/* Forward deployed engineer guide: hero, side rails, charts, components.
   Reuses --course-* tokens from courses.css. Scoped under .fde-* so it cannot leak. */
/* navfoot.css sets overflow-x:hidden on html and body, which makes body a scroll container and
   breaks position:sticky for the side rails. clip hides sideways overflow without that side effect. */
html:has(.fde-body), .fde-body, .fde-body.loaded { overflow-x: clip; overflow-y: visible; }
.fde-main { position: relative; color: #d8d8d8; }
.fde-main a { text-decoration: none; }

/* ---------- reading progress ---------- */
.fde-progress { position: fixed; top: 0; left: 0; right: 0; height: 3px; z-index: 1200; background: transparent; }
.fde-progress span { display: block; height: 100%; width: 0; background: linear-gradient(90deg, var(--course-primary), var(--course-accent)); }

/* ---------- hero ---------- */
.fde-hero { position: relative; isolation: isolate; padding: 150px 0 100px; overflow: hidden; background: #0a0a0a; }
.fde-hero-bg { position: absolute; inset: 0; z-index: -1; pointer-events: none; overflow: hidden; background: #08080b; }
.fde-hero-bg > i, .fde-hero-bg > span { position: absolute; display: block; }
/* warm spotlight from the top edge */
.fde-spot { inset: 0; background: radial-gradient(ellipse 62% 52% at 50% -6%, rgba(255,125,50,.34), transparent 72%), radial-gradient(ellipse 40% 34% at 88% 8%, rgba(120,92,255,.22), transparent 70%); }
/* big soft colour fields, drifting slowly */
.fde-aurora { border-radius: 50%; filter: blur(110px); will-change: transform; animation: fdeDrift 26s ease-in-out infinite alternate; width: 44vw; height: 44vw; max-width: 760px; max-height: 760px; }
.fde-aurora-1 { left: -14%; top: -26%; background: radial-gradient(circle, rgba(255,107,0,.34), transparent 66%); }
.fde-aurora-2 { right: -12%; top: 4%; background: radial-gradient(circle, rgba(108,92,231,.38), transparent 66%); animation-duration: 32s; animation-delay: -9s; }
.fde-aurora-3 { left: 30%; bottom: -30%; background: radial-gradient(circle, rgba(0,210,255,.18), transparent 66%); animation-duration: 29s; animation-delay: -15s; }
@keyframes fdeDrift { to { transform: translate3d(44px, 30px, 0) scale(1.12); } }
/* volumetric light rays fanning down from the top centre */
.fde-rays { left: 50%; top: -12%; width: 140%; height: 95%; margin-left: -70%; transform-origin: 50% 0; filter: blur(16px); will-change: transform;
    background: conic-gradient(from 180deg at 50% 0%, transparent 0deg 6deg, rgba(255,170,100,.2) 12deg, transparent 20deg 30deg, rgba(255,140,80,.12) 38deg, transparent 46deg 314deg, rgba(255,140,80,.12) 322deg, transparent 330deg 340deg, rgba(255,170,100,.2) 348deg, transparent 354deg 360deg);
    -webkit-mask-image: linear-gradient(to bottom, #000 0%, transparent 82%); mask-image: linear-gradient(to bottom, #000 0%, transparent 82%); animation: fdeRays 18s ease-in-out infinite alternate; }
@keyframes fdeRays { from { transform: rotate(-2.4deg); } to { transform: rotate(2.4deg); } }
/* glowing planet-rim horizon along the bottom */
.fde-arc { left: 50%; top: calc(100% - 96px); width: 230%; margin-left: -115%; aspect-ratio: 1 / 1; border-radius: 50%;
    background: radial-gradient(circle at 50% 0%, rgba(255,107,0,.2), rgba(10,10,10,0) 26%), #0a0a0a;
    box-shadow: inset 0 1.5px 0 rgba(255,196,150,.75), inset 0 26px 80px -18px rgba(255,107,0,.45), 0 -26px 110px 12px rgba(255,107,0,.13); }
/* tiny out-of-focus motes for photographic depth */
.fde-dust { inset: 0; }
.fde-dust i { position: absolute; left: var(--x); top: var(--y); width: var(--s); height: var(--s); border-radius: 50%; background: rgba(255,205,160,var(--o)); filter: blur(var(--b)); animation: fdeMote var(--d) ease-in-out infinite alternate; }
@keyframes fdeMote { to { transform: translate3d(14px, -24px, 0); } }
/* readability shade on the text side, and a fade into the page below */
.fde-shade { inset: 0; background: linear-gradient(to bottom, transparent calc(100% - 70px), #0a0a0a 100%), linear-gradient(90deg, rgba(8,8,11,.55) 0%, rgba(8,8,11,.12) 52%, transparent 70%); }
/* film grain */
.fde-grain { inset: 0; opacity: .08; mix-blend-mode: overlay; background-size: 160px 160px;
    background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='160' height='160'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='2' stitchTiles='stitch'/><feColorMatrix values='0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 .7 0'/></filter><rect width='100%' height='100%' filter='url(%23n)'/></svg>"); }

