:root {
  color-scheme: light;
  --bg: #faf8f3;
  --surface: #ffffff;
  --ink: #24272b;
  --ink-soft: #5b616b;
  --line: #e4ded0;
  --line-strong: #d3ccb8;
  --accent: #0f766e;
  --accent-ink: #ffffff;
  --accent-soft: #d7f0eb;
  --grid: rgba(15, 118, 110, 0.10);
  --shadow: 0 1px 2px rgba(20, 20, 20, 0.06), 0 8px 24px rgba(20, 20, 20, 0.05);
  --mono: ui-monospace, "SF Mono", "JetBrains Mono", Menlo, Consolas, "Liberation Mono", monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    color-scheme: dark;
    --bg: #16181c;
    --surface: #1e2126;
    --ink: #e7e7e5;
    --ink-soft: #9aa0a8;
    --line: #313640;
    --line-strong: #3d434e;
    --accent: #5eead4;
    --accent-ink: #10201d;
    --accent-soft: #1d322e;
    --grid: rgba(94, 234, 212, 0.09);
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.35), 0 10px 30px rgba(0, 0, 0, 0.35);
  }
}

* { box-sizing: border-box; }

[hidden] { display: none !important; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.55;
  -webkit-text-size-adjust: 100%;
}

a { color: var(--accent); }

/* ─────────────────────────────── шапка ─────────────────────────────────── */

.site-header {
  padding: 28px 24px 18px;
  border-bottom: 1px solid var(--line);
  background: var(--surface);
}

.site-title {
  display: inline-block;
  font-size: 22px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--ink);
  text-decoration: none;
}

.site-tagline {
  margin: 4px 0 0;
  color: var(--ink-soft);
  font-size: 14px;
}

.app {
  max-width: 860px;
  margin: 0 auto;
  padding: 28px 24px 64px;
}

.site-footer {
  max-width: 860px;
  margin: 0 auto;
  padding: 0 24px 48px;
  color: var(--ink-soft);
  font-size: 13px;
}

/* ─────────────────────────── главная страница ──────────────────────────── */

.lead {
  margin: 0 0 24px;
  color: var(--ink-soft);
  max-width: 60ch;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 340px), 1fr));
  gap: 16px;
}

.card {
  display: block;
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--surface);
  text-decoration: none;
  color: inherit;
  box-shadow: var(--shadow);
  transition: transform 0.12s ease, border-color 0.12s ease;
}

.card:hover {
  transform: translateY(-2px);
  border-color: var(--accent);
}

.card-title {
  margin: 0 0 6px;
  font-size: 17px;
  font-weight: 650;
  color: var(--ink);
}

.card-desc {
  margin: 0 0 12px;
  font-size: 14px;
  color: var(--ink-soft);
}

.card-eg {
  margin: 0;
  font-family: var(--mono);
  font-size: 13px;
  color: var(--accent);
  background: var(--accent-soft);
  padding: 6px 10px;
  border-radius: 8px;
  display: inline-block;
}

/* ────────────────────────── страница генератора ───────────────────────── */

.back-link {
  display: inline-block;
  margin-bottom: 14px;
  font-size: 14px;
  text-decoration: none;
}

.back-link:hover { text-decoration: underline; }

.gen-title {
  margin: 0 0 20px;
  font-size: 24px;
  letter-spacing: -0.01em;
}

.controls {
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--surface);
  padding: 18px;
  margin-bottom: 24px;
  box-shadow: var(--shadow);
}

.control-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 220px), 1fr));
  gap: 14px 18px;
  align-items: start;
}

.control {
  display: flex;
  flex-direction: column;
  gap: 5px;
  font-size: 13px;
}

.control-label {
  color: var(--ink-soft);
  font-weight: 550;
}

.control-input {
  font: inherit;
  font-size: 14px;
  padding: 7px 9px;
  border: 1px solid var(--line-strong);
  border-radius: 8px;
  background: var(--bg);
  color: var(--ink);
  width: 100%;
}

.control-input:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.control-check {
  flex-direction: row;
  align-items: center;
  gap: 8px;
}

.control-check input { width: 16px; height: 16px; accent-color: var(--accent); }

.control-topics { grid-column: 1 / -1; }

.topic-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 260px), 1fr));
  gap: 4px 14px;
  margin-top: 2px;
}

