:root {
  --bg: #070b14;
  --bg-2: #0b1220;
  --ink: #f8fafc;
  --ink-soft: #d5dde8;
  --line: rgba(255, 255, 255, 0.1);
  --glass: rgba(13, 20, 36, 0.6);
  --glass-line: rgba(255, 255, 255, 0.14);
  --blue: #3b82f6;
  --sky: #38bdf8;
  --accent: #ff7316;
  --accent-soft: #fb923c;
  --success: #34d399;
  --sans: "Inter", system-ui, sans-serif;
  --display: "Plus Jakarta Sans", "Inter", system-ui, sans-serif;
  --serif: "Instrument Serif", Georgia, serif;
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --gutter: clamp(16px, 4.5vw, 72px);
  --max: 1180px;
  --ease: cubic-bezier(0.2, 0.8, 0.2, 1);
  color-scheme: dark;
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; overflow-x: clip; scroll-behavior: smooth; scroll-padding-top: 84px; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 400 16px/1.6 var(--sans);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
img { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button, input, select { font: inherit; color: inherit; }
:focus-visible { outline: 2px solid var(--sky); outline-offset: 3px; border-radius: 6px; }
h1, h2, h3, h4 { font-family: var(--display); letter-spacing: -0.025em; margin: 0; }
em { font-family: var(--serif); font-style: italic; font-weight: 400; letter-spacing: -0.01em; }
code, pre { font-family: var(--mono); }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.skip-link { position: absolute; left: 16px; top: -60px; z-index: 50; padding: 10px 16px; border-radius: 999px; background: var(--accent); color: #1a0b00; font-weight: 600; }
.skip-link:focus { top: 12px; }
.shell { width: min(var(--max), 100% - 2 * var(--gutter)); margin-inline: auto; }
.nowrap { white-space: nowrap; }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 10px;
  padding: 15px 26px; border: 0; border-radius: 999px; cursor: pointer; white-space: nowrap;
  font: 600 16px/1 var(--display); letter-spacing: -0.01em;
  transition: transform 0.25s var(--ease), box-shadow 0.25s, background 0.25s;
}
.btn:hover { transform: translateY(-2px); }
.btn-primary {
  background: linear-gradient(180deg, #ff8a3d, var(--accent));
  color: #1a0b00;
  box-shadow: 0 10px 30px -8px rgba(255, 115, 22, 0.65), inset 0 1px 0 rgba(255, 255, 255, 0.35);
}
.btn-primary:hover { box-shadow: 0 16px 40px -8px rgba(255, 115, 22, 0.8), inset 0 1px 0 rgba(255, 255, 255, 0.35); }
.btn-ghost { background: rgba(255, 255, 255, 0.07); border: 1px solid rgba(255, 255, 255, 0.22); backdrop-filter: blur(10px); }
.btn-ghost:hover { background: rgba(255, 255, 255, 0.13); }
.btn-sm { padding: 11px 18px; font-size: 14px; }
.site-nav .btn-sm { padding: 14px 24px; font-size: 16px; }
.btn svg, .text-link svg { width: 16px; height: 16px; fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; transition: transform 0.25s var(--ease); }
.btn:hover svg, .text-link:hover svg { transform: translateX(3px); }
.text-link { display: inline-flex; align-items: center; gap: 8px; color: var(--accent-soft); font-weight: 600; }
.text-link:hover { color: #ffd7b5; }

/* ---------- nav ---------- */
.site-nav {
  position: fixed; inset: 0 0 auto; z-index: 20;
  display: flex; align-items: center; justify-content: space-between; gap: 24px;
  padding: 18px var(--gutter);
  border-bottom: 1px solid transparent;
  transition: background 0.35s, border-color 0.35s, padding 0.35s;
}
.site-nav.is-scrolled {
  padding-block: 12px;
  background: rgba(7, 11, 20, 0.74);
  border-bottom-color: rgba(255, 255, 255, 0.07);
  backdrop-filter: blur(16px) saturate(140%);
  -webkit-backdrop-filter: blur(16px) saturate(140%);
}
.brand { display: flex; align-items: center; gap: 12px; font: 700 24px/1 var(--display); letter-spacing: -0.02em; }
.brand img { width: 38px; height: 38px; border-radius: 9px; }
.brand b { color: var(--accent-soft); font-weight: 800; }
.brand-tag { margin-left: 2px; padding: 6px 10px; border-radius: 999px; border: 1px solid rgba(255, 115, 22, 0.45); background: rgba(255, 115, 22, 0.12); color: #ffd7b5; font: 600 12px/1 var(--sans); letter-spacing: 0.1em; text-transform: uppercase; }
#navigation { display: flex; align-items: center; gap: 18px; flex: 1; justify-content: space-between; }
.nav-links {
  display: flex; gap: 4px; padding: 5px; margin-inline: auto;
  background: rgba(10, 16, 30, 0.45); border: 1px solid var(--glass-line); border-radius: 999px;
  backdrop-filter: blur(14px) saturate(140%);
}
.nav-links a { padding: 11px 20px; white-space: nowrap; border-radius: 999px; font: 500 16px/1 var(--sans); color: var(--ink-soft); transition: background 0.2s, color 0.2s; }
.nav-links a:hover, .nav-links a.is-active { background: rgba(255, 255, 255, 0.1); color: var(--ink); }
.nav-actions { display: flex; align-items: center; gap: 24px; }
.nav-home { font: 500 16px/1 var(--sans); color: var(--ink-soft); }
.nav-home:hover { color: var(--ink); }
.menu-toggle { display: none; align-items: center; gap: 8px; padding: 10px 16px; border-radius: 999px; border: 1px solid var(--glass-line); background: rgba(10, 16, 30, 0.6); font: 600 14px/1 var(--sans); cursor: pointer; }
.menu-toggle i { position: relative; width: 16px; height: 2px; background: currentColor; border-radius: 2px; transition: background 0.2s; }
.menu-toggle i::before, .menu-toggle i::after { content: ""; position: absolute; left: 0; width: 16px; height: 2px; background: currentColor; border-radius: 2px; transition: transform 0.25s var(--ease); }
.menu-toggle i::before { top: -5px; }
.menu-toggle i::after { top: 5px; }
.menu-toggle[aria-expanded="true"] i { background: transparent; }
.menu-toggle[aria-expanded="true"] i::before { transform: translateY(5px) rotate(45deg); }
.menu-toggle[aria-expanded="true"] i::after { transform: translateY(-5px) rotate(-45deg); }

/* ---------- shared section type ---------- */
.section { padding-block: clamp(84px, 11vw, 150px); }
.eyebrow { display: inline-flex; align-items: center; gap: 10px; margin: 0 0 18px; font: 600 12.5px/1 var(--sans); letter-spacing: 0.16em; text-transform: uppercase; color: var(--accent-soft); }
.eyebrow .num { color: var(--ink-soft); }
.section-heading { display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr); gap: 48px; align-items: end; margin-bottom: clamp(44px, 6vw, 72px); }
.section-heading h2, .download-heading h2, .faq-intro h2 { font-size: clamp(36px, 5vw, 64px); line-height: 1.02; font-weight: 700; }
.section-heading h2 em, .download-heading h2 em, .faq-intro h2 em, .hero h1 em, .closing h2 em { color: var(--accent-soft); }
.section-heading > p { margin: 0; font-size: 18px; color: var(--ink-soft); }
.section-footnote { margin: 36px 0 0; color: var(--ink-soft); font-size: 14.5px; }