/* floating product-UI cards (decorative) */
.fde-hero-art { position: relative; }
.fde-float { position: absolute; z-index: 2; border-radius: 18px; border: 1px solid transparent;
    background: linear-gradient(rgba(16,16,22,.74), rgba(16,16,22,.74)) padding-box, linear-gradient(145deg, rgba(255,255,255,.38), rgba(255,255,255,.04) 42%, rgba(255,138,61,.38)) border-box;
    -webkit-backdrop-filter: blur(18px) saturate(1.4); backdrop-filter: blur(18px) saturate(1.4);
    box-shadow: 0 34px 60px -22px rgba(0,0,0,.85), 0 0 60px -20px rgba(255,107,0,.25);
    translate: calc(var(--px, 0) * -14px) calc(var(--py, 0) * -10px); transition: translate .3s ease-out;
    font-family: ui-monospace, "Cascadia Mono", Consolas, monospace; font-size: 12px; color: #d6d6d6; animation: fdeBob 7s ease-in-out infinite alternate; }
@keyframes fdeBob { to { transform: translateY(-9px); } }
.fde-float-term { width: 236px; left: 0; bottom: -2%; }
.fde-float-chat { width: 222px; left: 1%; top: -7%; font-family: 'Outfit', sans-serif; animation-delay: -3.5s; }
.ft-bar { display: flex; align-items: center; gap: 6px; padding: 9px 12px; border-bottom: 1px solid rgba(255,255,255,.08); }
.ft-bar i { width: 9px; height: 9px; border-radius: 50%; background: #ff5f56; }
.ft-bar i:nth-child(2) { background: #ffbd2e; } .ft-bar i:nth-child(3) { background: #27c93f; }
.ft-bar span { margin-left: 8px; color: #8f8f8f; font-size: 11px; }
.ft-body { padding: 10px 12px 12px; }
.ln { margin: 4px 0; white-space: nowrap; opacity: 0; animation: fdeLn 11s infinite; color: #d6d6d6; }
.ln b { color: #ff8a3d; } .ln.ok { color: #7be3a1; }
.ln:nth-child(1) { animation-delay: .4s; } .ln:nth-child(2) { animation-delay: 1.7s; } .ln:nth-child(3) { animation-delay: 3s; } .ln:nth-child(4) { animation-delay: 4.3s; }
@keyframes fdeLn { 0% { opacity: 0; transform: translateX(-6px); } 5%, 86% { opacity: 1; transform: none; } 95%, 100% { opacity: 0; } }
.cur { display: inline-block; width: 7px; height: 13px; margin-left: 5px; vertical-align: -2px; background: #ffb27a; animation: fdeBlink 1s steps(2) infinite; }
@keyframes fdeBlink { 50% { opacity: 0; } }
.fc-head { display: flex; align-items: center; gap: 9px; padding: 10px 12px; border-bottom: 1px solid rgba(255,255,255,.08); }
.fc-av { width: 28px; height: 28px; border-radius: 50%; display: grid; place-items: center; color: #fff; font-size: .9rem; background: linear-gradient(135deg, #6c5ce7, #00d2ff); }
.fc-head b { display: block; color: #fff; font-size: 12px; line-height: 1.2; } .fc-head small { color: #8f8f8f; font-size: 10.5px; }
.fc-dot { margin-left: auto; width: 8px; height: 8px; border-radius: 50%; background: #2ecc71; box-shadow: 0 0 8px #2ecc71; }
.fc-msg { margin: 8px 12px; padding: 7px 10px; width: fit-content; max-width: 88%; border-radius: 12px; font-size: 12px; line-height: 1.35; opacity: 0; animation: fdeLn 11s infinite; }
.fc-in { background: rgba(255,255,255,.09); color: #e8e8e8; animation-delay: .8s; }
.fc-out { margin-left: auto; color: #fff; background: linear-gradient(135deg, #ff8a3d, #ff6b00); animation-delay: 3.4s; }
.fc-typing { display: flex; gap: 4px; margin: -2px 12px 6px; height: 0; opacity: 0; animation: fdeTyping 11s infinite; animation-delay: 1.7s; }
.fc-typing i { width: 6px; height: 6px; border-radius: 50%; background: #9a9a9a; animation: fdeDot 1s ease-in-out infinite; }
.fc-typing i:nth-child(2) { animation-delay: .15s; } .fc-typing i:nth-child(3) { animation-delay: .3s; }
@keyframes fdeTyping { 0% { opacity: 0; height: 0; } 2%, 14% { opacity: 1; height: 12px; } 16%, 100% { opacity: 0; height: 0; } }
@keyframes fdeDot { 50% { transform: translateY(-3px); } }
@media (max-width: 1099px) { .fde-float { display: none; } }
.fde-hero-inner { position: relative; display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(0, .85fr); gap: 40px; align-items: center; }
