/* =================================================================== *
 * Curie — site stylesheet
 *
 * Palette: Marie Curie's lab — slate background, phosphorescent green
 * accent (the iconic radium glow), warm copper secondary.
 *
 * Structure:
 *   1. Reset + tokens
 *   2. Typography
 *   3. Layout (nav, container, footer)
 *   4. Hero + atom animation
 *   5. Periodic-cell feature grid
 *   6. Code blocks + terminal
 *   7. Docs
 *   8. Responsive
 * =================================================================== */

/* ---------- 1. Reset + tokens ---------- */

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  /* palette */
  --bg:          #0a0e14;
  --bg-elev-1:  #11161f;
  --bg-elev-2:  #161c27;
  --border:      rgba(167, 200, 220, 0.08);
  --border-warm: rgba(212, 144, 90, 0.18);

  --text-hi:    #e8edf2;
  --text-mid:   #aab3bf;
  --text-lo:    #6a7280;

  --accent:      #7df3a5;
  --accent-dim:  #4ec97a;
  --accent-glow: rgba(125, 243, 165, 0.18);
  --copper:      #d4905a;
  --copper-dim:  #a06b3f;

  --radius-sm: 4px;
  --radius:    10px;
  --radius-lg: 18px;

  --gap:        clamp(1rem, 2vw, 1.5rem);
  --gap-lg:     clamp(2rem, 5vw, 4rem);
  --container:  72rem;

  --shadow-soft: 0 1px 0 rgba(255,255,255,0.03) inset,
                 0 10px 32px -16px rgba(0,0,0,0.6);
  --shadow-glow: 0 0 0 1px rgba(125, 243, 165, 0.25),
                 0 0 32px -8px rgba(125, 243, 165, 0.35);
}

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text-hi);
  font-family: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  font-feature-settings: 'ss01', 'cv11';
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;

  /* graph-paper background — faint blue-print grid */
  background-image:
    linear-gradient(rgba(125, 243, 165, 0.025) 1px, transparent 1px),
    linear-gradient(90deg, rgba(125, 243, 165, 0.025) 1px, transparent 1px),
    radial-gradient(ellipse 80% 50% at 50% 0%, rgba(125, 243, 165, 0.05), transparent 60%);
  background-size: 48px 48px, 48px 48px, 100% 100%;
  background-attachment: fixed;
}

::selection { background: var(--accent); color: var(--bg); }

/* ---------- 2. Typography ---------- */

h1, h2, h3, h4 {
  font-family: 'Fraunces', 'Source Serif Pro', Georgia, serif;
  font-weight: 500;
  letter-spacing: -0.02em;
  line-height: 1.15;
  color: var(--text-hi);
}

h1 { font-size: clamp(2.5rem, 6vw, 4.5rem); font-weight: 400; }
h2 { font-size: clamp(1.75rem, 3.5vw, 2.5rem); }
h3 { font-size: 1.25rem; }
h4 { font-size: 1rem; letter-spacing: 0.06em; text-transform: uppercase; color: var(--text-mid); font-family: 'Inter', sans-serif; font-weight: 600; }

p { color: var(--text-mid); }
p + p { margin-top: 1rem; }

a { color: var(--accent); text-decoration: none; transition: color 120ms; }
a:hover { color: #b6f7c8; }

code, kbd, samp {
  font-family: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.92em;
}

p code, li code {
  background: var(--bg-elev-2);
  padding: 0.05em 0.4em;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  color: var(--text-hi);
  font-size: 0.88em;
}

.eyebrow {
  display: inline-block;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent-dim);
  padding: 0.3em 0.8em;
  border: 1px solid var(--border);
  border-radius: 100px;
  background: rgba(125, 243, 165, 0.04);
}

.lede {
  font-size: clamp(1.1rem, 1.6vw, 1.35rem);
  color: var(--text-mid);
  max-width: 38em;
  line-height: 1.55;
}

