/* The landing page, set like a book: a claim, a figure that proves it, and
   numbered sections with their names in the margin. See DESIGN.md. */

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

.hero { padding-block: clamp(48px, 8vw, 104px) clamp(64px, 9vw, 120px); }
.hero-grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  column-gap: var(--s6);
  align-items: start;
}
.hero-copy { grid-column: 1 / span 6; padding-block-start: var(--s3); }
.fig { grid-column: 7 / span 6; }

.kicker { font-size: .95rem; color: var(--ink-2); margin-block-end: var(--s5); }
.hero-h {
  font-size: clamp(3.2rem, 7.2vw, 6.4rem);
  font-weight: 600;
  line-height: 1.02;
  margin-block-end: var(--s5);
}
:root[dir="rtl"] .hero-h { line-height: 1.18; }
.hero-copy { position: relative; }
.hero-h > span { display: block; }
.hero-h .mark { display: inline; }
.hero-a, .hero-b { transition: opacity 200ms linear; }
.hero-h.is-out .hero-a, .hero-h.is-out .hero-b { opacity: 0; }

/* the counter and the pause, set small under the headline */
.hero-ticker {
  display: flex; align-items: baseline; gap: var(--s4);
  margin: calc(var(--s3) * -1) 0 var(--s5);
  font-size: .85rem; color: var(--ink-3);
}
.hero-count { font-variant-numeric: tabular-nums; min-inline-size: 4.5em; }
.hero-pause {
  all: unset; cursor: pointer;
  color: var(--ink-2);
  text-decoration: underline; text-decoration-thickness: 1px; text-underline-offset: .25em;
}
.hero-pause:hover { color: var(--ink); }
.hero-pause:focus-visible { outline: 2px solid var(--ink); outline-offset: 3px; }
.lede { font-size: clamp(1.08rem, 1.5vw, 1.24rem); color: var(--ink-2); max-inline-size: 34em; margin-block-end: var(--s6); }
.hero-actions { display: flex; flex-wrap: wrap; align-items: center; gap: var(--s4) var(--s6); margin-block-end: var(--s5); }
.fine { font-size: .9rem; color: var(--ink-3); margin: 0; }

/* ---------- figure 1: a real question, and the real page ---------- */

.fig { margin: 0; }
.fig-frame { border: var(--line-ink); background: var(--paper); }
.fig-qa { padding: var(--s5) var(--s5) var(--s4); border-block-end: var(--line); min-block-size: 11.5rem; }
.fig-q {
  font-family: var(--display);
  font-size: clamp(1.45rem, 2.2vw, 1.8rem);
  font-weight: 600;
  line-height: 1.35;
  margin-block-end: var(--s3);
}
.fig-qmark { display: inline-block; font-weight: 700; margin-inline-end: 6px; }
.fig-qmark::after { content: ":"; }
.fig-a { font-size: 1.02rem; line-height: 1.8; margin: 0; }
.fig-a .pagenum { margin-inline-start: 6px; }
.caret {
  display: inline-block; inline-size: 1.5px; block-size: 1.1em; margin-inline-start: 2px;
  background: var(--ink); vertical-align: -.2em;
  animation: caret 1s steps(2) infinite;
}
.fig.done .caret { display: none; }
@keyframes caret { 50% { opacity: 0; } }

.fig-page {
  position: relative;
  block-size: clamp(220px, 24vw, 300px);
  overflow: hidden;
  background: #FFFDF7;
}
.fig-page img {
  position: absolute;
  inset-inline-start: 0;
  inset-block-start: 0;
  inline-size: 100%;
  block-size: auto;
  transform: translateY(var(--crop, 0px));
  opacity: 0;
  transition: opacity var(--t-mid) linear;
}
.fig-page.ready img { opacity: 1; }
:root[data-theme="dark"] .fig-page img { filter: brightness(.9); }
.fig-page.empty { display: none; }
.fig-hl { position: absolute; inset: 0; pointer-events: none; }
.hlr {
  position: absolute;
  background: var(--marker);
  mix-blend-mode: multiply;
  transform: scaleX(0);
  transform-origin: right center;
}
:root[dir="ltr"] .hlr { transform-origin: right center; } /* the book is Arabic: it reads right to left in both languages */
.fig.lit .hlr { animation: hlr 520ms var(--ease-out) forwards; }
.fig.lit .hlr:nth-child(2) { animation-delay: 140ms; }
.fig.lit .hlr:nth-child(3) { animation-delay: 280ms; }
@keyframes hlr { to { transform: scaleX(1); } }