.fde-crumb { display: flex; flex-wrap: wrap; gap: 8px; font-size: .85rem; color: #8f8f8f; margin-bottom: 18px; }
.fde-crumb a { color: #b8b8b8; }
.fde-crumb a:hover { color: var(--course-accent); }
.fde-eyebrow { display: inline-flex; align-items: center; gap: 8px; padding: 6px 14px; border-radius: 999px; font-size: .82rem; font-weight: 600; letter-spacing: .04em;
    color: #ffb27a; background: rgba(255,107,0,.1); border: 1px solid rgba(255,107,0,.35); }
.fde-hero h1 { margin: 18px 0 18px; font-weight: 800; line-height: 1.08; letter-spacing: -.02em; font-size: clamp(2.1rem, 4.6vw, 3.7rem); color: #fff; }
.fde-grad { background: linear-gradient(100deg, #ff8a3d, #ff6b00 40%, #00d2ff); -webkit-background-clip: text; background-clip: text; color: transparent; }
.fde-lede { font-size: 1.12rem; line-height: 1.7; color: #c9c9c9; max-width: 640px; }
.fde-lede strong { color: #fff; font-weight: 600; }
.fde-hero-meta { display: flex; flex-wrap: wrap; gap: 10px 22px; list-style: none; padding: 0; margin: 20px 0; font-size: .9rem; color: #a8a8a8; }
.fde-hero-meta i { color: var(--course-accent); margin-right: 6px; }
.fde-hero-cta { display: flex; flex-wrap: wrap; gap: 12px; }
.fde-btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; padding: 12px 22px; border-radius: 12px; font-weight: 600; font-size: .95rem; transition: transform .2s, box-shadow .2s, border-color .2s; cursor: pointer; }
.fde-btn-primary { background: linear-gradient(135deg, #ff8a3d, #ff6b00); color: #fff !important; box-shadow: 0 10px 30px -10px rgba(255,107,0,.7); border: 0; }
.fde-btn-primary:hover { transform: translateY(-2px); box-shadow: 0 14px 34px -10px rgba(255,107,0,.9); }
.fde-btn-ghost { color: #fff !important; background: rgba(255,255,255,.04); border: 1px solid rgba(255,255,255,.18); }
.fde-btn-ghost:hover { border-color: var(--course-accent); transform: translateY(-2px); }
.fde-hero-art > svg { display: block; width: 100%; height: auto; transform: perspective(1200px) rotateY(calc(var(--px, 0) * 5deg)) rotateX(calc(var(--py, 0) * -4deg)); transition: transform .3s ease-out; }
@media (min-width: 1100px) { .fde-hero-art > svg { width: 86%; margin-left: auto; } }
@keyframes fdeDash { to { stroke-dashoffset: -22; } }
.fde-stats { position: relative; display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; margin-top: 46px; }
.fde-stat { --c: #ff8a3d; position: relative; padding: 20px 22px 20px; border-radius: 20px; border: 1px solid transparent; overflow: hidden;
    background: linear-gradient(rgba(14,14,19,.78), rgba(14,14,19,.78)) padding-box, linear-gradient(150deg, rgba(255,255,255,.3), rgba(255,255,255,.04) 40%, color-mix(in srgb, var(--c) 45%, transparent)) border-box;
    -webkit-backdrop-filter: blur(14px); backdrop-filter: blur(14px); box-shadow: 0 24px 50px -28px rgba(0,0,0,.9); transition: transform .3s, box-shadow .3s; }
.fde-stat::after { content: ""; position: absolute; width: 150px; height: 150px; right: -50px; top: -60px; border-radius: 50%; background: radial-gradient(circle, color-mix(in srgb, var(--c) 40%, transparent), transparent 70%); opacity: .55; pointer-events: none; }
.fde-stat:hover { transform: translateY(-4px); box-shadow: 0 30px 60px -26px color-mix(in srgb, var(--c) 55%, transparent); }
.st-o { --c: #ff8a3d; } .st-c { --c: #3fd8ff; } .st-p { --c: #a48cff; } .st-g { --c: #5ee09a; }
.fde-stat-ic { display: grid; place-items: center; width: 34px; height: 34px; margin-bottom: 14px; border-radius: 10px; font-size: 1rem; color: var(--c); background: color-mix(in srgb, var(--c) 16%, transparent); }
.fde-stat b { display: block; font-size: clamp(1.7rem, 3vw, 2.4rem); font-weight: 800; line-height: 1.08; letter-spacing: -.02em; background: linear-gradient(180deg, #fff 30%, var(--c)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.fde-stat > span { font-size: .85rem; color: #a8a8b2; line-height: 1.45; display: block; margin-top: 8px; }

