/* Cresendo — the umbrella page for Rheusk and Causaa.
 *
 * The design problem this file solves: the two products have opposite visual
 * languages. Rheusk is strictly monochrome, black-only, one geometric sans.
 * Causaa is old white paper, ink and highlighters. Rendering the umbrella in
 * either one would make the other look like a subsidiary of its sibling.
 *
 * So the shell is a third thing — warm neutral ground, editorial serif for
 * statements, system sans for everything else — and each product card is
 * rendered in its *own* palette, locked, ignoring the page theme. The cards
 * are the only place colour is spent, and what they spend it on is showing
 * you what each app actually looks like before you click through.
 *
 * No webfonts and no JavaScript anywhere. That is not minimalism for its own
 * sake: it is what lets the Caddy fragment ship `script-src 'none'` and
 * `font-src 'self'` with nothing to carve out, and it keeps the page a single
 * round trip on a phone. */

:root {
  --bg: #FBFAF8;
  --surface: #FFFFFF;
  --border: #E5E2DB;
  --border-strong: #CFCBC2;
  --ink: #14130F;
  --secondary: #4A4741;
  --muted: #78746C;
  --measure: 64ch;

  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia,
           ui-serif, serif;
  --sans: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui,
          sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

/* The shell follows the reader's system preference. The product cards below
   deliberately do not — see the note above each one. */
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0C0C0C;
    --surface: #151514;
    --border: #272725;
    --border-strong: #3A3A37;
    --ink: #F3F1ED;
    --secondary: #B7B3AC;
    --muted: #8A867E;
  }
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 400 16px/1.65 var(--sans);
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; }
a:hover { text-decoration-thickness: 2px; }

:focus-visible {
  outline: 2px solid currentColor;
  outline-offset: 3px;
  border-radius: 2px;
}

/* Header ------------------------------------------------------------------ */

.bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 22px 24px;
  border-bottom: 1px solid var(--border);
}

.mark {
  display: inline-flex;
  align-items: flex-end;
  gap: 8px;
  font-family: var(--serif);
  font-size: 21px;
  letter-spacing: -0.01em;
  text-decoration: none;
}

/* The one piece of iconography on the site: three bars getting taller. A
   crescendo is a thing that grows, and growing something small into something
   finished is the only claim both products actually share. Drawn in CSS
   because an <img> here would be a second request for eleven pixels. */
.bars {
  display: inline-flex;
  align-items: flex-end;
  gap: 3px;
  height: 0.95em;
  padding-bottom: 0.18em;
}
.bars i {
  display: block;
  width: 3px;
  background: currentColor;
  border-radius: 1px;
}
.bars i:nth-child(1) { height: 35%; }
.bars i:nth-child(2) { height: 65%; }
.bars i:nth-child(3) { height: 100%; }

.bar nav {
  display: flex;
  gap: 20px;
  font-size: 14px;
}
.bar nav a { color: var(--secondary); text-decoration: none; }
.bar nav a:hover { color: var(--ink); text-decoration: underline; }

/* Layout ------------------------------------------------------------------ */

main { max-width: 920px; margin: 0 auto; padding: 0 24px; }

section { padding: 72px 0; border-bottom: 1px solid var(--border); }
section:last-child { border-bottom: 0; }

h1 {
  font-family: var(--serif);
  font-size: clamp(30px, 5.4vw, 50px);
  font-weight: 400;
  line-height: 1.12;
  letter-spacing: -0.015em;
  margin: 0 0 22px;
  max-width: 20ch;
}

h2 {
  font-family: var(--serif);
  font-size: clamp(21px, 3vw, 27px);
  font-weight: 400;
  letter-spacing: -0.01em;
  margin: 0 0 14px;
}

h3 { font-size: 16px; font-weight: 600; margin: 0 0 8px; }

p { max-width: var(--measure); color: var(--secondary); margin: 0 0 16px; }
p:last-child { margin-bottom: 0; }

.lede { font-size: clamp(17px, 2.2vw, 19px); line-height: 1.6; }
.fine { font-size: 13px; color: var(--muted); }

.eyebrow {
  font-family: var(--sans);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 18px;
}

.hero { padding-top: 88px; }

/* The through-line diagram ------------------------------------------------ */

.diagram pre {
  overflow-x: auto;
  margin: 0;
  padding: 24px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  font-family: var(--mono);
  font-size: 12.5px;
  line-height: 1.55;
  color: var(--secondary);
  tab-size: 4;
}
.diagram .note { margin-top: 18px; }

/* Product cards ----------------------------------------------------------- */

.cards { display: grid; gap: 24px; }
@media (min-width: 860px) { .cards { grid-template-columns: 1fr 1fr; } }

.card {
  border-radius: 14px;
  padding: 30px 28px 28px;
  display: flex;
  flex-direction: column;
  border: 1px solid;
}

