:root{
  --ink:#1e2330; --muted:#5c6473; --line:#e7e9f1; --bg:#fbfbfe;
  --accent:#5a3ec8; --accent2:#8b5cf6; --accent-soft:#efeaff;
  --sb:#12142400; --sidebar:#111427; --sb-ink:#cdd2ea; --sb-mut:#868cae; --sb-line:#252a45; --sb-hover:#1c2140;
  --maxw:840px; --sbw:300px; --top:56px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);
  font-family:"Segoe UI",system-ui,-apple-system,Roboto,Helvetica,Arial,sans-serif;line-height:1.65;font-size:16px}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}
/* top bar (mobile) */
.topbar{position:sticky;top:0;z-index:40;display:none;align-items:center;gap:12px;
  height:var(--top);padding:0 14px;background:var(--sidebar);color:#fff;border-bottom:1px solid var(--sb-line)}
.hamb{appearance:none;border:0;background:transparent;color:#fff;font-size:22px;line-height:1;padding:8px;cursor:pointer;border-radius:8px}
.hamb:hover{background:var(--sb-hover)}
.topbar .tb-title{font-weight:800;font-size:15px;letter-spacing:.2px;color:#fff;text-decoration:none}
.topbar .tb-title span{color:var(--accent2)}
.layout{display:grid;grid-template-columns:var(--sbw) 1fr;align-items:start}
/* sidebar */
.sidebar{position:sticky;top:0;height:100vh;overflow-y:auto;background:var(--sidebar);
  color:var(--sb-ink);padding:22px 18px 40px;border-right:1px solid var(--sb-line)}
.brand{display:flex;align-items:center;gap:11px;padding:4px 6px 16px;border-bottom:1px solid var(--sb-line);margin-bottom:14px}
.brand-logo{width:36px;height:36px;border-radius:9px;flex:0 0 auto;box-shadow:0 2px 8px rgba(0,0,0,.35)}
.brand-text{display:flex;flex-direction:column;gap:2px;min-width:0}
.brand strong{font-size:16px;color:#fff;letter-spacing:.2px;font-weight:800}
.brand small{color:var(--sb-mut);font-size:12px;font-weight:600}
.nav-sec{margin:0 0 4px}
.nav-sec + .nav-sec{border-top:1px solid var(--sb-line);margin-top:14px;padding-top:14px}
.nav-sec h3{margin:2px 4px 9px;font-size:12px;text-transform:uppercase;letter-spacing:.7px;color:#ffffff;font-weight:800}
.nav-sub{margin:10px 4px 3px;font-size:12px;font-weight:800;color:#ffffff}
.nav-link{display:block;color:var(--sb-ink);font-size:13.5px;line-height:1.3;padding:3px 9px;border-radius:7px;margin:0}
.nav-link:hover{background:var(--accent);color:#fff;text-decoration:none}
.nav-link.active{background:var(--accent);color:#fff}
/* content */
.content{min-width:0;padding:0}
.wrap{max-width:var(--maxw);margin:0 auto;padding:34px 26px 80px}
.banner{width:100%;height:auto;border-radius:16px;border:1px solid var(--line);display:block;margin:0 0 22px;box-shadow:0 10px 30px rgba(30,25,60,.08)}
.kicker{display:inline-block;font-size:12px;font-weight:800;letter-spacing:.6px;text-transform:uppercase;
  color:var(--accent);background:var(--accent-soft);padding:5px 11px;border-radius:999px}
h1{font-size:34px;line-height:1.15;letter-spacing:-.5px;margin:14px 0 8px}
.lead{font-size:18px;line-height:28px;color:var(--muted);margin:0 0 22px}
.prose p{font-size:17px; line-height:24px;color:var(--muted);margin:0 0 14px}
.note{background:#fff8ec;border:1px solid #f3e2bd;border-radius:12px;padding:12px 14px;font-size:14.5px;color:#6b5a2e;margin:18px 0}
h2.sec{font-size:13px;text-transform:uppercase;letter-spacing:1px;color:var(--muted);margin:34px 0 14px;
  padding-bottom:8px;border-bottom:1px solid var(--line)}
.overview{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:14px}
