/* SPDX-License-Identifier: AGPL-3.0-only
 * mutual.black — low-reflectance surface.
 * Self-hosted by necessity: the site's CSP is script-src 'self'; style-src
 * 'self', so no CDN, no webfont service, and no inline style attribute.
 * Type is a system stack rather than a loaded face, for the same reason.
 */

:root {
  --void: #040406;
  --basalt: #09090d;
  --monolith: #0f0f15;
  --obsidian-900: #0c0c11;
  --obsidian-850: #121219;
  --obsidian-800: #191922;
  --obsidian-700: #252533;
  --titanium: #838694;
  --frost: #e2e4ec;
  --silver: rgba(255, 255, 255, 0.07);
  --silver-strong: rgba(255, 255, 255, 0.16);
  --cipher: #22c55e;
  --dissent: #dc3545;

  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Consolas, "Liberation Mono", monospace;

  --gutter: clamp(1.25rem, 5vw, 6rem);
  --rule: 1px solid var(--silver);
}

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

html {
  background: var(--void);
  color: var(--titanium);
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  /* Without this the browser paints a light scrollbar and light form
     controls over a near-black page, whatever the background says. */
  color-scheme: dark;
}

/* Firefox */
* { scrollbar-color: var(--obsidian-700) var(--void); scrollbar-width: thin; }

/* WebKit and Blink */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: var(--void); }
::-webkit-scrollbar-thumb { background: var(--obsidian-700); border: 2px solid var(--void); border-radius: 6px; }
::-webkit-scrollbar-thumb:hover { background: #33334a; }
::-webkit-scrollbar-corner { background: var(--void); }

body {
  margin: 0;
  font-family: var(--sans);
  font-weight: 300;
  line-height: 1.7;
  font-size: 16px;
  letter-spacing: -0.01em;
}

::selection { background: var(--obsidian-700); color: #fff; }

a { color: var(--frost); text-decoration: none; }
a:hover { color: #fff; }
a:focus-visible,
button:focus-visible { outline: 1px solid var(--silver-strong); outline-offset: 4px; }

.wrap {
  max-width: 78rem;
  margin: 0 auto;
  padding-inline: var(--gutter);
}

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

.eyebrow {
  font-family: var(--mono);
  font-size: 0.6875rem;
  font-weight: 400;
  text-transform: uppercase;
  letter-spacing: 0.25em;
  color: var(--titanium);
  margin: 0;
}

h1, h2, h3 {
  color: #fff;
  font-weight: 200;
  text-transform: uppercase;
  letter-spacing: -0.03em;
  margin: 0;
}

h1 { font-size: clamp(2.25rem, 7vw, 4.75rem); line-height: 1.06; }
h2 { font-size: clamp(1.5rem, 3.6vw, 2.5rem); line-height: 1.12; }
h3 { font-size: 1.0625rem; font-weight: 300; letter-spacing: 0.02em; }

.lede {
  font-size: clamp(1rem, 1.6vw, 1.1875rem);
  max-width: 46rem;
  color: var(--titanium);
}

.mono { font-family: var(--mono); }
.frost { color: var(--frost); }
.quiet { color: var(--titanium); }

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

section { padding-block: clamp(4rem, 10vw, 8rem); }
section + section { border-top: var(--rule); }

.hero { padding-block: clamp(6rem, 16vw, 12rem); }
.hero h1 { margin-block: 1.75rem 2rem; }

.stack > * + * { margin-top: 1.25rem; }

.grid {
  display: grid;
  gap: 1px;
  background: var(--silver);
  border: var(--rule);
  margin-top: 3rem;
}
@media (min-width: 40rem) { .grid.two { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 56rem) { .grid.three { grid-template-columns: repeat(3, 1fr); } }
@media (min-width: 64rem) { .grid.four { grid-template-columns: repeat(4, 1fr); } }

.cell {
  background: var(--basalt);
  padding: clamp(1.5rem, 3vw, 2.25rem);
}
.cell .eyebrow { margin-bottom: 1rem; }
.cell h3 { margin-bottom: 0.75rem; }
.cell p { margin: 0; font-size: 0.9375rem; }

.figure {
  font-family: var(--mono);
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 200;
  color: #fff;
  letter-spacing: -0.02em;
  display: block;
  margin-bottom: 0.5rem;
}

/* ---- actions ------------------------------------------------------- */

.actions { display: flex; flex-wrap: wrap; gap: 0.75rem; margin-top: 2.5rem; }

.action {
  font-family: var(--mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  padding: 0.9rem 1.6rem;
  border: 1px solid var(--silver-strong);
  color: var(--frost);
  background: transparent;
  cursor: pointer;
  transition: background 140ms ease, border-color 140ms ease;
}
.action:hover { background: var(--obsidian-800); border-color: var(--titanium); }

/* Nothing on this page glares. The primary is distinguished by a lit edge and
   a slightly raised surface, not by a white slab on a near-black field. */
.action.primary {
  background: var(--obsidian-850);
  color: #fff;
  border-color: var(--silver-strong);
  box-shadow: inset 0 1px 0 var(--silver);
}
.action.primary:hover { background: var(--obsidian-800); border-color: var(--titanium); }

/* ---- ledger -------------------------------------------------------- */

.ledger { margin-top: 3rem; display: grid; gap: 1px; background: var(--silver); border: var(--rule); }
@media (min-width: 56rem) { .ledger { grid-template-columns: repeat(3, 1fr); } }

.ledger section { all: unset; }
.column { background: var(--basalt); padding: clamp(1.5rem, 3vw, 2.25rem); }
.column ul { list-style: none; margin: 1.25rem 0 0; padding: 0; }
.column li {
  display: grid;
  grid-template-columns: 1.5rem 1fr;
  gap: 0.5rem;
  font-size: 0.9375rem;
  padding-block: 0.5rem;
  border-top: var(--rule);
}
.column li:first-child { border-top: 0; }
.mark { font-family: var(--mono); font-size: 0.8125rem; line-height: 1.9; }
.mark.on { color: var(--cipher); }
.mark.next { color: var(--titanium); }

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

footer { border-top: var(--rule); padding-block: 3rem; }
footer p { margin: 0 0 0.5rem; font-size: 0.8125rem; }
footer .eyebrow { margin-bottom: 1.25rem; }

hr.rule { border: 0; border-top: var(--rule); margin: 0; }

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