.lp-gate-message[data-state=error]{color:#a72b27}.lp-gate-message[data-state=success]{color:#13724a}.lp-part-confirm{margin-top:16px;white-space:normal!important}.lp-study-progress{padding:12px 16px;background:#edf6ef;border-radius:12px;color:#176140}.lp-player .lp-part-confirm{font-size:13px}[hidden]{display:none!important}