/* ============================================================
   Theme tokens — colors lifted from the reference design
   Light + dark follow the OS via prefers-color-scheme.
   ============================================================ */
:root {
  --radius: 0.625rem;
  --background: #faf9f7;      /* nudged off the reference's exact #f7f6f5 */
  --foreground: #0a0a0a;
  --card: #ffffff;
  --muted: #f4f3f1;
  --muted-foreground: #737373;
  --accent-foreground: #464646;
  --border: #e6e4e1;
  --ring: #a1a1a1;

  /* pill nav glass */
  --pill-bg: rgba(250, 249, 247, 0.55);
  --pill-border: rgba(255, 255, 255, 0.6);
  --pill-shadow: 0 12px 34px rgba(0, 0, 0, 0.09);
  --pill-active-bg: #ffffff;

  /* code */
  --code-bg: #f0efec;
  --code-border: #e6e4e1;

  /* accent — deep green */
  --accent: #2f6b4f;
  --accent-strong: #255a41;
  --accent-soft: rgba(47, 107, 79, 0.12);
}

@media (prefers-color-scheme: dark) {
  :root {
    --background: #0a0a0a;
    --foreground: #ededed;
    --card: #171717;
    --muted: #262626;
    --muted-foreground: #a1a1a1;
    --accent-foreground: #b5b5b5;
    --border: rgba(255, 255, 255, 0.1);
    --ring: #737373;

    --pill-bg: rgba(23, 23, 23, 0.55);
    --pill-border: rgba(255, 255, 255, 0.12);
    --pill-shadow: 0 12px 34px rgba(0, 0, 0, 0.5);
    --pill-active-bg: #262626;

    --code-bg: #161616;
    --code-border: rgba(255, 255, 255, 0.08);

    /* accent — green, lifted for contrast on #0a0a0a */
    --accent: #6bbf95;
    --accent-strong: #86cfa9;
    --accent-soft: rgba(107, 191, 149, 0.16);
  }
}

/* ============================================================
   Reset / base
   ============================================================ */
*, *::before, *::after { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }

body {
  background: var(--background);
  color: var(--foreground);
  font-family: "Geist", "Inter", ui-sans-serif, system-ui, -apple-system, sans-serif;
  font-size: 1rem;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: inherit; text-decoration: none; }

/* ============================================================
   Floating glass pill navigation
   ============================================================ */
.pill-nav {
  position: fixed;
  left: 50%;
  top: 0.75rem;
  transform: translateX(-50%);
  z-index: 100;
  display: flex;
  align-items: center;
  padding: 0.15rem;
  border-radius: 999px;              /* full pill (reference uses a rounded-rect) */
  border: 1px solid var(--pill-border);
  background: var(--pill-bg);
  box-shadow: var(--pill-shadow);
  -webkit-backdrop-filter: blur(20px);
  backdrop-filter: blur(20px);
}
@media (min-width: 768px) { .pill-nav { top: 1rem; } }

.pill-nav a {
  position: relative;
  z-index: 2;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.45rem 0.95rem;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--muted-foreground);
  border-radius: 999px;
  transition: color 0.25s ease, transform 0.1s ease;
  white-space: nowrap;
}
.pill-nav a:hover { color: var(--accent-foreground); }
.pill-nav a:active { transform: scale(0.97); }
.pill-nav a.active { color: var(--accent-strong); }

/* sliding highlight behind the active item */
.pill-indicator {
  position: absolute;
  z-index: 1;
  top: 0.15rem;
  left: 0;
  height: calc(100% - 0.3rem);
  border-radius: 999px;
  background: var(--pill-active-bg);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
  transition: transform 0.32s cubic-bezier(0.22, 1, 0.36, 1),
              width 0.32s cubic-bezier(0.22, 1, 0.36, 1);
  opacity: 0;
}
.pill-indicator.ready { opacity: 1; }

/* ============================================================
   Layout
   ============================================================ */
main {
  display: flex;
  min-height: 100vh;
  width: 100%;
  flex-direction: column;
  align-items: center;
  padding: 0 2rem;
}
.container {
  width: 100%;
  max-width: 48rem;
  padding: 6rem 0.25rem 6rem;
}
@media (min-width: 768px) {
  .container { padding: 7rem 1rem 12rem; }
}

