:root{
  --bg:#eef1ef;
  --surface:#ffffff;
  --surface-alt:#f7f7f4;
  --text:#23312c;
  --muted:#5d6d67;
  --accent:#8f2a6b;
  --accent-dark:#6f1f53;
  --accent-soft:#f3e4ec;
  --green:#2f6c53;
  --border:#d7dfda;
  --shadow:0 12px 28px rgba(24,37,31,.09);
  --radius:22px;
  --nav-height:82px;
  --max:1180px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  font-family:Inter, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background:
    radial-gradient(circle at top right, rgba(143,42,107,.08), transparent 28%),
    linear-gradient(180deg,#f7f8f7 0%, #edf1ef 100%);
  color:var(--text);
  opacity:0;
  transform:translateY(10px);
  transition:opacity .35s ease, transform .35s ease;
}
body.loaded{opacity:1;transform:none}
a{color:inherit}
.topbar{
  position:sticky;
  top:0;
  z-index:40;
  backdrop-filter:blur(14px);
  background:rgba(247,248,247,.84);
  border-bottom:1px solid rgba(215,223,218,.8);
}
.topbar-inner{
  max-width:var(--max);
  margin:0 auto;
  padding:14px 24px;
  display:grid;
  grid-template-columns:auto 1fr auto;
  gap:18px;
  align-items:center;
}
.brand{
  display:flex;
  gap:14px;
  align-items:center;
  min-width:0;
}
.brand-mark{
  width:46px;
  height:46px;
  border-radius:16px;
  display:grid;
  place-items:center;
  background:linear-gradient(135deg,var(--accent), var(--green));
  color:#fff;
  font-weight:800;
  box-shadow:var(--shadow);
}
.brand-copy{min-width:0}
.brand-copy strong{
  display:block;
  font-size:0.98rem;
  line-height:1.1;
}
.brand-copy span{
  display:block;
  font-size:.83rem;
  color:var(--muted);
}
.progress-wrap{
  min-width:0;
}
.progress-meta{
  display:flex;
  justify-content:space-between;
  gap:12px;
  font-size:.83rem;
  color:var(--muted);
  margin-bottom:6px;
}
.progress{
  height:10px;
  border-radius:999px;
  background:#dde5e0;
  overflow:hidden;
}
.progress-bar{
  height:100%;
  width:0;
  background:linear-gradient(90deg,var(--accent), var(--green));
  border-radius:999px;
  transition:width .35s ease;
}
.menu-toggle{
  border:1px solid var(--border);
  background:#fff;
  color:var(--text);
  border-radius:999px;
  padding:11px 16px;
  font-weight:600;
  cursor:pointer;
}
.menu{
  max-width:var(--max);
  margin:0 auto;
  padding:0 24px 12px;
}
.menu details{
  background:#fff;
  border:1px solid var(--border);
  border-radius:18px;
  box-shadow:var(--shadow);
  overflow:hidden;
}
.menu summary{
  cursor:pointer;
  list-style:none;
  padding:14px 18px;
  font-weight:700;
}
.menu summary::-webkit-details-marker{display:none}
.menu-grid{
  padding:0 12px 14px;
  display:grid;
  grid-template-columns:repeat(auto-fit, minmax(220px, 1fr));
  gap:10px;
}
.menu-link{
  display:block;
  text-decoration:none;
  background:var(--surface-alt);
  border:1px solid var(--border);
  border-radius:16px;
  padding:12px 14px;
  font-size:.95rem;
  line-height:1.35;
}
.menu-link.active{
  background:var(--accent-soft);
  border-color:rgba(143,42,107,.28);
}
.shell{
  max-width:var(--max);
  margin:0 auto;
  padding:28px 24px 120px;
}
.hero{
  display:grid;
  grid-template-columns:1.15fr .85fr;
  gap:26px;
  align-items:stretch;
}
.hero-copy, .hero-visual{
  background:var(--surface);
  border-radius:var(--radius);
  box-shadow:var(--shadow);
  border:1px solid rgba(215,223,218,.7);
}
.hero-copy{
  padding:34px;
}
.eyebrow{
  display:inline-flex;
  align-items:center;
  gap:10px;
  padding:8px 14px;
  border-radius:999px;
  background:var(--accent-soft);
  color:var(--accent-dark);
  font-size:.85rem;
  font-weight:700;
  margin-bottom:16px;
}
h1{
  margin:0 0 12px;
  font-size:clamp(2rem, 4vw, 3.4rem);
  line-height:.98;
  letter-spacing:-.03em;
}
.lead{
