/* The Prompt Files — site stylesheet (2026 rebuild)
   Brand green (#4c9f70) is kept from the 2023 original. */

:root {
  --green: #4c9f70;
  --green-strong: #2f7d52;
  --green-soft: #e3f3ea;
  --ink: #1b1f1d;
  --ink-2: #4a524d;
  --ink-3: #7a837d;
  --bg: #fbfcfb;
  --surface: #ffffff;
  --surface-2: #f1f5f2;
  --line: #dde5df;
  --code-bg: #f3f6f4;
  --shadow: 0 1px 2px rgba(20, 40, 28, .06), 0 8px 24px rgba(20, 40, 28, .06);
  --radius: 14px;
  --max: 1100px;
  --font: "Inter", ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --green: #6cc492;
    --green-strong: #8fd7ad;
    --green-soft: #173126;
    --ink: #e8ede9;
    --ink-2: #b7c1ba;
    --ink-3: #87938b;
    --bg: #0f1411;
    --surface: #161c18;
    --surface-2: #1d2520;
    --line: #2a342e;
    --code-bg: #121915;
    --shadow: 0 1px 2px rgba(0, 0, 0, .4), 0 8px 24px rgba(0, 0, 0, .35);
  }
}
:root[data-theme="dark"] {
  --green: #6cc492;
  --green-strong: #8fd7ad;
  --green-soft: #173126;
  --ink: #e8ede9;
  --ink-2: #b7c1ba;
  --ink-3: #87938b;
  --bg: #0f1411;
  --surface: #161c18;
  --surface-2: #1d2520;
  --line: #2a342e;
  --code-bg: #121915;
  --shadow: 0 1px 2px rgba(0, 0, 0, .4), 0 8px 24px rgba(0, 0, 0, .35);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.6;
  color: var(--ink);
  background: var(--bg);
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--green-strong); text-decoration: none; }
a:hover { text-decoration: underline; }
h1, h2, h3, h4 { line-height: 1.2; margin: 0 0 .5em; letter-spacing: -.01em; }
h1 { font-size: clamp(2rem, 5vw, 3.25rem); font-weight: 800; }
h2 { font-size: clamp(1.5rem, 3vw, 2rem); font-weight: 750; }
h3 { font-size: 1.2rem; font-weight: 700; }
p { margin: 0 0 1em; }
code, pre { font-family: var(--mono); font-size: .9em; }
pre {
  background: var(--code-bg); border: 1px solid var(--line); border-radius: 10px;
  padding: 1rem; overflow-x: auto; white-space: pre-wrap; word-break: break-word;
}
code { background: var(--code-bg); padding: .1em .35em; border-radius: 5px; }
pre code { background: none; padding: 0; }
.wrap { max-width: var(--max); margin: 0 auto; padding: 0 16px; }
.muted { color: var(--ink-2); }
.small { font-size: .9rem; }
[hidden] { display: none !important; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
:focus-visible { outline: 3px solid var(--green); outline-offset: 2px; border-radius: 6px; }

/* Header / nav */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.site-header .wrap { display: flex; align-items: center; justify-content: space-between; gap: 1rem; min-height: 64px; }
.brand { display: flex; align-items: center; gap: .6rem; color: var(--ink); font-weight: 800; font-size: 1.1rem; }
.brand:hover { text-decoration: none; }
.brand img { width: 34px; height: 34px; }
.nav { display: flex; align-items: center; gap: .25rem; }
.nav a { color: var(--ink-2); padding: .5rem .7rem; border-radius: 8px; font-weight: 600; font-size: .95rem; }
.nav a:hover, .nav a[aria-current="page"] { color: var(--ink); background: var(--surface-2); text-decoration: none; }
.nav a[aria-current="page"] { color: var(--green-strong); }
.icon-btn {
  appearance: none; border: 1px solid var(--line); background: var(--surface); color: var(--ink);
  width: 40px; height: 40px; border-radius: 10px; cursor: pointer; display: inline-flex;
  align-items: center; justify-content: center; font-size: 1.1rem;
}
.icon-btn:hover { background: var(--surface-2); }
.menu-btn { display: none; }
@media (max-width: 820px) {
  .menu-btn { display: inline-flex; }
  .nav {
    display: none; position: absolute; left: 0; right: 0; top: 100%;
    flex-direction: column; align-items: stretch; padding: .75rem 16px 1rem;
    background: var(--bg); border-bottom: 1px solid var(--line); box-shadow: var(--shadow);
  }
  .nav.open { display: flex; }
  .nav a { padding: .8rem .9rem; font-size: 1.05rem; }
}

