/* Спокойная «бумажная» тема: тёплый фон, крупный шрифт, много воздуха.
   Сайтом пользуются школьники и учитель, поэтому всё крупное и контрастное. */
:root {
  --paper: #faf7f1;
  --paper-2: #f3eee4;
  --card: #ffffff;
  --ink: #24201b;
  --ink-soft: #6b6156;
  --line: #e4dccf;
  --accent: #8b4a2b;
  --accent-2: #b8763f;
  --accent-soft: #f6ece1;
  --ok: #2c6e49;
  --ok-bg: #eaf3ec;
  --bad: #a72b1e;
  --bad-bg: #fbeeec;
  --warn: #8a6100;
  --warn-bg: #fbf3e0;
  --r: 18px;
  --shadow: 0 1px 2px rgba(60, 40, 20, .05), 0 8px 24px -12px rgba(60, 40, 20, .18);
  --shadow-hi: 0 2px 4px rgba(60, 40, 20, .06), 0 16px 32px -14px rgba(60, 40, 20, .28);
  --fs: 18px;
}

* { box-sizing: border-box; }
html { font-size: var(--fs); scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: "Georgia", "PT Serif", "Times New Roman", serif;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

/* ---------- шапка ---------- */
header.site {
  background: rgba(250, 247, 241, .92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: 0;
  z-index: 20;
}
header.site .inner {
  max-width: 64rem;
  margin: 0 auto;
  padding: 0.75rem 1.25rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 1.6rem;
  align-items: center;
}
header.site a {
  color: var(--ink-soft);
  text-decoration: none;
  font-size: 0.95rem;
  letter-spacing: .01em;
  padding: 0.15rem 0;
  border-bottom: 2px solid transparent;
}
header.site a:hover { color: var(--accent); border-bottom-color: var(--accent-2); }
header.site a.home { color: var(--ink); font-weight: 700; margin-right: auto; }

main { max-width: 64rem; margin: 0 auto; padding: 2rem 1.25rem 5rem; }
main.narrow { max-width: 48rem; }

h1 { font-size: clamp(1.8rem, 4.5vw, 2.6rem); line-height: 1.15; letter-spacing: -.015em; margin: 0.2rem 0 1rem; }
h2 { font-size: 1.4rem; line-height: 1.25; margin: 2.4rem 0 0.8rem; }
h3 { font-size: 1.08rem; margin: 1.6rem 0 0.4rem; color: var(--accent); }
p { margin: 0.7rem 0; }
a { color: var(--accent); text-underline-offset: 3px; }
ul, ol { padding-left: 1.3rem; }
li { margin: 0.3rem 0; }
i, em { color: #4a4137; }

.lead { font-size: 1.15rem; color: var(--ink-soft); max-width: 40rem; }
.muted { color: var(--ink-soft); font-size: 0.9rem; }
.center { text-align: center; }
.hidden { display: none !important; }

/* ---------- карточки ---------- */
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--r);
  padding: 1.4rem 1.5rem;
  margin: 1.1rem 0;
  box-shadow: var(--shadow);
}
.card.tight { padding: 1rem 1.1rem; }
.grid { display: grid; gap: 1.1rem; grid-template-columns: repeat(auto-fit, minmax(17rem, 1fr)); }

/* карточка-ссылка: кликается вся площадь */
a.card-link {
  display: flex;
  flex-direction: column;
  text-decoration: none;
  color: inherit;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--r);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: transform .16s ease, box-shadow .16s ease, border-color .16s ease;
}
a.card-link:hover, a.card-link:focus-visible {
  transform: translateY(-3px);
  box-shadow: var(--shadow-hi);
  border-color: var(--accent-2);
}
a.card-link .pic { background: var(--accent-soft); display: block; line-height: 0; }
a.card-link .pic svg { width: 100%; height: auto; display: block; }
a.card-link .body { padding: 1.1rem 1.3rem 1.3rem; display: flex; flex-direction: column; gap: 0.35rem; flex: 1; }
a.card-link .title { font-size: 1.2rem; font-weight: 700; line-height: 1.25; }
a.card-link .tag {
  align-self: flex-start;
  font-size: 0.75rem;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--accent);
  background: var(--accent-soft);
  border-radius: 999px;
  padding: 0.1rem 0.6rem;
}
a.card-link .desc { color: var(--ink-soft); font-size: 0.95rem; }
a.card-link .more { margin-top: auto; padding-top: 0.6rem; color: var(--accent); font-weight: 700; font-size: 0.95rem; }

/* ---------- главная ---------- */
.hero { padding: 2.5rem 0 1rem; }
.hero h1 { max-width: 20ch; }
.hero .lead { margin-top: 0.8rem; }
.hero-art { margin: 1.5rem 0 0; }
.hero-art svg { width: 100%; max-width: 44rem; height: auto; display: block; }

