/* Bender — site styles. One family (Newsreader, optical sizes), one accent. */

:root {
  --paper: #f5f3ee;
  --ink: #17160f;
  --ink-2: #5f5b52;
  --ink-3: #6a655a; /* 5.2:1 on paper; used for every small mono label */
  --rule: #d9d5cb;
  --depth: #22408f;
  --depth-soft: #b9c4e3;
  --serif:
    "Newsreader", "Iowan Old Style", "Palatino Linotype", Palatino, Georgia,
    serif;
  --mono:
    ui-monospace, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  --gutter: 16px;
  --measure: 34rem;
  color-scheme: light;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  background: var(--paper);
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  overflow-x: clip;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--serif);
  font-optical-sizing: auto;
  font-size: 1.125rem;
  line-height: 1.5;
  font-feature-settings: "kern", "liga", "onum";
  -webkit-font-smoothing: antialiased;
  overflow-x: clip;
}

/* ---- layout ---------------------------------------------------------------- */

.wrap {
  width: 100%;
  max-width: 1360px;
  margin-inline: auto;
  padding-inline: var(--gutter);
}

@media (min-width: 720px) {
  :root {
    --gutter: 32px;
  }
}

@media (min-width: 1100px) {
  :root {
    --gutter: 48px;
  }
}

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

/* ---- skip link ---------------------------------------------------------------- */

.skip {
  position: absolute;
  top: -100px;
  left: var(--gutter);
  z-index: 10;
  padding: 0.6rem 1rem;
  background: var(--ink);
  color: var(--paper);
  font-size: 1rem;
  text-decoration: none;
  border-radius: 999px;
}

.skip:focus {
  top: 0.75rem;
}

/* ---- header ----------------------------------------------------------------- */

.site-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  padding-block: 1.25rem 1rem;
  border-bottom: 1px solid var(--rule);
}

.wordmark {
  font-size: 1.375rem;
  font-weight: 400;
  letter-spacing: -0.01em;
  color: var(--ink);
  text-decoration: none;
}

.wordmark:hover {
  color: var(--depth);
}

.site-nav {
  display: flex;
  gap: 1.5rem;
  font-size: 1rem;
}

.site-nav a {
  color: var(--ink-2);
  text-decoration: none;
  padding-block: 0.2rem;
  border-bottom: 1px solid transparent;
}

.site-nav a:hover {
  color: var(--ink);
}

.site-nav a[aria-current="page"] {
  color: var(--ink);
  border-bottom-color: var(--ink);
}

/* ---- type -------------------------------------------------------------------- */

h1,
h2,
h3 {
  font-weight: 400;
  margin: 0;
  letter-spacing: -0.02em;
  text-wrap: balance;
}

h1 {
  font-size: clamp(2.75rem, 0.6rem + 6.3vw, 7.25rem);
  line-height: 0.98;
  letter-spacing: -0.035em;
}

h2 {
  font-size: clamp(2rem, 1.2rem + 3.2vw, 3.5rem);
  line-height: 1.02;
  letter-spacing: -0.025em;
}

h3 {
  font-size: 1.375rem;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

p {
  margin: 0 0 1.2em;
  max-width: var(--measure);
}

.deck {
  font-size: clamp(1.25rem, 1rem + 1.1vw, 1.75rem);
  line-height: 1.32;
  letter-spacing: -0.01em;
  max-width: 28em;
  color: var(--ink);
}

.kicker {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin: 0 0 1.5rem;
  max-width: none;
}

em {
  font-style: italic;
}

a {
  color: inherit;
  text-decoration-color: var(--depth-soft);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.16em;
}

a:hover {
  text-decoration-color: var(--depth);
}

:focus-visible {
  outline: 2px solid var(--depth);
  outline-offset: 3px;
  border-radius: 2px;
}

::selection {
  background: var(--depth-soft);
  color: var(--ink);
}

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

.hero {
  padding-block: clamp(2.5rem, 6vw, 5.5rem) clamp(1.5rem, 3vw, 2.5rem);
}

.hero .deck {
  margin-top: clamp(1.25rem, 2.6vw, 2.25rem);
}

.hero-row {
  display: grid;
  gap: 1.5rem 3rem;
}

@media (min-width: 900px) {
  .hero-row {
    grid-template-columns: minmax(0, 1fr) minmax(16rem, 24rem);
    align-items: end;
    align-items: last baseline; /* deck's last line sits on the headline's baseline */
  }

  .hero .deck {
    margin: 0;
  }
}

/* ---- figure 1: the depth frame ---------------------------------------------- */