/* Hero */
.hero { padding: clamp(3rem, 8vw, 6rem) 0 2.5rem; position: relative; overflow: hidden; }
.hero::before {
  content: ""; position: absolute; inset: -40% -20% auto; height: 120%;
  background: radial-gradient(60% 50% at 20% 30%, color-mix(in srgb, var(--green) 22%, transparent), transparent 70%);
  pointer-events: none; z-index: -1;
}
.eyebrow { display: inline-block; font-size: .8rem; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; color: var(--green-strong); margin-bottom: .75rem; }
.lead { font-size: clamp(1.05rem, 1.8vw, 1.3rem); color: var(--ink-2); max-width: 46rem; }
.gradient-text {
  background: linear-gradient(90deg, var(--green) 0%, var(--ink) 100%);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.cta-row { display: flex; flex-wrap: wrap; gap: .75rem; margin-top: 1.5rem; }
.btn {
  display: inline-flex; align-items: center; gap: .5rem; padding: .7rem 1.1rem; border-radius: 10px;
  font-weight: 700; border: 1px solid transparent; cursor: pointer; font-size: .95rem; font-family: inherit;
  transition: transform .15s ease, background .15s ease;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn:disabled { opacity: .6; cursor: progress; transform: none; }
.btn-primary { background: var(--green); color: #fff; }
.btn-primary:hover { background: var(--green-strong); }
:root[data-theme="dark"] .btn-primary, :root:not([data-theme="light"]) .btn-primary { color: #0f1411; }
@media (prefers-color-scheme: light) { :root:not([data-theme="dark"]) .btn-primary { color: #fff; } }
.btn-ghost { background: var(--surface); color: var(--ink); border-color: var(--line); }
.btn-ghost:hover { background: var(--surface-2); }
.btn-sm { padding: .4rem .7rem; font-size: .85rem; }

/* Sections, cards */
.section { padding: 2.5rem 0; }
.section-head { display: flex; align-items: end; justify-content: space-between; gap: 1rem; flex-wrap: wrap; margin-bottom: 1.25rem; }
.section-head p { margin: 0; }
.grid { display: grid; gap: 1rem; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); }
.card {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 1.25rem; box-shadow: var(--shadow);
}
.card h3 { margin-top: 0; }
.card .meta { color: var(--ink-3); font-size: .85rem; margin-bottom: .4rem; }
.stat { font-size: 2rem; font-weight: 800; letter-spacing: -.02em; }
.stat-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 1rem; }
.pill {
  display: inline-block; font-size: .72rem; font-weight: 700; letter-spacing: .04em; text-transform: uppercase;
  padding: .2em .6em; border-radius: 999px; background: var(--green-soft); color: var(--green-strong);
}
.pill.models { background: color-mix(in srgb, #3b82f6 16%, transparent); color: #2b63c7; }
.pill.reasoning { background: color-mix(in srgb, #a855f7 16%, transparent); color: #8b3fd9; }
.pill.prompting { background: var(--green-soft); color: var(--green-strong); }
.pill.agents { background: color-mix(in srgb, #f59e0b 20%, transparent); color: #b36b00; }
.pill.alignment { background: color-mix(in srgb, #ef4444 16%, transparent); color: #c22d2d; }
.pill.architecture { background: color-mix(in srgb, #06b6d4 18%, transparent); color: #0b7f93; }
.pill.evals { background: color-mix(in srgb, #64748b 18%, transparent); color: #4b5a6d; }
.pill.foundations { background: color-mix(in srgb, #8b5e34 18%, transparent); color: #8b5e34; }
:root[data-theme="dark"] .pill.models, :root:not([data-theme="light"]) .pill.models { color: #8fb6ff; }
:root[data-theme="dark"] .pill.reasoning, :root:not([data-theme="light"]) .pill.reasoning { color: #cfa4ff; }
:root[data-theme="dark"] .pill.agents, :root:not([data-theme="light"]) .pill.agents { color: #ffc766; }
:root[data-theme="dark"] .pill.alignment, :root:not([data-theme="light"]) .pill.alignment { color: #ff9c9c; }
:root[data-theme="dark"] .pill.architecture, :root:not([data-theme="light"]) .pill.architecture { color: #7fe0f0; }
:root[data-theme="dark"] .pill.evals, :root:not([data-theme="light"]) .pill.evals { color: #b6c2d2; }
:root[data-theme="dark"] .pill.foundations, :root:not([data-theme="light"]) .pill.foundations { color: #d9b48f; }
@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) .pill.models { color: #2b63c7; }
  :root:not([data-theme="dark"]) .pill.reasoning { color: #8b3fd9; }
  :root:not([data-theme="dark"]) .pill.agents { color: #b36b00; }
  :root:not([data-theme="dark"]) .pill.alignment { color: #c22d2d; }
  :root:not([data-theme="dark"]) .pill.architecture { color: #0b7f93; }
  :root:not([data-theme="dark"]) .pill.evals { color: #4b5a6d; }
  :root:not([data-theme="dark"]) .pill.foundations { color: #8b5e34; }
}

