/* =========================================================================
   sebs.github.io — editorial developer hub
   Hand-written CSS (no CDN). Dark default + light theme via [data-theme].
   ========================================================================= */

/* ---- Design tokens ----------------------------------------------------- */
:root {
  --font-display: "Geist", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-body: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: ui-monospace, "SFMono-Regular", "Geist Mono", Menlo, Consolas, monospace;

  --container: 1120px;
  --gutter: 32px;
  --margin: 20px;
  --section-gap: 80px;

  --radius: 2px;
  --radius-lg: 8px;

  --ease: cubic-bezier(0.2, 0.6, 0.2, 1);
}

/* Dark (default) */
[data-theme="dark"] {
  --bg: #0e141a;
  --surface: #161c23;
  --surface-2: #1a2027;
  --surface-3: #252b31;
  --border: #45474b;
  --border-strong: #6c6e74;
  --text: #dde3ec;
  --text-muted: #c6c6cb;
  --text-faint: #8f9095;
  --accent: #4fdbc8;
  --accent-strong: #71f8e4;
  --accent-ink: #00201c;
  --glow: rgba(79, 219, 200, 0.06);
  --shadow: rgba(0, 0, 0, 0.4);
  color-scheme: dark;
}

/* Light */
[data-theme="light"] {
  --bg: #f6f8fb;
  --surface: #ffffff;
  --surface-2: #eef2f7;
  --surface-3: #e3e9f1;
  --border: #d4dbe4;
  --border-strong: #9aa4b0;
  --text: #141c25;
  --text-muted: #41505f;
  --text-faint: #66717f;
  --accent: #0b8576;
  --accent-strong: #096b5f;
  --accent-ink: #ffffff;
  --glow: rgba(11, 133, 118, 0.05);
  --shadow: rgba(20, 28, 37, 0.1);
  color-scheme: light;
}

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

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

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  scroll-padding-top: 96px;
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }

::selection { background: color-mix(in srgb, var(--accent) 30%, transparent); }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: var(--radius);
}

.icon { width: 1.15em; height: 1.15em; flex: none; vertical-align: -0.18em; }

.mono {
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.02em;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 100;
  background: var(--accent);
  color: var(--accent-ink);
  padding: 10px 16px;
  font-weight: 600;
}
.skip-link:focus { left: 12px; top: 12px; }

/* ---- Layout helpers ---------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--margin);
}
@media (min-width: 768px) {
  .container { padding-inline: var(--gutter); }
}

.section {
  padding-block: var(--section-gap);
  border-top: 1px solid var(--border);
}

.section__head {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin-bottom: var(--gutter);
}
@media (min-width: 768px) {
  .section__head { flex-direction: row; align-items: flex-end; justify-content: space-between; }
}

.eyebrow {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--text-faint);
}

h1, h2, h3, h4 { font-family: var(--font-display); font-weight: 600; line-height: 1.15; }

.h-section { font-size: clamp(26px, 4vw, 32px); letter-spacing: -0.02em; }
.h-card { font-size: 20px; font-weight: 600; }

.lead { color: var(--text-muted); max-width: 52ch; }

.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent);
}
.link-arrow .icon { width: 16px; height: 16px; transition: transform 0.2s var(--ease); }
.link-arrow:hover .icon { transform: translateX(4px); }

/* ---- Buttons ----------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 22px;
  font-family: var(--font-body);
  font-weight: 600;
  font-size: 15px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: border-color 0.2s var(--ease), background 0.2s var(--ease), color 0.2s var(--ease);
  cursor: pointer;
}
.btn--sm { padding: 8px 16px; font-size: 14px; }
.btn--solid { background: var(--text); color: var(--bg); border-color: var(--text); }
.btn--solid:hover { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.btn--ghost { background: transparent; color: var(--text); }
.btn--ghost:hover { border-color: var(--accent); color: var(--accent); }