/* reveal on scroll */
.reveal { opacity: 0; transform: translateY(28px); transition: opacity 0.9s var(--ease), transform 0.9s var(--ease); transition-delay: var(--d, 0s); }
.reveal.in { opacity: 1; transform: none; }

/* ---------- hero ---------- */
.hero { position: relative; padding: clamp(130px, 18vh, 190px) 0 0; overflow: clip; isolation: isolate; }
.hero-photo { position: absolute; inset: 0 0 auto; height: min(100svh, 1000px); z-index: -2; overflow: hidden; }
.hero-photo img { width: 100%; height: 100%; object-fit: cover; object-position: 70% 30%; transform: scale(1.06); animation: hero-drift 18s ease-in-out infinite alternate; }
@keyframes hero-drift { to { transform: scale(1.12) translate(-1.2%, -1%); } }
.hero::before {
  content: ""; position: absolute; inset: 0; z-index: -1;
  height: min(100svh, 1000px);
  background:
    linear-gradient(90deg, rgba(7, 11, 20, 0.94) 0%, rgba(7, 11, 20, 0.78) 34%, rgba(7, 11, 20, 0.12) 66%, rgba(7, 11, 20, 0.2) 100%),
    linear-gradient(180deg, rgba(7, 11, 20, 0.5) 0%, rgba(7, 11, 20, 0) 22%, rgba(7, 11, 20, 0) 62%, var(--bg) 100%);
}
.hero-copy { position: relative; max-width: 640px; }
.hero .eyebrow { padding: 8px 14px; border-radius: 999px; border: 1px solid var(--glass-line); background: rgba(10, 16, 30, 0.55); backdrop-filter: blur(10px); color: var(--ink); letter-spacing: 0.12em; }
.pulse { width: 8px; height: 8px; border-radius: 50%; background: var(--accent); box-shadow: 0 0 0 0 rgba(255, 115, 22, 0.6); animation: pulse 2.2s infinite; }
@keyframes pulse { 70% { box-shadow: 0 0 0 10px rgba(255, 115, 22, 0); } 100% { box-shadow: 0 0 0 0 rgba(255, 115, 22, 0); } }
.hero h1 { font-size: clamp(52px, 8.4vw, 112px); line-height: 0.95; font-weight: 800; letter-spacing: -0.045em; }
.hero h1 .line { display: block; overflow: hidden; padding-bottom: 0.06em; }
.hero h1 .line > span { display: inline-block; transform: translateY(105%); animation: rise 1.1s var(--ease) forwards; animation-delay: calc(0.12s * var(--i, 0) + 0.15s); }
@keyframes rise { to { transform: none; } }
.hero-description { max-width: 520px; margin: 26px 0 0; font-size: clamp(17px, 1.6vw, 20px); color: var(--ink-soft); }
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin-top: 34px; }
.hero-modes { display: flex; flex-wrap: wrap; gap: 8px; margin: 30px 0 0; padding: 0; list-style: none; }
.hero-modes li { padding: 7px 12px; border-radius: 999px; background: rgba(255, 255, 255, 0.06); border: 1px solid var(--line); font-size: 13.5px; color: var(--ink-soft); }
.hero-fade { opacity: 0; animation: fade-up 1s var(--ease) forwards; animation-delay: var(--d, 0.6s); }
@keyframes fade-up { from { opacity: 0; transform: translateY(18px); } to { opacity: 1; transform: none; } }

.hero-stage { position: relative; margin-top: clamp(64px, 14vh, 150px); perspective: 1800px; }
.hero-stage .window-fit { max-width: 1040px; margin-inline: auto; transform: rotateX(var(--tilt, 14deg)) scale(var(--zoom, 0.94)); transform-origin: 50% 0; }
.hero-stage::before { content: ""; position: absolute; inset: 10% 8% -6%; z-index: -1; background: radial-gradient(closest-side, rgba(255, 115, 22, 0.28), transparent), radial-gradient(closest-side at 30% 60%, rgba(59, 130, 246, 0.3), transparent); filter: blur(40px); }
.stage-caption { display: flex; justify-content: center; gap: 10px; margin: 22px 0 0; color: var(--ink-soft); font-size: 14px; }
.stage-caption b { color: var(--ink); font-weight: 600; }

/* ---------- marquee ---------- */
.marquee { overflow: hidden; padding: 30px 0; border-block: 1px solid var(--line); margin-top: clamp(64px, 8vw, 110px); mask-image: linear-gradient(90deg, transparent, #000 10%, #000 90%, transparent); }
.marquee-track { display: flex; gap: 14px; width: max-content; animation: marquee 48s linear infinite; }
.marquee:hover .marquee-track { animation-play-state: paused; }
.marquee span { display: inline-flex; align-items: center; gap: 12px; padding: 10px 18px; border-radius: 999px; border: 1px solid var(--line); background: rgba(255, 255, 255, 0.03); font: 600 15px/1 var(--display); color: var(--ink-soft); white-space: nowrap; }
.marquee span::before { content: ""; width: 6px; height: 6px; border-radius: 50%; background: var(--accent); }
@keyframes marquee { to { transform: translateX(calc(-50% - 7px)); } }

/* ---------- why ---------- */
.why-block { margin-top: clamp(64px, 8vw, 110px); }
.why-block:first-of-type { margin-top: 0; }
.why-label { display: grid; grid-template-columns: 180px minmax(0, 1fr); gap: 32px; align-items: baseline; margin-bottom: 32px; }
.why-label .kicker { margin: 0; font: 600 12px/1.4 var(--sans); letter-spacing: 0.16em; text-transform: uppercase; color: var(--accent-soft); }
.why-label h3 { font-size: clamp(24px, 3vw, 36px); line-height: 1.12; font-weight: 700; }

.role-shift { display: grid; gap: 12px; margin: 0; padding: 0; list-style: none; }
.role-shift li {
  position: relative; display: grid; grid-template-columns: minmax(0, 1fr) 56px minmax(0, 1.15fr); align-items: center; gap: 12px;
  padding: 22px 26px; border-radius: 20px; border: 1px solid var(--line);
  background: linear-gradient(90deg, rgba(255, 255, 255, 0.025), rgba(255, 115, 22, 0.05));
  overflow: hidden;
}
.shift-from { position: relative; justify-self: start; color: var(--ink-soft); font-size: 17px; }
.shift-from::after { content: ""; position: absolute; left: 0; right: 0; top: 52%; height: 2px; background: rgba(248, 250, 252, 0.55); transform: scaleX(0); transform-origin: left; transition: transform 0.7s var(--ease) 0.35s; }
.shift-arrow { position: relative; height: 2px; background: linear-gradient(90deg, transparent, var(--accent)); transform: scaleX(0); transform-origin: left; transition: transform 0.6s var(--ease) 0.75s; }
.shift-arrow::after { content: ""; position: absolute; right: -1px; top: -5px; width: 10px; height: 10px; border-top: 2px solid var(--accent); border-right: 2px solid var(--accent); transform: rotate(45deg); }
.shift-to { font: 600 clamp(17px, 1.8vw, 21px)/1.3 var(--display); opacity: 0; transform: translateX(-14px); transition: opacity 0.6s var(--ease) 1.05s, transform 0.6s var(--ease) 1.05s; }
.role-shift li.in .shift-from::after, .role-shift li.in .shift-arrow { transform: none; }
.role-shift li.in .shift-to { opacity: 1; transform: none; }

