/*
 * dpdap landing page.
 * Single sheet, no build step. Works as well in lynx as it does in Safari.
 */

:root {
  --bg: #fbfaf7;
  --bg-tint: #f1ede4;
  --ink: #22323f;
  --ink-soft: #5b6b7e;
  --rule: #d8d2c4;
  --accent: #1e3a5f;
  --accent-2: #1e6f4d;
  --code-bg: #1f2a36;
  --code-ink: #e6efef;
  --maxw: 60rem;
  --narrow: 42rem;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 17px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  font-feature-settings: "kern", "liga", "calt";
}

p { text-wrap: pretty; }

a {
  color: var(--accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
}
a:hover { color: var(--accent-2); }

.skip {
  position: absolute;
  left: -9999px;
}
.skip:focus {
  left: 1rem;
  top: 1rem;
  background: var(--ink);
  color: #fff;
  padding: 0.5rem 0.75rem;
  border-radius: 4px;
  z-index: 10;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 5;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1.5rem;
  padding: 1rem clamp(1.25rem, 5vw, 4rem);
  border-bottom: 1px solid rgba(34, 50, 63, 0.12);
  background: rgba(251, 250, 247, 0.94);
  backdrop-filter: blur(12px);
}

.brand {
  color: var(--ink);
  font-weight: 700;
  text-decoration: none;
}

.topbar nav {
  display: flex;
  flex-wrap: wrap;
  gap: 1.1rem;
  color: var(--ink-soft);
  font-size: 0.88rem;
}

.topbar nav a {
  color: inherit;
  text-decoration: none;
}

.topbar nav a:hover {
  color: var(--accent-2);
}

.container {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 1.5rem;
}
.container.narrow {
  max-width: var(--narrow);
}

/* hero ---------------------------------------------------------- */

.hero {
  background: linear-gradient(180deg, var(--bg-tint) 0%, var(--bg) 100%);
  border-bottom: 1px solid var(--rule);
  padding: 4.5rem 0 3.5rem;
}
.hero .eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--ink-soft);
  font-size: 0.78rem;
  font-weight: 600;
  margin: 0 0 1rem;
  position: relative;
  padding-left: 1.75rem;
}
.hero .eyebrow::before {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  width: 1.25rem;
  height: 1px;
  background: var(--ink-soft);
}
.hero h1 {
  font: 700 clamp(2.1rem, 6.2vw, 3.4rem)/1.08 "Iowan Old Style", "Charter", "Georgia", serif;
  margin: 0 0 1.5rem;
  color: var(--ink);
  letter-spacing: -0.015em;
  text-wrap: balance;
  max-width: 22ch;
}
.hero .lede {
  font-size: clamp(1.05rem, 2.4vw, 1.18rem);
  line-height: 1.55;
  max-width: 38rem;
  color: var(--ink);
  margin: 0 0 2rem;
}

.ctas { margin: 0; display: flex; flex-wrap: wrap; gap: 0.6rem; }

.btn {
  display: inline-block;
  padding: 0.7rem 1.15rem;
  border-radius: 6px;
  border: 1px solid var(--accent);
  color: var(--accent);
  background: transparent;
  font-weight: 500;
  text-decoration: none;
  transition: background-color 120ms ease, color 120ms ease, border-color 120ms ease;
}
.btn:hover {
  background: var(--accent);
  color: #fff;
}
.btn.primary {
  background: var(--accent);
  color: #fff;
}
.btn.primary:hover {
  background: var(--accent-2);
  border-color: var(--accent-2);
}

/* sections ------------------------------------------------------ */

.band {
  padding: 3.25rem 0;
  border-bottom: 1px solid var(--rule);
}
.band.tinted {
  background: var(--bg-tint);
}

h2 {
  font: 700 1.55rem/1.25 "Iowan Old Style", "Charter", "Georgia", serif;
  margin: 0 0 1.25rem;
  color: var(--ink);
}

h3 {
  font: 600 1.05rem/1.3 -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  margin: 0 0 0.75rem;
  color: var(--ink);
}

p { margin: 0 0 1rem; }

p code,
li code {
  background: rgba(30, 58, 95, 0.08);
  border-radius: 3px;
  padding: 0.05em 0.35em;
  font: 0.94em "JetBrains Mono", "SFMono-Regular", Menlo, Consolas, monospace;
}

pre {
  background: var(--code-bg);
  color: var(--code-ink);
  border-radius: 8px;
  padding: 1rem 1.1rem;
  font: 0.86rem/1.5 "JetBrains Mono", "SFMono-Regular", Menlo, Consolas, monospace;
  overflow-x: auto;
  margin: 1rem 0;
}
pre code { background: transparent; padding: 0; color: inherit; }

ul.callouts {
  list-style: none;
  padding: 0;
  margin: 0;
}
ul.callouts li {
  padding: 0.85rem 0 0.85rem 1.5rem;
  border-top: 1px solid var(--rule);
  position: relative;
}
ul.callouts li:last-child { border-bottom: 1px solid var(--rule); }
ul.callouts li::before {
  content: "";
  position: absolute;
  left: 0; top: 1.35rem;
  width: 0.5rem; height: 0.5rem;
  background: var(--accent);
  border-radius: 50%;
}

ol.agenda {
  margin: 1rem 0;
  padding-left: 1.4rem;
}
ol.agenda li {
  margin-bottom: 0.85rem;
}