/* ---- App bar ----------------------------------------------------------- */
.appbar {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 50;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.appbar__inner {
  max-width: var(--container);
  margin-inline: auto;
  padding: 14px var(--margin);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}
@media (min-width: 768px) { .appbar__inner { padding-inline: var(--gutter); } }

.appbar__brand { font-family: var(--font-display); font-weight: 700; font-size: 18px; }
.appbar__nav { display: none; align-items: center; gap: 28px; }
@media (min-width: 768px) { .appbar__nav { display: flex; } }
.appbar__nav a { color: var(--text-muted); font-size: 15px; transition: color 0.2s var(--ease); }
.appbar__nav a:hover, .appbar__nav a[aria-current="page"] { color: var(--accent); }
.appbar__nav a.btn { color: var(--bg); }
.appbar__nav a.btn:hover { color: var(--accent-ink); }

.theme-toggle {
  display: inline-grid;
  place-items: center;
  width: 40px; height: 40px;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text-muted);
  cursor: pointer;
  transition: border-color 0.2s var(--ease), color 0.2s var(--ease);
}
.theme-toggle:hover { color: var(--accent); border-color: var(--accent); }
.theme-toggle .icon { width: 20px; height: 20px; }
[data-theme="dark"] .theme-toggle__dark { display: none; }
[data-theme="light"] .theme-toggle__light { display: none; }

/* ---- Hero -------------------------------------------------------------- */
main { padding-top: 70px; }

.hero {
  position: relative;
  overflow: hidden;
  display: grid;
  gap: 48px;
  padding-block: clamp(48px, 8vw, var(--section-gap));
  align-items: center;
}
@media (min-width: 900px) {
  .hero { grid-template-columns: 1.1fr 0.9fr; gap: var(--section-gap); }
}
.hero__glow {
  position: absolute;
  top: -200px; left: -160px;
  width: 600px; height: 600px;
  background: radial-gradient(circle at 50% 50%, var(--glow) 0%, transparent 70%);
  pointer-events: none;
  z-index: 0;
}
.hero__content { position: relative; z-index: 1; }
.hero h1 {
  font-size: clamp(40px, 7vw, 56px);
  letter-spacing: -0.04em;
  font-weight: 700;
  margin-bottom: 16px;
}
.hero__identity {
  font-size: clamp(18px, 2.4vw, 20px);
  color: var(--accent);
  font-weight: 500;
  max-width: 34ch;
  margin-bottom: 16px;
}
.hero__known { color: var(--text-muted); max-width: 46ch; margin-bottom: var(--gutter); }
.hero__ctas { display: flex; flex-wrap: wrap; gap: 12px; }

.hero__visual {
  position: relative;
  z-index: 1;
  aspect-ratio: 1 / 1;
  border: 1px solid var(--border);
  background:
    linear-gradient(135deg, color-mix(in srgb, var(--accent) 8%, transparent), transparent 60%),
    var(--surface);
  overflow: hidden;
  display: grid;
  place-items: center;
}
@media (min-width: 900px) { .hero__visual { aspect-ratio: auto; height: 460px; } }
.hero__visual::before {
  /* subtle code-grid texture, no image dependency */
  content: "";
  position: absolute; inset: 0;
  background-image:
    linear-gradient(var(--border) 1px, transparent 1px),
    linear-gradient(90deg, var(--border) 1px, transparent 1px);
  background-size: 32px 32px;
  opacity: 0.25;
  mask-image: radial-gradient(circle at 50% 50%, #000 30%, transparent 75%);
}
.hero__coords {
  position: absolute;
  bottom: 16px; right: 16px;
  background: color-mix(in srgb, var(--bg) 80%, transparent);
  backdrop-filter: blur(6px);
  border: 1px solid var(--border);
  padding: 8px 14px;
  color: var(--accent);
}
.hero__mark {
  font-family: var(--font-mono);
  font-size: clamp(40px, 9vw, 96px);
  font-weight: 700;
  color: var(--text-faint);
  opacity: 0.5;
  letter-spacing: -0.05em;
  user-select: none;
}