.mentor-grid { display: grid; grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr); gap: 28px; align-items: stretch; }
.mentor-photo { position: relative; margin: 0; border-radius: 28px; overflow: hidden; min-height: 420px; }
.mentor-photo img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; transform: scale(var(--pz, 1.08)); transition: transform 0.2s linear; }
.mentor-photo figcaption { position: absolute; left: 18px; right: 18px; bottom: 18px; padding: 16px 18px; border-radius: 18px; background: rgba(7, 11, 20, 0.7); border: 1px solid var(--glass-line); backdrop-filter: blur(14px); font-size: 15px; color: var(--ink-soft); }
.mentor-photo figcaption b { display: block; color: var(--ink); font: 700 17px/1.3 var(--display); margin-bottom: 4px; }
.why-cards { display: grid; gap: 16px; }
.why-card { display: grid; grid-template-columns: 52px minmax(0, 1fr); gap: 18px; padding: 26px; border-radius: 22px; border: 1px solid var(--line); background: rgba(255, 255, 255, 0.03); transition: border-color 0.3s, background 0.3s, transform 0.3s var(--ease); }
.why-card:hover { border-color: rgba(255, 115, 22, 0.4); background: rgba(255, 115, 22, 0.05); transform: translateX(4px); }
.why-icon { display: grid; place-items: center; width: 52px; height: 52px; border-radius: 16px; background: rgba(255, 115, 22, 0.12); color: var(--accent-soft); }
.why-icon svg { width: 24px; height: 24px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.why-card h4 { font-size: 19px; margin-bottom: 6px; }
.why-card p { margin: 0; color: var(--ink-soft); }

.act-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; margin: 0; padding: 0; list-style: none; counter-reset: act; }
.act-grid li { position: relative; padding: 30px 26px 28px; border-radius: 22px; border: 1px solid var(--line); background: linear-gradient(180deg, rgba(255, 255, 255, 0.04), rgba(255, 255, 255, 0.01)); color: var(--ink-soft); counter-increment: act; }
.act-grid li::before { content: "0" counter(act); display: block; margin-bottom: 26px; font: 800 44px/1 var(--display); color: transparent; -webkit-text-stroke: 1px rgba(255, 115, 22, 0.75); }
.act-grid strong { display: block; margin-bottom: 8px; color: var(--ink); font: 700 20px/1.25 var(--display); }
.act-cta { margin-top: 30px; }

/* ---------- paths ---------- */
.path-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 20px; align-items: start; }
.path-card { display: flex; flex-direction: column; border-radius: 26px; border: 1px solid var(--line); background: var(--bg-2); overflow: hidden; transition: transform 0.35s var(--ease), border-color 0.35s, box-shadow 0.35s; }
.path-card:hover { transform: translateY(-6px); border-color: rgba(255, 115, 22, 0.45); box-shadow: 0 30px 60px -30px rgba(255, 115, 22, 0.35); }
.path-photo { position: relative; margin: 0; aspect-ratio: 4 / 3; overflow: hidden; }
.path-photo img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.9s var(--ease); }
.path-card:hover .path-photo img { transform: scale(1.06); }
.path-photo::after { content: ""; position: absolute; inset: 0; background: linear-gradient(180deg, transparent 45%, var(--bg-2)); }
.path-index { position: absolute; top: 16px; left: 16px; z-index: 1; padding: 7px 11px; border-radius: 999px; background: rgba(7, 11, 20, 0.7); border: 1px solid var(--glass-line); backdrop-filter: blur(8px); font: 700 12px/1 var(--sans); letter-spacing: 0.12em; }
.path-chip { position: absolute; left: 16px; bottom: 14px; z-index: 1; display: inline-flex; align-items: center; gap: 8px; padding: 8px 12px; border-radius: 12px; background: rgba(7, 11, 20, 0.78); border: 1px solid var(--glass-line); font: 500 13px/1 var(--mono); color: var(--ink); }
.path-chip b { color: var(--success); font-weight: 600; }
.path-copy { display: flex; flex-direction: column; flex: 1; padding: 8px 26px 26px; }
.path-type { margin: 0 0 10px; font: 600 12px/1.4 var(--sans); letter-spacing: 0.14em; text-transform: uppercase; color: var(--accent-soft); }
.path-copy h3 { font-size: 24px; line-height: 1.15; margin-bottom: 10px; }
.path-copy > p { margin: 0 0 18px; color: var(--ink-soft); }
@media (min-width: 901px) { .path-copy > p { min-height: 8em; } }
.topic-tags { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 18px; }
.topic-tags span { padding: 6px 11px; border-radius: 999px; background: rgba(255, 255, 255, 0.06); border: 1px solid var(--line); font-size: 13px; }
.path-copy details { border-top: 1px solid var(--line); padding-top: 14px; }
.path-copy summary, .faq-list summary, .course-outline summary, .release-checksum summary { list-style: none; cursor: pointer; }
.path-copy summary::-webkit-details-marker, .faq-list summary::-webkit-details-marker, .course-outline summary::-webkit-details-marker, .release-checksum summary::-webkit-details-marker { display: none; }
.path-copy summary { display: flex; justify-content: space-between; align-items: center; font-weight: 600; }
.plus { position: relative; width: 26px; height: 26px; border-radius: 50%; border: 1px solid var(--glass-line); flex: none; transition: transform 0.3s var(--ease), background 0.3s; }
.plus::before, .plus::after { content: ""; position: absolute; left: 50%; top: 50%; width: 10px; height: 1.6px; background: currentColor; transform: translate(-50%, -50%); }
.plus::after { transform: translate(-50%, -50%) rotate(90deg); }
details[open] > summary .plus { transform: rotate(45deg); background: rgba(255, 115, 22, 0.18); }
.path-copy details ol { margin: 14px 0 10px; padding-left: 20px; color: var(--ink-soft); }
.path-copy details ol li { margin-bottom: 6px; }
.path-copy details p { margin: 0; font-size: 14px; color: var(--ink-soft); }