  font-size:1.1rem;
  line-height:1.65;
  color:#31423c;
}
.hero-visual{
  padding:18px;
  display:flex;
  align-items:center;
  justify-content:center;
  min-height:380px;
}
.hero-visual img{
  width:100%;
  height:100%;
  object-fit:cover;
  border-radius:18px;
  border:1px solid rgba(215,223,218,.8);
  background:#e3e9e5;
}
.grid{
  margin-top:26px;
  display:grid;
  gap:20px;
}
.panel{
  background:var(--surface);
  border:1px solid rgba(215,223,218,.75);
  border-radius:var(--radius);
  box-shadow:var(--shadow);
  padding:28px;
}
.panel-grid{
  display:grid;
  grid-template-columns:1.2fr .8fr;
  gap:22px;
  align-items:start;
}
.panel h2{
  margin:0 0 14px;
  font-size:1.5rem;
  line-height:1.15;
}
.panel h3{
  margin:0 0 10px;
  font-size:1.08rem;
}
.panel p{
  margin:0 0 14px;
  line-height:1.72;
  color:#31413c;
}
.panel p:last-child{margin-bottom:0}
.tick-list,.number-list{
  margin:0;
  padding-left:1.3rem;
  line-height:1.7;
}
.tick-list li,.number-list li{margin-bottom:10px}
.feature-stack{
  display:grid;
  gap:14px;
}
.feature-item, .compare-card, .recap-card, .highlight-card{
  background:var(--surface-alt);
  border:1px solid var(--border);
  border-radius:18px;
  padding:18px;
}
.callout{
  background:linear-gradient(180deg, #fbf4f8, #f4f7f5);
  border:1px solid rgba(143,42,107,.15);
  border-radius:20px;
  padding:20px;
}
.callout p:last-child{margin-bottom:0}
.mini-equation{
  display:flex;
  flex-wrap:wrap;
  gap:10px;
  align-items:center;
  margin-top:16px;
}
.mini-equation span{
  background:var(--surface-alt);
  border:1px solid var(--border);
  border-radius:999px;
  padding:8px 12px;
  font-weight:600;
  font-size:.95rem;
}
.compare-grid, .recap-grid{
  display:grid;
  grid-template-columns:repeat(auto-fit, minmax(220px, 1fr));
  gap:14px;
}
.recap-card h3,
.compare-card h3,
.highlight-card h3{margin-bottom:8px}
.muted{color:var(--muted)}
.takeaway{
  border-left:6px solid var(--green);
  background:#f2f7f4;
}
.knowledge{
  background:linear-gradient(180deg,#fff,#faf7fa);
}
.knowledge button{
  margin-top:10px;
}
.answer{
  margin-top:12px;
  padding:14px 16px;
  border-radius:16px;
  background:var(--accent-soft);
  border:1px solid rgba(143,42,107,.2);
}
.answer[hidden]{display:none !important}
.image-note img{
  width:100%;
  border-radius:18px;
  border:1px solid var(--border);
}
.footer-nav{
  position:fixed;
  left:0;
  right:0;
  bottom:0;
  z-index:45;
  padding:14px 18px 18px;
  background:linear-gradient(180deg, rgba(237,241,239,0), rgba(237,241,239,.95) 36%, rgba(237,241,239,1) 100%);
}
.footer-inner{
  max-width:var(--max);
  margin:0 auto;
  display:flex;
  justify-content:space-between;
  gap:14px;
}
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:10px;
  min-width:160px;
  padding:14px 18px;
  border-radius:999px;
  text-decoration:none;
  font-weight:700;
  border:1px solid var(--border);
  background:#fff;
  box-shadow:var(--shadow);
}
.btn:hover{transform:translateY(-1px)}
.btn-primary{
  background:linear-gradient(135deg,var(--accent), var(--green));
  color:#fff;
  border:none;
}
.btn[aria-disabled="true"], .btn.is-disabled{
  opacity:.45;
  pointer-events:none;
}
.btn-inline{
  margin-top:8px;
  min-width:0;
}
.module-footer{
  margin-top:8px;
  text-align:center;
  color:var(--muted);
  font-size:.9rem;
}
@media (max-width: 980px){
  .hero, .panel-grid{
    grid-template-columns:1fr;
  }
  .hero-visual{min-height:280px}
}
@media (max-width: 720px){
  .topbar-inner{
    grid-template-columns:1fr;
  }
  .footer-inner{
    flex-direction:column;
  }
  .btn{width:100%}
  .shell{padding:22px 16px 132px}
  .hero-copy,.panel{padding:22px}
  .menu{padding:0 16px 12px}
}