:root {
  color-scheme: light;
  font-family: Montserrat, Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: #18181b;
  background: #202020;
  font-synthesis: none;
  --ink: #18181b;
  --muted: #5b6260;
  --surface: #ffffff;
  --line: #dfe8e2;
  --accent: #67eb93;
  --accent-dark: #168f4e;
  --accent-soft: #eafff0;
  --night: #181a19;
  --night-soft: #303331;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-width: 320px;
  background:
    radial-gradient(circle at 8% 4%, rgb(103 235 147 / 20%), transparent 27rem),
    radial-gradient(circle at 92% 28%, rgb(103 235 147 / 10%), transparent 24rem),
    linear-gradient(135deg, #111311 0%, #303330 55%, #494b49 100%);
  background-attachment: fixed;
  color: var(--ink);
  line-height: 1.7;
}

a { color: var(--accent-dark); text-underline-offset: .18em; }
a:hover { color: var(--accent); }

.skip-link {
  position: fixed;
  left: 12px;
  top: -60px;
  z-index: 100;
  padding: 10px 14px;
  border-radius: 8px;
  background: var(--accent);
  color: #101210;
}
.skip-link:focus { top: 12px; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid rgb(255 255 255 / 10%);
  background: rgb(19 21 20 / 86%);
  backdrop-filter: blur(16px);
}

.site-header__inner,
.content-shell,
.site-footer__inner {
  width: min(1040px, calc(100% - 32px));
  margin-inline: auto;
}

.site-header__inner {
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: white;
  font-weight: 800;
  text-decoration: none;
}

.brand__mark {
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  border-radius: 11px;
  background: linear-gradient(135deg, #67eb93, #39c873);
  color: #101210;
  box-shadow: 0 8px 24px rgb(103 235 147 / 28%);
}

.site-nav { display: flex; flex-wrap: wrap; gap: 18px; }
.site-nav a { color: #d5dad7; font-size: .88rem; font-weight: 650; text-decoration: none; }
.site-nav a[aria-current="page"], .site-nav a:hover { color: var(--accent); }

.mobile-nav { display: none; position: relative; }
.mobile-nav summary {
  cursor: pointer;
  padding: 9px 13px;
  border: 1px solid rgb(103 235 147 / 45%);
  border-radius: 10px;
  color: white;
  font-size: .82rem;
  font-weight: 750;
  list-style: none;
}
.mobile-nav summary::-webkit-details-marker { display: none; }
.mobile-nav summary::after { content: " +"; color: var(--accent); }
.mobile-nav[open] summary::after { content: " −"; }
.mobile-nav__panel {
  position: absolute;
  top: calc(100% + 10px);
  right: 0;
  width: min(310px, calc(100vw - 22px));
  display: grid;
  overflow: hidden;
  border: 1px solid rgb(103 235 147 / 38%);
  border-radius: 16px;
  background: #1d211f;
  box-shadow: 0 22px 55px rgb(0 0 0 / 45%);
}
.mobile-nav__panel a {
  padding: 13px 16px;
  border-bottom: 1px solid rgb(255 255 255 / 8%);
  color: #f4f4f5;
  font-size: .86rem;
  font-weight: 680;
  text-decoration: none;
}
.mobile-nav__panel a:last-child { border-bottom: 0; }
.mobile-nav__panel a:hover, .mobile-nav__panel a[aria-current="page"] { color: var(--accent); background: rgb(103 235 147 / 7%); }

.content-shell { padding-block: clamp(34px, 7vw, 72px); }

.breadcrumbs {
  margin-bottom: 22px;
  color: #c2c8c4;
  font-size: .82rem;
}
.breadcrumbs ol { display: flex; flex-wrap: wrap; gap: 7px; margin: 0; padding: 0; list-style: none; }
.breadcrumbs a { color: var(--accent); }
.breadcrumbs li:not(:last-child)::after { content: "/"; margin-left: 7px; color: #89908b; }

.hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  padding: clamp(28px, 6vw, 58px);
  border: 1px solid var(--line);
  border-radius: 30px;
  background: var(--surface);
  box-shadow: 0 28px 80px rgb(0 0 0 / 28%);
}
.hero::before {
  content: "";
  position: absolute;
  z-index: -1;
  top: -42%;
  right: -12%;
  width: clamp(220px, 38vw, 430px);
  aspect-ratio: 1;
  border-radius: 38% 62% 65% 35% / 45% 35% 65% 55%;
  background: linear-gradient(145deg, rgb(103 235 147 / 38%), rgb(103 235 147 / 6%));
  transform: rotate(-12deg);
}
.hero::after {
  content: "";
  position: absolute;
  left: clamp(28px, 6vw, 58px);
  bottom: 0;
  width: min(35%, 260px);
  height: 5px;
  border-radius: 5px 5px 0 0;
  background: linear-gradient(90deg, var(--accent), transparent);
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--accent-dark);
  font-size: .78rem;
  font-weight: 800;
  letter-spacing: .1em;
  text-transform: uppercase;
}

h1, h2, h3 { line-height: 1.18; }
h1 { max-width: 820px; margin: 0; font-size: clamp(2.25rem, 7vw, 4.7rem); letter-spacing: -.045em; }
h2 { margin: 0 0 16px; font-size: clamp(1.55rem, 4vw, 2.35rem); letter-spacing: -.025em; }
h3 { margin: 0 0 8px; font-size: 1.08rem; }

.hero__intro {
  max-width: 720px;
  margin: 20px 0 0;
  color: var(--muted);
  font-size: clamp(1rem, 2vw, 1.18rem);
}

.hero__actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; }
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 10px 17px;
  border: 1px solid var(--line);
  border-radius: 13px;
  background: white;
  color: var(--ink);
  font-weight: 750;
  text-decoration: none;
  transition: transform .2s ease, box-shadow .2s ease, border-color .2s ease, background-color .2s ease;
}
.button:hover { transform: translateY(-2px); border-color: var(--accent); box-shadow: 0 10px 24px rgb(22 143 78 / 16%); }
.button--primary { border-color: var(--accent); background: var(--accent); color: #101210; box-shadow: 0 10px 26px rgb(103 235 147 / 28%); }
.button--primary:hover { background: #4fda80; color: #101210; }

.reading-meta { display: flex; flex-wrap: wrap; gap: 14px; margin-top: 20px; color: #71717a; font-size: .82rem; }

.article-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 260px;
  gap: clamp(28px, 5vw, 58px);
  margin-top: 42px;
  align-items: start;
}

.article-content {
  min-width: 0;
  padding: clamp(24px, 5vw, 48px);
  border: 1px solid rgb(255 255 255 / 14%);
  border-radius: 28px;
  background: rgb(255 255 255 / 97%);
  box-shadow: 0 24px 64px rgb(0 0 0 / 24%);
}
.article-content section { scroll-margin-top: 90px; margin-bottom: 48px; }
.article-content p, .article-content li { color: #3f3f46; }
.article-content ul, .article-content ol { padding-left: 24px; }
.article-content li + li { margin-top: 8px; }
.directory-content { margin-top: 42px; }
.directory-content > section { scroll-margin-top: 90px; margin-bottom: 56px; }

.toc {
  position: sticky;
  top: 88px;
  padding: 20px;
  border: 1px solid rgb(103 235 147 / 40%);
  border-radius: 18px;
  background: rgb(255 255 255 / 96%);
  box-shadow: 0 18px 48px rgb(0 0 0 / 20%);
}
.toc p { margin: 0 0 10px; font-weight: 800; }
.toc ol { margin: 0; padding-left: 20px; }
.toc li + li { margin-top: 6px; }
.toc a { color: #52525b; font-size: .86rem; text-decoration: none; }
.toc a:hover { color: var(--accent-dark); }

.side-rail {
  position: sticky;
  top: 88px;
  display: grid;
  gap: 18px;
  max-height: calc(100vh - 108px);
  overflow-y: auto;
  scrollbar-width: thin;
}

.side-rail .toc { position: static; }

.promo-rail {
  padding: 18px;
  border: 1px solid rgb(103 235 147 / 40%);
  border-radius: 18px;
  background: rgb(255 255 255 / 96%);
  box-shadow: 0 18px 48px rgb(0 0 0 / 20%);
}

.promo-rail__title { margin: 0 0 13px; font-size: 1rem; letter-spacing: -.01em; }
.promo-rail__grid { display: grid; gap: 12px; }
.promo-rail .button { width: 100%; margin-top: 13px; padding-inline: 10px; font-size: .78rem; text-align: center; }

.promo-card {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--surface);
  transition: transform .2s ease, border-color .2s ease, box-shadow .2s ease;
}
.promo-card:hover { transform: translateY(-2px); border-color: var(--accent); box-shadow: 0 12px 26px rgb(22 143 78 / 14%); }
.promo-card__link { display: block; color: var(--ink); text-decoration: none; }
.promo-card__image { display: block; width: 100%; aspect-ratio: 2 / 1; object-fit: contain; background: #f4f4f5; }
.promo-card h3 { margin: 0; padding: 12px 13px 14px; font-size: .9rem; }