.depth-fig {
  margin: 0 0 clamp(3rem, 8vw, 7rem);
}

.fig-frame {
  position: relative;
  width: 100%;
  aspect-ratio: 1 / 1; /* reserved before the SVG paints: no jank */
  overflow: hidden;
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
  color: var(--depth);
  background: var(--paper);
}

@media (min-width: 600px) {
  .fig-frame {
    aspect-ratio: 3 / 2;
  }
}

@media (min-width: 900px) {
  .fig-frame {
    aspect-ratio: 2.45 / 1;
  }
}

.scene {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
}

.lv path {
  fill: none;
  stroke: currentColor;
  stroke-opacity: var(--o);
  stroke-width: var(--w);
  stroke-linejoin: round;
  stroke-linecap: round;
}

/* Draw-in, nearest depth first: the frame "resolves" toward the far edge.
   `html.arm` is set by a tiny inline script only when it can also guarantee
   `html.play` within two seconds; without script the drawing is simply there. */
html.arm .fig-frame .lv path {
  stroke-dasharray: 1;
  stroke-dashoffset: 1;
}

html.arm.play .fig-frame .lv path {
  animation: draw 900ms cubic-bezier(0.3, 0, 0.2, 1) forwards;
  animation-delay: calc(var(--k) * 1200ms);
}

@keyframes draw {
  to {
    stroke-dashoffset: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  html.arm .fig-frame .lv path,
  html.arm.play .fig-frame .lv path {
    stroke-dasharray: none;
    stroke-dashoffset: 0;
    animation: none;
  }
}

.fig-marks {
  position: absolute;
  inset: 0;
  pointer-events: none;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-3);
}

.fig-marks span {
  position: absolute;
  padding: 0.6rem 0.5rem;
  background: var(--paper); /* knocks the contour lines out behind the label */
}

.fig-marks .tl {
  top: 0;
  left: 0;
  padding-left: 0;
}

.fig-marks .tr {
  top: 0;
  right: 0;
  padding-right: 0;
  text-align: right;
}

.fig-marks .bl {
  bottom: 0;
  left: 0;
  padding-left: 0;
}

.fig-marks .br {
  bottom: 0;
  right: 0;
  padding-right: 0;
  text-align: right;
}

@media (max-width: 599px) {
  .fig-marks .tr,
  .fig-marks .br {
    display: none;
  }
}

figcaption {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.75rem 1.25rem;
  align-items: baseline;
  padding-top: 0.9rem;
  color: var(--ink-2);
  font-style: italic;
  font-size: 1rem;
  line-height: 1.45;
  max-width: 44rem;
}

figcaption .fig-no {
  font-family: var(--mono);
  font-style: normal;
  font-size: 0.68rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-3);
}

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

.section {
  border-top: 1px solid var(--rule);
  padding-block: clamp(2.25rem, 5vw, 4.5rem);
  display: grid;
  gap: 1.5rem 3rem;
}

@media (min-width: 900px) {
  .section {
    grid-template-columns: minmax(12rem, 2fr) minmax(0, 5fr);
  }
}

.section-no {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin-bottom: 0.75rem;
}

.section h2 {
  margin-bottom: 1.5rem;
}

@media (min-width: 900px) {
  .section h2 {
    margin-bottom: 0;
    position: sticky;
    top: 1.5rem;
  }
}

.section-body > p:first-child,
.section-body > .lede {
  font-size: clamp(1.25rem, 1.05rem + 0.8vw, 1.5rem);
  line-height: 1.35;
  letter-spacing: -0.01em;
  max-width: 30em;
}

/* channel table: what a session contains */
.channels {
  width: 100%;
  max-width: 44rem;
  margin: 2rem 0 0;
  border-collapse: collapse;
  border-top: 1px solid var(--rule);
}

.channels th,
.channels td {
  text-align: left;
  vertical-align: baseline;
  padding: 0.9rem 1rem 0.9rem 0;
  border-bottom: 1px solid var(--rule);
  font-weight: 400;
}

.channels thead th {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-3);
  padding-block: 0.7rem;
}

.channels tbody th {
  font-family: var(--mono);
  font-size: 0.85rem;
  letter-spacing: 0.02em;
  color: var(--depth);
  white-space: nowrap;
  width: 6.5rem;
}

.channels td.rate {
  font-family: var(--mono);
  font-size: 0.8rem;
  color: var(--ink-2);
  white-space: nowrap;
  padding-right: 0;
  width: 11rem;
}

@media (max-width: 600px) {
  .channels thead {
    display: none;
  }

  .channels tr {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 0.25rem 1rem;
    padding: 0.9rem 0;
    border-bottom: 1px solid var(--rule);
  }

  .channels th,
  .channels td {
    display: block;
    padding: 0;
    border: 0;
    width: auto;
  }