/* ---------- page width: same outer edges as the navbar (.nav-wrapper is max 1400px inside a 12px-gutter container-fluid) ---------- */
.fde-wrap { width: min(1400px, calc(100% - 24px)); margin-inline: auto; }

/* ---------- 3-column shell ---------- */
.fde-shell { padding-top: 40px; padding-bottom: 60px; }
.fde-grid { display: grid; grid-template-columns: minmax(0, 1fr); gap: 36px; max-width: 800px; margin: 0 auto; }
.fde-rail { display: none; }
@media (min-width: 1200px) {
    .fde-grid { grid-template-columns: 250px minmax(0, 1fr) 310px; gap: 40px; max-width: none; align-items: start; }
    .fde-rail { display: block; position: sticky; top: 110px; align-self: start; max-height: calc(100vh - 130px); overflow-y: auto; scrollbar-width: none; }
    .fde-rail::-webkit-scrollbar { display: none; }
    .fde-toc-inline { display: none; }
}
.fde-rail-card { padding: 18px 18px 16px; margin-bottom: 14px; border-radius: 16px; background: var(--course-surface); border: 1px solid var(--glass-border); font-size: .9rem; }
.fde-rail-card p { color: #b8b8b8; line-height: 1.6; margin: 8px 0 0; }
.fde-rail-title { display: flex; align-items: center; gap: 8px; color: #fff; font-size: .95rem; margin-bottom: 4px; }
.fde-rail-title i { color: var(--course-primary); }
.fde-quick { border-color: rgba(255,107,0,.4); background: linear-gradient(160deg, rgba(255,107,0,.12), var(--course-surface)); }
.fde-rail-cta { border-color: rgba(0,210,255,.35); background: linear-gradient(160deg, rgba(0,210,255,.1), var(--course-surface)); }
.fde-rail-cta .fde-btn { width: 100%; margin-top: 10px; padding: 10px 14px; font-size: .88rem; }
.fde-method { font-size: .84rem; }
.fde-keynums { list-style: none; padding: 0; margin: 10px 0 0; display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.fde-keynums li { padding: 8px 10px; border-radius: 10px; background: rgba(255,255,255,.04); color: #a8a8a8; font-size: .78rem; line-height: 1.35; }
.fde-keynums b { display: block; font-size: 1.1rem; color: #fff; }
@media (min-width: 1200px) and (max-height: 940px) { .fde-method { display: none; } }
.fde-share { display: flex; gap: 10px; margin-top: 10px; }
.fde-share a, .fde-share button { width: 42px; height: 42px; display: grid; place-items: center; border-radius: 12px; background: rgba(255,255,255,.06); border: 1px solid var(--glass-border); color: #fff; font-size: 1.1rem; cursor: pointer; transition: background .2s, transform .2s; }
.fde-share a:hover, .fde-share button:hover { background: var(--course-primary); transform: translateY(-2px); }