.step-grid, .trust-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.guide-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 16px;
}

.pathway-grid, .hub-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.pathway-card, .hub-card {
  display: flex;
  flex-direction: column;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 19px;
  background: linear-gradient(145deg, #fff, #f4faf6);
}
.pathway-card__icon { font-size: 1.7rem; line-height: 1; }
.pathway-card h3, .hub-card h3 { margin: 13px 0 7px; font-size: 1.06rem; }
.pathway-card p, .hub-card p { margin: 0 0 16px; font-size: .9rem; }
.pathway-card a, .hub-card a { margin-top: auto; color: var(--accent-dark); font-weight: 800; text-decoration: none; }

.section-heading { display: flex; align-items: end; justify-content: space-between; gap: 18px; margin-bottom: 18px; }
.section-heading h2 { margin: 0; }
.section-heading a { flex: none; color: var(--accent-dark); font-size: .88rem; font-weight: 800; }

.filter-links { display: flex; flex-wrap: wrap; gap: 9px; margin: 0 0 24px; }
.filter-links a { padding: 8px 12px; border: 1px solid var(--line); border-radius: 999px; color: #3f3f46; font-size: .8rem; font-weight: 750; text-decoration: none; background: white; }
.filter-links a:hover { border-color: var(--accent-dark); color: var(--accent-dark); }

.figure-gallery { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 18px; }
.figure-card { overflow: hidden; border: 1px solid var(--line); border-radius: 19px; background: white; }
.figure-card img { display: block; width: 100%; aspect-ratio: 16 / 9; object-fit: cover; background: #e7e9e8; }
.figure-card__body { padding: 18px; }
.figure-card__meta { display: flex; flex-wrap: wrap; gap: 7px; margin-bottom: 10px; }
.difficulty { padding: 5px 8px; border-radius: 999px; background: #e8f8ed; color: #166534; font-size: .7rem; font-weight: 800; text-transform: uppercase; letter-spacing: .04em; }
.difficulty--intermediate { background: #fff4d7; color: #854d0e; }
.figure-card h3 { margin: 0 0 7px; font-size: 1.08rem; }
.figure-card p { margin: 0 0 12px; font-size: .88rem; }
.figure-card a { color: var(--accent-dark); font-weight: 800; text-decoration: none; }
.figure-card__prerequisite { display: block; margin-bottom: 13px; color: #71717a; font-size: .76rem; }

.material-section + .material-section { padding-top: 14px; border-top: 1px solid var(--line); }
.material-section > p { max-width: 66ch; }
.promo-rail[data-promo-details="true"] { box-shadow: none; background: #f7faf8; }
.promo-rail[data-promo-details="true"] .promo-rail__grid { grid-template-columns: repeat(auto-fit, minmax(190px, 1fr)); }
.promo-rail[data-promo-details="true"] .promo-card__description { margin: -5px 13px 15px; color: #52525b; font-size: .8rem; }

.step, .guide-card, .trust-card {
  padding: 21px;
  border: 1px solid var(--line);
  border-radius: 19px;
  background: linear-gradient(145deg, var(--surface) 70%, var(--accent-soft));
  box-shadow: 0 12px 32px rgb(24 24 27 / 7%);
  transition: transform .22s ease, border-color .22s ease, box-shadow .22s ease;
}
.step:hover, .guide-card:hover, .trust-card:hover {
  transform: translateY(-3px);
  border-color: rgb(103 235 147 / 75%);
  box-shadow: 0 18px 38px rgb(22 143 78 / 14%);
}
.step__number {
  width: 32px;
  height: 32px;
  display: grid;
  place-items: center;
  margin-bottom: 15px;
  border-radius: 10px;
  background: var(--accent-soft);
  color: var(--accent-dark);
  font-weight: 850;
}
.step p, .guide-card p, .trust-card p { margin: 6px 0 0; color: var(--muted); font-size: .91rem; }

.guide-card { display: flex; flex-direction: column; }
.guide-card__tag { color: var(--accent-dark); font-size: .72rem; font-weight: 800; text-transform: uppercase; }
.guide-card a { margin-top: auto; padding-top: 18px; color: var(--accent-dark); font-weight: 750; }

.callout {
  margin: 24px 0;
  padding: 20px 22px;
  border-left: 4px solid var(--accent);
  border-radius: 12px;
  background: var(--accent-soft);
}
.callout strong { display: block; margin-bottom: 4px; }
.callout p { margin: 0; }

