:root{
  --bg:#0b1020;
  --bg2:#0d1630;
  --card:#111a33;
  --text:#e8eefc;
  --muted:#b8c3e1;
  --border:rgba(255,255,255,.10);
  --brand:#6ee7ff;
  --brand2:#a78bfa;
  --btn:#16234a;
  --shadow: 0 18px 45px rgba(0,0,0,.35);
  --radius: 16px;
}
*{ box-sizing:border-box; }
html,body{ height:100%; }
body{
  margin:0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
  background: radial-gradient(1200px 900px at 20% -10%, rgba(110,231,255,.25), transparent 55%),
              radial-gradient(900px 700px at 85% 0%, rgba(167,139,250,.25), transparent 55%),
              linear-gradient(180deg, var(--bg), var(--bg2));
  color: var(--text);
  line-height: 1.55;
}
.container{ max-width: 1100px; margin: 0 auto; padding: 0 22px; }

.site-header{
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(14px);
  background: rgba(11,16,32,.55);
  border-bottom: 1px solid var(--border);
}
.header-inner{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap: 14px;
  padding: 14px 0;
}
.brand{ display:flex; align-items:center; gap: 12px; text-decoration:none; color: var(--text); }
.brand-logo{ width: 34px; height: 34px; }
.brand-text{ display:flex; flex-direction:column; }
.brand-name{ font-weight: 700; letter-spacing: .2px; }
.brand-tag{ font-size: 12px; color: var(--muted); }

.nav{ display:flex; align-items:center; gap: 16px; flex-wrap: wrap; }
.nav a{
  color: var(--muted);
  text-decoration:none;
  font-size: 14px;
}
.nav a:hover{ color: var(--text); }

.hero{ padding: 56px 0 30px; }
.hero-grid{ display:grid; grid-template-columns: 1.1fr .9fr; gap: 26px; align-items:center; }
.hero-copy h1{ margin:0 0 10px; font-size: 42px; line-height: 1.1; letter-spacing: -0.5px; }
.hero-copy p{ margin: 0 0 18px; color: var(--muted); font-size: 16px; }

.hero-art{
  background: linear-gradient(180deg, rgba(17,26,51,.7), rgba(17,26,51,.35));
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 18px;
  text-align:center;
}
.hero-art img{ width: 100%; height:auto; display:block; }
.hero-caption{ margin-top: 10px; font-size: 12px; color: var(--muted); }

.section{ padding: 34px 0; }
.section h2{ margin: 0 0 10px; font-size: 26px; }
.section p{ margin: 0 0 16px; color: var(--muted); }

.grid-2{ display:grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.grid-3{ display:grid; grid-template-columns: 1fr 1fr 1fr; gap: 16px; }

.card{
  background: linear-gradient(180deg, rgba(17,26,51,.82), rgba(17,26,51,.52));
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
  box-shadow: var(--shadow);
}
.card h3{ margin: 0 0 8px; font-size: 16px; }
.card p{ margin: 0 0 12px; }
.link-card{ text-decoration:none; color: var(--text); }
.link-card:hover{ border-color: rgba(110,231,255,.35); }

.muted{ color: var(--muted); }

pre{
  margin: 0;
  overflow:auto;
  padding: 14px;
  border-radius: 12px;
  background: rgba(0,0,0,.28);
  border: 1px solid rgba(255,255,255,.08);
}
code{ font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace; font-size: 13px; }

ul{ margin: 10px 0 0 18px; color: var(--muted); }
li{ margin: 7px 0; }

/* Tool navigation tabs (colored pills) */
.tool-tabs{
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-top: 14px;
}
.tool-tab{
  --accent: var(--brand);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 8px 12px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: rgba(22,35,74,.55);
  color: var(--muted);
  text-decoration: none;
  font-weight: 650;
  font-size: 13px;
  line-height: 1;
  transition: border-color .15s ease, background .15s ease, color .15s ease, transform .15s ease;
}
.tool-tab:hover{
  color: var(--text);
  border-color: var(--accent);
  transform: translateY(-1px);
}
.tool-tab.is-active{
  color: var(--text);
  border-color: var(--accent);
  background: linear-gradient(135deg, rgba(255,255,255,.10), rgba(22,35,74,.55));
}