.fig-cap {
  display: flex; justify-content: space-between; align-items: baseline; gap: var(--s4);
  margin-block-start: var(--s3);
  font-size: .9rem; color: var(--ink-2); line-height: 1.6;
}
.fig-cap b { color: var(--ink); font-weight: 700; margin-inline-end: 4px; }
.fig-cap .link-arrow--btn { flex: none; font-size: .9rem; color: var(--ink); }

/* typing: glyphs laid out first, then shown, so lines never rewrap */
.ch { visibility: hidden; }
.ch.on { visibility: visible; }
.w { white-space: nowrap; }

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

.sec { border-block-start: var(--line-ink); padding-block: clamp(56px, 8vw, 96px); }
.sec-grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  column-gap: var(--s6);
}
.sec-label {
  grid-column: 1 / span 3;
  margin: 0;
  display: flex; gap: var(--s3); align-items: baseline;
  font-size: .95rem; font-weight: 600;
}
.sec-label span:first-child { font-family: var(--mono); font-weight: 500; color: var(--ink-3); }
:root[dir="rtl"] .sec-label span:first-child { font-family: var(--sans); }
.sec-body { grid-column: 4 / span 9; }
.sec-h { font-size: clamp(2.3rem, 4.8vw, 3.8rem); max-inline-size: 16em; margin-block-end: var(--s5); }
.sec-p { font-size: 1.14rem; color: var(--ink-2); max-inline-size: 38em; margin-block-end: var(--s7); }

.cols { columns: 2; column-gap: var(--s7); column-rule: var(--line); }
.cols p { font-size: 1.08rem; color: var(--ink-2); break-inside: avoid; }

/* ---------- the comparison: two columns and a rule ---------- */

.vs { display: grid; grid-template-columns: 1fr 1fr; border-block-start: var(--line); }
.vs-col { position: relative; padding-block: var(--s5); }
.vs-col--plain { padding-inline-end: var(--s6); border-inline-end: var(--line); }
.vs-col--light { padding-inline-start: var(--s6); }
.vs-who { font-size: .9rem; font-weight: 600; color: var(--ink-2); margin-block-end: var(--s3); }
.vs-q { font-family: var(--display); font-size: 1.5rem; font-weight: 600; line-height: 1.35; margin-block-end: var(--s3); }
.vs-a { font-size: 1.04rem; line-height: 1.8; min-block-size: 5.4em; margin-block-end: var(--s4); transition: color var(--t-mid) linear; }
.vs-a .pagenum, .vs-cite { margin-inline-start: 6px; }
.vs-foot { display: flex; flex-wrap: wrap; gap: var(--s2) var(--s4); align-items: baseline; margin: 0; min-block-size: 1.8em; }
.vs-nosource { color: var(--ink-2); visibility: hidden; }
.vs.asked .vs-nosource { visibility: visible; }
.vs.stamped .vs-nosource { text-decoration: line-through; text-decoration-color: var(--pen); text-decoration-thickness: 2px; }
.vs-verdict { font-weight: 600; visibility: hidden; }
.vs-verdict--bad { color: var(--pen); }
.vs-verdict--good { color: var(--good); }
.vs.stamped .vs-verdict--bad, .vs.cited .vs-verdict--good { visibility: visible; }
.vs.stamped .vs-col--plain .vs-a { color: var(--ink-3); }