.tiles { display: grid; gap: 1rem; grid-template-columns: repeat(auto-fit, minmax(15rem, 1fr)); margin-top: 1.5rem; }
a.tile {
  display: flex; gap: 0.9rem; align-items: flex-start;
  text-decoration: none; color: inherit;
  background: var(--card); border: 1px solid var(--line); border-radius: var(--r);
  padding: 1.1rem 1.2rem; box-shadow: var(--shadow);
  transition: transform .16s ease, box-shadow .16s ease, border-color .16s ease;
}
a.tile:hover, a.tile:focus-visible { transform: translateY(-3px); box-shadow: var(--shadow-hi); border-color: var(--accent-2); }
a.tile .ico { flex: 0 0 2.4rem; }
a.tile .ico svg { width: 2.4rem; height: 2.4rem; display: block; }
a.tile b { display: block; font-size: 1.05rem; }
a.tile span { color: var(--ink-soft); font-size: 0.92rem; }

hr.soft { border: 0; border-top: 1px solid var(--line); margin: 3rem 0 2rem; }

/* ---------- кнопки и поля ---------- */
.btn {
  display: inline-block; font: inherit; font-weight: 700;
  background: var(--accent); color: #fff;
  border: 2px solid var(--accent); border-radius: 12px;
  padding: 0.6rem 1.3rem; cursor: pointer; text-decoration: none; min-height: 2.7rem;
  transition: background .15s ease, transform .15s ease;
}
.btn:hover { background: var(--accent-2); border-color: var(--accent-2); transform: translateY(-1px); }
.btn.secondary { background: #fff; color: var(--accent); }
.btn.secondary:hover { background: var(--accent-soft); }
.btn.ghost { background: transparent; color: var(--ink); border-color: var(--line); }
.btn.ghost:hover { background: var(--paper-2); border-color: var(--ink-soft); }
.btn:disabled { opacity: .5; cursor: default; transform: none; }
.btn.small { padding: 0.3rem 0.8rem; font-size: 0.85rem; min-height: 0; }

input[type=text], input[type=password], select, textarea {
  font: inherit; padding: 0.6rem 0.75rem;
  border: 2px solid var(--line); border-radius: 12px;
  background: #fff; color: var(--ink); width: 100%; max-width: 100%;
}
textarea { min-height: 7rem; resize: vertical; line-height: 1.6; }
input:focus, select:focus, textarea:focus, .btn:focus-visible, a:focus-visible {
  outline: 3px solid var(--accent-2); outline-offset: 2px;
}
label.field { display: block; margin: 0.9rem 0; font-weight: 700; }
label.field span.hint { display: block; font-weight: 400; font-size: 0.85rem; color: var(--ink-soft); }
label.field input, label.field select { margin-top: 0.3rem; }

.row { display: flex; gap: 0.8rem; flex-wrap: wrap; align-items: center; }

/* ---------- задания ---------- */
.task { scroll-margin-top: 5rem; }
.task .head { display: flex; gap: 0.7rem; align-items: baseline; flex-wrap: wrap; margin-bottom: 0.5rem; }
.task .num {
  background: var(--accent-soft); color: var(--accent);
  font-weight: 700; border-radius: 8px; padding: 0.1rem 0.65rem; white-space: nowrap; font-size: 0.9rem;
}
.task .topic { font-size: 0.82rem; color: var(--ink-soft); }
.task .qtext { white-space: pre-wrap; margin: 0.4rem 0 0.9rem; }
.task .items { margin: 0 0 0.9rem; }

.opt {
  display: block; margin: 0.35rem 0; padding: 0.55rem 0.8rem;
  border: 2px solid transparent; border-radius: 12px; cursor: pointer;
}
.opt:hover { background: var(--accent-soft); }
.opt input { margin-right: 0.6rem; transform: scale(1.2); accent-color: var(--accent); }
.opt.picked { border-color: var(--accent); background: var(--accent-soft); }

.match { width: 100%; border-collapse: collapse; }
.match td { padding: 0.45rem 0.3rem; vertical-align: top; border-bottom: 1px solid var(--line); }
.match td.k { font-weight: 700; width: 2rem; color: var(--accent); }
.match td.sel { width: 6rem; }
.match select { width: 5.5rem; }
.match-right { margin: 0.6rem 0 0; }

.verdict { border-radius: 12px; padding: 0.7rem 0.9rem; margin-top: 0.8rem; }
.verdict.right { background: var(--ok-bg); border-left: 5px solid var(--ok); }
.verdict.wrong { background: var(--bad-bg); border-left: 5px solid var(--bad); }
.verdict.partial, .verdict.manual, .verdict.empty { background: var(--warn-bg); border-left: 5px solid var(--warn); }
.verdict b { display: block; }
.verdict .explain { margin-top: 0.4rem; }