/* Timeline */
.filters { display: flex; flex-wrap: wrap; gap: .5rem; align-items: center; margin: 1rem 0 1.5rem; }
.filters input[type="search"] {
  flex: 1 1 220px; min-width: 0; padding: .6rem .8rem; border: 1px solid var(--line); border-radius: 10px;
  background: var(--surface); color: var(--ink); font: inherit;
}
.chip {
  appearance: none; border: 1px solid var(--line); background: var(--surface); color: var(--ink-2);
  padding: .35rem .75rem; border-radius: 999px; font: inherit; font-size: .85rem; font-weight: 600; cursor: pointer;
}
.chip[aria-pressed="true"] { background: var(--green); border-color: var(--green); color: #fff; }
.timeline { position: relative; margin: 0; padding: 0; list-style: none; }
.timeline::before { content: ""; position: absolute; left: 7px; top: 0; bottom: 0; width: 2px; background: var(--line); }
.era { position: relative; padding-left: 2rem; margin: 2.5rem 0 1rem; }
.era::before {
  content: ""; position: absolute; left: 0; top: .55em; width: 16px; height: 16px; border-radius: 50%;
  background: var(--green); box-shadow: 0 0 0 4px var(--bg);
}
.era h2 { margin-bottom: .2rem; }
.era p { color: var(--ink-2); margin: 0; max-width: 48rem; }
.paper { position: relative; padding-left: 2rem; margin: 0 0 .9rem; }
.paper::before {
  content: ""; position: absolute; left: 4px; top: 1.15rem; width: 8px; height: 8px; border-radius: 50%;
  background: var(--ink-3); box-shadow: 0 0 0 3px var(--bg);
}
.paper .card { padding: 1rem 1.1rem; }
.paper .title { font-weight: 700; font-size: 1.02rem; }
.paper .title a { color: var(--ink); }
.paper .meta { display: flex; flex-wrap: wrap; gap: .5rem .75rem; align-items: center; margin: .25rem 0 .4rem; }
.paper .why { margin: 0; color: var(--ink-2); font-size: .95rem; }
.paper .links { margin-top: .5rem; display: flex; gap: .75rem; flex-wrap: wrap; font-size: .85rem; }
.paper.featured .card { border-color: var(--green); }
.paper[hidden] { display: none; }
.empty { color: var(--ink-3); padding: 2rem 0 2rem 2rem; }

/* Library accordions */
details.entry { border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); margin-bottom: .75rem; box-shadow: var(--shadow); }
details.entry summary {
  cursor: pointer; padding: 1rem 1.25rem; font-weight: 700; list-style: none; display: flex; justify-content: space-between; gap: 1rem; align-items: center;
}
details.entry summary::-webkit-details-marker { display: none; }
details.entry summary::after { content: "+"; font-size: 1.3rem; color: var(--ink-3); flex: none; }
details.entry[open] summary::after { content: "–"; }
details.entry .body { padding: 0 1.25rem 1.25rem; border-top: 1px solid var(--line); padding-top: 1rem; }
details.entry .body > :last-child { margin-bottom: 0; }
.prompt-block { position: relative; }
.prompt-block .copy { position: absolute; top: .5rem; right: .5rem; }

/* Forms */
.field { margin-bottom: 1rem; }
.field label { display: block; font-weight: 600; margin-bottom: .35rem; }
.field .hint { color: var(--ink-3); font-size: .85rem; margin: .25rem 0 0; }
input[type="text"], input[type="email"], textarea, select {
  width: 100%; padding: .65rem .8rem; border: 1px solid var(--line); border-radius: 10px;
  background: var(--surface); color: var(--ink); font: inherit;
}
textarea { resize: vertical; min-height: 90px; }
.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 1.25rem; }
@media (max-width: 820px) { .two-col { grid-template-columns: 1fr; } }
.notice { padding: .8rem 1rem; border-radius: 10px; background: var(--green-soft); color: var(--ink); border: 1px solid color-mix(in srgb, var(--green) 40%, transparent); }
.notice.warn { background: color-mix(in srgb, #f59e0b 14%, transparent); border-color: color-mix(in srgb, #f59e0b 50%, transparent); }

/* About */
.about-grid { display: grid; grid-template-columns: 300px 1fr; gap: 2rem; align-items: start; }
.about-grid img { border-radius: var(--radius); box-shadow: var(--shadow); }
@media (max-width: 820px) { .about-grid { grid-template-columns: 1fr; } .about-grid img { max-width: 320px; margin: 0 auto; } }
.history { list-style: none; padding: 0; margin: 0; }
.history li { display: grid; grid-template-columns: 90px 1fr; gap: 1rem; padding: .6rem 0; border-bottom: 1px solid var(--line); }
.history li strong { color: var(--green-strong); }

/* Footer */
.site-footer { border-top: 1px solid var(--line); margin-top: 3rem; padding: 2rem 0; color: var(--ink-3); font-size: .9rem; }
.site-footer .wrap { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 1rem; }
.site-footer a { color: var(--ink-2); }

@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } .btn { transition: none; } }
@media print { .site-header, .site-footer, .filters, .cta-row { display: none; } .card { box-shadow: none; } }