/* ---------- catalog ---------- */
.catalog-section { position: relative; background: radial-gradient(1200px 500px at 85% 0%, rgba(59, 130, 246, 0.12), transparent 60%), radial-gradient(900px 500px at 0% 100%, rgba(255, 115, 22, 0.08), transparent 60%), var(--bg-2); border-block: 1px solid var(--line); }
.catalog-notice { display: inline-flex; align-items: center; gap: 8px; margin: 0 0 20px; padding: 7px 13px; border-radius: 999px; background: rgba(52, 211, 153, 0.1); border: 1px solid rgba(52, 211, 153, 0.35); color: #b9f5dd; font-size: 13.5px; }
.catalog-notice::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: var(--success); }
.catalog-controls { display: grid; grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr); gap: 14px; padding: 14px; border-radius: 22px; border: 1px solid var(--glass-line); background: rgba(7, 11, 20, 0.55); backdrop-filter: blur(12px); }
.catalog-controls label { display: grid; gap: 8px; font: 600 12px/1 var(--sans); letter-spacing: 0.12em; text-transform: uppercase; color: var(--ink-soft); }
.catalog-controls input, .catalog-controls select, .download-card select {
  width: 100%; padding: 14px 16px; border-radius: 14px; border: 1px solid var(--glass-line); background: rgba(255, 255, 255, 0.05);
  font: 500 16px/1.2 var(--sans); letter-spacing: 0; text-transform: none; color: var(--ink); transition: border-color 0.2s, background 0.2s;
}
.catalog-controls input:focus, .catalog-controls select:focus, .download-card select:focus { outline: none; border-color: var(--accent); background: rgba(255, 115, 22, 0.06); }
.catalog-controls select option, .download-card select option { background: #0b1220; }
.catalog-status { margin: 22px 0 18px; color: var(--ink-soft); font-size: 14.5px; }
.course-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; align-items: start; }
.course-card { position: relative; display: flex; flex-direction: column; padding: 24px; border-radius: 22px; border: 1px solid var(--line); background: rgba(7, 11, 20, 0.55); transition: transform 0.3s var(--ease), border-color 0.3s; animation: card-in 0.6s var(--ease) both; }
.course-card:nth-child(3n + 2) { animation-delay: 0.06s; }
.course-card:nth-child(3n + 3) { animation-delay: 0.12s; }
@keyframes card-in { from { opacity: 0; transform: translateY(16px); } }
.course-card:hover { transform: translateY(-4px); border-color: rgba(255, 115, 22, 0.4); }
.course-category { align-self: flex-start; margin: 0 0 16px; padding: 6px 10px; border-radius: 8px; background: rgba(59, 130, 246, 0.14); color: #bcd4ff; font: 600 11.5px/1 var(--sans); letter-spacing: 0.1em; text-transform: uppercase; }
.course-card h3 { font-size: 21px; line-height: 1.2; margin-bottom: 10px; }
.course-description { margin: 0 0 16px; color: var(--ink-soft); font-size: 15px; }
.course-meta { margin: 0 0 14px; padding-top: 14px; border-top: 1px solid var(--line); font-size: 13.5px; color: var(--ink); font-weight: 500; }
.course-offer { margin: 0 0 4px; color: var(--ink); font-size: 14px; }
.course-offer strong { font-size: 20px; }
.course-access { margin: 0 0 16px; color: var(--ink-soft); font-size: 13.5px; }
.course-outline summary { display: inline-flex; gap: 8px; align-items: center; color: var(--accent-soft); font-weight: 600; font-size: 14.5px; }
.course-outline summary::after { content: "→"; transition: transform 0.25s var(--ease); }
.course-outline[open] summary::after { transform: rotate(90deg); }
.course-outline ol { margin: 12px 0 0; padding-left: 20px; color: var(--ink-soft); font-size: 14px; }
.course-preparation { margin: 12px 0 0; font-size: 13.5px; color: var(--ink-soft); }
.catalog-footer { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 18px; margin-top: 30px; }
.catalog-footer .btn[hidden] { display: none; }

/* ---------- workspace (scripted app) ---------- */
.workspace-section { position: relative; }
.experience-grid { display: grid; grid-template-columns: minmax(0, 340px) minmax(0, 1fr); gap: 32px; align-items: start; }
.experience-tabs { display: grid; gap: 10px; position: sticky; top: 100px; }
.experience-tabs button {
  position: relative; display: grid; grid-template-columns: 40px minmax(0, 1fr); gap: 14px; align-items: start;
  padding: 18px 18px 20px; border-radius: 18px; border: 1px solid var(--line); background: rgba(255, 255, 255, 0.02);
  text-align: left; cursor: pointer; overflow: hidden; transition: background 0.3s, border-color 0.3s;
}
.experience-tabs button:hover { background: rgba(255, 255, 255, 0.05); }
.experience-tabs button[aria-selected="true"] { border-color: rgba(255, 115, 22, 0.5); background: rgba(255, 115, 22, 0.07); }
.mode-icon { display: grid; place-items: center; width: 40px; height: 40px; border-radius: 12px; background: rgba(255, 255, 255, 0.06); color: var(--ink-soft); transition: background 0.3s, color 0.3s; }
.mode-icon svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.experience-tabs button[aria-selected="true"] .mode-icon { background: var(--accent); color: #1a0b00; }
.experience-tabs strong { display: block; font: 700 16.5px/1.3 var(--display); }
.experience-tabs small { display: block; margin-top: 4px; color: var(--ink-soft); font-size: 14px; line-height: 1.45; }
.tab-progress { position: absolute; left: 0; bottom: 0; height: 3px; width: 100%; background: var(--accent); transform: scaleX(0); transform-origin: left; }
.experience-stage { min-width: 0; }
.workspace-note { margin: 28px 0 0; color: var(--ink-soft); font-size: 14.5px; }

/* ---------- downloads ---------- */
.download-section { position: relative; }
.download-heading { max-width: 760px; margin-bottom: 32px; }
.download-heading > p:last-child { margin: 20px 0 0; font-size: 18px; color: var(--ink-soft); }
.platform-notice { display: inline-flex; margin: 0 0 18px; padding: 10px 16px; border-radius: 14px; background: rgba(56, 189, 248, 0.1); border: 1px solid rgba(56, 189, 248, 0.35); color: #cdeefe; font-size: 14.5px; }
.preview-release-notice { display: grid; grid-template-columns: auto minmax(0, 1fr); gap: 16px; align-items: start; margin-bottom: 28px; padding: 20px 22px; border-radius: 20px; border: 1px solid rgba(255, 115, 22, 0.35); background: rgba(255, 115, 22, 0.06); }
.preview-release-notice strong { padding: 6px 11px; border-radius: 999px; background: var(--accent); color: #1a0b00; font: 700 12px/1 var(--sans); letter-spacing: 0.1em; text-transform: uppercase; white-space: nowrap; }
.preview-release-notice p { margin: 0; color: var(--ink-soft); }
.download-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 18px; }
.download-card { position: relative; display: flex; flex-direction: column; padding: 28px; border-radius: 26px; border: 1px solid var(--line); background: linear-gradient(180deg, rgba(255, 255, 255, 0.045), rgba(255, 255, 255, 0.01)); transition: border-color 0.3s, transform 0.3s var(--ease); }
.download-card:hover { transform: translateY(-4px); }
.download-card.detected { border-color: rgba(255, 115, 22, 0.6); box-shadow: 0 30px 70px -40px rgba(255, 115, 22, 0.55); }
.download-card.detected::before { content: "Your computer"; position: absolute; top: 22px; right: 22px; padding: 6px 10px; border-radius: 999px; background: rgba(255, 115, 22, 0.16); color: #ffd7b5; font: 600 11.5px/1 var(--sans); letter-spacing: 0.08em; text-transform: uppercase; }
.os-icon { display: grid; place-items: center; width: 56px; height: 56px; margin-bottom: 20px; border-radius: 16px; background: rgba(255, 255, 255, 0.07); color: var(--ink); font: 700 18px/1 var(--mono); }
.os-icon svg { width: 28px; height: 28px; }
.windows-icon { grid-template-columns: repeat(2, 12px); gap: 3px; place-content: center; }
.windows-icon i { width: 12px; height: 12px; border-radius: 2px; background: var(--sky); }
.download-card h3 { font-size: 24px; }
.download-card > p { margin: 6px 0 20px; color: var(--ink-soft); }
.file-type { margin-left: 6px; padding: 3px 7px; border-radius: 6px; background: rgba(255, 255, 255, 0.08); font: 600 12.5px/1 var(--mono); color: var(--ink); }
.download-card label { margin-bottom: 8px; font: 600 12px/1 var(--sans); letter-spacing: 0.12em; text-transform: uppercase; color: var(--ink-soft); }
.release-action { display: grid; gap: 10px; margin-top: 18px; }
.download-button { display: inline-flex; align-items: center; justify-content: center; width: 100%; padding: 15px 20px; border: 0; border-radius: 999px; background: linear-gradient(180deg, #ff8a3d, var(--accent)); color: #1a0b00; font: 700 15.5px/1 var(--display); cursor: pointer; box-shadow: 0 10px 30px -10px rgba(255, 115, 22, 0.6); transition: transform 0.25s var(--ease); }
.download-button:hover { transform: translateY(-2px); }
.download-button:disabled { cursor: default; transform: none; background: rgba(255, 255, 255, 0.08); color: var(--ink-soft); box-shadow: none; }
.release-alternate { justify-self: center; font-size: 14px; color: var(--accent-soft); font-weight: 600; }
.release-alternate:hover { color: #ffd7b5; }
.release-meta { margin: 14px 0 0; font-size: 13.5px; color: var(--ink-soft); }
.release-checksum { margin-top: 10px; font-size: 13.5px; }
.release-checksum summary { color: var(--ink-soft); text-decoration: underline; text-underline-offset: 3px; }
.release-checksum code { display: block; margin-top: 8px; padding: 10px; border-radius: 10px; background: rgba(0, 0, 0, 0.35); font-size: 11.5px; word-break: break-all; color: var(--ink-soft); }
.release-checksum p { margin: 10px 0 0; }
.existing-vscode { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center; gap: 16px; margin-top: 24px; padding: 22px 24px; border-radius: 20px; border: 1px dashed var(--glass-line); }
.existing-vscode p { margin: 4px 0 0; color: var(--ink-soft); }