.ov-card{display:flex;flex-direction:column;gap:5px;background:#fff;border:1px solid var(--line);
  border-radius:14px;padding:15px 16px;transition:.15s;color:var(--ink)}
.ov-card:hover{border-color:var(--accent);box-shadow:0 8px 22px rgba(90,62,200,.12);transform:translateY(-2px);text-decoration:none}
.ov-title{font-weight:800;font-size:15.5px}
.ov-desc{color:var(--muted);font-size:13.5px;line-height:1.5;flex:1}
.ov-go{color:var(--accent);font-weight:800;font-size:14.5px;margin-top:4px}
.xnote{font-style:italic;color:#5f7d63;font-size:13.5px;line-height:1.65;margin:30px 0 0}
.footer{margin-top:26px;padding-top:20px;border-top:1px solid var(--line);color:var(--muted);font-size:13.5px}
/* overlay for mobile drawer */
.overlay{position:fixed;inset:0;background:rgba(10,10,25,.5);opacity:0;pointer-events:none;transition:.2s;z-index:35}
@media (max-width:900px){
  .topbar{display:flex}
  .layout{grid-template-columns:1fr}
  .sidebar{position:fixed;top:0;left:0;bottom:0;width:min(84vw,320px);height:100vh;z-index:45;
    transform:translateX(-100%);transition:transform .22s ease;box-shadow:0 0 40px rgba(0,0,0,.4)}
  body.nav-open .sidebar{transform:translateX(0)}
  body.nav-open .overlay{opacity:1;pointer-events:auto}
  .wrap{padding:22px 18px 70px}
  h1{font-size:27px}
  .lead{font-size:16.5px}
}
@media only screen and (max-width: 600px), screen and (max-device-width: 600px)  {
	.hide {display: none !important;}
}
.nav-soon{opacity:.5}
.nav-soon .nav-link{pointer-events:none;cursor:default}
.ov-card--feature{position:relative;border-color:var(--accent);box-shadow:0 6px 20px rgba(90,62,200,.14)}
.ov-corner{position:absolute;top:0;right:0;width:70px;height:63px;pointer-events:none;border-top-right-radius:14px;overflow:hidden}
.ov-corner img{width:70px;height:63px;display:block}
.ov-soon{opacity:.55;pointer-events:none}
.ov-soon .ov-go{color:var(--muted)}
.crumb{font-size:13px;color:var(--muted);margin:0 0 10px}
.crumb a{color:var(--muted)}
.crumb strong{color:var(--ink)}
.byline{font-size:15px;color:var(--muted);margin:8px 0 0}
.byline strong{color:var(--ink);font-weight:700}
.intro-sep{border:0;border-top:1px solid var(--line);margin:34px 0 30px}
.intro-fig{margin:18px 0}
.intro-fig .fig-imgs{display:flex;flex-wrap:wrap;gap:14px}
.fig-img{display:block;max-width:100%}
.fig-img img{max-width:100%;height:auto;border-radius:12px;border:1px solid var(--line);box-shadow:0 6px 18px rgba(30,25,60,.10)}
.intro-fig figcaption{margin-top:9px;font-size:13.5px;color:var(--muted);line-height:1.55}
.fig-row{display:flex;flex-wrap:wrap;gap:16px;align-items:center;margin:18px 0}
.fig-item{flex:1 1 240px;max-width:360px;margin:0}
.fig-item img{max-width:100%;height:auto;border-radius:12px;border:1px solid var(--line);box-shadow:0 6px 18px rgba(30,25,60,.10)}
.fig-item figcaption{margin-top:8px;font-size:13.5px;color:var(--muted);line-height:1.5}
.fig-arrow{flex:0 0 auto;font-size:30px;color:var(--muted);line-height:1}
.step{margin:24px 0;padding-top:22px;border-top:1px solid var(--line)}
.step:first-of-type{border-top:0;padding-top:4px}
.step-head{display:flex;align-items:center;gap:12px;margin:0 0 12px}
.step-num{flex:0 0 auto;width:34px;height:34px;border-radius:10px;background:var(--accent);color:#fff;display:flex;align-items:center;justify-content:center;font-weight:800;font-size:16px}