/* fade-in-up entrance applied when a view is rendered */
.view { animation: fade-up 0.5s cubic-bezier(0.22, 1, 0.36, 1) both; }
@keyframes fade-up {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ============================================================
   Typography
   ============================================================ */
h1, h2, h3, h4 { font-weight: 700; line-height: 1.25; }
.greeting { font-size: 1.05rem; font-weight: 700; margin: 0 0 1.25rem; }
.lead { margin: 0; color: var(--foreground); }
.lead + .lead { margin-top: 1rem; }

.section-title {
  font-size: 1.05rem;
  font-weight: 700;
  margin: 0 0 1.75rem;
}
.muted { color: var(--muted-foreground); }

/* Index: understated "Now" line */
.now {
  margin: 1.75rem 0 0;
  color: var(--muted-foreground);
  font-size: 0.95rem;
}
.now-label {
  font-family: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--accent);
  border: 1px solid var(--accent-soft);
  background: var(--accent-soft);
  border-radius: 0.35rem;
  padding: 0.1rem 0.4rem;
  margin-right: 0.6rem;
}

/* Index: focus-areas middot line */
.focus {
  margin: 0.85rem 0 0;
  color: var(--muted-foreground);
  font-size: 0.9rem;
}
.focus .mid {
  color: var(--accent);
  opacity: 0.7;
  margin: 0 0.55rem;
}

/* ============================================================
   Animated underline links (Index social row, inline links)
   ============================================================ */
.link-row { display: flex; flex-wrap: wrap; gap: 0.75rem 1.5rem; margin-top: 2rem; }
.ulink {
  position: relative;
  padding: 0.25rem 0;
  color: var(--accent-foreground);
  white-space: nowrap;
  transition: color 0.3s ease, transform 0.3s ease;
}
.ulink::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -0.1rem;
  height: 1px;
  width: 100%;
  background: var(--accent);
  opacity: 0.35;
  transition: width 0.3s ease, opacity 0.3s ease;
}
@media (min-width: 768px) {
  .ulink::after { width: 0; opacity: 1; }
}
.ulink:hover {
  color: var(--accent-strong);
  transform: translateX(2px);
}
.ulink:hover::after { width: 100%; opacity: 1; }

/* ============================================================
   Work list
   ============================================================ */
.entry-list { display: flex; flex-direction: column; gap: 2rem; }
.entry { display: flex; flex-direction: column; gap: 0.35rem; }
.entry-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.25rem 1rem;
}
.entry-role { font-weight: 600; }
.entry-org { color: var(--muted-foreground); }
.entry-dates { font-size: 0.85rem; color: var(--muted-foreground); white-space: nowrap; }
.entry-desc { margin: 0.15rem 0 0; color: var(--foreground); }

/* ============================================================
   Blog list
   ============================================================ */
.post-list { display: flex; flex-direction: column; gap: 1.75rem; }
.post-item { display: flex; flex-direction: column; gap: 0.3rem; }
.post-link {
  font-weight: 600;
  transition: color 0.25s ease, transform 0.25s ease;
  width: fit-content;
}
.post-link:hover { color: var(--accent-strong); transform: translateX(2px); }
.post-date { font-size: 0.85rem; color: var(--muted-foreground); }
.post-excerpt { margin: 0.1rem 0 0; color: var(--muted-foreground); }
/* Only ever rendered in local preview — drafts are filtered out when deployed. */
.draft-badge {
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  padding: 0.1rem 0.45rem;
  border-radius: 999px;
  border: 1px dashed var(--muted-foreground);
  color: var(--muted-foreground);
  width: fit-content;
}

/* ============================================================
   Projects
   ============================================================ */
.project-list { display: flex; flex-direction: column; gap: 1.75rem; }
.project { display: flex; flex-direction: column; gap: 0.4rem; }
.project-name { font-weight: 600; width: fit-content; transition: transform 0.25s ease; }
.project-name:hover { transform: translateX(2px); }
.project-desc { margin: 0; color: var(--muted-foreground); }
.tag-row { display: flex; flex-wrap: wrap; gap: 0.4rem; margin-top: 0.15rem; }
.tag {
  font-size: 0.72rem;
  font-weight: 500;
  padding: 0.15rem 0.55rem;
  border-radius: 999px;
  border: 1px solid var(--accent-soft);
  color: var(--accent);
  background: var(--accent-soft);
}