ol.numlist {
  margin: 1rem 0;
  padding-left: 1.4rem;
}
ol.numlist li {
  margin-bottom: 0.85rem;
}

ul.reading {
  margin: 0.5rem 0 1.5rem;
  padding-left: 1.4rem;
}
ul.reading li {
  margin-bottom: 0.6rem;
}

sup.fn {
  font-size: 0.72em;
  line-height: 0;
  vertical-align: super;
}
sup.fn a {
  text-decoration: none;
  padding: 0 0.05em;
}

ol.footnotes {
  margin: 0.5rem 0 1rem;
  padding-left: 1.4rem;
  font-size: 0.94rem;
}
ol.footnotes li {
  margin-bottom: 0.75rem;
  padding-left: 0.15rem;
}
.fnback {
  text-decoration: none;
  margin-left: 0.4em;
  color: var(--ink-soft);
}
.fnback:hover {
  color: var(--accent-2);
}

/* h3 used as an inline section sub-heading inside narrow prose
 * (e.g. "Foundational" / "Current work" inside Further reading).
 * Scoped to direct descendants of .container.narrow so it does not
 * affect h3 inside .card. */
.container.narrow > h3 {
  margin-top: 1.6rem;
  font: 600 1.0rem/1.3 -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--accent);
  letter-spacing: 0.01em;
}
.container.narrow > h3:first-of-type {
  margin-top: 1rem;
}

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(20rem, 1fr));
  gap: 1.5rem;
}
.card {
  background: #fff;
  border: 1px solid var(--rule);
  border-radius: 10px;
  padding: 1.5rem;
}
.card h3 { color: var(--accent); }
.card p.muted { font-size: 0.9rem; color: var(--ink-soft); }

ul.status {
  list-style: none;
  padding: 0;
  margin: 0;
}
ul.status li {
  padding: 0.6rem 0;
  border-top: 1px solid var(--rule);
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
}
ul.status li:last-child { border-bottom: 1px solid var(--rule); }
.dot {
  display: inline-block;
  width: 0.7rem; height: 0.7rem;
  border-radius: 50%;
  margin-top: 0.5em;
  flex-shrink: 0;
}
.dot.done { background: var(--accent-2); }
.dot.now  { background: #d97706; }
.dot.next { background: #b9b1a0; }

.about p { color: var(--ink); }
.muted { color: var(--ink-soft); font-size: 0.94rem; }

/* diagrams ------------------------------------------------------ */

.diagram-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(18rem, 1fr));
  gap: 1.25rem;
}
.diagram {
  margin: 0;
  padding: 1.25rem;
  background: #fff;
  border: 1px solid var(--rule);
  border-radius: 10px;
}
.diagram figcaption {
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 0.78rem;
  color: var(--ink-soft);
  margin-bottom: 0.5rem;
}
.diagram svg {
  width: 100%;
  height: auto;
  display: block;
}

/* probe panels (the big image, split for mobile) ---------------- */

.centered {
  text-align: center;
  margin-bottom: 0.5rem;
}
.section-lede {
  text-align: center;
  color: var(--ink-soft);
  font-size: 1rem;
  max-width: 40rem;
  margin: 0 auto 2rem;
  line-height: 1.55;
}
.probe-panels {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(22rem, 1fr));
  gap: 1.5rem;
  max-width: 60rem;
  margin: 0 auto;
}
.probe-panel {
  margin: 0;
  padding: 1.25rem 1.25rem 1.1rem;
  background: #fff;
  border: 1px solid var(--rule);
  border-radius: 10px;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}
.probe-panel img {
  width: 100%;
  height: auto;
  display: block;
}
.probe-panel figcaption {
  font-size: 0.95rem;
  line-height: 1.55;
  color: var(--ink-soft);
  margin: 0;
}
.probe-panel figcaption strong {
  color: var(--ink);
  font-weight: 600;
}

/* mobile polish ------------------------------------------------- */

@media (max-width: 640px) {
  body { font-size: 16.5px; }
  .container { padding: 0 1.15rem; }

  .topbar {
    position: static;
    align-items: flex-start;
    flex-direction: column;
  }

  .hero { padding: 3rem 0 2.5rem; }
  .hero h1 { margin-bottom: 1.15rem; max-width: none; }
  .hero .lede { margin-bottom: 1.5rem; }
  .hero .eyebrow { margin-bottom: 0.85rem; }
  .ctas .btn { flex: 1 1 auto; text-align: center; min-width: 9rem; }

  .band { padding: 2.5rem 0; }
  h2 { font-size: 1.4rem; margin-bottom: 1rem; }

  .probe-panels { gap: 1rem; }
  .probe-panel { padding: 1rem; }

  .diagram-grid { gap: 1rem; }
  .diagram { padding: 1rem; }

  .cards { gap: 1rem; }
  .card { padding: 1.25rem; }

  ul.callouts li { padding: 0.75rem 0 0.75rem 1.25rem; }
  ul.callouts li::before { top: 1.2rem; }
}

@media (max-width: 380px) {
  .container { padding: 0 1rem; }
  .ctas { flex-direction: column; align-items: stretch; }
  .ctas .btn { width: 100%; }
}

/* footer -------------------------------------------------------- */

footer {
  padding: 2.5rem 0;
  background: var(--ink);
  color: #c8d3da;
}
footer .container { color: inherit; }
footer a { color: #fff; }
footer p { margin: 0 0 0.4rem; }
footer p.muted { color: #8a98a3; }