/* ---------- 3. Layout ---------- */

.container {
  width: min(var(--container), 100% - 2.5rem);
  margin-inline: auto;
}

nav.site {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(14px);
  background: rgba(10, 14, 20, 0.72);
  border-bottom: 1px solid var(--border);
}

nav.site .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  padding: 0.9rem 0;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  color: var(--text-hi);
  font-family: 'Fraunces', serif;
  font-size: 1.15rem;
  letter-spacing: -0.01em;
}
.brand-mark {
  width: 32px;
  height: 32px;
  display: grid;
  place-items: center;
  background: var(--bg-elev-2);
  border: 1px solid var(--accent);
  border-radius: var(--radius-sm);
  font-family: 'Fraunces', serif;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent);
  position: relative;
}
.brand-mark::after {
  content: '96';
  position: absolute;
  top: 2px; left: 3px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.45rem;
  color: var(--text-lo);
  font-weight: 400;
}

nav.site ul {
  list-style: none;
  display: flex;
  gap: 1.5rem;
  align-items: center;
}
nav.site ul a {
  color: var(--text-mid);
  font-size: 0.9rem;
}
nav.site ul a:hover, nav.site ul a.active { color: var(--text-hi); }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.65rem 1.1rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  font-size: 0.92rem;
  font-weight: 500;
  font-family: 'Inter', sans-serif;
  letter-spacing: 0.01em;
  transition: all 160ms;
  cursor: pointer;
}
.btn-primary {
  background: var(--accent);
  color: #03100a;
  border-color: var(--accent);
}
.btn-primary:hover {
  background: #b6f7c8;
  color: #03100a;
  box-shadow: var(--shadow-glow);
}
.btn-ghost {
  background: transparent;
  color: var(--text-hi);
}
.btn-ghost:hover {
  background: var(--bg-elev-2);
  border-color: var(--accent-dim);
  color: var(--text-hi);
}

footer.site {
  margin-top: var(--gap-lg);
  padding: 3rem 0 2.5rem;
  border-top: 1px solid var(--border);
  color: var(--text-lo);
  font-size: 0.88rem;
}
footer.site .container {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  justify-content: space-between;
  align-items: center;
}
footer.site a { color: var(--text-mid); }
footer.site a:hover { color: var(--accent); }

section { padding: var(--gap-lg) 0; }

/* ---------- 4. Hero + atom animation ---------- */

.hero {
  position: relative;
  padding: clamp(3rem, 8vw, 6rem) 0 var(--gap-lg);
  overflow: hidden;
}
.hero .container {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: var(--gap-lg);
  align-items: center;
}

.hero h1 {
  margin: 1.25rem 0 1.5rem;
}
.hero h1 .glow { color: var(--accent); }
.hero .lede { margin-bottom: 2rem; }
.hero-ctas { display: flex; flex-wrap: wrap; gap: 0.75rem; }

.hero-stats {
  margin-top: 2.5rem;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}
.hero-stat {
  border-left: 2px solid var(--accent);
  padding-left: 0.9rem;
}
.hero-stat .num {
  font-family: 'Fraunces', serif;
  font-size: 1.5rem;
  color: var(--text-hi);
  display: block;
  line-height: 1;
}
.hero-stat .label {
  font-size: 0.8rem;
  color: var(--text-lo);
  margin-top: 0.35rem;
  font-family: 'JetBrains Mono', monospace;
  letter-spacing: 0.05em;
}

/* atom — orbits + electrons */
.atom-wrap {
  position: relative;
  width: 100%;
  aspect-ratio: 1;
  max-width: 460px;
  margin-inline: auto;
}
.atom {
  width: 100%;
  height: 100%;
  filter: drop-shadow(0 0 60px rgba(125, 243, 165, 0.12));
}
.atom .orbit {
  fill: none;
  stroke: rgba(125, 243, 165, 0.22);
  stroke-width: 1.2;
}
.atom .nucleus {
  fill: var(--accent);
  filter: drop-shadow(0 0 14px var(--accent));
}
.atom .electron {
  fill: var(--accent);
  filter: drop-shadow(0 0 8px var(--accent));
}
.atom .electron-group {
  transform-origin: 200px 200px;
  transform-box: view-box;
}
.atom .e1 { animation: orbit  9s linear infinite; }
.atom .e2 { animation: orbit 13s linear infinite reverse; }
.atom .e3 { animation: orbit 17s linear infinite; }

@keyframes orbit {
  from { transform: rotate(0deg); }
  to   { transform: rotate(360deg); }
}