/* ---- Projects ---------------------------------------------------------- */
.cards { display: grid; gap: var(--gutter); }
@media (min-width: 768px) { .cards { grid-template-columns: 1fr 1fr; } }

.card {
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border);
  background: var(--surface);
  padding: var(--gutter);
  transition: border-color 0.2s var(--ease), transform 0.2s var(--ease);
}
.card:hover { border-color: var(--accent); }
.card__top { display: flex; justify-content: space-between; align-items: flex-start; gap: 12px; margin-bottom: 14px; }
.card__tags { display: flex; flex-wrap: wrap; gap: 6px; }
.tag {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 4px 8px;
  background: var(--surface-3);
  color: var(--text-muted);
  white-space: nowrap;
}
.tag--active { background: color-mix(in srgb, var(--accent) 18%, transparent); color: var(--accent); }
.card__desc { color: var(--text-muted); margin-bottom: var(--gutter); flex: 1; }

.card__foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  border-top: 1px solid var(--border);
  padding-top: 16px;
  margin-top: auto;
}
.card__signals { display: flex; flex-wrap: wrap; gap: 16px; }
.signal { display: inline-flex; align-items: center; gap: 6px; font-family: var(--font-mono); font-size: 13px; color: var(--text-muted); }
.signal .icon { width: 16px; height: 16px; }
.signal--accent { color: var(--accent); }
.card__links { display: flex; gap: 14px; }
.card__links a { color: var(--text-muted); transition: color 0.2s var(--ease); }
.card__links a:hover { color: var(--accent); }
.card__links .icon { width: 20px; height: 20px; }

/* ---- Writing ----------------------------------------------------------- */
.rows { border-top: 1px solid var(--border); }
.row {
  display: grid;
  grid-template-columns: 1fr;
  gap: 6px;
  align-items: center;
  padding: 22px 8px;
  border-bottom: 1px solid var(--border);
  transition: background 0.2s var(--ease);
}
.row:hover { background: var(--surface); }
@media (min-width: 768px) {
  .row { grid-template-columns: 130px 1fr auto; gap: 24px; padding-inline: 12px; }
}
.row__date { font-family: var(--font-mono); font-size: 13px; color: var(--text-faint); text-transform: uppercase; }
.row__title { font-size: 18px; color: var(--text); transition: color 0.2s var(--ease); }
.row:hover .row__title { color: var(--accent); }
.row__meta { display: flex; align-items: center; gap: 14px; color: var(--text-faint); font-family: var(--font-mono); font-size: 13px; }
.row__meta .icon { width: 16px; height: 16px; }
.row__arrow .icon { color: var(--text-faint); transition: transform 0.2s var(--ease), color 0.2s var(--ease); }
.row:hover .row__arrow .icon { color: var(--accent); transform: translate(3px, -3px); }

.writing__empty { color: var(--text-faint); padding: 24px 8px; font-family: var(--font-mono); font-size: 14px; }

.callout {
  margin-top: var(--section-gap);
  display: flex;
  flex-direction: column;
  gap: 16px;
  border: 1px solid var(--border);
  background: var(--surface);
  padding: 24px;
}
@media (min-width: 768px) { .callout { flex-direction: row; align-items: center; justify-content: space-between; } }
.callout h3 { font-size: 20px; margin-bottom: 4px; }
.callout p { color: var(--text-muted); }
.callout__link {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--accent);
  border-bottom: 1px solid var(--accent);
  padding-bottom: 2px;
  white-space: nowrap;
}
.callout__link:hover { color: var(--text); border-color: var(--text); }