/* toc */
.fde-toc { list-style: none; counter-reset: toc; padding: 0; margin: 10px 0 0; }
.fde-toc li { counter-increment: toc; }
.fde-toc a { display: flex; gap: 10px; padding: 7px 10px; border-radius: 10px; color: #a8a8a8; font-size: .88rem; line-height: 1.35; border-left: 2px solid transparent; transition: background .2s, color .2s; }
.fde-toc a::before { content: counter(toc, decimal-leading-zero); color: #666; font-weight: 700; font-size: .75rem; padding-top: 2px; }
.fde-toc a:hover { color: #fff; background: rgba(255,255,255,.05); }
.fde-toc a.is-active { color: #fff; background: rgba(255,107,0,.12); border-left-color: var(--course-primary); }
.fde-toc a.is-active::before { color: var(--course-primary); }
.fde-readmeter { display: flex; justify-content: space-between; margin-top: 14px; color: #8f8f8f; font-size: .78rem; }
.fde-readmeter b { color: #fff; }
.fde-meter { height: 6px; border-radius: 999px; background: #242424; overflow: hidden; margin-top: 6px; }
.fde-meter i { display: block; height: 100%; width: 0; border-radius: inherit; background: linear-gradient(90deg, var(--course-primary), var(--course-accent)); transition: width .25s; }
.fde-toc-inline { margin-bottom: 26px; border-radius: 14px; background: var(--course-surface); border: 1px solid var(--glass-border); padding: 4px 16px; }
.fde-toc-inline summary { cursor: pointer; padding: 12px 0; font-weight: 600; color: #fff; list-style: none; }
.fde-toc-inline summary i { color: var(--course-primary); margin-right: 8px; }
.fde-toc-inline .fde-toc { margin-bottom: 10px; }

/* ---------- article ---------- */
.fde-article { min-width: 0; counter-reset: sec; }
.fde-article p, .fde-article li { color: #cfcfcf; line-height: 1.75; font-size: 1.04rem; }
.fde-article a:not(.fde-btn) { color: var(--course-accent); }
.fde-article a:not(.fde-btn):hover { text-decoration: underline; }
.fde-sec { margin-bottom: 64px; counter-increment: sec; scroll-margin-top: 100px; }
.fde-sec h2 { position: relative; font-size: clamp(1.5rem, 2.8vw, 2rem); font-weight: 800; line-height: 1.2; color: #fff; margin: 0 0 18px; padding-top: 34px; scroll-margin-top: 100px; }
.fde-sec h2::before { content: counter(sec, decimal-leading-zero); position: absolute; top: 0; left: 0; font-size: .8rem; font-weight: 700; letter-spacing: .14em; color: var(--course-primary); }
.fde-sec h2::after { content: ""; display: block; width: 56px; height: 3px; border-radius: 3px; margin-top: 14px; background: linear-gradient(90deg, var(--course-primary), var(--course-accent)); }
.fde-sec h3 { font-size: 1.15rem; font-weight: 700; color: #fff; margin: 26px 0 10px; }
.fde-note { font-size: .88rem !important; color: #8f8f8f !important; }

/* reveal (only when JS is on, so the page is fully readable without it) */
.fde-js .fde-reveal { opacity: 0; transform: translateY(22px); transition: opacity .7s ease, transform .7s ease; }
.fde-js .fde-reveal.is-in { opacity: 1; transform: none; }

/* cards */
.fde-cards { display: grid; gap: 14px; margin: 22px 0; }
.fde-cards-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.fde-cards-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.fde-cards-4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.fde-card { padding: 20px; border-radius: 16px; background: var(--course-surface); border: 1px solid var(--glass-border); transition: transform .25s, border-color .25s, background .25s; }
.fde-card:hover { transform: translateY(-4px); border-color: rgba(255,107,0,.5); background: var(--course-surface-2); }
.fde-card > i { display: inline-grid; place-items: center; width: 44px; height: 44px; border-radius: 12px; font-size: 1.3rem; color: #fff; margin-bottom: 12px; background: linear-gradient(135deg, #ff8a3d, #ff6b00); }
.fde-card:nth-child(2n) > i { background: linear-gradient(135deg, #00d2ff, #2a7fff); }
.fde-card:nth-child(3n) > i { background: linear-gradient(135deg, #8d78ff, #6c5ce7); }
.fde-card h3 { margin: 0 0 8px; font-size: 1.05rem; }
.fde-card p { margin: 0; font-size: .95rem; line-height: 1.6; }

/* callouts */
.fde-callout { margin: 26px 0; padding: 20px 22px; border-radius: 16px; background: linear-gradient(160deg, rgba(0,210,255,.09), rgba(0,210,255,.02)); border: 1px solid rgba(0,210,255,.3); }
.fde-callout h3 { margin: 0 0 8px; font-size: 1.05rem; display: flex; align-items: center; gap: 8px; }
.fde-callout h3 i { color: var(--course-accent); }
.fde-callout p { margin: 0; }
.fde-callout-warn { background: linear-gradient(160deg, rgba(255,193,7,.1), rgba(255,193,7,.02)); border-color: rgba(255,193,7,.35); }
.fde-callout-warn h3 i { color: #ffc107; }
.fde-callout-key { background: linear-gradient(160deg, rgba(255,107,0,.12), rgba(255,107,0,.02)); border-color: rgba(255,107,0,.4); }
.fde-callout-key h3 i { color: var(--course-primary); }

