/* ---------- palette ----------
   The home page is graphite on ivory paper. The blog and posts switch to
   light text on near-black (data-theme="dark" on <html>). The ASCII field
   uses the --grad-* tones at --ascii-alpha; the one splash of color is the
   blue gradient on the typed words after "I build". */
:root {
  --font: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --bg: #f3f0e8;
  --surface: #ece8de;
  --border: #d6d1c5;
  --border-strong: #b3aea2;
  --text: #1c1b19;
  --muted: #55534e;
  --faint: #8a867d;
  --accent: #1c1b19;
  --grad-from: #1c1b19;
  --grad-mid: #9a968d;
  --grad-to: #46443f;
  --ascii-alpha: 0.11;
  --blue-from: #1e3a8a;
  --blue-mid: #2563eb;
  --blue-to: #0284c7;
  --blue-grad: linear-gradient(120deg, var(--blue-from), var(--blue-mid), var(--blue-to));
  --mono: ui-monospace, "Cascadia Mono", Consolas, Menlo, monospace;
}

[data-theme="dark"] {
  color-scheme: dark;
  --bg: #0a0a0a;
  --surface: #181818;
  --border: #272727;
  --border-strong: #3d3d3d;
  --text: #f2f2f2;
  --muted: #b4b4b4;
  --faint: #7c7c7c;
  --accent: #f2f2f2;
  --grad-from: #f2f2f2;
  --grad-mid: #6e6e6e;
  --grad-to: #b8b8b8;
  --ascii-alpha: 0.09;
  /* lighter blues, so typed words stay readable on black */
  --blue-from: #a5c8ff;
  --blue-mid: #60a5fa;
  --blue-to: #38bdf8;
}

/* ---------- page transitions ----------
   Home <-> blog: the new page wipes across the old one with a wide, soft
   edge, so light fades into dark (and back) as it sweeps. transitions.js
   tags which way; every other link keeps the default crossfade. Browsers
   without cross-document view transitions just change pages. */
@media (prefers-reduced-motion: no-preference) {
  @view-transition { navigation: auto; }
}

html:active-view-transition-type(to-blog, to-home)::view-transition-old(root) { animation: none; }
html:active-view-transition-type(to-blog)::view-transition-new(root) {
  -webkit-mask: linear-gradient(to left, #000 40%, transparent 60%) 0 0 / 300% 100% no-repeat;
  mask: linear-gradient(to left, #000 40%, transparent 60%) 0 0 / 300% 100% no-repeat;
  animation: wipe-from-right 0.9s cubic-bezier(0.65, 0, 0.35, 1) both;
}
html:active-view-transition-type(to-home)::view-transition-new(root) {
  -webkit-mask: linear-gradient(to right, #000 40%, transparent 60%) 0 0 / 300% 100% no-repeat;
  mask: linear-gradient(to right, #000 40%, transparent 60%) 0 0 / 300% 100% no-repeat;
  animation: wipe-from-left 0.9s cubic-bezier(0.65, 0, 0.35, 1) both;
}
@keyframes wipe-from-right {
  from { -webkit-mask-position: 0% 0; mask-position: 0% 0; }
  to { -webkit-mask-position: 100% 0; mask-position: 100% 0; }
}
@keyframes wipe-from-left {
  from { -webkit-mask-position: 100% 0; mask-position: 100% 0; }
  to { -webkit-mask-position: 0% 0; mask-position: 0% 0; }
}

/* ---------- base ---------- */
*, *::before, *::after { box-sizing: border-box; }
[hidden] { display: none !important; }

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

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

body {
  margin: 0;
  padding: 0 16px;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 15px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

main { max-width: 680px; margin: 0 auto; padding: 56px 0 24px; }

/* ASCII field drawn by ascii.js */
.bg-ascii {
  position: fixed;
  inset: 0;
  z-index: -1;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

h1, h2, h3 { font-weight: 600; line-height: 1.25; letter-spacing: -0.01em; }
h1 { font-size: 1.75rem; margin: 0 0 0.25em; }
h2 { font-size: 1.1rem; margin: 2em 0 0.75em; }
h3 { font-size: 1rem; margin: 0; }
p { margin: 0 0 0.9em; }
strong { font-weight: 600; }

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }
a:focus-visible, button:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

code {
  font-family: var(--mono);
  font-size: 0.9em;
  padding: 0.1em 0.35em;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 4px;
}

/* ---------- landing ---------- */
.home { text-align: center; padding-top: 80px; }

.avatar {
  display: block;
  width: 128px;
  height: 128px;
  margin: 0 auto 24px;
  border-radius: 50%;
  object-fit: cover;
  border: 1px solid var(--border);
}

.lead { font-size: 1.05rem; font-weight: 600; margin: 0 0 0.2em; }
.headline { font-size: 2.1rem; font-weight: 600; letter-spacing: -0.02em; line-height: 1.2; margin: 0 0 0.45em; }
.intro { max-width: 480px; margin: 0 auto 28px; font-size: 0.92rem; font-style: italic; line-height: 1.45; color: var(--muted); text-wrap: balance; }