/* ---------- faq ---------- */
.faq-section { display: grid; grid-template-columns: minmax(0, 0.8fr) minmax(0, 1.2fr); gap: 56px; align-items: start; }
.faq-intro { position: sticky; top: 110px; }
.faq-intro > p:last-child { margin: 22px 0 0; color: var(--ink-soft); }
.faq-list { display: grid; gap: 12px; }
.faq-list details { border-radius: 20px; border: 1px solid var(--line); background: rgba(255, 255, 255, 0.025); transition: border-color 0.3s, background 0.3s; }
.faq-list details[open] { border-color: rgba(255, 115, 22, 0.4); background: rgba(255, 115, 22, 0.04); }
.faq-list summary { display: flex; justify-content: space-between; align-items: center; gap: 16px; padding: 20px 22px; font: 600 17px/1.35 var(--display); }
.faq-list details p { margin: 0; padding: 0 22px 22px; color: var(--ink-soft); }
.faq-list details p strong { color: var(--ink); }

/* ---------- closing ---------- */
.closing { position: relative; margin: 0 var(--gutter); border-radius: 36px; overflow: hidden; isolation: isolate; padding: clamp(80px, 12vw, 150px) clamp(24px, 6vw, 80px); text-align: center; }
.closing img { position: absolute; inset: 0; z-index: -2; width: 100%; height: 100%; object-fit: cover; transform: scale(var(--pz, 1.1)); }
.closing::before { content: ""; position: absolute; inset: 0; z-index: -1; background: radial-gradient(ellipse at 50% 60%, rgba(7, 11, 20, 0.55), rgba(7, 11, 20, 0.88)); }
.closing h2 { max-width: 860px; margin: 0 auto 32px; font-size: clamp(36px, 5.6vw, 72px); line-height: 1.02; font-weight: 800; }
.closing .eyebrow { justify-content: center; }
.closing-actions { display: flex; flex-wrap: wrap; justify-content: center; gap: 14px; }

/* ---------- footer ---------- */
.site-foot { position: relative; padding: clamp(64px, 8vw, 96px) var(--gutter) 36px; margin-top: clamp(64px, 8vw, 110px); border-top: 1px solid var(--line); background: linear-gradient(180deg, rgba(255, 255, 255, 0.02), transparent 40%); }
.foot-grid { display: grid; grid-template-columns: minmax(0, 1.5fr) repeat(3, minmax(0, 1fr)); gap: 40px; max-width: var(--max); margin: 0 auto; }
.foot-brand .brand { display: inline-flex; }
.foot-brand p { max-width: 340px; margin: 16px 0 0; font-size: 14.5px; line-height: 1.6; color: var(--ink-soft); }
.foot-brand .foot-built a { color: var(--accent-soft); text-decoration: underline; text-underline-offset: 3px; }
.foot-cta { display: inline-flex; align-items: center; gap: 8px; margin-top: 20px; padding: 10px 16px; border-radius: 999px; background: rgba(255, 115, 22, 0.12); border: 1px solid rgba(255, 115, 22, 0.4); color: #ffd7b5; font: 600 14px/1 var(--sans); transition: background 0.25s, color 0.25s; }
.foot-cta svg { width: 16px; height: 16px; fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; transition: transform 0.25s; }
.foot-cta:hover { background: var(--accent); color: #1a0b00; }
.foot-cta:hover svg { transform: translateX(3px); }
.foot-col { display: flex; flex-direction: column; align-items: flex-start; gap: 11px; font-size: 14.5px; color: var(--ink-soft); }
.foot-col h5 { margin: 0 0 6px; font: 700 12px/1 var(--sans); letter-spacing: 0.14em; text-transform: uppercase; color: var(--ink); }
.foot-col ul { display: grid; gap: 11px; margin: 0; padding: 0; list-style: none; }
.foot-col a:hover { color: var(--ink); }
.foot-col address { font-style: normal; line-height: 1.6; }
.foot-contact { color: var(--ink); font-weight: 500; }
.foot-contact:hover { color: var(--accent-soft) !important; }
.foot-bottom { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 12px 24px; max-width: var(--max); margin: 48px auto 0; padding-top: 22px; border-top: 1px solid rgba(255, 255, 255, 0.08); font-size: 13.5px; color: var(--ink-soft); }
.foot-bottom p { margin: 0; }
.foot-bottom nav { display: flex; flex-wrap: wrap; gap: 8px 22px; }
.foot-bottom a:hover { color: var(--ink); }
.to-top { position: absolute; right: var(--gutter); top: -22px; display: grid; place-items: center; width: 44px; height: 44px; border-radius: 50%; background: var(--accent); color: #1a0b00; box-shadow: 0 10px 30px -8px rgba(255, 115, 22, 0.7); transition: transform 0.25s var(--ease); }
.to-top:hover { transform: translateY(-3px); }
.to-top svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 2.2; stroke-linecap: round; stroke-linejoin: round; }

