/* Shift: mantle.chat's own tokens, type and buttons (read off the live site), then the site's pages.
   Everything sits on one centred axis. About reads top to bottom: serif headline, lede and two buttons, a facts strip,
   how it started, why, who it's for, one dark band for the worries that closes on the learning-by-sharing
   line, and the two of us last: small round photos and the invitation. */
:root {
  --background: hsl(0 0.25% 96.23%);
  --foreground: hsl(236.05 1.7% 18.33%);
  --muted: hsl(0 0.96% 36.56%);
  --border: hsl(0 0.05% 84.58%);
  --card: hsl(0 0.85% 98.87%);
  --primary: hsl(236.05 1.7% 18.33%);
  --primary-fg: hsl(0 0.25% 96.23%);
  --band: hsl(220 24% 7%);
  --band-fg: hsl(220 13% 98%);
  --band-muted: hsl(220 8% 68%);
  --band-rule: hsl(220 12% 20%);
  --soft: color-mix(in srgb, var(--foreground) 6%, transparent);
  --warn: hsl(24 70% 42%);
  --radius: 0.5rem;
  --font-display: 'Fraunces', 'Fraunces Fallback', Georgia, serif;
  --font-body: 'Inter', -apple-system, system-ui, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme='light']) {
    --background: hsl(235.12 13.45% 9.8%);
    --foreground: hsl(236.06 14.46% 90.66%);
    --muted: hsl(236 8% 66%);
    --border: hsl(235 10% 22%);
    --card: hsl(235 12% 13%);
    --primary: hsl(236 14% 90%);
    --primary-fg: hsl(235 13% 10%);
    --band: hsl(235 12% 15%);
    --band-fg: hsl(236 14% 92%);
    --band-muted: hsl(236 8% 66%);
    --band-rule: hsl(235 10% 26%);
    --warn: hsl(28 80% 64%);
    color-scheme: dark;
  }
}
:root[data-theme='dark'] {
  --background: hsl(235.12 13.45% 9.8%);
  --foreground: hsl(236.06 14.46% 90.66%);
  --muted: hsl(236 8% 66%);
  --border: hsl(235 10% 22%);
  --card: hsl(235 12% 13%);
  --primary: hsl(236 14% 90%);
  --primary-fg: hsl(235 13% 10%);
  --band: hsl(235 12% 15%);
  --band-fg: hsl(236 14% 92%);
  --band-muted: hsl(236 8% 66%);
  --band-rule: hsl(235 10% 26%);
  --warn: hsl(28 80% 64%);
  color-scheme: dark;
}
* {
  box-sizing: border-box;
}
body {
  margin: 0;
  background: var(--background);
  color: var(--foreground);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
}
a {
  color: inherit;
}
p {
  margin: 0;
}
h1,
h2,
h3 {
  margin: 0;
  font-family: var(--font-display);
  font-optical-sizing: auto;
  text-wrap: balance;
}
h1 {
  font-weight: 450;
  letter-spacing: -0.015em;
  line-height: 1.06;
}
h2 {
  font-weight: 470;
  letter-spacing: -0.012em;
  line-height: 1.15;
}
h3 {
  font-weight: 470;
  letter-spacing: -0.01em;
  line-height: 1.2;
}
.wrap {
  max-width: 1080px;
  margin: 0 auto;
  padding-inline: 20px;
}
.narrow {
  max-width: 680px;
  margin-inline: auto;
}
.eyebrow {
  font-size: 11px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
}
:focus-visible {
  outline: 2px solid var(--foreground);
  outline-offset: 3px;
  border-radius: 4px;
}
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  height: 44px;
  padding: 0 24px;
  border-radius: 999px;
  background: var(--primary);
  color: var(--primary-fg);
  font: inherit;
  font-size: 15px;
  font-weight: 500;
  text-decoration: none;
  white-space: nowrap;
  border: 0;
}
.btn:hover {
  opacity: 0.9;
}
.textbtn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  height: 44px;
  font-size: 15px;
  font-weight: 500;
  text-decoration: none;
  color: var(--foreground);
}
.textbtn:hover {
  text-decoration: underline;
  text-underline-offset: 4px;
}
.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 24px;
  justify-content: center;
  align-items: center;
}
.link {
  text-decoration: underline;
  text-decoration-color: var(--border);
  text-underline-offset: 4px;
}
.link:hover {
  text-decoration-color: currentColor;
}