/* ---------- components rewritten from performative-ui (MIT) ----------
   https://performative-ui.cncl.co. Behavior lives in components.js. */

/* GradientText */
.grad-text {
  display: inline-block;
  background: var(--blue-grad);
  background-size: 200% 200%;
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  -webkit-text-fill-color: transparent;
  animation: grad-shift 8s ease infinite;
}
@keyframes grad-shift {
  0%, 100% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
}

/* Rotator: the typed word and its blinking block cursor */
.rotator { display: inline-block; text-align: left; white-space: nowrap; }
.rotator-cursor {
  display: inline-block;
  width: 0.5em;
  height: 1em;
  margin-left: 3px;
  vertical-align: -0.12em;
  border-radius: 1px;
  background: var(--blue-mid);
  animation: caret 1.05s steps(2, start) infinite;
}
@keyframes caret { 50% { opacity: 0; } }

/* Section links: simple buttons with an icon and a label */
.links { display: flex; flex-wrap: wrap; justify-content: center; gap: 10px; }
.link-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  padding: 10px 18px;
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text);
  background: var(--bg);
  border: 1px solid var(--border-strong);
  border-radius: 10px;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
}
.link-btn svg { flex: none; width: 17px; height: 17px; }
.link-btn:hover { text-decoration: none; color: var(--bg); background: var(--text); border-color: var(--text); }

/* ---------- back link at the top of the blog and posts ---------- */
.topbar { max-width: 1120px; margin: 0 auto; padding-top: 28px; }
.back { display: inline-flex; align-items: center; gap: 6px; font-size: 0.9rem; color: var(--muted); }
.back:hover { color: var(--text); text-decoration: none; }
.back svg { width: 16px; height: 16px; }

/* ---------- blog list, after OpenAI News ---------- */
.blog { max-width: 1120px; padding: 56px 0 96px; }
/* Same size as the "I build" line on the home page */
.blog-title { font-size: 2.1rem; font-weight: 600; letter-spacing: -0.02em; line-height: 1.2; margin: 0 0 24px; }

/* Category tabs, built by script.js from each post's data-category */
.tabs {
  display: flex;
  gap: 8px 28px;
  margin-bottom: 40px;
  overflow-x: auto;
  scrollbar-width: none;
}
.tab {
  flex: none;
  padding: 0;
  font: inherit;
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--faint);
  background: none;
  border: 0;
  cursor: pointer;
  transition: color 0.15s;
}
.tab:hover, .tab[aria-pressed="true"] { color: var(--text); }

/* As many ~150px cards per row as fit: about six on a desktop, two on a phone. */
.post-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); gap: 36px 18px; margin: 0; padding: 0; list-style: none; }

/* Shown only while the list is empty */
.blog-empty { color: var(--faint); }
.post-grid:has(li) ~ .blog-empty { display: none; }

.post-card { display: block; color: var(--text); }
.post-card:hover { text-decoration: none; }
.post-title { display: block; margin-bottom: 8px; font-size: 0.95rem; line-height: 1.45; letter-spacing: -0.01em; text-wrap: pretty; }
.post-meta { display: flex; flex-wrap: wrap; gap: 2px 10px; font-size: 0.8rem; }
.post-meta time { color: var(--faint); }

/* Square covers: put an <img> inside to use a picture, otherwise the cards
   cycle through six soft gradients. */
.cover {
  display: block;
  aspect-ratio: 1;
  margin-bottom: 12px;
  overflow: hidden;
  background: var(--surface);
  border-radius: 6px;
  transition: opacity 0.25s;
}
.cover img { display: block; width: 100%; height: 100%; object-fit: cover; }
.post-card:hover .cover { opacity: 0.85; }

.post-grid > li:nth-child(6n + 1) .cover:empty { background: radial-gradient(90% 80% at 20% 20%, #a5c8ff, transparent 60%), radial-gradient(80% 80% at 85% 80%, #2f5bd3, transparent 65%), linear-gradient(150deg, #23345e, #0d1424); }
.post-grid > li:nth-child(6n + 2) .cover:empty { background: radial-gradient(85% 75% at 25% 25%, #ececec, transparent 60%), radial-gradient(80% 90% at 80% 85%, #5b616e, transparent 65%), linear-gradient(140deg, #3a3d45, #141518); }
.post-grid > li:nth-child(6n + 3) .cover:empty { background: radial-gradient(80% 80% at 20% 85%, #6fe3d2, transparent 60%), radial-gradient(85% 75% at 80% 15%, #6aa8ff, transparent 60%), linear-gradient(160deg, #1c3d5c, #0b1a2a); }
.post-grid > li:nth-child(6n + 4) .cover:empty { background: radial-gradient(80% 70% at 75% 25%, #b9c3ff, transparent 60%), radial-gradient(90% 85% at 20% 80%, #4b3fd0, transparent 65%), linear-gradient(140deg, #231f55, #0e0c22); }
.post-grid > li:nth-child(6n + 5) .cover:empty { background: radial-gradient(85% 80% at 30% 20%, #d5dde8, transparent 60%), radial-gradient(80% 80% at 80% 85%, #34445c, transparent 65%), linear-gradient(150deg, #263244, #0e141d); }
.post-grid > li:nth-child(6n + 6) .cover:empty { background: radial-gradient(80% 75% at 80% 20%, #e3f4ff, transparent 55%), radial-gradient(90% 85% at 20% 80%, #2fa3e6, transparent 65%), linear-gradient(160deg, #0f4a70, #072235); }