/* the teacher's red stamp, pressed on at an angle */
.vs-stamp {
  position: absolute;
  inset-block-start: 38%;
  inset-inline-end: var(--s6);
  padding: 4px 12px;
  border: 2px solid var(--pen);
  color: var(--pen);
  font-family: var(--display);
  font-size: 1.5rem;
  font-weight: 700;
  line-height: 1.3;
  rotate: -7deg;
  visibility: hidden;
}
.vs.stamped .vs-stamp { visibility: visible; animation: press 160ms ease-out; }
@keyframes press { from { transform: scale(1.18); opacity: 0; } to { transform: none; opacity: 1; } }

/* ---------- what's in it: an index, not cards ---------- */

.index { margin: 0; border-block-start: var(--line-ink); }
.index-row {
  display: grid;
  grid-template-columns: minmax(10rem, 16rem) minmax(0, 1fr);
  gap: var(--s5);
  padding-block: var(--s4);
  border-block-end: var(--line);
  align-items: baseline;
}
.index dt { font-family: var(--display); font-size: 1.55rem; font-weight: 600; line-height: 1.3; }
.index dd { margin: 0; color: var(--ink-2); font-size: 1.04rem; }

/* ---------- curriculum: a table that fills itself ---------- */

.table-wrap { overflow-x: auto; }
.table { inline-size: 100%; border-collapse: collapse; font-size: 1rem; }
.table th {
  text-align: start; font-size: .88rem; font-weight: 600; color: var(--ink-2);
  padding: 0 var(--s4) var(--s2) 0; border-block-end: var(--line-ink);
}
:root[dir="rtl"] .table th, :root[dir="rtl"] .table td { padding-inline: 0 var(--s4); }
.table td { padding: var(--s3) var(--s4) var(--s3) 0; border-block-end: var(--line); vertical-align: baseline; }
.table td:first-child { font-weight: 600; }
.table .soon { color: var(--ink-3); }
.table tr.is-open td { color: var(--ink); }

/* ---------- the close ---------- */

.close { border-block-start: var(--line-ink); padding-block: clamp(64px, 9vw, 112px) var(--s6); }
.close-grid { display: grid; grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr); gap: var(--s8); align-items: end; }
.close-h { font-size: clamp(3.2rem, 8vw, 6.4rem); line-height: 1.05; margin-block-end: var(--s4); }
.close-p { font-size: 1.16rem; color: var(--ink-2); margin-block-end: var(--s6); }

.notify { display: grid; gap: var(--s3); }
.notify-h { display: block; font-weight: 600; font-size: 1.04rem; }
.notify-row { flex-direction: row; gap: 0; }
.notify-row input { flex: 1; min-inline-size: 0; }
.notify-row .btn { block-size: auto; border-inline-start: 0; }
.notify-row .btn:hover { background: var(--ink); color: var(--paper); }

/* ---------- responsive ---------- */

@media (max-width: 960px) {
  .hero-copy, .fig { grid-column: 1 / -1; }
  .fig { margin-block-start: var(--s7); }
  .sec-label { grid-column: 1 / -1; margin-block-end: var(--s4); }
  .sec-body { grid-column: 1 / -1; }
  .close-grid { grid-template-columns: 1fr; gap: var(--s6); }
}
@media (max-width: 640px) {
  .vs { grid-template-columns: 1fr; }
  .vs-col--plain { padding-inline-end: 0; border-inline-end: 0; border-block-end: var(--line); }
  .vs-col--light { padding-inline-start: 0; }
  .vs-stamp { inset-inline-end: 0; }
  .cols { columns: 1; }
  .index-row { grid-template-columns: 1fr; gap: var(--s1); }
  .fig-cap { flex-direction: column; gap: var(--s2); }
  .fig-qa { padding: var(--s4); }
}

@media (prefers-reduced-motion: reduce) {
  .ch { visibility: visible; }
  .caret { display: none; }
  .hlr { transform: none; }
}