/* element badge floating beneath the atom */
.element-badge {
  position: absolute;
  bottom: 6%;
  right: 4%;
  width: 96px;
  height: 116px;
  border: 1.5px solid var(--accent);
  border-radius: 6px;
  background: rgba(13, 17, 23, 0.85);
  backdrop-filter: blur(6px);
  display: grid;
  grid-template-rows: auto 1fr auto;
  padding: 0.6rem;
  box-shadow: var(--shadow-glow);
}
.element-badge .num {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem;
  color: var(--text-mid);
}
.element-badge .sym {
  align-self: center;
  text-align: center;
  font-family: 'Fraunces', serif;
  font-size: 2.6rem;
  color: var(--accent);
  line-height: 1;
}
.element-badge .name {
  font-size: 0.7rem;
  color: var(--text-mid);
  text-align: center;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

/* ---------- 5. Periodic-cell feature grid ---------- */

.features { padding-block: var(--gap-lg); }
.features header {
  text-align: center;
  margin-bottom: clamp(2rem, 4vw, 3.5rem);
}
.features header p { max-width: 36em; margin-inline: auto; margin-top: 1rem; }

.periodic {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
}

.element {
  position: relative;
  display: grid;
  grid-template-rows: auto 1fr auto auto;
  padding: 1.1rem;
  min-height: 200px;
  background: var(--bg-elev-1);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: all 220ms cubic-bezier(0.2, 0.7, 0.3, 1);
  text-decoration: none;
  color: inherit;
  overflow: hidden;
}
.element::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 50% 0%, var(--accent-glow), transparent 70%);
  opacity: 0;
  transition: opacity 220ms;
  pointer-events: none;
}
.element:hover {
  transform: translateY(-4px);
  border-color: var(--accent-dim);
  background: var(--bg-elev-2);
  box-shadow: var(--shadow-soft);
}
.element:hover::before { opacity: 1; }
.element:hover .sym { color: var(--accent); text-shadow: 0 0 24px var(--accent-glow); }

.element .num {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem;
  color: var(--text-lo);
  letter-spacing: 0.05em;
}
.element .sym {
  font-family: 'Fraunces', serif;
  font-size: 2.4rem;
  font-weight: 500;
  color: var(--text-hi);
  text-align: center;
  margin: 0.4rem 0 0.1rem;
  transition: all 220ms;
  line-height: 1;
}
.element .name {
  text-align: center;
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text-hi);
  margin-bottom: 0.4rem;
}
.element .tag {
  text-align: center;
  font-size: 0.78rem;
  color: var(--text-lo);
  line-height: 1.4;
}

/* feature-row alternative: heavier cards in a 2-col layout */
.feature-rows {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
}
.feature-card {
  padding: 1.6rem;
  background: var(--bg-elev-1);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.feature-card h3 { margin-bottom: 0.5rem; }
.feature-card p { font-size: 0.95rem; }
.feature-card .badge {
  display: inline-block;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.72rem;
  color: var(--accent);
  background: rgba(125, 243, 165, 0.08);
  border: 1px solid rgba(125, 243, 165, 0.25);
  padding: 0.15rem 0.55rem;
  border-radius: 100px;
  margin-bottom: 0.9rem;
}

/* ---------- 6. Code blocks + terminal ---------- */

.code-pair {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.code, .term {
  background: var(--bg-elev-1);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}
.code header, .term header {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.55rem 0.9rem;
  background: var(--bg-elev-2);
  border-bottom: 1px solid var(--border);
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem;
  color: var(--text-lo);
}
.code header .dot, .term header .dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #2a3441;
}
.code header .dot.live, .term header .dot.live {
  background: var(--accent);
  box-shadow: 0 0 8px var(--accent);
}
.code pre, .term pre {
  margin: 0;
  padding: 1.1rem 1.25rem;
  overflow-x: auto;
  font-size: 0.88rem;
  line-height: 1.65;
  color: var(--text-hi);
}
.code .kw   { color: #d4905a; }            /* copper for keys / keywords */
.code .str  { color: var(--accent); }       /* green for strings */
.code .num  { color: #c79aff; }             /* lilac for numbers */
.code .com  { color: var(--text-lo); font-style: italic; }
.term .ok   { color: var(--accent); }
.term .pkg  { color: #c79aff; }
.term .dim  { color: var(--text-lo); }
.term .em   { color: var(--copper); }
.term .prompt { color: var(--accent); user-select: none; }