/* ---------- post pages, after OpenAI's article layout ---------- */
.article { max-width: 1120px; padding: 72px 0 112px; }

.article-head { max-width: 760px; margin: 0 auto; text-align: center; }
.article-meta { display: flex; justify-content: center; gap: 14px; margin-bottom: 26px; font-size: 0.9rem; }
.article-meta span { color: var(--faint); }
.article-head h1 { margin: 0 0 22px; font-size: clamp(2.4rem, 6vw, 3.6rem); font-weight: 500; line-height: 1.08; letter-spacing: -0.03em; text-wrap: balance; }
.dek { max-width: 560px; margin: 0 auto; font-size: 1.05rem; text-wrap: balance; }

.article-bar {
  display: flex;
  align-items: center;
  gap: 16px;
  max-width: 620px;
  margin: 72px auto 0;
  padding-top: 18px;
  border-top: 1px solid var(--border);
}
.listen, .share {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 0;
  font: inherit;
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text);
  background: none;
  border: 0;
  cursor: pointer;
}
.share { margin-left: auto; }
.share svg { width: 15px; height: 15px; }
.share:hover .share-label { text-decoration: underline; text-underline-offset: 3px; }

.listen-icon { display: grid; place-items: center; width: 30px; height: 30px; background: var(--surface); border-radius: 50%; transition: background 0.15s; }
.listen:hover .listen-icon { background: var(--border-strong); }
.listen-icon svg { width: 12px; height: 12px; }
.listen .icon-pause, .listen.is-playing .icon-play { display: none; }
.listen.is-playing .icon-pause { display: block; }
.listen-time { padding-left: 12px; color: var(--muted); border-left: 1px solid var(--border); font-variant-numeric: tabular-nums; }

/* Sidebar contents on the left, reading column in the middle */
.article-layout { display: grid; grid-template-columns: 1fr minmax(0, 620px) 1fr; column-gap: 40px; margin-top: 56px; }

.toc { position: sticky; top: 32px; grid-column: 1; align-self: start; justify-self: start; max-width: 200px; font-size: 0.8rem; }
.toc a { display: block; padding: 4px 0; line-height: 1.35; color: var(--faint); }
.toc a:hover { color: var(--text); text-decoration: none; }
.toc a.is-active { color: var(--text); }
.toc a.sub { padding-left: 12px; }

.article-body { grid-column: 2; font-size: 1.06rem; line-height: 1.7; }
.article-body p { margin: 0 0 1.2em; }
.article-body h2 { margin: 2.2em 0 0.6em; font-size: 1.5rem; font-weight: 500; letter-spacing: -0.01em; scroll-margin-top: 24px; }
.article-body h3 { margin: 1.8em 0 0.5em; font-size: 1.15rem; font-weight: 500; scroll-margin-top: 24px; }
.article-body ul, .article-body ol { margin: 0 0 1.2em; padding-left: 1.3em; }
.article-body li { margin: 0.4em 0; }
.article-body a { text-decoration: underline; text-decoration-thickness: 1px; text-underline-offset: 3px; }

/* ---------- small screens ---------- */
@media (max-width: 1000px) {
  .article-layout { grid-template-columns: minmax(0, 620px); justify-content: center; }
  .toc { display: none; }
  .article-body { grid-column: 1; }
}

@media (max-width: 600px) {
  main { padding-top: 40px; }
  .home { padding-top: 48px; }
  .headline { font-size: 1.6rem; }

  .blog { padding-top: 36px; }
  .blog-title { font-size: 1.6rem; }

  .article { padding-top: 44px; }
  .article-bar { margin-top: 48px; }
}

@media (prefers-reduced-motion: reduce) {
  .link-btn, .tab, .cover, .listen-icon { transition: none; }
  .grad-text, .rotator-cursor { animation: none; }
}

@media print {
  :root, [data-theme] {
    --bg: #fff; --surface: #fff; --text: #000; --muted: #333; --faint: #555; --border: #ccc; --accent: #000;
  }
  main { padding-top: 0; }
  .topbar, .bg-ascii, .article-bar, .toc { display: none; }
}