:root {
  /* default to dark, JS can override to light */
  --bg: #0b0f16;
  --text: #e8eefc;
  --muted: #a9b6d3;
  --line: rgba(255,255,255,0.08);

  --panelTop: rgba(255,255,255,0.04);
  --panelBottom: rgba(255,255,255,0.02);
  --boxBg: rgba(255,255,255,0.03);

  --accentBg: rgba(122,162,255,0.14);
  --accentBorder: rgba(122,162,255,0.35);

  --shadow: 0 10px 30px rgba(0,0,0,0.35);
  --radius: 16px;
}

/* Light theme overrides when html has data-theme="light" */
html[data-theme="light"] {
  --bg: #f6f7fb;
  --text: #0b1220;
  --muted: #44506a;
  --line: rgba(10,15,25,0.10);

  --panelTop: rgba(10,15,25,0.04);
  --panelBottom: rgba(10,15,25,0.02);
  --boxBg: rgba(10,15,25,0.03);

  --accentBg: rgba(66, 102, 245, 0.12);
  --accentBorder: rgba(66, 102, 245, 0.35);

  --shadow: 0 10px 30px rgba(10,15,25,0.12);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial;
  background:
    radial-gradient(1200px 600px at 20% 0%, rgba(122,162,255,0.18), transparent 55%),
    radial-gradient(900px 500px at 80% 10%, rgba(110,231,183,0.10), transparent 55%),
    var(--bg);
  color: var(--text);
}

html[data-theme="light"] body {
  background:
    radial-gradient(1200px 600px at 20% 0%, rgba(66,102,245,0.10), transparent 55%),
    radial-gradient(900px 500px at 80% 10%, rgba(16,185,129,0.08), transparent 55%),
    var(--bg);
}

.page { max-width: 980px; margin: 0 auto; padding: 28px 18px 42px; }
h1 { margin: 0; font-size: 36px; }
.subtitle { margin: 6px 0 0; color: var(--muted); }

.pillRow { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 14px; }
.pill {
  border: 1px solid var(--line);
  background: rgba(255,255,255,0.03);
  color: var(--muted);
  padding: 8px 10px;
  border-radius: 999px;
  font-size: 13px;
}

.cards {
  display: grid;
  grid-template-columns: repeat(2, 1fr); /* 2 cards side by side */
  gap: 16px;
  margin: 16px 0 24px;
}

@media (max-width: 900px) {
  .cards {
    grid-template-columns: 1fr; /* stack on mobile */
  }
}

.card {
  background: linear-gradient(180deg, var(--panelTop), var(--panelBottom));
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 14px;
}

.card h2 { margin: 0 0 10px; font-size: 16px; }
.card ul { margin: 0; padding-left: 18px; color: var(--muted); }
.card li { margin: 6px 0; }

.btnRow { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 8px; }
.btn {
  text-decoration: none;
  color: var(--text);
  background: var(--accentBg);
  border: 1px solid var(--accentBorder);
  padding: 10px 12px;
  border-radius: 12px;
  font-weight: 700;
  font-size: 14px;
}
.btn:hover { background: rgba(122,162,255,0.20); }

.sectionTitle { margin: 0; font-size: 18px; }
.sectionHint { margin: 8px 0 12px; color: var(--muted); font-size: 13.5px; }

.accordion { display: grid; gap: 10px; margin-top: 10px; }

.accItem {
  width: 100%;
  text-align: left;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: linear-gradient(180deg, var(--panelTop), var(--panelBottom));
  box-shadow: var(--shadow);
  color: var(--text);
  overflow: hidden;
}

/* CLEAN ONE-LINE HEADER */
.accTop{
  width:100%;
  display:flex;
  align-items:center;
  justify-content:space-between;

  padding:16px 18px;
  cursor:pointer;
  user-select:none;
}

.accTitle{
  font-size:15px;
  font-weight:900;
  letter-spacing:0.3px;
  white-space:nowrap;
}

.accActions{
  display:flex;
  align-items:center;
  gap:10px;
  flex-shrink:0;
}

/* How button: small, subtle */
.howBtn{
  border:1px solid var(--line);
  background: transparent;
  color: var(--muted);
  padding:6px 10px;
  border-radius:999px;
  font-weight:700;
  font-size:12px;
  cursor:pointer;
  line-height:1;
}
.howBtn:hover{
  color: var(--text);
  border-color: var(--accentBorder);
}
.accItem.howOpen .howBtn{
  border-color: var(--accentBorder);
}

/* + / – icon */
.accIcon{
  width:32px;
  height:32px;
  display:grid;
  place-items:center;
  border-radius:10px;

  background: rgba(255,255,255,0.06);
  border:1px solid var(--line);

  font-size:18px;
  font-weight:900;
  color: var(--muted);
}

.accBody { padding: 0 14px 14px; border-top: 1px solid var(--line); }
.labTitle { margin: 12px 0 10px; font-size: 16px; }

.grid2 { display: grid; gap: 10px; grid-template-columns: 1fr 1fr; }
@media (max-width: 900px){ .grid2 { grid-template-columns: 1fr; } }

.box {
  background: var(--boxBg);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 12px;
  margin-top: 10px;
}

.box h4 {
  margin: 0 0 8px;
  font-size: 13px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.3px;
}
.box p, .box li { color: var(--muted); line-height: 1.5; }
.box ol, .box ul { margin: 0; padding-left: 18px; }

.footer {
  margin-top: 18px;
  color: var(--muted);
  font-size: 13px;
  text-align: center;
  border-top: 1px solid var(--line);
  padding-top: 14px;
}

.titleRow{
  display:flex;
  align-items:flex-start;
  justify-content:space-between;
  gap:12px;
}

.iconBtn{
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding:10px 12px;
  border-radius:12px;
  border:1px solid var(--line);
  background: linear-gradient(180deg, var(--panelTop), var(--panelBottom));
  color: var(--text);
  box-shadow: var(--shadow);
  cursor:pointer;
  font-weight:800;
  font-size:13px;
}
.iconBtn:hover{
  transform: translateY(-1px);
}
#themeIcon{
  font-size:16px;
}

/* Side-by-side layout when HOW is open */
.labSplit{
  display:grid;
  grid-template-columns: 1fr;
  gap:12px;
}
.accItem.howOpen .labSplit{
  grid-template-columns: 1fr 0.95fr;
}
@media (max-width: 900px){
  .accItem.howOpen .labSplit{
    grid-template-columns: 1fr;
  }
  .accItem.howOpen .labHow{
    order: 2;
  }
}