/* nav, like the site's */
.nav {
  position: sticky;
  top: env(safe-area-inset-top, 0px);
  z-index: 5;
  background: color-mix(in srgb, var(--background) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.nav .wrap {
  display: flex;
  align-items: center;
  gap: 12px;
  padding-block: 12px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
  font-size: 15px;
  text-decoration: none;
}
.brand svg {
  width: 12px;
  height: 18px;
  fill: currentColor;
}
.nav .links {
  margin-left: auto;
  display: flex;
  gap: 2px;
}
.nav .links a {
  font-size: 13px;
  white-space: nowrap;
  color: var(--muted);
  text-decoration: none;
  padding: 8px 12px;
  border-radius: 999px;
}
.nav .links a[aria-current='page'] {
  color: var(--foreground);
  font-weight: 500;
}
.nav .links a:hover {
  color: var(--foreground);
  background: color-mix(in srgb, var(--foreground) 6%, transparent);
}

/* hero, centred */
.hero {
  padding: 80px 0 64px;
  display: grid;
  justify-items: center;
  text-align: center;
  gap: 20px;
}
.hero h1 {
  font-size: clamp(44px, 6.4vw, 68px);
  max-width: 16ch;
}
.hero .lede {
  font-size: 18px;
  color: var(--muted);
  max-width: 52ch;
}
@media (prefers-reduced-motion: no-preference) {
  .rise {
    animation: rise 0.8s cubic-bezier(0.2, 0.7, 0.2, 1) both;
  }
  .rise.d1 {
    animation-delay: 0.06s;
  }
  .rise.d2 {
    animation-delay: 0.12s;
  }
  .rise.d3 {
    animation-delay: 0.18s;
  }
  .rise.d4 {
    animation-delay: 0.24s;
  }
  @keyframes rise {
    from {
      transform: translateY(10px);
    }
  }
}

/* real numbers from the project */
.facts {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  border-block: 1px solid var(--border);
  text-align: center;
}
.facts.three {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}
.facts > * {
  padding: 24px 12px;
  display: grid;
  gap: 4px;
  justify-items: center;
}
.facts > * + * {
  border-left: 1px solid var(--border);
}
.facts b {
  font-family: var(--font-display);
  font-weight: 450;
  font-size: clamp(36px, 4.4vw, 52px);
  line-height: 1;
  letter-spacing: -0.015em;
}
.facts span {
  font-size: 13.5px;
  color: var(--muted);
  max-width: 20ch;
}

/* sections */
section.s {
  padding-block: clamp(64px, 9vw, 104px);
}
.head {
  display: grid;
  gap: 12px;
  justify-items: center;
  text-align: center;
  margin-bottom: 36px;
}
.head h2 {
  font-size: clamp(30px, 3.8vw, 44px);
  max-width: 22ch;
}
.head p {
  font-size: 18px;
  color: var(--muted);
  max-width: 56ch;
}
.prose {
  display: grid;
  gap: 16px;
  font-size: 18px;
  text-align: center;
}
.cards {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  display: grid;
  gap: 10px;
  align-content: start;
  text-align: center;
  justify-items: center;
}
/* the two "who it's for" titles break into two balanced lines */
.card h3 {
  font-size: 24px;
  max-width: 20ch;
}
.card p {
  color: var(--muted);
  max-width: 44ch;
}

