:root {
  --bg: #f6f7f9;
  --surface: #ffffff;
  --text: #0f172a;
  --muted: #475569;
  --line: #e2e8f0;
  --shadow: 0 1px 2px rgb(15 23 42 / 6%), 0 8px 24px rgb(15 23 42 / 6%);
  --link: #1f4e9a;
  --focus: #2563eb;
  --calc: #1e7a46;
  --write: #1f4e9a;
  --show: #c2410c;
  --calc-2: #2da866;
  --write-2: #3b7dd8;
  --show-2: #f0763a;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b1120;
    --surface: #131c2e;
    --text: #e2e8f0;
    --muted: #a3b0c2;
    --line: #243147;
    --shadow: 0 1px 2px rgb(0 0 0 / 30%);
    --link: #8db4f0;
    --focus: #93c5fd;
  }
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.55 system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}
a { color: var(--link); text-underline-offset: 0.18em; }
a:focus-visible { outline: 3px solid var(--focus); outline-offset: 3px; border-radius: 6px; }
code { font: 0.92em ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; }
.visually-hidden {
  position: absolute; width: 1px; height: 1px; margin: -1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap;
}

.stripe { display: flex; height: 4px; }
.stripe span { flex: 1; background: var(--calc-2); }
.stripe span:nth-child(2) { background: var(--write-2); }
.stripe span:nth-child(3) { background: var(--show-2); }

.hero, main, footer { width: 100%; max-width: 1080px; margin: 0 auto; padding: 0 16px; }
.hero { padding-top: clamp(40px, 9vw, 88px); padding-bottom: clamp(28px, 5vw, 48px); text-align: center; }
.brand { display: inline-flex; align-items: center; gap: 16px; }
.brand img { width: clamp(48px, 10vw, 64px); height: auto; border-radius: 22%; }
@media (prefers-color-scheme: dark) { .brand img { box-shadow: 0 0 0 1px var(--line); } }
h1 { margin: 0; font-size: clamp(2.25rem, 7vw, 3.25rem); font-weight: 700; letter-spacing: -0.03em; line-height: 1.1; }
.lead { margin: 20px auto 0; max-width: 34ch; font-size: clamp(1.15rem, 3.2vw, 1.45rem); line-height: 1.4; letter-spacing: -0.01em; text-wrap: balance; }
.sub { margin: 14px auto 0; max-width: 52ch; color: var(--muted); text-wrap: pretty; }

.apps {
  list-style: none; margin: 0; padding: 0;
  display: grid; gap: 20px;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 288px), 1fr));
}
.card {
  --accent: var(--calc);
  position: relative;
  display: flex; flex-direction: column;
  padding: 28px 24px 24px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 16px;
  box-shadow: var(--shadow);
}
.card[data-app="write"] { --accent: var(--write); }
.card[data-app="show"] { --accent: var(--show); }
.card img { width: 72px; height: 72px; }
.card h3 { margin: 18px 0 0; font-size: 1.5rem; line-height: 1.2; letter-spacing: -0.02em; }
.card h3 span { display: block; margin-top: 4px; font-size: 0.875rem; font-weight: 600; letter-spacing: 0.04em; text-transform: uppercase; color: var(--muted); }
.card p { margin: 12px 0 24px; color: var(--muted); flex: 1; }
.actions { display: flex; flex-wrap: wrap; align-items: center; gap: 12px 20px; }
.button {
  display: inline-flex; align-items: center; justify-content: center;
  min-height: 44px; padding: 10px 18px;
  border-radius: 10px;
  background: var(--accent); color: #fff;
  font-weight: 600; text-decoration: none;
  transition: filter 0.15s ease, transform 0.15s ease;
}
.button:hover { filter: brightness(1.1); }
.button:active { transform: translateY(1px); }
.button:focus-visible { outline: 3px solid var(--focus); outline-offset: 3px; border-radius: 10px; }
.more { font-weight: 500; font-size: 0.95rem; }

footer { margin-top: auto; padding-top: clamp(40px, 8vw, 72px); padding-bottom: 32px; text-align: center; color: var(--muted); font-size: 0.9rem; }
footer p { margin: 6px 0; }
footer .note strong { color: var(--text); }
.meta { display: flex; flex-wrap: wrap; justify-content: center; gap: 4px 10px; }
#version { font-variant-numeric: tabular-nums; }

@media (prefers-reduced-motion: reduce) { .button { transition: none; } }

/* Language switch (P7-11) */
.lang { position: absolute; top: 14px; right: 16px; display: inline-flex; border: 1px solid var(--line); border-radius: 8px; overflow: hidden; background: var(--surface); }
.lang button { appearance: none; border: 0; background: transparent; color: var(--muted); font: 600 0.8rem/1 system-ui, sans-serif; padding: 7px 10px; cursor: pointer; }
.lang button + button { border-left: 1px solid var(--line); }
.lang button[aria-pressed="true"] { background: var(--text); color: var(--surface); }
.lang button:focus-visible { outline: 3px solid var(--focus); outline-offset: -3px; }