/* figures and charts */
.fde-figure { margin: 26px 0; padding: 18px; border-radius: 18px; background: var(--course-surface); border: 1px solid var(--glass-border); }
.fde-figure svg { width: 100%; height: auto; display: block; }
.fde-figure figcaption { margin-top: 12px; font-size: .86rem; line-height: 1.5; color: #8f8f8f; }
.fde-figure figcaption b { color: #d0d0d0; }
.fde-charts { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; }
.fde-charts .fde-figure { margin: 8px 0 18px; }
.fde-split { display: grid; grid-template-columns: minmax(0, 1fr) 190px; gap: 22px; align-items: center; margin: 6px 0; }
.fde-donut { margin: 0; padding: 12px; text-align: center; }
.fde-donut figcaption { font-size: .78rem; line-height: 1.9; }
.lg { display: inline-block; width: 9px; height: 9px; border-radius: 50%; margin: 0 5px 0 6px; }
.lg-o { background: #ff6b00; } .lg-c { background: #00d2ff; } .lg-p { background: #6c5ce7; }
.dn-seg { transition: stroke-dasharray 1.2s ease; }
.fde-js .fde-reveal:not(.is-in) .dn-seg { stroke-dasharray: 0 100; }

/* bars grow in when revealed */
.fde-bar { transform-box: fill-box; transform-origin: left center; transition: transform .9s cubic-bezier(.2,.8,.2,1); }
.fde-bar-v { transform-origin: center bottom; }
.fde-js .fde-reveal:not(.is-in) .fde-bar { transform: scaleX(0); }
.fde-js .fde-reveal:not(.is-in) .fde-bar-v { transform: scaleY(0); }

/* horizontal css bars */
.fde-hbars { margin: 24px 0; padding: 18px; border-radius: 18px; background: var(--course-surface); border: 1px solid var(--glass-border); }
.fde-hbars-title { font-size: .86rem; color: #8f8f8f; margin-bottom: 12px; }
.fde-hbar { display: grid; grid-template-columns: 90px minmax(0, 1fr) 54px; align-items: center; gap: 12px; margin: 10px 0; color: #e0e0e0; font-size: .95rem; }
.fde-hbar div { height: 14px; border-radius: 999px; background: #232323; overflow: hidden; }
.fde-hbar i { display: block; height: 100%; width: var(--w); border-radius: inherit; background: linear-gradient(90deg, var(--course-primary), #ffb27a); transform-origin: left; transition: transform 1s cubic-bezier(.2,.8,.2,1); }
.fde-hbar:nth-of-type(2) i { background: linear-gradient(90deg, #00d2ff, #7be3ff); }
.fde-hbar b { text-align: right; color: #fff; }
.fde-js .fde-reveal:not(.is-in) .fde-hbar i { transform: scaleX(0); }

/* two-pane lists */
.fde-two { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; margin: 22px 0; }
.fde-pane { padding: 20px 22px; border-radius: 16px; background: var(--course-surface); border: 1px solid var(--glass-border); }
.fde-pane h3 { margin: 0 0 10px; display: flex; align-items: center; gap: 10px; font-size: 1.1rem; }
.fde-pane ul { margin: 0; padding-left: 1.1rem; }
.fde-pane li { font-size: .97rem; line-height: 1.6; margin: 6px 0; }
.fde-pane-eng { border-top: 3px solid var(--course-accent); } .fde-pane-eng h3 i { color: var(--course-accent); }
.fde-pane-del { border-top: 3px solid var(--course-primary); } .fde-pane-del h3 i { color: var(--course-primary); }
.fde-pane-up { border-top: 3px solid #2ecc71; } .fde-pane-up h3 i { color: #2ecc71; }
.fde-pane-down { border-top: 3px solid #ff5d5d; } .fde-pane-down h3 i { color: #ff5d5d; }

/* tables */
.fde-table { margin: 22px 0; border-radius: 16px; border: 1px solid var(--glass-border); overflow: hidden; }
.fde-table .table { --bs-table-bg: transparent; --bs-table-border-color: rgba(255,255,255,.07); margin: 0; font-size: .92rem; }
.fde-table th { background: rgba(255,255,255,.05); color: #fff; font-weight: 600; white-space: nowrap; }
.fde-table td, .fde-table th { color: #dcdcdc; padding: 12px 14px; }
.fde-table tr.is-hl td { background: rgba(255,107,0,.1); }