/* ============================================================
   Blog post (single) — prose
   ============================================================ */
.back-link {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.875rem;
  color: var(--muted-foreground);
  margin-bottom: 2rem;
  transition: color 0.25s ease, transform 0.25s ease;
}
.back-link:hover { color: var(--foreground); transform: translateX(-2px); }

.post-header { margin-bottom: 2.5rem; }
.post-header h1 { font-size: 1.7rem; margin: 0 0 0.6rem; line-height: 1.2; }
.post-meta { font-size: 0.85rem; color: var(--muted-foreground); display: flex; flex-wrap: wrap; gap: 0.5rem 0.75rem; align-items: center; }
.post-meta .dot { opacity: 0.5; }

.prose { color: var(--foreground); }
.prose > * + * { margin-top: 1.15rem; }
.prose h2 {
  font-size: 1.3rem;
  margin-top: 2.5rem;
  margin-bottom: 0.25rem;
  scroll-margin-top: 5rem;
}
.prose h3 {
  font-size: 1.08rem;
  margin-top: 1.75rem;
  margin-bottom: 0.25rem;
  scroll-margin-top: 5rem;
}
.prose p { margin: 0; }
/* Paragraph gap. Ties `.prose p` on specificity (0-1-1), so it must stay AFTER
   that reset to win on source order. Matches the 1.6 body line-height, i.e. one
   blank line. `* +` keeps the first paragraph of a post flush to the top. */
.prose > * + p { margin-top: 1.6rem; }
/* ...but a heading keeps its own tight lead-in to the paragraph below it. */
.prose > h2 + p, .prose > h3 + p { margin-top: 0.25rem; }
.prose a:not(.ulink) {
  color: var(--accent-strong);
  text-decoration: underline;
  text-underline-offset: 2px;
  text-decoration-color: var(--accent-soft);
}
.prose a:not(.ulink):hover { text-decoration-color: var(--accent); }
.prose strong { font-weight: 700; }
.prose hr { border: none; border-top: 1px solid var(--border); margin: 2.5rem 0; }
.prose ul, .prose ol { margin: 0; padding-left: 1.4rem; }
.prose li { margin: 0.3rem 0; }

/* tables — wrapped in .table-scroll so wide ones scroll instead of breaking the page */
.prose .table-scroll { overflow-x: auto; -webkit-overflow-scrolling: touch; }
.prose table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
  min-width: 32rem;
}
.prose thead th {
  text-align: left;
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted-foreground);
  font-weight: 600;
  border-bottom: 1px solid var(--border);
  padding: 0 0.9rem 0.5rem 0;
}
.prose tbody td {
  padding: 0.6rem 0.9rem 0.6rem 0;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
  font-variant-numeric: tabular-nums;
}
.prose tbody tr:last-child td { border-bottom: none; }
.prose th:last-child, .prose td:last-child { padding-right: 0; }

/* inline + block code */
.prose code {
  font-family: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.85em;
  color: var(--accent-strong);
  background: var(--code-bg);
  border: 1px solid var(--code-border);
  border-radius: 0.35rem;
  padding: 0.1rem 0.35rem;
}
.prose pre {
  background: var(--code-bg);
  border: 1px solid var(--code-border);
  border-radius: var(--radius);
  padding: 1rem 1.15rem;
  overflow-x: auto;
  line-height: 1.5;
}
.prose pre code {
  color: var(--foreground);
  background: none;
  border: none;
  padding: 0;
  font-size: 0.85rem;
}

/* figures with SVG diagrams (dark card, like source) */
.prose figure {
  margin: 1.75rem 0;
  background: #1e1e2e;
  border: 1px solid #313244;
  border-radius: 12px;
  padding: 1.5rem 1rem 1rem;
  text-align: center;
}
.prose figure img { max-width: 100%; height: auto; }
.prose figcaption {
  font-size: 0.85rem;
  color: #a6adc8;
  margin-top: 0.85rem;
}