.prose { max-width: 70ch; }
.prose h2 { margin: 28px 0 6px; font-size: 1.15rem; }
.prose p { margin: 6px 0; text-wrap: pretty; }
.sub.privacy a { color: inherit; }

/* Site navigation and the Downloads page (P8-41) */
.topnav { position: absolute; top: 14px; left: 16px; display: flex; gap: 16px; font-weight: 600; font-size: 0.95rem; }
.topnav a { text-decoration: none; padding: 6px 2px; }
.topnav a:hover { text-decoration: underline; }
.downloads .hero { padding-top: clamp(56px, 8vw, 72px); padding-bottom: 24px; }
.downloads h1 { font-size: clamp(2rem, 6vw, 2.75rem); }
.downloads .lead { max-width: none; }
.pill { display: inline-block; padding: 1px 10px; border-radius: 999px; border: 1px solid var(--line); background: var(--surface); color: var(--text); font-size: 0.8rem; font-weight: 600; }
.unsigned { margin: 0 0 24px; padding: 16px 20px; border-radius: 12px; border: 1px solid #f59e0b; background: rgb(245 158 11 / 10%); }
.unsigned h2 { margin: 0 0 6px; font-size: 1.05rem; }
.unsigned p { margin: 0; color: var(--muted); }
#os-list { display: grid; gap: 20px; }
.os { padding: 20px 24px; background: var(--surface); border: 1px solid var(--line); border-radius: 16px; box-shadow: var(--shadow); }
.os.recommended { border-color: var(--focus); box-shadow: 0 0 0 1px var(--focus), var(--shadow); }
.os h2 { margin: 0; font-size: 1.35rem; display: flex; flex-wrap: wrap; align-items: center; gap: 6px 12px; }
.badge { padding: 2px 10px; border-radius: 999px; background: var(--focus); color: var(--surface); font-size: 0.78rem; font-weight: 600; letter-spacing: 0.02em; }
.os .warn { margin: 8px 0 12px; color: var(--muted); font-size: 0.92rem; }
.dl-list { list-style: none; margin: 0; padding: 0; }
.dl-app { display: grid; grid-template-columns: 40px minmax(140px, 1fr) auto; align-items: center; gap: 10px 16px; padding: 12px 0; border-top: 1px solid var(--line); }
.dl-app[data-app="calc"] { --accent: var(--calc); }
.dl-app[data-app="write"] { --accent: var(--write); }
.dl-app[data-app="show"] { --accent: var(--show); }
.dl-name { display: flex; flex-direction: column; line-height: 1.3; }
.dl-name span { color: var(--muted); font-size: 0.85rem; }
.dl-buttons { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 8px; }
.dl-buttons .button { min-height: 40px; padding: 6px 14px; flex-direction: column; align-items: flex-start; gap: 0; line-height: 1.25; font-size: 0.92rem; }
.dl-buttons .button small { font-weight: 500; opacity: 0.85; font-size: 0.76rem; }
.button.secondary { background: transparent; color: var(--accent); box-shadow: inset 0 0 0 1.5px var(--accent); }
.muted { color: var(--muted); font-size: 0.9rem; }
.sums { margin-top: 10px; font-size: 0.85rem; color: var(--muted); }
.sums summary { cursor: pointer; font-weight: 600; color: var(--text); padding: 4px 0; }
.sums dl { display: grid; grid-template-columns: minmax(0, max-content) minmax(0, 1fr); gap: 4px 16px; margin: 8px 0 0; }
.sums dt { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; overflow-wrap: anywhere; }
.sums dd { margin: 0; overflow-wrap: anywhere; }
@media (max-width: 640px) {
  .dl-app { grid-template-columns: 40px 1fr; }
  .dl-buttons { grid-column: 1 / -1; justify-content: flex-start; }
  .sums dl { grid-template-columns: 1fr; }
  .sums dd { margin-bottom: 6px; }
}

/* rusuit.es wordmark and the open-source statement (P8-47). System fonts only. */
:root { --wm-a: #1f4e9a; --wm-b: #c2410c; }
@media (prefers-color-scheme: dark) { :root { --wm-a: #8db4f0; --wm-b: #f0763a; } }
.wordmark { display: inline-block; color: var(--wm-a); text-decoration: none; font-weight: 800; letter-spacing: -0.04em; font-family: ui-rounded, "Segoe UI", system-ui, -apple-system, Roboto, sans-serif; }
.wordmark .wm-b { color: var(--wm-b); font-weight: 600; }
.wordmark:focus-visible { outline: 3px solid var(--focus); outline-offset: 4px; border-radius: 6px; }
a.wordmark { display: block; width: fit-content; margin: 0 auto 8px; font-size: 1.4rem; }
.statement { margin: 20px auto 0; max-width: 52ch; font-size: 1.05rem; text-wrap: pretty; }
.opensource { max-width: 70ch; margin: clamp(32px, 6vw, 56px) auto 0; padding: 20px 24px; background: var(--surface); border: 1px solid var(--line); border-radius: 16px; }
.opensource h2 { margin: 0 0 8px; font-size: 1.25rem; letter-spacing: -0.01em; }
.opensource p { margin: 8px 0; }
.opensource ul { margin: 8px 0; padding-left: 1.3em; }