/* ---------- responsive ---------- */
@media (max-width: 1080px) {
  .course-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .experience-grid { grid-template-columns: minmax(0, 1fr); }
  .experience-tabs { position: static; grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .experience-tabs button { grid-template-columns: minmax(0, 1fr); }
  .experience-tabs small { display: none; }
}
@media (max-width: 1300px) {
  .menu-toggle { display: inline-flex; }
  #navigation {
    position: absolute; top: calc(100% + 8px); left: var(--gutter); right: var(--gutter);
    display: none; flex-direction: column; align-items: stretch; gap: 14px; padding: 16px;
    border-radius: 22px; border: 1px solid var(--glass-line); background: rgba(7, 11, 20, 0.96); backdrop-filter: blur(16px);
  }
  #navigation.open { display: flex; }
  .nav-links { flex-direction: column; margin: 0; padding: 0; background: none; border: 0; }
  .nav-links a { padding: 13px 14px; font-size: 16px; }
  .nav-actions { justify-content: space-between; padding: 12px 14px 0; border-top: 1px solid var(--line); }
}
@media (max-width: 900px) {
  .section-heading, .why-label, .mentor-grid, .faq-section { grid-template-columns: minmax(0, 1fr); gap: 20px; }
  .faq-intro { position: static; }
  .path-grid, .download-grid, .act-grid { grid-template-columns: minmax(0, 1fr); }
  .path-grid { max-width: 560px; }
  .foot-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .foot-brand { grid-column: 1 / -1; }
}
@media (max-width: 820px) {
  .hero { padding-top: 120px; }
  .hero::before { background: linear-gradient(180deg, rgba(7, 11, 20, 0.35) 0%, rgba(7, 11, 20, 0.7) 40%, rgba(7, 11, 20, 0.92) 70%, var(--bg) 92%); }
  .hero-photo img { object-position: 50% 20%; }
  .role-shift li { grid-template-columns: minmax(0, 1fr); gap: 10px; padding: 18px 20px; }
  .shift-arrow { width: 56px; }
  .mentor-photo { min-height: 360px; }
}
@media (max-width: 640px) {
  .brand-tag { display: none; }
  .brand { font-size: 21px; }
  .brand img { width: 32px; height: 32px; }
  .course-grid { grid-template-columns: minmax(0, 1fr); }
  .catalog-controls { grid-template-columns: minmax(0, 1fr); }
  .experience-tabs { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 8px; }
  .experience-tabs button { padding: 12px; gap: 8px; }
  .experience-tabs strong { font-size: 14px; }
  .preview-release-notice { grid-template-columns: minmax(0, 1fr); }
  .closing { margin: 0 12px; border-radius: 26px; }
  .foot-grid { grid-template-columns: minmax(0, 1fr); }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 0.01ms !important; animation-iteration-count: 1 !important; transition-duration: 0.01ms !important; scroll-behavior: auto !important; }
  .reveal { opacity: 1; transform: none; }
  .hero h1 .line > span { transform: none; }
  .hero-fade { opacity: 1; }
}

/* ======================================================================
   Desktop app replica (VS Code Light Modern + dhimantAI learning views)
   The window is laid out at 1040×640 and scaled to fit by site.js (--s).
   ====================================================================== */
.window-fit { position: relative; width: 100%; height: calc(640px * var(--s, 1)); }
.window {
  --wf: system-ui, "Segoe UI", Ubuntu, "Droid Sans", sans-serif;
  --w-fg: #3b3b3b; --w-muted: #6e6e6e; --w-line: #e5e5e5; --w-side: #f8f8f8; --w-blue: #005fb8;
  position: absolute; left: 0; top: 0; width: 1040px; height: 640px;
  transform-origin: 0 0; scale: var(--s, 1);
  display: flex; flex-direction: column; overflow: hidden;
  border-radius: 12px; background: #fff; color: var(--w-fg);
  font: 400 13px/1.5 var(--wf); letter-spacing: 0;
  box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.12), 0 50px 120px -30px rgba(0, 0, 0, 0.8), 0 30px 60px -40px rgba(255, 115, 22, 0.35);
}
.window h4, .window h5 { font-family: var(--wf); letter-spacing: 0; }
.window svg { width: 16px; height: 16px; flex: none; fill: none; stroke: currentColor; stroke-width: 1.3; stroke-linecap: round; stroke-linejoin: round; }
.window code, .window pre { font-family: var(--mono); font-size: 12.5px; }
.window code { padding: 1px 4px; border-radius: 4px; background: #f3f3f3; }
.w-title { position: relative; display: flex; align-items: center; justify-content: center; height: 34px; background: var(--w-side); border-bottom: 1px solid var(--w-line); color: var(--w-fg); font-size: 12.5px; }
.w-dots { position: absolute; left: 14px; display: flex; gap: 7px; }
.w-dots i { width: 11px; height: 11px; border-radius: 50%; background: #ff5f57; }
.w-dots i:nth-child(2) { background: #febc2e; }
.w-dots i:nth-child(3) { background: #28c840; }
.w-main { display: flex; flex: 1; min-height: 0; }
.w-side { width: 196px; flex: none; padding: 4px 0; background: var(--w-side); border-right: 1px solid var(--w-line); font-size: 13px; }
.w-side-head { margin: 0; padding: 8px 20px; font-size: 11px; text-transform: uppercase; letter-spacing: 0.04em; }
.w-sec { display: flex; align-items: center; gap: 2px; margin: 0; padding: 3px 4px; font-size: 11px; font-weight: 700; text-transform: uppercase; border-top: 1px solid var(--w-line); }
.w-sec.open { border-top: 0; }
.w-nav { margin: 2px 0 6px; padding: 0; list-style: none; }
.w-nav li { display: flex; align-items: center; gap: 8px; padding: 3px 0 3px 26px; transition: background 0.2s; }
.w-nav li.on { background: #e4e6f1; box-shadow: inset 1px 0 0 var(--w-blue); }
.w-editor { flex: 1; min-width: 0; display: flex; flex-direction: column; }
.w-tabs { display: flex; height: 35px; flex: none; background: var(--w-side); border-bottom: 1px solid var(--w-line); }
.w-tab { display: flex; align-items: center; gap: 7px; padding: 0 12px; background: #fff; border-right: 1px solid var(--w-line); box-shadow: inset 0 1px 0 var(--w-blue); margin-bottom: -1px; }
.w-tab svg { color: var(--w-blue); }
.w-tab i { margin-left: 8px; font-style: normal; color: var(--w-muted); }
.w-views { position: relative; flex: 1; min-height: 0; }
.view { position: absolute; inset: 0; overflow: hidden; opacity: 0; visibility: hidden; transition: opacity 0.35s, visibility 0s 0.35s; }
.view.on { opacity: 1; visibility: visible; transition: opacity 0.35s; }
.w-status { display: flex; justify-content: space-between; align-items: center; height: 22px; padding: 0 10px; background: var(--w-side); border-top: 1px solid var(--w-line); font-size: 12px; }
.w-status-item { display: flex; align-items: center; gap: 5px; }
.w-status svg { width: 14px; height: 14px; }