/* the one dark band */
.band {
  background: var(--band);
  color: var(--band-fg);
}
.band .eyebrow {
  color: var(--band-muted);
}
.band .head p {
  color: var(--band-muted);
}
.worries {
  list-style: none;
  margin: 0 auto;
  padding: 0;
  max-width: 760px;
  border-top: 1px solid var(--band-rule);
}
.worries li {
  display: grid;
  gap: 6px;
  padding-block: 24px;
  border-bottom: 1px solid var(--band-rule);
  text-align: center;
  justify-items: center;
}
.worries b {
  font-family: var(--font-display);
  font-weight: 450;
  font-size: clamp(26px, 3.2vw, 36px);
  line-height: 1.1;
  letter-spacing: -0.015em;
}
.worries span {
  color: var(--band-muted);
  max-width: 56ch;
}
.share {
  margin: 64px auto 0;
  display: grid;
  gap: 16px;
  justify-items: center;
  text-align: center;
  max-width: 820px;
}
.share blockquote {
  margin: 0;
  font-family: var(--font-display);
  font-style: italic;
  font-weight: 350;
  font-size: clamp(30px, 4.2vw, 52px);
  line-height: 1.12;
  letter-spacing: -0.015em;
  max-width: 22ch;
}
.share p {
  color: var(--band-muted);
  font-size: 18px;
  max-width: 48ch;
}

/* the two of us, last and small */
.me {
  display: grid;
  gap: 12px;
  justify-items: center;
  text-align: center;
  padding-block: clamp(56px, 8vw, 88px);
  max-width: 640px;
}
.avatar {
  width: 112px;
  height: 112px;
  border-radius: 50%;
  object-fit: cover;
  object-position: 50% 30%;
  border: 1px solid var(--border);
}
.me .avatar {
  width: 80px;
  height: 80px;
}
.people {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 20px 48px;
  margin-bottom: 8px;
}
.person {
  display: grid;
  justify-items: center;
  gap: 6px;
  font-size: 14.5px;
}
.person a {
  font-weight: 500;
  text-decoration: none;
}
.person a:hover {
  text-decoration: underline;
  text-underline-offset: 4px;
}
.person span {
  color: var(--muted);
  font-size: 13.5px;
}
.me h2 {
  font-size: clamp(28px, 3.4vw, 36px);
}
.me p:not(.eyebrow) {
  color: var(--muted);
  max-width: 48ch;
}
.me .btn {
  margin-top: 8px;
}
footer {
  border-top: 1px solid var(--border);
  padding-block: 28px 40px;
}
footer .wrap {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 24px;
  justify-content: center;
  font-size: 14px;
  color: var(--muted);
  text-align: center;
}

@media (max-width: 760px) {
  .facts {
    grid-template-columns: 1fr 1fr;
  }
  .facts > :nth-child(3) {
    border-left: 0;
  }
  .facts > :nth-child(n + 3) {
    border-top: 1px solid var(--border);
  }
  /* three numbers still fit in one row on a phone */
  .facts.three {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .facts.three > :nth-child(3) {
    border-left: 1px solid var(--border);
    border-top: 0;
  }
  .cards {
    grid-template-columns: 1fr;
  }
  /* the page links drop to their own row and spread across it; Blog stays in the footer */
  .nav .wrap {
    flex-wrap: wrap;
    row-gap: 4px;
    padding-block: 10px 6px;
  }
  .nav .btn {
    margin-left: auto;
  }
  .nav .links {
    order: 3;
    flex: 1 0 100%;
    margin: 0 -6px;
    justify-content: space-between;
    overflow-x: auto;
    scrollbar-width: none;
  }
  .nav .links::-webkit-scrollbar {
    display: none;
  }
  .nav .links a {
    padding: 8px 4px;
    font-size: 12.5px;
  }
  .nav .links .ext {
    display: none;
  }
}

/* ---------- the AI at Work site: About's mantle.chat language, applied to every page ---------- */
[hidden] {
  display: none !important;
}
ul,
ol {
  margin: 0;
  padding: 0;
  list-style: none;
}
button {
  font: inherit;
  color: inherit;
}
.muted {
  color: var(--muted);
}
.btn.small {
  height: 36px;
  padding: 0 16px;
  font-size: 14px;
}
.btn.ghost {
  background: transparent;
  color: var(--foreground);
  border: 1px solid var(--border);
}
.btn.ghost:hover {
  border-color: var(--foreground);
  opacity: 1;
}
button.btn {
  cursor: pointer;
}
button.link {
  background: none;
  border: 0;
  padding: 0;
  cursor: pointer;
}

/* the site's name, Shift, with a quiet maker's mark next to it */
.nav .by {
  font-size: 13px;
  color: var(--muted);
  text-decoration: none;
  margin-left: -4px;
  white-space: nowrap;
}
.nav .by:hover {
  color: var(--foreground);
}