  .channels tbody th {
    grid-column: 1;
    grid-row: 1;
  }

  .channels td.rate {
    grid-column: 2;
    grid-row: 1;
    white-space: normal;
    text-align: right;
  }

  .channels td.what {
    grid-column: 1 / -1;
    grid-row: 2;
  }
}

.after-table {
  margin-top: 1.5rem;
}

/* figure 2: one clock, drawn with CSS ticks so the labels stay legible at any width */
.clock-fig {
  margin: 2.5rem 0 0;
  max-width: 44rem;
}

.clock {
  --pitch: 24px;
  --at: 7; /* which frame tick the highlighted instant sits on */
  position: relative;
  display: grid;
  gap: 0.6rem;
  color: var(--depth);
  padding: 1rem 0 0.25rem;
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
}

.clock .lane {
  display: grid;
  grid-template-columns: 4rem 1fr;
  gap: 1rem;
  align-items: center;
}

.clock .lab {
  font-family: var(--mono);
  font-size: 0.8rem;
  letter-spacing: 0.02em;
  color: var(--depth);
}

.clock .ticks {
  display: block;
  height: 1.1rem;
  background: repeating-linear-gradient(
    to right,
    currentColor 0 2px,
    transparent 2px var(--pitch)
  );
  opacity: 0.72;
}

.clock .ticks.dense {
  background: repeating-linear-gradient(
    to right,
    currentColor 0 1.5px,
    transparent 1.5px calc(var(--pitch) / 4)
  );
  opacity: 0.55;
}

.clock .axis {
  margin-top: 0.2rem;
}

.clock .axis .lab {
  color: var(--ink-3);
}

.clock .axis-line {
  display: block;
  position: relative;
  height: 1px;
  background: var(--ink-2);
}

.clock .axis-line::after {
  content: "time";
  position: absolute;
  right: 0;
  top: 0.35rem;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-3);
}

.clock .instant {
  position: absolute;
  top: 0.75rem;
  bottom: 1.35rem;
  left: calc(5rem + var(--pitch) * var(--at));
  width: 2px;
  background: var(--ink);
}

.clock .instant::before {
  content: "";
  position: absolute;
  top: -0.5rem;
  left: -3px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--ink);
}

/* numbered steps */
.steps {
  list-style: none;
  margin: 0;
  padding: 0;
  counter-reset: step;
  max-width: 44rem;
}

.steps li {
  counter-increment: step;
  display: grid;
  grid-template-columns: 4.5rem 1fr;
  gap: 0.5rem 1rem;
  padding: 1.25rem 0;
  border-top: 1px solid var(--rule);
}

.steps li::before {
  content: counter(step, decimal-leading-zero);
  font-size: 2.25rem;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--depth);
  font-variant-numeric: lining-nums;
}

.steps h3 {
  margin-bottom: 0.4rem;
}

.steps p {
  margin-bottom: 0;
}

@media (max-width: 480px) {
  .steps li {
    grid-template-columns: 1fr;
  }
}

/* ---- prose (about, privacy) --------------------------------------------------- */

.prose {
  max-width: var(--measure);
}

.prose h2 {
  font-size: clamp(1.6rem, 1.2rem + 1.6vw, 2.25rem);
  margin: 2.75rem 0 0.9rem;
}

.prose h2:first-child {
  margin-top: 0;
}

.prose p + p {
  text-indent: 1.6em;
}

.prose .lede {
  text-indent: 0;
}

.prose ul {
  margin: 0 0 1.2em;
  padding-left: 1.2em;
}

.prose li {
  margin-bottom: 0.35em;
}

.page-head {
  padding-block: clamp(2.5rem, 6vw, 5.5rem) clamp(2rem, 4vw, 3.5rem);
}

.page-head h1 {
  font-size: clamp(2.5rem, 1.2rem + 5.5vw, 5.5rem);
}

.page-head .deck {
  margin-top: 1.5rem;
}

.about-grid {
  display: grid;
  gap: 2rem 3rem;
  padding-bottom: clamp(3rem, 8vw, 7rem);
}

@media (min-width: 900px) {
  .about-grid {
    grid-template-columns: minmax(12rem, 2fr) minmax(0, 5fr);
  }
}

.toc {
  list-style: none;
  margin: 0;
  padding: 0;
  font-size: 1rem;
  color: var(--ink-2);
}

.toc li {
  padding: 0.35rem 0;
  border-bottom: 1px solid var(--rule);
}

.toc a {
  text-decoration: none;
  display: flex;
  gap: 1rem;
  align-items: baseline;
}

.toc a:hover {
  color: var(--ink);
}

.toc .n {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  color: var(--ink-3);
}