.flag { background: var(--warn-bg); border-left: 5px solid var(--warn); padding: 0.55rem 0.85rem; border-radius: 12px; font-size: 0.88rem; margin-top: 0.6rem; }

.text-passage {
  background: #fffdf9; border: 1px solid var(--line); border-radius: var(--r);
  padding: 1.2rem 1.4rem; white-space: pre-wrap; line-height: 1.75;
}

.sticky-bar {
  position: sticky; bottom: 0;
  background: var(--paper);
  border-top: 1px solid var(--line);
  box-shadow: 0 -8px 20px -14px rgba(60, 40, 20, .5);
  padding: 0.8rem 1.25rem;
  margin: 2rem -1.25rem 0;
  display: flex; gap: 0.9rem; align-items: center; flex-wrap: wrap;
}

/* ---------- справочник ---------- */
.toc { display: flex; flex-wrap: wrap; gap: 0.4rem 0.9rem; }
.toc a { text-decoration: none; border-bottom: 1px solid var(--line); }
.toc a:hover { border-bottom-color: var(--accent); }

.topic-hero { display: flex; gap: 1.5rem; align-items: center; flex-wrap: wrap; margin-bottom: 1rem; }
.topic-hero .art { flex: 0 0 12rem; }
.topic-hero .art svg { width: 12rem; height: auto; display: block; }
.topic-hero .txt { flex: 1 1 18rem; }

.rule-box {
  background: var(--accent-soft); border-radius: 12px;
  padding: 0.8rem 1rem; margin: 1rem 0;
  border-left: 5px solid var(--accent-2);
}
.rule-box b:first-child { color: var(--accent); }

.pair { display: grid; grid-template-columns: 1fr 1fr; gap: 0.5rem 1.2rem; margin: 0.8rem 0; }
.pair > div { background: var(--paper-2); border-radius: 10px; padding: 0.5rem 0.8rem; font-size: 0.95rem; }

.scheme { margin: 1.2rem 0 0.6rem; }
.scheme img { width: 100%; height: auto; display: block; border: 1px solid var(--line); border-radius: 12px; background: #fffdf9; padding: 0.6rem; }
.scheme figcaption { font-size: 0.85rem; color: var(--ink-soft); margin-top: 0.4rem; }

/* ---------- таблицы и метки ---------- */
table.list { width: 100%; border-collapse: collapse; }
table.list th, table.list td { text-align: left; padding: 0.6rem 0.5rem; border-bottom: 1px solid var(--line); }
table.list th { font-size: 0.8rem; color: var(--ink-soft); text-transform: uppercase; letter-spacing: .05em; }
table.list tr:hover td { background: var(--paper-2); }

.badge { display: inline-block; border-radius: 999px; padding: 0.05rem 0.7rem; font-size: 0.8rem; font-weight: 700; }
.badge.new { background: var(--warn-bg); color: var(--warn); }
.badge.checked { background: var(--ok-bg); color: var(--ok); }

.code-box {
  font-family: ui-monospace, Menlo, Consolas, monospace;
  font-size: 1.7rem; letter-spacing: .25em; font-weight: 700;
  background: var(--accent-soft); color: var(--accent);
  border-radius: 14px; padding: 0.6rem 1.1rem; display: inline-block;
}

.score-big { font-size: 2.2rem; font-weight: 700; }
.mark { font-size: 3rem; font-weight: 700; color: var(--accent); line-height: 1; }

.err { background: var(--bad-bg); border-left: 5px solid var(--bad); padding: 0.7rem 0.9rem; border-radius: 12px; margin: 0.9rem 0; }
.ok-msg { background: var(--ok-bg); border-left: 5px solid var(--ok); padding: 0.7rem 0.9rem; border-radius: 12px; margin: 0.9rem 0; }

.progress { height: 0.5rem; background: var(--line); border-radius: 999px; overflow: hidden; }
.progress > div { height: 100%; background: var(--ok); width: 0; transition: width .25s; }

footer.site {
  border-top: 1px solid var(--line);
  color: var(--ink-soft);
  font-size: 0.85rem;
  padding: 1.5rem 1.25rem 2.5rem;
}
footer.site .inner { max-width: 64rem; margin: 0 auto; }

@media (max-width: 40rem) {
  :root { --fs: 17px; }
  main { padding: 1.2rem 1rem 3rem; }
  .card { padding: 1.1rem 1rem; }
  .topic-hero .art { flex-basis: 8rem; }
  .topic-hero .art svg { width: 8rem; }
  .pair { grid-template-columns: 1fr; }
  .sticky-bar { margin: 1.5rem -1rem 0; padding: 0.7rem 1rem; }
}

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

@media print {
  header.site, footer.site, .sticky-bar, .btn { display: none; }
  body { background: #fff; }
  .card { border-color: #999; box-shadow: none; break-inside: avoid; }
}