/* page heads reuse About's .hero; sections reuse its .s and .head */
section.s.tight {
  padding-top: 0;
}
/* the four steps reuse About's facts strip: a big serif numeral, a title, one muted line */
.steps strong {
  font-weight: 600;
  font-size: 15px;
  margin-top: 6px;
}
.steps span {
  max-width: 24ch;
}
.col {
  max-width: 760px;
  margin-inline: auto;
  display: grid;
  gap: 20px;
}
.foot-note {
  text-align: center;
  color: var(--muted);
  font-size: 15px;
}

/* interviews */
.proof {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
  font-size: 14.5px;
  color: var(--muted);
  max-width: 60ch;
}
.proof b {
  color: var(--foreground);
  font-weight: 600;
}
.avs {
  display: flex;
  align-items: center;
}
.avs > * {
  width: 30px;
  height: 30px;
  border-radius: 50%;
  border: 2px solid var(--background);
  margin-left: -8px;
  object-fit: cover;
  background: var(--card);
  display: grid;
  place-items: center;
  font-size: 11px;
  font-weight: 600;
  color: var(--muted);
}
.avs > :first-child {
  margin-left: 0;
}
.avs.lg > * {
  width: 40px;
  height: 40px;
  margin-left: -10px;
}
.nextpart {
  margin-top: 40px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: clamp(28px, 5vw, 48px);
  display: grid;
  gap: 14px;
  justify-items: center;
  text-align: center;
}
.nextpart h2 {
  font-size: clamp(28px, 3.6vw, 40px);
}
.nextpart .meta {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 4px 16px;
  font-size: 14px;
  color: var(--muted);
}
.nextpart .meta b {
  color: var(--foreground);
  font-weight: 600;
}
.nextpart > p.muted {
  max-width: 52ch;
}

/* status chips and kind dots */
.status {
  display: inline-flex;
  align-items: center;
  font-size: 12.5px;
  font-weight: 500;
  padding: 2px 10px;
  border-radius: 999px;
  background: var(--soft);
  white-space: nowrap;
  color: var(--muted);
}
/* open parts read a shade stronger than full ones, in the site's greys */
.status.open {
  background: color-mix(in srgb, var(--foreground) 10%, transparent);
  color: var(--foreground);
}
.status.published {
  color: var(--foreground);
}
.dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--c, var(--muted));
  flex: none;
}
.k-series,
.k-profession {
  --c: var(--foreground);
}
.k-article,
.k-interview {
  --c: var(--muted);
}
.k-later {
  --c: var(--warn);
}

/* rows: the schedule, Topics and Lab lists */
details > summary {
  list-style: none;
  cursor: pointer;
}
details > summary::-webkit-details-marker {
  display: none;
}
.rows > li,
.tlist > li {
  border-top: 1px solid var(--border);
}
.rows > li:last-child,
.tlist > li:last-child {
  border-bottom: 1px solid var(--border);
}
.row > summary {
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr) auto;
  gap: 16px;
  align-items: center;
  padding-block: 16px;
}
.row .date {
  text-align: center;
}
.row .date b {
  font-family: var(--font-display);
  font-size: 30px;
  font-weight: 450;
  line-height: 1;
  display: block;
}
.row .date span {
  font-size: 11px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}
.row .t,
.trow .t {
  font-weight: 500;
}
.row .t small,
.trow .t small {
  display: block;
  font-weight: 400;
  color: var(--muted);
  font-size: 13.5px;
}
.row .side {
  display: flex;
  align-items: center;
  gap: 12px;
}
.row .detail {
  padding: 0 0 20px 80px;
  display: grid;
  gap: 14px;
}
.row .detail p {
  color: var(--muted);
  max-width: 62ch;
}
.row .cal {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  align-items: center;
}
.gcal {
  font-size: 14px;
  color: var(--muted);
}
.trow > summary {
  display: grid;
  grid-template-columns: 10px minmax(0, 1fr) auto;
  gap: 14px;
  align-items: center;
  padding-block: 14px;
}
.trow .more {
  padding: 0 0 16px 24px;
  display: grid;
  gap: 6px;
  color: var(--muted);
  font-size: 14.5px;
  max-width: 64ch;
}
.trow .more b {
  color: var(--foreground);
  font-weight: 500;
}
.peoplelist {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 10px 18px;
}
.peoplelist li {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 10px;
  align-items: center;
  font-size: 13.5px;
  line-height: 1.35;
}
.peoplelist img,
.peoplelist .ini {
  width: 34px;
  height: 34px;
  border-radius: 50%;
  object-fit: cover;
  background: var(--card);
  border: 1px solid var(--border);
  display: grid;
  place-items: center;
  font-size: 11px;
  font-weight: 600;
  color: var(--muted);
}
.peoplelist a {
  font-weight: 500;
  text-decoration: none;
}
.peoplelist a:hover {
  text-decoration: underline;
}
.peoplelist span {
  display: block;
  color: var(--muted);
  font-size: 12.5px;
}