/* ---- Talks ------------------------------------------------------------- */
.talks { display: flex; flex-direction: column; gap: 48px; }
.talk {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}
@media (min-width: 768px) { .talk { grid-template-columns: 120px 1fr; gap: var(--gutter); } }
.talk__year { font-family: var(--font-mono); font-size: 13px; letter-spacing: 0.14em; color: var(--text-faint); text-transform: uppercase; padding-top: 4px; }
.talk__body { display: flex; flex-direction: column; gap: 16px; }
.talk h2, .talk h3 { font-size: clamp(22px, 3vw, 28px); transition: color 0.2s var(--ease); }
.talk:hover h2, .talk:hover h3 { color: var(--accent); }
.talk__venue { display: inline-flex; align-items: center; gap: 8px; color: var(--text-muted); font-family: var(--font-mono); font-size: 14px; }
.talk__venue .icon { width: 16px; height: 16px; }
.talk__desc { color: var(--text-muted); max-width: 62ch; }
.talk__links { display: flex; flex-wrap: wrap; gap: 12px; }

.deck {
  aspect-ratio: 16 / 9;
  width: 100%;
  border: 1px solid var(--border);
  background:
    linear-gradient(135deg, color-mix(in srgb, var(--accent) 14%, transparent), transparent 60%),
    var(--surface);
  display: grid;
  place-items: center;
  gap: 12px;
  color: var(--text-faint);
  text-align: center;
}
.deck .icon { width: 40px; height: 40px; }
.deck iframe { width: 100%; height: 100%; border: 0; }
.deck__pdf { width: 100%; height: 100%; }

.talk-divider { border: none; border-top: 1px solid color-mix(in srgb, var(--border) 60%, transparent); }

/* Historical log table */
.log {
  border: 1px solid var(--border);
  background: var(--surface);
  font-family: var(--font-mono);
  font-size: 13px;
  overflow: hidden;
}
.log__row { display: grid; grid-template-columns: 70px 1fr; gap: 16px; padding: 14px 16px; border-bottom: 1px solid var(--border); }
@media (min-width: 640px) { .log__row { grid-template-columns: 90px 1fr 1fr; } }
.log__row:last-child { border-bottom: none; }
.log__row--head { background: var(--surface-2); color: var(--text-faint); letter-spacing: 0.08em; }
.log__year { color: var(--text-faint); }
.log__title { color: var(--text); }
.log__venue { color: var(--text-muted); }
.log__venue--head, .log__title--head { color: var(--text-faint); }
@media (max-width: 639px) { .log__venue { display: none; } }

.divider-head { display: flex; align-items: center; gap: 16px; margin-bottom: 28px; }
.divider-head .eyebrow { white-space: nowrap; }
.divider-head::after { content: ""; flex: 1; height: 1px; background: var(--border); }

/* ---- Footer ------------------------------------------------------------ */
.footer { border-top: 1px solid var(--border); }
.footer__inner {
  max-width: var(--container);
  margin-inline: auto;
  padding: var(--section-gap) var(--margin) var(--gutter);
  display: flex;
  flex-direction: column;
  gap: 28px;
}
@media (min-width: 768px) {
  .footer__inner { flex-direction: row; justify-content: space-between; align-items: flex-start; padding-inline: var(--gutter); }
}
.footer__name { text-transform: uppercase; letter-spacing: 0.16em; font-weight: 500; display: block; margin-bottom: 8px; }
.footer__tag { color: var(--text-muted); font-size: 14px; }
.footer__pitch { color: var(--text-faint); font-size: 14px; max-width: 40ch; margin-top: 8px; }
.footer__links { display: flex; flex-wrap: wrap; gap: 20px; }
.footer__links a {
  color: var(--text-muted);
  font-size: 14px;
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 4px;
  transition: color 0.2s var(--ease);
}
.footer__links a:hover { color: var(--accent); }
.footer__sponsor { color: var(--accent) !important; }
.footer__legal {
  max-width: var(--container);
  margin-inline: auto;
  padding: 18px var(--margin);
  border-top: 1px solid var(--border);
  color: var(--text-faint);
}
@media (min-width: 768px) { .footer__legal { padding-inline: var(--gutter); } }

/* ---- Page header (sub-pages) ------------------------------------------- */
.page-head { padding-block: clamp(40px, 7vw, var(--section-gap)); }
.page-head h1 { font-size: clamp(40px, 7vw, 56px); letter-spacing: -0.04em; font-weight: 700; margin-bottom: 16px; }