/* controls */
.vb { display: inline-flex; align-items: center; gap: 6px; padding: 5px 12px; border-radius: 4px; background: #e5e5e5; color: var(--w-fg); font-size: 12.5px; white-space: nowrap; transition: background 0.2s, box-shadow 0.2s; }
.vb.primary { background: var(--w-blue); color: #fff; }
.vb.icon { padding: 5px 6px; }
.vb svg { width: 14px; height: 14px; }
.vb.pressed { box-shadow: 0 0 0 3px rgba(0, 95, 184, 0.3); filter: brightness(0.92); }
.vi { display: block; padding: 6px 9px; border: 1px solid #cecece; border-radius: 4px; background: #fff; color: #8b8b8b; min-height: 30px; white-space: pre-wrap; }
.vi.typing, .vi.filled { color: var(--w-fg); }
.vi.typing { border-color: var(--w-blue); box-shadow: 0 0 0 1px var(--w-blue); }
.vi.typing::after { content: ""; display: inline-block; width: 1px; height: 14px; margin-left: 1px; vertical-align: -2px; background: var(--w-fg); animation: caret 0.9s steps(1) infinite; }
@keyframes caret { 50% { opacity: 0; } }
.vi.mono { font-family: var(--mono); font-size: 12px; }
.vi.grow { min-height: 44px; }

/* cursor */
.w-cursor { position: absolute; left: 0; top: 0; z-index: 9; width: 22px; height: 22px; pointer-events: none; opacity: 0; transition: opacity 0.3s;
  background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath d='M5 3l14 8-6 1.6L10 19z' fill='%23111' stroke='%23fff' stroke-width='1.6' stroke-linejoin='round'/%3E%3C/svg%3E") no-repeat 0 0 / contain; }
.w-cursor.show { opacity: 1; }
.w-cursor::after { content: ""; position: absolute; left: -9px; top: -9px; width: 26px; height: 26px; border-radius: 50%; background: rgba(255, 115, 22, 0.45); transform: scale(0); opacity: 0; }
.w-cursor.tap::after { animation: tap 0.5s ease-out; }
@keyframes tap { 0% { transform: scale(0.2); opacity: 1; } 100% { transform: scale(1.6); opacity: 0; } }

/* course catalog */
.cc { max-width: 800px; padding: 22px 28px; }
.cc-head { display: flex; justify-content: space-between; align-items: flex-start; gap: 12px; }
.cc-head small { color: var(--w-muted); }
.cc-head h4 { font-size: 24px; font-weight: 600; line-height: 1.2; }
.cc-head-btns { display: flex; gap: 6px; }
.cc-intro { margin: 10px 0 14px; }
.cc-search { display: grid; gap: 5px; max-width: 380px; margin-bottom: 14px; font-weight: 600; font-size: 12.5px; }
.cc-cat { margin: 0 0 10px; font-size: 15px; font-weight: 600; }
.cc-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 14px; }
.cc-card { display: flex; flex-direction: column; padding: 16px; border: 1px solid var(--w-line); border-radius: 10px; transition: opacity 0.4s, transform 0.4s; }
.cc-card.gone { opacity: 0; transform: scale(0.96); }
.cc-card small { color: var(--w-muted); font-size: 12px; }
.cc-card h5 { margin: 4px 0 6px; font-size: 16px; font-weight: 600; line-height: 1.25; }
.cc-card p { margin: 0 0 10px; font-size: 12.5px; }
.cc-outline { color: var(--w-blue); font-size: 12.5px; }
.cc-access { margin: 8px 0 10px; font-size: 12.5px; }
.cc-btns { display: flex; gap: 6px; margin-top: auto; }

/* notebook (Instructor / Doubt Solver) */
.nb { display: flex; flex-direction: column; height: 100%; }
.nb-head { display: flex; justify-content: space-between; align-items: flex-start; padding: 16px 24px 10px; border-bottom: 1px solid var(--w-line); }
.nb-head small { font-size: 10px; letter-spacing: 0.13em; font-weight: 650; color: var(--w-muted); }
.nb-head h4 { font-size: 20px; font-weight: 600; line-height: 1.25; }
.nb-head-r { display: flex; gap: 6px; }
.nb-tools { display: flex; gap: 16px; padding: 6px 24px; border-bottom: 1px solid var(--w-line); font-size: 12px; color: var(--w-muted); }
.nb-tools em { font-style: normal; padding: 1px 6px; border: 1px solid var(--w-line); border-radius: 3px; }
.nb-tools-r { margin-left: auto; }
.nb-feed { flex: 1; min-height: 0; overflow: hidden; padding: 14px 24px; display: flex; flex-direction: column; gap: 10px; }
.nb-empty { margin: auto; color: var(--w-muted); }
.cell { flex: none; padding: 12px 16px; border: 1px solid var(--w-line); border-radius: 10px; animation: cell-in 0.45s var(--ease) both; }
.cell[hidden] { display: none; }
@keyframes cell-in { from { opacity: 0; transform: translateY(10px); } }
.cell > small { display: block; margin-bottom: 4px; font-size: 11px; font-weight: 600; color: var(--w-muted); }
.cell p { margin: 0 0 6px; }
.cell p:last-child { margin-bottom: 0; }
.cell.me { align-self: flex-end; max-width: 72%; background: #f0f6fd; border-color: #cfe3f7; }
.cell.good { border-color: #b7e2c5; background: #f4fbf6; }
.tick { color: #388a34; font-weight: 700; }
.thinking { padding-block: 10px; }
.dots { display: inline-flex; gap: 4px; }
.dots i { width: 6px; height: 6px; border-radius: 50%; background: #9a9a9a; animation: dot 1s infinite; }
.dots i:nth-child(2) { animation-delay: 0.15s; }
.dots i:nth-child(3) { animation-delay: 0.3s; }
@keyframes dot { 50% { transform: translateY(-4px); background: var(--w-blue); } }
.code { margin: 6px 0; padding: 8px 12px; border-radius: 6px; background: #1f1f1f; color: #d4d4d4; line-height: 1.6; white-space: pre; }
.code b { display: inline-block; width: 20px; color: #6e7681; font-weight: 400; }
.code n { color: #b5cea8; }
.code f { color: #dcdcaa; }
.code k { color: #569cd6; }
.code c { color: #6a9955; }
.code.inline { display: inline-block; margin: 0; }
.out { margin: 6px 0; padding: 7px 12px; border-left: 3px solid var(--w-blue); background: #f3f3f3; font-weight: 500; }
.turn { margin-top: 8px; padding: 8px 12px; border-radius: 6px; background: #fff7e6; border: 1px solid #f5dfae; }
.turn b { display: block; font-size: 11.5px; color: #8a5a00; }
.chips { display: flex; gap: 6px; flex-wrap: wrap; margin-top: 8px; }
.chips span { padding: 3px 10px; border: 1px solid #cecece; border-radius: 999px; font-size: 12px; }
.composer { flex: none; padding: 10px 24px 12px; border-top: 1px solid var(--w-line); background: #fafafa; display: grid; gap: 7px; }
.stuck { display: flex; align-items: center; gap: 10px; font-size: 12.5px; }
.comp-row { display: flex; align-items: center; gap: 8px; color: var(--w-muted); font-size: 11.5px; }
.comp-r { display: flex; gap: 6px; margin-left: auto; }
.tried-field { display: grid; gap: 3px; color: var(--w-muted); }
.tried { display: block; margin-bottom: 4px; color: var(--w-muted); font-size: 12px; }