/* topics */
.roles {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
}
.roles button {
  font-size: 14px;
  padding: 8px 16px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--card);
  cursor: pointer;
  min-height: 38px;
}
.roles button:hover {
  border-color: var(--foreground);
}
.roles button[aria-checked='true'] {
  background: var(--primary);
  color: var(--primary-fg);
  border-color: var(--primary);
}
.seg {
  display: inline-flex;
  flex-wrap: wrap;
  justify-content: center;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 3px;
}
.seg button {
  font-size: 14px;
  border: 0;
  background: transparent;
  color: var(--muted);
  padding: 6px 16px;
  border-radius: 999px;
  cursor: pointer;
}
.seg button:hover {
  color: var(--foreground);
}
.seg button[aria-pressed='true'] {
  background: var(--primary);
  color: var(--primary-fg);
}
.tnote {
  text-align: center;
  color: var(--muted);
  font-size: 15px;
}

/* community invite on Topics */
.callout {
  margin-top: 40px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: clamp(28px, 5vw, 44px);
  display: grid;
  gap: 12px;
  justify-items: center;
  text-align: center;
}
.callout h2 {
  font-size: clamp(26px, 3.2vw, 34px);
}
.callout p:not(.eyebrow) {
  color: var(--muted);
  max-width: 50ch;
}
.callout .btn {
  margin-top: 6px;
}

/* lab */
.student-cta {
  justify-self: center;
}

/* questions */
.faq details {
  border-top: 1px solid var(--border);
  padding-block: 18px;
}
.faq details:last-child {
  border-bottom: 1px solid var(--border);
}
.faq summary {
  font-family: var(--font-display);
  font-weight: 470;
  font-size: 21px;
  display: flex;
  justify-content: space-between;
  gap: 16px;
}
.faq summary::after {
  content: '+';
  font-family: var(--font-body);
  color: var(--muted);
}
.faq details[open] summary::after {
  content: '–';
}
.faq details p {
  color: var(--muted);
  margin-top: 8px;
  max-width: 62ch;
}

/* compose dialog */
dialog {
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--card);
  color: var(--foreground);
  padding: 0;
  width: min(520px, calc(100vw - 32px));
  max-height: calc(100dvh - 32px);
}
dialog::backdrop {
  background: rgb(10 10 20 / 0.4);
}
dialog form {
  padding: 24px;
  display: grid;
  gap: 14px;
}
dialog h2 {
  font-size: 28px;
}
.field {
  display: grid;
  gap: 6px;
  font-size: 13.5px;
  font-weight: 500;
}
.field textarea {
  font: inherit;
  font-weight: 400;
  font-size: 15px;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--background);
  color: var(--foreground);
  width: 100%;
  resize: vertical;
}
.note {
  font-size: 12.5px;
  color: var(--muted);
}
.err {
  font-size: 13px;
  color: var(--warn);
  min-height: 1em;
}

@media (max-width: 760px) {
  .row > summary {
    grid-template-columns: 48px minmax(0, 1fr);
  }
  .row .side {
    grid-column: 2;
  }
  .row .detail {
    padding-left: 0;
  }
}
@media (prefers-reduced-motion: no-preference) {
  .btn,
  .roles button,
  .seg button {
    transition:
      background-color 0.15s,
      border-color 0.15s,
      color 0.15s,
      opacity 0.15s;
  }
}