/* ---- Long-form posts --------------------------------------------------- */
.post { max-width: 760px; padding-block: clamp(32px, 6vw, 64px); }
.post__head { margin-bottom: var(--gutter); }
.post__meta {
  display: flex; gap: 10px; align-items: center;
  font-family: var(--font-mono); font-size: 13px; color: var(--text-faint);
  margin-bottom: 14px;
}
.post__back { color: var(--text-muted); }
.post__back:hover { color: var(--accent); }
.post__title {
  font-family: var(--font-display);
  font-size: clamp(30px, 5vw, 44px); line-height: 1.15;
  letter-spacing: -0.03em; font-weight: 700;
}
.post__tags { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 18px; }
.post__foot {
  margin-top: var(--section-gap); padding-top: var(--gutter);
  border-top: 1px solid var(--border);
}

/* Prose — rendered markdown body */
.prose { font-size: 17px; line-height: 1.7; }
.prose > * + * { margin-top: 1.2em; }
.prose h2 {
  font-family: var(--font-display); font-size: 1.5em; font-weight: 600;
  letter-spacing: -0.02em; line-height: 1.25; margin-top: 1.9em;
}
.prose h3 { font-family: var(--font-display); font-size: 1.2em; font-weight: 600; margin-top: 1.6em; }
.prose a {
  color: var(--accent); text-decoration: underline;
  text-decoration-thickness: 1px; text-underline-offset: 3px;
}
.prose a:hover { color: var(--accent-strong); }
.prose ul, .prose ol { padding-left: 1.4em; }
.prose li + li { margin-top: 0.4em; }
.prose strong { font-weight: 600; }
.prose blockquote {
  border-left: 3px solid var(--border-strong); padding-left: 1em;
  color: var(--text-muted); font-style: italic;
}
.prose figure { margin-block: 1.6em; }
.prose figcaption { font-size: 14px; color: var(--text-faint); margin-top: 8px; }
.prose hr { border: 0; border-top: 1px solid var(--border); margin-block: 2em; }

/* Inline + block code */
.prose :not(pre) > code {
  font-family: var(--font-mono); font-size: 0.88em;
  background: var(--surface-3); color: var(--accent-strong);
  padding: 2px 6px; border-radius: var(--radius);
}
.prose pre {
  font-family: var(--font-mono); font-size: 14px; line-height: 1.55;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 18px 20px; overflow-x: auto;
}
.prose pre code { background: none; color: var(--text); padding: 0; font-size: inherit; }

/* ---- Archive listings -------------------------------------------------- */
.archive-year { margin-bottom: var(--section-gap); }
.archive-year__label {
  font-family: var(--font-mono); font-size: 14px; color: var(--text-faint);
  letter-spacing: 0.08em; padding-bottom: 10px;
  border-bottom: 1px solid var(--border); margin-bottom: 4px;
}
.archive-list { list-style: none; padding: 0; }
.archive-item a {
  display: grid; grid-template-columns: 70px 1fr; gap: 16px; align-items: baseline;
  padding: 14px 4px; border-bottom: 1px solid var(--border);
  transition: padding-left 0.2s var(--ease);
}
.archive-item a:hover { padding-left: 12px; }
.archive-item a:hover .archive-item__title { color: var(--accent); }
.archive-item__date {
  font-family: var(--font-mono); font-size: 13px;
  color: var(--text-faint); white-space: nowrap;
}
.archive-item__title { font-weight: 600; font-size: 1.05rem; }
.archive-item__tags {
  display: none; font-family: var(--font-mono); font-size: 11px; color: var(--text-faint);
}
@media (min-width: 768px) {
  .archive-item a { grid-template-columns: 88px 1fr auto; }
  .archive-item__tags { display: inline; }
}

/* ---- Motion / a11y ----------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { transition: none !important; animation: none !important; }
}