/* timelines and steps */
.fde-timeline { position: relative; margin: 22px 0; padding-left: 8px; }
.fde-timeline::before { content: ""; position: absolute; left: 29px; top: 10px; bottom: 10px; width: 2px; background: linear-gradient(var(--course-primary), var(--course-accent)); opacity: .5; }
.fde-tl { position: relative; display: flex; gap: 18px; padding: 10px 0; }
.fde-tl > i { flex: 0 0 44px; height: 44px; display: grid; place-items: center; border-radius: 50%; background: #101010; border: 2px solid var(--course-primary); color: var(--course-primary); font-size: 1.1rem; z-index: 1; }
.fde-tl b { color: #fff; } .fde-tl p { margin: 2px 0 0; font-size: .97rem; }
.fde-steps { list-style: none; padding: 0; margin: 22px 0; counter-reset: step; }
.fde-steps li { counter-increment: step; position: relative; display: flex; gap: 16px; align-items: flex-start; padding: 16px 18px 16px 18px; margin-bottom: 12px; border-radius: 16px; background: var(--course-surface); border: 1px solid var(--glass-border); transition: border-color .25s, transform .25s; }
.fde-steps li:hover { border-color: rgba(255,107,0,.5); transform: translateX(4px); }
.fde-steps li > i { flex: 0 0 46px; height: 46px; display: grid; place-items: center; border-radius: 14px; font-size: 1.3rem; color: #fff; background: linear-gradient(135deg, #ff8a3d, #ff6b00); position: relative; }
.fde-steps li > i::after { content: counter(step); position: absolute; top: -8px; right: -8px; width: 22px; height: 22px; border-radius: 50%; background: #0a0a0a; border: 1px solid var(--course-accent); color: var(--course-accent); font-size: .72rem; font-weight: 700; display: grid; place-items: center; font-style: normal; }
.fde-steps b { color: #fff; }

/* checklist */
.fde-checks { list-style: none; padding: 0; margin: 18px 0; }
.fde-checks li { position: relative; padding: 10px 0 10px 36px; border-bottom: 1px solid var(--glass-border); }
.fde-checks li::before { content: "\F26A"; font-family: "bootstrap-icons"; position: absolute; left: 0; top: 9px; font-size: 1.3rem; color: #2ecc71; }

/* quiz */
.fde-quiz { margin: 26px 0; padding: 22px; border-radius: 18px; background: linear-gradient(160deg, rgba(108,92,231,.14), var(--course-surface)); border: 1px solid rgba(108,92,231,.4); }
.fde-quiz h3 { margin: 0 0 4px; display: flex; gap: 10px; align-items: center; }
.fde-quiz h3 i { color: #a48cff; }
.fde-quiz-sub { font-size: .88rem !important; color: #9a9a9a !important; margin: 0 0 12px; }
.fde-quiz label { display: flex; gap: 12px; align-items: flex-start; padding: 10px 12px; margin: 6px 0; border-radius: 12px; background: rgba(255,255,255,.04); cursor: pointer; font-size: .97rem; line-height: 1.5; color: #dcdcdc; transition: background .2s; }
.fde-quiz label:hover { background: rgba(255,255,255,.08); }
.fde-quiz input { accent-color: var(--course-primary); width: 18px; height: 18px; margin-top: 3px; flex: 0 0 auto; }
.fde-quiz-result { margin-top: 14px; }
.fde-quiz-result p { margin: 10px 0 0; font-size: .98rem; }
.fde-quiz-result b { color: #fff; margin-right: 6px; }

/* cta band */
.fde-cta { display: flex; flex-wrap: wrap; gap: 18px; align-items: center; justify-content: space-between; margin-top: 30px; padding: 26px; border-radius: 20px; background: linear-gradient(120deg, rgba(255,107,0,.2), rgba(108,92,231,.18)); border: 1px solid rgba(255,107,0,.4); }
.fde-cta > div { flex: 1 1 320px; }
.fde-cta h3 { margin: 0 0 6px; font-size: 1.3rem; }
.fde-cta p { margin: 0; font-size: .98rem; }

/* faq */
.fde-faq { margin: 10px 0; border-radius: 14px; background: var(--course-surface); border: 1px solid var(--glass-border); transition: border-color .2s; }
.fde-faq[open] { border-color: rgba(255,107,0,.45); }
.fde-faq summary { list-style: none; cursor: pointer; padding: 16px 52px 16px 18px; position: relative; }
.fde-faq summary::-webkit-details-marker { display: none; }
.fde-faq summary h3 { margin: 0; font-size: 1.02rem; font-weight: 600; color: #fff; }
.fde-faq summary::after { content: "\F4FE"; font-family: "bootstrap-icons"; position: absolute; right: 18px; top: 50%; transform: translateY(-50%); color: var(--course-primary); font-size: 1.2rem; transition: transform .25s; }
.fde-faq[open] summary::after { content: "\F2EA"; }
.fde-faq p { margin: 0; padding: 0 18px 18px; font-size: .98rem; }