/* ---------- 7. Docs ---------- */

.docs-layout {
  display: grid;
  grid-template-columns: 14rem 1fr;
  gap: 3rem;
  padding-block: var(--gap-lg);
}
.docs-nav {
  position: sticky;
  top: 5rem;
  align-self: start;
}
.docs-nav h4 {
  font-size: 0.72rem;
  color: var(--text-lo);
  letter-spacing: 0.14em;
  margin-bottom: 0.75rem;
}
.docs-nav ul { list-style: none; }
.docs-nav li { margin-bottom: 0.35rem; }
.docs-nav a {
  display: block;
  padding: 0.4rem 0.7rem;
  border-radius: var(--radius-sm);
  color: var(--text-mid);
  font-size: 0.92rem;
  border-left: 2px solid transparent;
}
.docs-nav a:hover { background: var(--bg-elev-1); color: var(--text-hi); }
.docs-nav a.active {
  border-left-color: var(--accent);
  color: var(--text-hi);
  background: var(--bg-elev-1);
}

.prose { max-width: 44rem; }
.prose h1 { font-size: clamp(1.8rem, 3.5vw, 2.6rem); margin-bottom: 0.75rem; }
.prose .eyebrow { margin-bottom: 1rem; }
.prose h2 { margin: 2.5rem 0 1rem; }
.prose h3 { margin: 2rem 0 0.75rem; color: var(--text-hi); font-family: 'Inter', sans-serif; font-weight: 600; font-size: 1.05rem; }
.prose p, .prose ul, .prose ol { margin-bottom: 1rem; }
.prose ul, .prose ol { padding-left: 1.4rem; color: var(--text-mid); }
.prose li { margin-bottom: 0.4rem; }
.prose .code, .prose .term { margin: 1.4rem 0; }
.prose hr { border: 0; border-top: 1px solid var(--border); margin: 2.5rem 0; }
.prose blockquote {
  margin: 1.4rem 0;
  padding: 0.9rem 1.25rem;
  background: var(--bg-elev-1);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius-sm);
  color: var(--text-mid);
}

/* prev / next strip at the bottom of docs pages */
.pager {
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  font-size: 0.92rem;
}
.pager a {
  display: inline-flex;
  flex-direction: column;
  padding: 0.7rem 1rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-elev-1);
  color: var(--text-mid);
  min-width: 12rem;
}
.pager a span { font-size: 0.72rem; color: var(--text-lo); letter-spacing: 0.1em; text-transform: uppercase; }
.pager a strong { color: var(--text-hi); font-weight: 500; }
.pager a:hover { border-color: var(--accent-dim); }

/* ---------- 8. Comparison table ---------- */

.compare {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  margin-block: 1.5rem;
  font-size: 0.92rem;
  background: var(--bg-elev-1);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}
.compare th, .compare td {
  padding: 0.75rem 1rem;
  text-align: left;
  border-bottom: 1px solid var(--border);
}
.compare th {
  background: var(--bg-elev-2);
  font-weight: 500;
  font-size: 0.85rem;
  color: var(--text-lo);
  letter-spacing: 0.04em;
}
.compare th:first-child, .compare td:first-child { font-weight: 500; color: var(--text-hi); }
.compare th.curie { color: var(--accent); }
.compare td.curie { color: var(--accent); }
.compare tr:last-child td { border-bottom: 0; }

/* ---------- 9. Responsive ---------- */

@media (max-width: 880px) {
  .hero .container { grid-template-columns: 1fr; }
  .atom-wrap { max-width: 320px; }
  .hero-stats { grid-template-columns: 1fr; gap: 0.75rem; }
  .periodic { grid-template-columns: repeat(2, 1fr); }
  .feature-rows { grid-template-columns: 1fr; }
  .code-pair { grid-template-columns: 1fr; }
  .docs-layout { grid-template-columns: 1fr; gap: 1.5rem; }
  .docs-nav { position: static; }
  nav.site ul { gap: 0.9rem; }
  nav.site ul li.hide-sm { display: none; }
}

@media (max-width: 480px) {
  .periodic { grid-template-columns: 1fr 1fr; gap: 0.6rem; }
  .element { padding: 0.85rem; min-height: 160px; }
  .element .sym { font-size: 1.9rem; }
  .pager { flex-direction: column; }
  .element-badge { width: 76px; height: 92px; }
  .element-badge .sym { font-size: 2rem; }
}

@media (prefers-reduced-motion: reduce) {
  .atom .e1, .atom .e2, .atom .e3 { animation: none; }
  html { scroll-behavior: auto; }
}