/* study */
.st { position: relative; display: flex; flex-direction: column; height: 100%; background: #fff; }
.st-head { display: flex; align-items: center; gap: 18px; padding: 10px 20px; border-bottom: 1px solid var(--w-line); }
.st-head > b { font-size: 16px; }
.st-field { display: flex; align-items: center; gap: 6px; color: var(--w-muted); font-size: 12px; }
.st-page { position: relative; flex: 1; min-height: 0; overflow: hidden; background: #f6f6f6; }
.st-book { width: 520px; margin: 16px auto; padding: 26px 40px; background: #fffdf8; box-shadow: 0 2px 10px rgba(0, 0, 0, 0.08); font: 400 15px/1.7 Georgia, "Times New Roman", serif; color: #222; transition: transform 1.2s var(--ease); }
.st-book h5 { margin: 0 0 10px; font: 700 21px/1.3 Georgia, serif; }
.st-kicker { margin: 0; font: 600 12px/1 var(--wf); color: #1687ff; letter-spacing: 0.1em; }
.st-book p { margin: 0 0 12px; }
.st-book mark { background: linear-gradient(90deg, rgba(22, 135, 255, 0.25), rgba(22, 135, 255, 0.25)) no-repeat 0 0 / 0% 100%; color: inherit; transition: background-size 1.1s linear; }
.st-book mark.sel { background-size: 100% 100%; }
.st-book code { font-size: 13px; }
.st-pop { position: absolute; left: 50%; bottom: 14px; width: 470px; translate: -50% 0; padding: 12px 14px; background: #fff; border: 1px solid var(--w-line); border-radius: 8px; box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15); animation: cell-in 0.35s var(--ease) both; }
.st-pop[hidden] { display: none; }
.st-pop blockquote { margin: 0 0 8px; padding-left: 10px; border-left: 3px solid #1687ff; color: var(--w-muted); font-style: italic; }
.st-pop div { display: flex; gap: 6px; }
.st-bar { display: flex; align-items: center; gap: 8px; padding: 8px 16px; border-top: 1px solid var(--w-line); font-size: 12px; }
.st-size { margin-left: 8px; color: var(--w-muted); }
.st-bar-r { display: flex; gap: 6px; margin-left: auto; }
.st-dialog { position: absolute; inset: 0; display: flex; flex-direction: column; padding: 14px 26px; background: #fff; animation: slide-in 0.45s var(--ease) both; }
.st-dialog[hidden] { display: none; }
@keyframes slide-in { from { opacity: 0; transform: translateX(30px); } }
.st-back { color: var(--w-blue); font-size: 12.5px; }
.st-dialog h5 { margin: 6px 0 4px; font-size: 20px; font-weight: 600; }
.st-sel { margin: 0 0 8px; color: var(--w-muted); font-size: 12.5px; }
.st-answer { flex: 1; min-height: 0; }
.st-answer p { margin: 0 0 8px; }
.thinking-line { padding: 8px 0; }
.alias { position: relative; width: 300px; height: 100px; margin: 4px 0 10px; }
.alias svg { position: absolute; left: 50px; top: 24px; width: 200px; height: 60px; stroke: #1687ff; stroke-width: 2; stroke-dasharray: 140; stroke-dashoffset: 140; animation: draw 1s 0.3s forwards; }
@keyframes draw { to { stroke-dashoffset: 0; } }
.alias .tag { position: absolute; top: 0; padding: 2px 10px; border-radius: 4px; background: #fff7e6; border: 1px solid #f5dfae; font: 500 12px/1.6 var(--mono); }
.alias .t1 { left: 46px; }
.alias .t2 { left: 172px; }
.alias .box { position: absolute; left: 100px; top: 68px; padding: 4px 14px; border: 2px solid #1687ff; border-radius: 6px; font: 600 13px/1.4 var(--mono); }

/* practice */
.pr { height: 100%; padding: 16px 26px; overflow: hidden; }
.pr-kicker { color: var(--w-muted); font-size: 11.5px; }
.pr h4 { font-size: 19px; font-weight: 600; }
.pr-task { margin: 2px 0 6px; }
.pr .editor { margin: 6px 0 8px; font-size: 12.5px; }
.pr .editor [data-body] { transition: background 0.3s; }
.pr .editor [data-body].edit { background: rgba(0, 95, 184, 0.45); }
.pr-tests small { color: var(--w-muted); font-size: 11.5px; }
.pr-tests [hidden] { display: none; }
.pr-predict { display: grid; grid-template-columns: auto minmax(0, 300px); justify-content: start; align-items: center; gap: 10px; margin-bottom: 8px; font-weight: 600; font-size: 12.5px; }
.pr-btns { display: flex; gap: 6px; }
.pr-status { margin: 8px 0 4px; color: var(--w-muted); font-size: 12.5px; }
.pr-tests { display: grid; gap: 2px; padding: 8px 12px; border: 1px solid var(--w-line); border-radius: 8px; font-size: 12.5px; animation: cell-in 0.4s var(--ease) both; }
.pr-tests[hidden], .pr .out[hidden], .pr-note[hidden], .pr-tests p[hidden] { display: none; }
.pr-tests .pass { color: #388a34; }
.pr-tests .fail { color: #c72e0f; }
.pr-tests p { margin: 4px 0 0; color: #388a34; font-weight: 600; }
.pr-note { margin: 6px 0 0; color: var(--w-muted); font-size: 11.5px; }

/* doubt solver diagram */
.shallow { position: relative; width: 320px; height: 84px; margin: 4px 0 10px; }
.shallow .sl, .shallow .sr { position: absolute; padding: 2px 10px; border-radius: 4px; font: 500 12px/1.6 var(--mono); }
.shallow .sl { left: 0; background: #fff7e6; border: 1px solid #f5dfae; }
.shallow .sl:nth-of-type(1) { top: 4px; }
.shallow .sl:nth-of-type(2) { top: 50px; }
.shallow .sr { left: 230px; border: 2px solid #1687ff; }
.shallow .sr:nth-of-type(3) { top: 2px; color: #c72e0f; }
.shallow .sr:nth-of-type(4) { top: 48px; }
.shallow svg { position: absolute; left: 6px; top: 2px; width: 240px; height: 70px; stroke: #1687ff; stroke-width: 1.6; stroke-dasharray: 160; stroke-dashoffset: 160; animation: draw 1.2s 0.3s forwards; }

/* compact window for phones */
.window-fit.compact .window { width: 600px; }
.compact .w-side, .compact .cc-head-btns, .compact .nb-tools, .compact .comp-row small, .compact .st-size,
.compact .st-bar-r .vb:not(.primary), .compact .pr-btns .vb:nth-child(2), .compact .pr-btns .vb:nth-child(3), .compact .w-status-r { display: none; }
.compact .cc { padding: 16px 18px; }
.compact .cc-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.compact .nb-head, .compact .nb-feed, .compact .composer { padding-inline: 16px; }
.compact .st-head { gap: 10px; padding-inline: 14px; }
.compact .st-book { width: auto; margin: 12px 16px; padding: 20px 24px; }
.compact .st-pop { width: 90%; }
.compact .pr { padding-inline: 18px; }
.compact .cell.me { max-width: 88%; }