.step-tag{display:inline-flex;align-items:center;padding:5px 12px;border-radius:999px;background:var(--accent-soft);color:var(--accent);font-weight:800;font-size:12px;text-transform:uppercase;letter-spacing:.5px}
.step-title{flex:1;min-width:0;margin:0;font-size:20px;letter-spacing:-.2px;line-height:1.25;font-style:normal}
@media(max-width:759px){.step-text + .step-imgs{margin-top:14px}}
.step-text{font-size:15.5px;line-height:1.7}
.step-text p{margin:0 0 12px}
.step-text p:last-child{margin-bottom:0}
.step-text strong{font-weight:700}
.step-text .note{margin:14px 0}
.step-text img{max-height:22px;width:auto;vertical-align:middle;margin:0 2px;image-rendering:-webkit-optimize-contrast;image-rendering:pixelated}
.step-imgs{display:flex;flex-direction:column;gap:12px}
.step-img{display:block}
.step-img img{max-width:100%;height:auto;border-radius:12px;border:1px solid var(--line);box-shadow:0 8px 22px rgba(30,25,60,.10)}
@media(min-width:760px){.step{display:grid;grid-template-columns:1fr minmax(0,400px);grid-template-rows:1fr auto auto 1fr;column-gap:24px}.step-head{grid-column:1;grid-row:2}.step-text{grid-column:1;grid-row:3}.step-imgs{grid-column:2;grid-row:1 / span 4;align-self:center}}
.pager{display:flex;justify-content:space-between;gap:10px;margin:36px 0 0;flex-wrap:wrap}
.pager a{display:inline-flex;align-items:center;gap:8px;background:var(--accent);color:#fff;font-weight:700;font-size:14.5px;line-height:1.3;padding:11px 16px;border-radius:12px;max-width:48%}
.pager a:hover{filter:brightness(1.06);text-decoration:none}
.pager a.prev{background:transparent;color:var(--accent);border:1px solid var(--line)}
.pager a.prev:hover{background:var(--accent-soft);filter:none}
.lesson-list{display:flex;flex-direction:column;gap:16px;margin-top:8px}
.lesson{display:grid;grid-template-columns:1fr;background:#fff;border:1px solid var(--line);border-radius:16px;overflow:hidden;transition:.15s}
.lesson:hover{box-shadow:0 12px 30px rgba(30,25,60,.12);transform:translateY(-2px)}
.lesson-thumb{display:block;background:#eef0f6;overflow:hidden}
.lesson-thumb img{width:100%;height:100%;object-fit:cover;display:block;aspect-ratio:16/9}
.lesson-thumb--ph{display:flex;align-items:center;justify-content:center;aspect-ratio:16/9;background:linear-gradient(135deg,#5a3ec8,#8b5cf6)}
.lesson-thumb--ph span{color:#fff;font-size:40px;font-weight:800;opacity:.85}
.lesson-info{padding:16px 18px 18px}
.lesson-idx{display:inline-block;font-size:13.5px;font-weight:800;letter-spacing:.6px;text-transform:uppercase;color:var(--accent);background:var(--accent-soft);padding:4px 10px;border-radius:999px}
.lesson-info h2{margin:9px 0 6px;font-size:19px;line-height:1.25}
.lesson-info h2 a{color:var(--ink)}
.lesson-info h2 a:hover{color:var(--accent);text-decoration:none}
.lesson-info p{margin:0 0 12px;color:var(--muted);font-size:14.5px;line-height:1.6}
.lesson-more{color:var(--accent);font-weight:800;font-size:15.5px}
@media(min-width:620px){.lesson{grid-template-columns:300px 1fr}.lesson-thumb img,.lesson-thumb--ph{height:100%;aspect-ratio:auto;min-height:150px}}
.byline strong{color:var(--muted);font-weight:700}
/* coming-soon greying (single items) */
.nav-link.soon{opacity:.45;pointer-events:none;cursor:default}
.lesson--soon{opacity:.55;pointer-events:none}
.lesson--soon .lesson-more{color:var(--muted)}