.topic-row {
  display: flex;
  align-items: baseline;
  gap: 8px;
  font-size: 13px;
  color: var(--ink);
  padding: 3px 0;
  cursor: pointer;
}

.topic-row input { accent-color: var(--accent); }

.topic-bar {
  margin-top: 8px;
  display: flex;
  gap: 14px;
}

.linklike {
  background: none;
  border: none;
  padding: 0;
  font: inherit;
  font-size: 13px;
  color: var(--accent);
  cursor: pointer;
  text-decoration: underline;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  margin-top: 18px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
}

.btn {
  font: inherit;
  font-size: 14px;
  padding: 8px 14px;
  border-radius: 9px;
  border: 1px solid var(--line-strong);
  background: var(--bg);
  color: var(--ink);
  cursor: pointer;
  transition: border-color 0.12s ease, background 0.12s ease;
}

.btn:hover { border-color: var(--accent); }

.btn.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--accent-ink);
  font-weight: 600;
}

.btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.seed {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-left: auto;
  font-size: 13px;
  color: var(--ink-soft);
}

.seed-input {
  font-family: var(--mono);
  font-size: 13px;
  padding: 7px 9px;
  border: 1px solid var(--line-strong);
  border-radius: 8px;
  background: var(--bg);
  color: var(--ink);
  width: 12ch;
}

.seed-input:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

/* ──────────────────────────────── задания ─────────────────────────────── */

.results {
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 8px 22px 22px;
  background:
    linear-gradient(var(--grid) 1px, transparent 1px) 0 0 / 100% 28px,
    var(--surface);
}

.group-title {
  margin: 26px 0 10px;
  font-size: 16px;
  font-weight: 650;
  color: var(--ink);
  padding-bottom: 6px;
  border-bottom: 1px solid var(--line);
}

.group-title:first-child { margin-top: 14px; }

.item {
  display: grid;
  grid-template-columns: 2.6em 1fr;
  gap: 10px;
  padding: 12px 0;
  border-bottom: 1px dashed var(--line);
}

.item:last-child { border-bottom: none; }

.num {
  font-variant-numeric: tabular-nums;
  color: var(--ink-soft);
  font-size: 14px;
  padding-top: 1px;
}

.body { min-width: 0; }

.task {
  margin: 0;
  white-space: pre-wrap;
  word-break: break-word;
  font-size: 15.5px;
}

pre.task,
pre.col {
  font-family: var(--mono);
  font-size: 14px;
  line-height: 1.4;
  overflow-x: auto;
  tab-size: 4;
}

.answer {
  margin: 8px 0 0;
  padding: 8px 12px;
  border-left: 3px solid var(--accent);
  background: var(--accent-soft);
  border-radius: 0 8px 8px 0;
  font-size: 14px;
  white-space: pre-wrap;
  word-break: break-word;
  display: none;
}

pre.answer {
  font-family: var(--mono);
  line-height: 1.4;
  overflow-x: auto;
}

.results.show-answers .answer,
.item.revealed .answer {
  display: block;
}

.reveal {
  margin-top: 8px;
  background: none;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  padding: 2px 12px;
  font: inherit;
  font-size: 12px;
  color: var(--ink-soft);
  cursor: pointer;
}

.reveal:hover { border-color: var(--accent); color: var(--accent); }

.results.show-answers .reveal { display: none; }

.hint {
  margin: 16px 4px;
  color: var(--ink-soft);
  font-size: 14px;
}

/* ──────────────────────────────── печать ──────────────────────────────── */

@media print {
  .site-header,
  .site-footer,
  .back-link,
  .controls,
  .reveal { display: none !important; }

  body { background: #fff; color: #000; font-size: 12pt; }

  .app { max-width: none; padding: 0; }

  .gen-title { font-size: 18pt; margin-bottom: 12pt; }

  .results {
    border: none;
    padding: 0;
    background: none;
  }

  .item { break-inside: avoid; border-bottom: 1px solid #ddd; }

  .answer {
    background: none;
    border-left: 2px solid #999;
    color: #000;
  }

  .group-title { break-after: avoid; }
}