.card .name {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 4px;
}
.card .name h2 { margin: 0; }

.status {
  flex: none;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 4px 10px;
  border-radius: 999px;
  border: 1px solid;
}

.card .tagline { font-size: 15px; margin: 10px 0 20px; }

.card ul { list-style: none; padding: 0; margin: 0 0 24px; flex: 1; }
.card li { font-size: 14.5px; padding: 9px 0; border-bottom: 1px solid; }
.card li:last-child { border-bottom: 0; }
.card li strong { font-weight: 600; }

.card .go {
  align-self: flex-start;
  text-decoration: none;
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  padding: 12px 22px;
  border-radius: 8px;
  border: 1px solid transparent;
}
.card .go:hover { opacity: 0.88; text-decoration: none; }

/* Rheusk: black, one hue channel, the 45° slash. Locked to the product's own
   palette in both page themes — this card is a window into the app, and the
   app has no light mode to show. */
.card.rheusk {
  background: #000000;
  border-color: #262626;
  color: #FFFFFF;
  font-family: var(--sans);
}
.card.rheusk h2 { font-family: var(--sans); font-weight: 600; font-size: 24px; letter-spacing: -0.02em; }
.card.rheusk .tagline,
.card.rheusk li { color: #A3A3A3; }
.card.rheusk li { border-bottom-color: #1F1F1F; }
.card.rheusk li strong { color: #FFFFFF; }
.card.rheusk .status { color: #8A8A8A; border-color: #333333; }
.card.rheusk .go { background: #FFFFFF; color: #000000; }

/* The app's whole visual signature is a diagonal through the R, and it is the
   only non-rectilinear thing it draws. Reproduced here rather than approximated
   with an italic or a slash glyph, which sit at the font's angle, not 45°. */
.card.rheusk .glyph {
  position: relative;
  display: inline-block;
  width: 1.35em;
  font-weight: 600;
}
.card.rheusk .glyph span {
  position: absolute;
  left: 0.12em;
  top: -0.12em;
  width: 1px;
  height: 1.45em;
  background: #FFFFFF;
  transform: rotate(45deg);
  transform-origin: center;
}

/* Causaa: old white paper, ink, highlighters. Also locked — the notebook is
   the product, and a dark notebook is a different app. */
.card.causaa {
  background: #FCFBF4;
  border-color: #E3DFCF;
  color: #2B2A26;
}
.card.causaa h2 { font-family: var(--serif); color: #2B2A26; }
.card.causaa .tagline,
.card.causaa li { color: #57544B; }
.card.causaa li { border-bottom-color: #EAE6D8; }
.card.causaa li strong { color: #2B2A26; }
.card.causaa .status { color: #6F6B5E; border-color: #DDD8C6; }
.card.causaa .go { background: #2B2A26; color: #FCFBF4; }

/* The highlighter swipe behind "Causaa" — the app marks its active tab with a
   hand-drawn stroke, so the umbrella page marks its name the same way. Skewed
   and unevenly inset so it reads as drawn rather than as a rectangle. */
.card.causaa .swipe {
  position: relative;
  display: inline-block;
  padding: 0 2px;
}
.card.causaa .swipe::before {
  content: "";
  position: absolute;
  left: -3px;
  right: -5px;
  bottom: 0.06em;
  height: 0.62em;
  background: #F6E27A;
  opacity: 0.75;
  transform: rotate(-0.6deg) skewX(-9deg);
  border-radius: 2px 6px 3px 5px;
  z-index: -1;
}

/* Shared-build section ---------------------------------------------------- */

.stack { display: grid; gap: 28px; }
@media (min-width: 720px) { .stack { grid-template-columns: 1fr 1fr; } }
.stack p { font-size: 15px; }

.facts { list-style: none; padding: 0; margin: 0; }
.facts li {
  display: flex;
  gap: 14px;
  font-size: 14.5px;
  color: var(--secondary);
  padding: 10px 0;
  border-bottom: 1px solid var(--border);
}
.facts li:last-child { border-bottom: 0; }
.facts b {
  flex: none;
  width: 8.5em;
  color: var(--ink);
  font-weight: 600;
  font-size: 13px;
  letter-spacing: 0.02em;
  padding-top: 1px;
}
@media (max-width: 520px) {
  .facts li { flex-direction: column; gap: 2px; }
  .facts b { width: auto; }
}

/* Legal pages ------------------------------------------------------------- */

.legal { max-width: var(--measure); }
.legal h2 { margin-top: 34px; font-size: 21px; }
.legal ul { padding-left: 20px; color: var(--secondary); }
.legal li { margin-bottom: 8px; }

/* Footer ------------------------------------------------------------------ */

footer {
  border-top: 1px solid var(--border);
  padding: 34px 24px 48px;
  text-align: center;
}
footer p { max-width: none; margin: 6px auto; }
footer a { color: var(--secondary); font-size: 14px; }