/* coming-soon visuals (override) */
.ov-soon{opacity:1;pointer-events:none}
.ov-soon .ov-title{color:#9aa0b3}
.ov-soon .ov-desc{opacity:.8}
.ov-soon .ov-go{color:var(--accent);font-weight:800}
.lesson--soon{opacity:1;pointer-events:none}
.lesson--soon .lesson-thumb img{filter:grayscale(1);opacity:.8}
.lesson--soon .lesson-info h2{color:#9aa0b3}
.lesson--soon .lesson-info p{opacity:.75}
.lesson--soon .lesson-more{color:var(--accent);font-weight:800}
/* clickable brand */
.brand{text-decoration:none}
a.brand:hover{opacity:.92}
a.brand:hover .brand-text strong{color:#fff}

/* uniform lesson-card height (essential knowledge listing) */
@media(min-width:620px){
  .lesson{height:230px}
  .lesson-info{display:flex;flex-direction:column;overflow:hidden}
  .lesson-info h2{display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
  .lesson-info p{display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
  .lesson-info .lesson-more,.lesson-info span.lesson-more{margin-top:auto}
}

/* decorative squares beside the lesson pill */
.lesson-top{display:flex;align-items:center;gap:12px;margin-bottom:2px}
.lesson-top .lesson-idx{margin:0;flex:0 0 auto}
.lesson-deco{flex:1;display:flex;justify-content:flex-end;align-items:center;gap:6px;height:26px;overflow:hidden}.lesson-deco i{width:9px;height:9px;border-radius:2px;background:#9c8bde;transform:rotate(15deg);animation:decotwinkle 3s ease-in-out infinite}.lesson-deco i:nth-child(even){background:#d0c8ef}.lesson-deco i:nth-child(1){animation-delay:0s}.lesson-deco i:nth-child(2){animation-delay:.5s}.lesson-deco i:nth-child(3){animation-delay:1.1s}.lesson-deco i:nth-child(4){animation-delay:.3s}.lesson-deco i:nth-child(5){animation-delay:1.7s}.lesson-deco i:nth-child(6){animation-delay:.8s}.lesson-deco i:nth-child(7){animation-delay:2.2s}.lesson-deco i:nth-child(8){animation-delay:1.3s}@keyframes decotwinkle{0%,100%{opacity:.35;transform:rotate(15deg) scale(.8)}50%{opacity:1;transform:rotate(15deg) scale(1.05)}}@media(prefers-reduced-motion:reduce){.lesson-deco i{animation:none;opacity:.85;transform:rotate(15deg)}}
.lesson--soon .lesson-deco{opacity:.35}

.intro-fig--sm .fig-imgs{max-width:560px}

/* divider between thumb and info (helps when screenshot is white) */
.lesson-info{border-top:1px solid var(--line)}
@media(min-width:620px){.lesson-info{border-top:0;border-left:1px solid var(--line)}}

.pager a .pg-ico{font-size:15px;line-height:1;display:inline-block;transform:scaleY(.82)}

.ov-go{display:inline-flex;align-items:center;gap:7px}
.ov-go .pg-ico{font-size:14px;line-height:1;display:inline-block;transform:scaleY(.82)}

.lesson-more{display:inline-flex;align-items:center;gap:7px}
.lesson-more .pg-ico{font-size:13px;line-height:1;display:inline-block;transform:scaleY(.82)}

/* nudge the featured "View section" arrow */
@keyframes pointright{0%,100%{transform:scaleY(.82) translateX(0)}50%{transform:scaleY(.82) translateX(5px)}}
.ov-card--feature .ov-go .pg-ico{animation:pointright 1.1s ease-in-out infinite}
@media(prefers-reduced-motion:reduce){.ov-card--feature .ov-go .pg-ico{animation:none}}

/* method group sub-header (e.g. MUST_010 Method 1/2) */
.method-head{display:flex;align-items:center;gap:10px;flex-wrap:wrap;font-size:14px;font-weight:800;color:var(--muted);text-transform:uppercase;letter-spacing:.6px;margin:40px 0 0}
.method-tag{background:var(--accent-soft);color:var(--accent);padding:5px 13px;border-radius:999px;font-size:12.5px}
.method-head + .step{border-top:0;padding-top:12px;margin-top:10px}

.method-sep{border:0;border-top:1px solid var(--line);margin:44px 0 0}
.method-sep + .method-head{margin-top:22px}

/* steps under a method header hug the header (no top gap) */
.method-head + .step{grid-template-rows:auto auto 1fr}
.method-head + .step .step-head{grid-row:1}
.method-head + .step .step-text{grid-row:2}
.method-head + .step .step-imgs{grid-row:1 / span 3;align-self:start}

/* temporarily-unlinked cross-references to unpublished chapters */
.xref-soon{color:inherit;font-weight:inherit}