/* sources */
.fde-sources { padding-top: 10px; border-top: 1px solid var(--glass-border); }
.fde-sources h2 { font-size: 1.1rem; color: #fff; margin: 20px 0 10px; }
.fde-sources ul { columns: 1; padding-left: 1.1rem; }
.fde-sources li { font-size: .86rem; line-height: 1.5; margin: 4px 0; break-inside: avoid; }

/* ---------- responsive ---------- */
@media (min-width: 992px) { .fde-cards-4 { grid-template-columns: repeat(4, minmax(0, 1fr)); } .fde-sources ul { columns: 2; column-gap: 28px; } }
@media (min-width: 1200px) { .fde-cards-4 { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (min-width: 1200px) and (max-width: 1399px) { .fde-grid { grid-template-columns: 210px minmax(0, 1fr) 270px; gap: 28px; } }
@media (max-width: 991px) {
    .fde-hero { padding-top: 120px; }
    .fde-hero-inner { grid-template-columns: 1fr; }
    .fde-hero-art { width: 100%; max-width: 560px; margin: 0 auto; }
    .fde-stats { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 700px) {
    .fde-hero-copy, .fde-article, .fde-stats { padding-inline: 6px; }
    .fde-cards-2, .fde-cards-3, .fde-charts, .fde-two { grid-template-columns: 1fr; }
    .fde-split { grid-template-columns: 1fr; }
    .fde-donut { max-width: 220px; }
    .fde-hbar { grid-template-columns: 70px minmax(0, 1fr) 46px; }
    .fde-sec { margin-bottom: 48px; }
    .fde-figure { padding: 12px; }
}
@media (prefers-reduced-motion: reduce) {
    .fde-aurora, .fde-floor i, .fde-beam, .fde-float, .fde-flow path, .cur, .fc-typing i { animation: none; }
    .ln, .fc-msg { animation: none; opacity: 1; }
    .fc-typing { display: none; }
    .fde-js .fde-reveal, .fde-bar, .fde-hbar i, .dn-seg { transition: none; }
}

.fde-pulse { transform-box: fill-box; transform-origin: center; animation: fdePulse 4.4s ease-in-out infinite; }
.fde-pulse-2 { animation-delay: -2.2s; }
@keyframes fdePulse { 0%, 100% { opacity: .35; transform: scale(1); } 50% { opacity: 1; transform: scale(1.05); } }
@media (prefers-reduced-motion: reduce) { .fde-rays, .fde-dust i, .fde-pulse, .fde-aurora { animation: none; } .fde-float, .fde-hero-art > svg { transition: none; translate: none; transform: none; } }

/* modern surfaces: glass fill with a gradient hairline instead of a flat grey border */
.fde-card, .fde-rail-card:not(.fde-quick):not(.fde-rail-cta), .fde-figure, .fde-pane, .fde-hbars, .fde-faq, .fde-steps li, .fde-table, .fde-toc-inline {
    border: 1px solid transparent;
    background: linear-gradient(#0e0e13, #0e0e13) padding-box, linear-gradient(145deg, rgba(255,255,255,.17), rgba(255,255,255,.035) 38%, rgba(255,255,255,.03) 64%, rgba(255,138,61,.24)) border-box;
    box-shadow: 0 22px 44px -28px rgba(0,0,0,.9); }
.fde-pane-eng, .fde-pane-del, .fde-pane-up, .fde-pane-down { border-top-width: 3px; }
.fde-faq[open] { background: linear-gradient(#0e0e13, #0e0e13) padding-box, linear-gradient(145deg, rgba(255,138,61,.7), rgba(255,255,255,.05) 45%, rgba(0,210,255,.4)) border-box; }
.fde-shell { position: relative; }
.fde-shell::before { content: ""; position: absolute; inset: 0; pointer-events: none; z-index: 0;
    background: radial-gradient(520px 420px at 0% 6%, rgba(255,107,0,.07), transparent 70%), radial-gradient(560px 460px at 100% 26%, rgba(108,92,231,.09), transparent 70%), radial-gradient(520px 420px at 0% 52%, rgba(0,210,255,.05), transparent 70%), radial-gradient(560px 460px at 100% 78%, rgba(255,107,0,.06), transparent 70%); }
.fde-grid { position: relative; z-index: 1; }