.video-card {
  margin: 26px 0 10px;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: var(--surface);
  box-shadow: 0 22px 50px rgb(24 24 27 / 14%);
}

.youtube-player {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: #18181b;
}

.youtube-player iframe,
.video-poster,
.video-poster img {
  width: 100%;
  height: 100%;
}

.youtube-player iframe { display: block; border: 0; }

.video-poster {
  position: relative;
  display: block;
  padding: 0;
  border: 0;
  background: #18181b;
  cursor: pointer;
}

.video-poster img {
  display: block;
  object-fit: cover;
  transition: transform .28s ease, opacity .28s ease;
}

.video-poster::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, transparent 45%, rgb(0 0 0 / 38%));
}

.video-poster:hover img { transform: scale(1.015); opacity: .92; }

.video-play {
  position: absolute;
  left: 50%;
  top: 50%;
  z-index: 2;
  width: 72px;
  height: 52px;
  display: grid;
  place-items: center;
  transform: translate(-50%, -50%);
  border-radius: 16px;
  background: var(--accent);
  color: #101210;
  box-shadow: 0 12px 30px rgb(103 235 147 / 38%);
  font-size: 1.35rem;
  transition: transform .2s ease, background-color .2s ease;
}

.video-poster:hover .video-play { transform: translate(-50%, -50%) scale(1.06); background: #4fda80; }
.video-poster:focus-visible { outline: 4px solid var(--accent); outline-offset: -4px; }

.video-card figcaption {
  padding: 15px 18px 17px;
  color: var(--muted);
  font-size: .86rem;
}
.video-card figcaption strong { color: var(--ink); }
.video-card figcaption a { margin-left: 4px; font-weight: 700; }

.video-privacy {
  display: block;
  margin-top: 5px;
  color: #71717a;
  font-size: .74rem;
}

.practice-plan { width: 100%; border-collapse: collapse; overflow: hidden; border-radius: 14px; }
.practice-plan th, .practice-plan td { padding: 12px 14px; border: 1px solid var(--line); text-align: left; }
.practice-plan th { background: #fafafa; }

.author-box {
  display: flex;
  gap: 18px;
  align-items: flex-start;
  margin-top: 52px;
  padding: 24px;
  border-radius: 20px;
  border: 1px solid rgb(103 235 147 / 22%);
  background: linear-gradient(135deg, #171a18, #303531);
  color: white;
  box-shadow: 0 20px 44px rgb(0 0 0 / 22%);
}
.author-box__mark { flex: 0 0 auto; width: 52px; height: 52px; display: grid; place-items: center; border-radius: 16px; background: linear-gradient(135deg, #67eb93, #39c873); color: #101210; box-shadow: 0 10px 28px rgb(103 235 147 / 24%); font-size: 1.4rem; font-weight: 850; }
.author-box h2 { margin: 0 0 5px; font-size: 1.15rem; }
.author-box p { margin: 0; color: #d4d4d8; font-size: .9rem; }

.site-footer { border-top: 1px solid rgb(255 255 255 / 9%); background: #161817; }
.site-footer__inner { display: flex; justify-content: space-between; gap: 20px; padding-block: 25px; color: #aeb5b0; font-size: .82rem; }
.site-footer nav { display: flex; flex-wrap: wrap; gap: 14px; }
.site-footer a { color: #d5dad7; }
.site-footer a:hover { color: var(--accent); }

@media (max-width: 820px) {
  .article-layout { grid-template-columns: 1fr; }
  .side-rail { position: static; order: -1; max-height: none; overflow: visible; }
  .toc { position: static; }
  .step-grid, .guide-grid, .trust-grid, .pathway-grid, .hub-grid { grid-template-columns: 1fr; }
  .promo-rail__grid { grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); }
}

@media (max-width: 640px) {
  .site-header__inner { min-height: 58px; }
  .site-nav { display: none; }
  .mobile-nav { display: block; }
  .content-shell { width: min(100% - 22px, 1040px); padding-top: 24px; }
  .hero { padding: 25px 20px; border-radius: 22px; }
  .hero::after { left: 20px; }
  .article-content { padding: 24px 19px; border-radius: 22px; }
  h1 { font-size: clamp(2rem, 12vw, 3.1rem); }
  .site-footer__inner { flex-direction: column; }
  .practice-plan { font-size: .85rem; }
  .practice-plan th, .practice-plan td { padding: 9px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .video-poster img, .video-play, .button, .step, .guide-card, .trust-card, .promo-card { transition: none; }
}