/* translation-progress bar on an overview card (edit --p on the element) */
.ov-prog{display:flex;align-items:center;gap:8px;margin-top:4px}
.ov-prog-track{position:relative;flex:1;height:6px;background:var(--line);border-radius:999px;overflow:hidden}
.ov-prog-fill{position:relative;z-index:1;display:block;height:100%;width:calc(var(--p,0)*1%);background:linear-gradient(90deg,var(--accent),var(--accent2));border-radius:999px;position:relative;overflow:hidden}
.ov-prog-fill::after{content:"";position:absolute;inset:0;background:linear-gradient(90deg,transparent,rgba(255,255,255,.55),transparent);transform:translateX(-100%);animation:ovshimmer 1.6s linear infinite}
.ov-prog-pct{font-size:12px;font-weight:800;color:var(--accent);white-space:nowrap}
.ov-prog-pct::after{counter-reset:p var(--p,0);content:counter(p) "%"}
@keyframes ovshimmer{100%{transform:translateX(100%)}}
@media(prefers-reduced-motion:reduce){.ov-prog-fill::after{animation:none}}

.ov-prog-track::before{content:"";position:absolute;inset:0;background:repeating-linear-gradient(45deg,rgba(90,62,200,.10) 0 6px,transparent 6px 12px);animation:ovstripes 1s linear infinite}
@keyframes ovstripes{to{background-position:17px 0}}
/* active-category pointer arrow in sidebar */
.nav-sec h3 .sec-here{display:inline-block;width:15px;height:15px;margin-left:5px;vertical-align:-3px;background:url("data:image/svg+xml,%3Csvg%20xmlns%3D%27http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%27%20viewBox%3D%270%200%2012%2014%27%20shape-rendering%3D%27crispEdges%27%20fill%3D%27%23fff%27%3E%3Crect%20x%3D%279%27%20y%3D%272%27%20width%3D%272%27%20height%3D%2710%27%2F%3E%3Crect%20x%3D%275%27%20y%3D%272%27%20width%3D%272%27%20height%3D%2710%27%2F%3E%3Crect%20x%3D%273%27%20y%3D%274%27%20width%3D%272%27%20height%3D%276%27%2F%3E%3Crect%20x%3D%271%27%20y%3D%276%27%20width%3D%272%27%20height%3D%272%27%2F%3E%3C%2Fsvg%3E") no-repeat center/contain;animation:secpoint 1.1s ease-in-out infinite}
@keyframes secpoint{0%,100%{transform:translateX(0)}50%{transform:translateX(-3px)}}
@media(prefers-reduced-motion:reduce){.ov-prog-track::before,.nav-sec h3 .sec-here{animation:none}}
/* before/after images side-by-side inside a step */
.step-imgs.step-imgs--row{display:flex;flex-direction:row;flex-wrap:nowrap;align-items:center;gap:8px}
.step-imgs.step-imgs--row .step-img{flex:1 1 0;min-width:0}
.step-imgs.step-imgs--row .step-img img{width:100%}
.step-imgs.step-imgs--row .step-arrow{flex:0 0 auto;font-size:22px;color:var(--muted);line-height:1}

/* bold purple in-text links (prose only, not nav/pager/breadcrumb) */
.step-text a,.lead a,.note a,.fig-item figcaption a{font-weight:700}

/* slightly larger reading font on mobile */
@media(max-width:759px){.step-text{font-size:16.5px}.step-text .note{font-size:15.5px}}

/* slightly larger UI + text on mobile (menu, body, cards, headings) */
@media(max-width:768px){
  body{font-size:17px}
  .topbar .tb-title{font-size:16px}
  .brand strong{font-size:17px}
  .brand small{font-size:12.5px}
  .nav-sec h3{font-size:13px}
  .nav-sub{font-size:13px}
  .nav-link{font-size:15px}
  .crumb{font-size:14px}
  h1{font-size:29px}
  .lead{font-size:17.5px}
  .step-title{font-size:21px}
  .step-text{font-size:16.5px}
  .note,.step-text .note{font-size:15.5px}
  .byline{font-size:16px}
  .xnote{font-size:14.5px}
  .footer{font-size:14.5px}
  .lesson-info h2{font-size:20px}
  .lesson-info p{font-size:15.5px}
  .lesson-idx{font-size:14px}
  .lesson-more{font-size:16.5px}
  .ov-title{font-size:16.5px}
  .ov-desc{font-size:14.5px}
  .ov-go{font-size:15.5px}
  .ov-prog-track{height:10px}
}