/* interactive training-loop explainer */
.prose figure.training-loop-figure {
  padding: 1rem 1rem 0.9rem;
  text-align: left;
}
.prose figure.training-loop-figure figcaption { text-align: center; }
.training-loop {
  --tl-bg: #1e1e2e;
  --tl-panel: #252637;
  --tl-panel-strong: #2a2b3c;
  --tl-border: #45475a;
  --tl-text: #cdd6f4;
  --tl-muted: #a6adc8;
  --tl-blue: #89b4fa;
  --tl-blue-soft: #243b56;
  --tl-green: #a6e3a1;
  --tl-green-soft: #1f3a2c;
  --tl-peach: #fab387;
  --tl-pink: #f38ba8;
  color: var(--tl-text);
  min-width: 0;
}
.training-loop-sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}
.training-loop-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem 1rem;
  margin-bottom: 1rem;
}
.training-loop-learning-rate {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.4rem;
}
.training-loop-control-label,
.training-loop-epoch {
  color: var(--tl-muted);
  font-family: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.72rem;
}
.training-loop-control-label { margin-right: 0.25rem; }
.training-loop-epoch { margin: 0; white-space: nowrap; }
.training-loop button {
  appearance: none;
  border: 1px solid var(--tl-border);
  border-radius: 0.45rem;
  background: var(--tl-panel);
  color: var(--tl-text);
  cursor: pointer;
  font-family: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.72rem;
  font-weight: 500;
  line-height: 1;
  padding: 0.52rem 0.65rem;
}
.training-loop button span { color: var(--tl-muted); }
.training-loop button:hover:not(:disabled) { border-color: var(--tl-blue); }
.training-loop button:active:not(:disabled) { transform: translateY(1px); }
.training-loop button:focus-visible {
  outline: 3px solid var(--tl-blue);
  outline-offset: 2px;
}
.training-loop button[aria-pressed="true"] {
  border-color: var(--tl-blue);
  background: var(--tl-blue-soft);
  color: var(--tl-blue);
}
.training-loop button:disabled { cursor: not-allowed; opacity: 0.4; }
.training-loop-phases {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.45rem;
  list-style: none;
  margin: 0;
  padding: 0 0 1.5rem;
}
.training-loop-phases li {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  min-width: 0;
  border: 1px solid var(--tl-border);
  border-radius: 0.45rem;
  color: var(--tl-muted);
  font-size: 0.75rem;
  line-height: 1.25;
  margin: 0;
  padding: 0.55rem 0.6rem;
}
.training-loop-phases li span {
  display: inline-flex;
  flex: 0 0 1.35rem;
  width: 1.35rem;
  height: 1.35rem;
  align-items: center;
  justify-content: center;
  border: 1px solid currentColor;
  border-radius: 50%;
  font-family: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.68rem;
}
.training-loop-phases li.active {
  border-color: var(--tl-green);
  background: var(--tl-green-soft);
  color: var(--tl-green);
}
.training-loop-status {
  min-height: 2.8em;
  margin: 0;
  color: var(--tl-text);
  font-family: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.72rem;
  line-height: 1.4;
}
.training-loop-chart {
  display: block;
  width: 100%;
  height: auto;
  margin-top: 0.25rem;
}
.training-loop-chart text {
  font-family: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
}
.training-loop-svg-heading { fill: var(--tl-text); font-size: 14px; font-weight: 500; }
.training-loop-svg-value { fill: var(--tl-blue); font-size: 12px; }
.training-loop-gradient-value { fill: var(--tl-peach); font-size: 11px; }
.training-loop-plot-bg { fill: var(--tl-panel); stroke: var(--tl-border); stroke-width: 1.5; }
.training-loop-grid { stroke: var(--tl-border); stroke-width: 1; opacity: 0.55; stroke-dasharray: 3 5; }
.training-loop-axis { stroke: var(--tl-muted); stroke-width: 1.25; opacity: 0.75; }
.training-loop-axis-label { fill: var(--tl-muted); font-size: 10px; }
.training-loop-model-line {
  stroke: var(--tl-blue);
  stroke-width: 3.5;
  stroke-linecap: round;
  fill: none;
}
.training-loop-model-line-previous {
  stroke: var(--tl-muted);
  stroke-width: 2;
  stroke-dasharray: 7 6;
  opacity: 0.75;
}
.training-loop-target-point { fill: var(--tl-green-soft); stroke: var(--tl-green); stroke-width: 2.5; }
.training-loop-target-center { fill: var(--tl-green); }
.training-loop-prediction-point { fill: var(--tl-blue); stroke: var(--tl-bg); stroke-width: 1.5; }
.training-loop-residual { stroke: var(--tl-muted); stroke-width: 1.5; stroke-dasharray: 4 4; opacity: 0.65; }
.training-loop-residual-active { stroke: var(--tl-pink); stroke-width: 2.5; opacity: 1; }
.training-loop-update-arrow { stroke: var(--tl-peach); stroke-width: 2.5; stroke-dasharray: 4 3; }
.training-loop-arrowhead { fill: var(--tl-peach); }
.training-loop-legend-text { fill: var(--tl-muted); font-size: 10px; }
.training-loop-loss-line { fill: none; stroke: var(--tl-peach); stroke-width: 2.5; stroke-linejoin: round; stroke-linecap: round; }
.training-loop-loss-point { fill: var(--tl-peach); stroke: var(--tl-bg); stroke-width: 1.5; }
.training-loop-loss-point-pending { fill: var(--tl-panel); stroke: var(--tl-peach); stroke-width: 2.5; }
.training-loop-actions {
  display: flex;
  gap: 0.5rem;
  justify-content: flex-end;
  margin-top: 0.4rem;
}
.training-loop-actions button[data-training-loop-action="next"] {
  border-color: var(--tl-green);
  background: var(--tl-green-soft);
  color: var(--tl-green);
}
@media (max-width: 620px) {
  .training-loop-toolbar { align-items: flex-start; flex-direction: column; }
  .training-loop-phases { grid-template-columns: 1fr; }
  .training-loop-phases li { padding: 0.45rem 0.55rem; }
  .training-loop-status { min-height: 4.2em; }
}
@media (max-width: 420px) {
  .prose figure.training-loop-figure { margin-left: -0.5rem; margin-right: -0.5rem; padding-left: 0.65rem; padding-right: 0.65rem; }
  .training-loop-learning-rate { align-items: stretch; }
  .training-loop-control-label { flex-basis: 100%; }
  .training-loop-learning-rate button { flex: 1 1 0; padding-left: 0.35rem; padding-right: 0.35rem; }
  .training-loop-learning-rate button span { display: block; margin-top: 0.25rem; }
  .training-loop-actions { justify-content: stretch; }
  .training-loop-actions button { flex: 1 1 0; }
}
@media (prefers-reduced-motion: no-preference) {
  .training-loop button,
  .training-loop-phases li,
  .training-loop-model-line,
  .training-loop-loss-line { transition: color 0.18s ease, background-color 0.18s ease, border-color 0.18s ease, opacity 0.18s ease; }
}