/* Per-tool accent colors */
.tool-tab[data-tool="molprop-calc-v4"]{ --accent:#38bdf8; }
.tool-tab[data-tool="molprop-calc-v5"]{ --accent:#22c55e; }
.tool-tab[data-tool="ligand-prep"]{ --accent:#a78bfa; }
.tool-tab[data-tool="molprop-analyze"]{ --accent:#fbbf24; }
.tool-tab[data-tool="molprop-report"]{ --accent:#fb7185; }
.tool-tab[data-tool="molprop-sketch"]{ --accent:#60a5fa; }
.tool-tab[data-tool="molprop-series"]{ --accent:#2dd4bf; }
.tool-tab[data-tool="molprop-picklists"]{ --accent:#f97316; }
.tool-tab[data-tool="molprop-similarity"]{ --accent:#ef4444; }
.tool-tab[data-tool="molprop-featurize"]{ --accent:#84cc16; }
.tool-tab[data-tool="molprop-retro"]{ --accent:#c084fc; }
.tool-tab[data-tool="validate-schema"]{ --accent:#94a3b8; }

/* Simple CSS-only tabs (radio-button tabs) */
.tabs{
  margin-top: 12px;
}
.tabs input[type="radio"]{
  position: absolute;
  opacity: 0;
  pointer-events: none;
}
.tab-labels{
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin: 0 0 12px;
}
.tab-labels label{
  cursor: pointer;
  user-select: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 8px 12px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: rgba(22,35,74,.55);
  color: var(--muted);
  font-weight: 650;
  font-size: 13px;
}
.tab-labels label:hover{
  color: var(--text);
  border-color: rgba(110,231,255,.35);
}
.tab-panels .tab-panel{ display:none; }
.tab-panel .card{ margin-top: 0; }

/* Active label */
#prep-standard:checked ~ .tab-labels label[for="prep-standard"],
#prep-audit:checked ~ .tab-labels label[for="prep-audit"],
#prep-3d:checked ~ .tab-labels label[for="prep-3d"],
#prep-minimal:checked ~ .tab-labels label[for="prep-minimal"]{
  color: var(--text);
  border-color: rgba(110,231,255,.35);
  background: linear-gradient(135deg, rgba(110,231,255,.16), rgba(167,139,250,.12));
}

/* Active panel */
#prep-standard:checked ~ .tab-panels .tab-standard,
#prep-audit:checked ~ .tab-panels .tab-audit,
#prep-3d:checked ~ .tab-panels .tab-3d,
#prep-minimal:checked ~ .tab-panels .tab-minimal{ display:block; }

.cta-row{ display:flex; gap: 12px; flex-wrap: wrap; align-items:center; margin: 14px 0 0; }
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  padding: 10px 14px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: rgba(22,35,74,.8);
  color: var(--text);
  text-decoration:none;
  font-weight: 600;
  font-size: 14px;
}
.btn:hover{ border-color: rgba(110,231,255,.35); }
.btn.primary{
  background: linear-gradient(135deg, rgba(110,231,255,.22), rgba(167,139,250,.18));
  border-color: rgba(110,231,255,.35);
}

.meta-row{ display:flex; gap: 10px; flex-wrap: wrap; margin-top: 12px; }
.pill{
  display:inline-flex;
  padding: 6px 10px;
  border-radius: 999px;
  border: 1px solid rgba(255,255,255,.10);
  background: rgba(0,0,0,.18);
  color: var(--muted);
  text-decoration:none;
  font-size: 13px;
}
.pill:hover{ color: var(--text); border-color: rgba(255,255,255,.18); }

.site-footer{
  border-top: 1px solid var(--border);
  padding: 22px 0;
  margin-top: 26px;
  background: rgba(11,16,32,.55);
}
.footer-inner{ display:flex; justify-content:space-between; gap: 16px; align-items:flex-start; flex-wrap: wrap; }
.footer-title{ font-weight: 800; margin-bottom: 4px; }
.footer-links{ display:flex; gap: 14px; flex-wrap: wrap; }
.footer-links a{ color: var(--muted); text-decoration:none; }
.footer-links a:hover{ color: var(--text); }

@media (max-width: 940px){
  .hero-grid{ grid-template-columns: 1fr; }
  .grid-3{ grid-template-columns: 1fr; }
  .grid-2{ grid-template-columns: 1fr; }
  .hero-copy h1{ font-size: 34px; }
}