@media (min-width: 900px) {
  .toc {
    position: sticky;
    top: 1.5rem;
  }
}

/* draft banner (privacy page only) */
.draft {
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
  background: #ebe7dc;
}

.draft .wrap {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 1.5rem;
  align-items: baseline;
  padding-block: 0.7rem;
  font-size: 1rem;
  color: var(--ink-2);
}

.draft .k {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink);
}

.draft p {
  margin: 0;
  max-width: none;
}

.dated {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin-top: 2.5rem;
}

/* ---- call to action ----------------------------------------------------------- */

.cta {
  border-top: 1px solid var(--rule);
  padding-block: clamp(3rem, 8vw, 7rem);
}

.cta h2 {
  font-size: clamp(2.5rem, 1.2rem + 5vw, 5rem);
  max-width: 14ch;
  margin-bottom: 1.5rem;
}

.cta p {
  font-size: 1.25rem;
}

.cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1rem;
  margin-top: 2rem;
}

.button {
  display: inline-block;
  font-family: var(--serif);
  font-size: 1.125rem;
  line-height: 1;
  color: var(--paper);
  background: var(--ink);
  border: 1px solid var(--ink);
  border-radius: 999px;
  padding: 0.9rem 1.5rem;
  text-decoration: none;
  cursor: pointer;
}

.button:hover {
  background: var(--depth);
  border-color: var(--depth);
}

.button.ghost {
  background: transparent;
  color: var(--ink);
}

.button.ghost:hover {
  color: var(--depth);
}

.button:disabled {
  opacity: 0.6;
  cursor: progress;
}

/* ---- contact form ------------------------------------------------------------- */

.contact-grid {
  display: grid;
  gap: 2rem 3rem;
  padding-bottom: clamp(3rem, 8vw, 7rem);
}

@media (min-width: 900px) {
  .contact-grid {
    grid-template-columns: minmax(12rem, 2fr) minmax(0, 5fr);
  }
}

.aside p {
  font-size: 1rem;
  color: var(--ink-2);
}

.aside .k {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin-bottom: 0.4rem;
}

.form {
  max-width: 40rem;
}

.field {
  display: grid;
  gap: 0.35rem;
  padding: 1rem 0 1.1rem;
  border-top: 1px solid var(--rule);
}

.field:last-of-type {
  border-bottom: 1px solid var(--rule);
}

.field label {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 1rem;
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-3);
}

.field label .opt {
  text-transform: none;
  letter-spacing: 0.04em;
  font-family: var(--serif);
  font-style: italic;
  font-size: 0.95rem;
  color: var(--ink-2);
}

.field input,
.field textarea {
  font: inherit;
  font-size: 1.25rem;
  line-height: 1.35;
  color: var(--ink);
  background: transparent;
  border: 0;
  border-bottom: 1px solid transparent;
  padding: 0.15rem 0 0.35rem;
  width: 100%;
  border-radius: 0;
}

.field textarea {
  min-height: 9rem;
  resize: vertical;
}

.field input::placeholder,
.field textarea::placeholder {
  color: var(--ink-3);
  opacity: 1;
  font-style: italic;
}

/* focus: a 2 px rule in the accent under the field, plus the label and hairline recolouring */
.field input:focus-visible,
.field textarea:focus-visible {
  outline: none;
  border-bottom-color: var(--depth);
  box-shadow: 0 1px 0 0 var(--depth);
}

.field:focus-within {
  border-top-color: var(--depth);
}

.field:focus-within label {
  color: var(--depth);
}

/* honeypot: hidden from people, present for bots */
.hp {
  position: absolute;
  left: -10000px;
  top: auto;
  width: 1px;
  height: 1px;
  overflow: hidden;
}

.form-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem 1.5rem;
  align-items: center;
  margin-top: 1.5rem;
}

.form-note {
  font-size: 1rem;
  color: var(--ink-2);
  margin: 0;
}

.form-status {
  margin-top: 1.5rem;
  padding: 1.25rem 0;
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
  font-size: 1.25rem;
  line-height: 1.35;
  max-width: 40rem;
}

.form-status[hidden] {
  display: none;
}

.form-status:target {
  display: block; /* no-JS landing from the server's redirect */
}

.form-status p {
  margin: 0;
  max-width: none;
}

.form-status .k {
  display: block;
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--depth);
  margin-bottom: 0.5rem;
}

.form-status.failure .k {
  color: var(--ink-2);
}

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

.site-foot {
  border-top: 1px solid var(--rule);
  padding-block: 1.5rem 2.5rem;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.5rem 2rem;
  font-size: 0.95rem;
  color: var(--ink-2);
}

.site-foot a {
  color: inherit;
}

.site-foot p {
  margin: 0;
  max-width: none;
}