/* table of contents */
.toc {
  border: 1px solid var(--border);
  background: var(--card);
  border-radius: var(--radius);
  padding: 1.1rem 1.35rem;
  margin: 1.75rem 0;
}
.toc-title {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted-foreground);
  margin: 0 0 0.6rem;
}
.toc ol { margin: 0; padding-left: 1.2rem; }
.toc li { margin: 0.25rem 0; }
.toc a {
  color: var(--accent-foreground);
  text-decoration: none;
  transition: color 0.2s ease;
}
.toc a:hover { color: var(--accent-strong); text-decoration: underline; text-underline-offset: 2px; }

/* callout */
.callout {
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  background: var(--muted);
  border-radius: var(--radius);
  padding: 1rem 1.15rem;
  margin: 1.75rem 0;
}
.callout-title {
  font-weight: 700;
  font-size: 0.95rem;
  margin: 0 0 0.4rem;
}
.callout p { margin: 0; color: var(--foreground); }

/* inline update / footnote — lighter than a callout */
.prose .note {
  font-size: 0.9rem;
  line-height: 1.6;
  color: var(--muted-foreground);
  border-left: 2px solid var(--border);
  padding-left: 0.95rem;
  margin: 1.1rem 0;
}
.prose .note strong { color: var(--foreground); }

/* trailing italic note */
.prose em { color: var(--muted-foreground); }