/* ============================================================
   СУДОКУ — BRUTALIST MONO
   Raw concrete brutalism, monospace type, hard rectangular edges.
   No rounded corners. No gradients. No soft shadows.
   ============================================================ */
:root {
  --bg: #e8e4d8;
  --ink: #141414;
  --surface: #dcd8cb;
  --surface-strong: #cfcabb;
  --accent: #c13b1d;
  --accent-soft: #d84a2a;
  --line: #141414;
  --line-heavy: #050505;
  --white: #f4f1e8;
  --muted: #55514a;
  --stamp: rgba(193, 59, 29, 0.85);
  --shadow-hard: 6px 6px 0 #141414;
  --fluid: clamp(1rem, 2vw, 1.4rem);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

[hidden] { display: none !important; }

body {
  font-family: "Courier New", "Consolas", "Lucida Console", monospace;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.55;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background-image: repeating-linear-gradient(
    90deg,
    rgba(20, 20, 20, 0.03) 0px,
    rgba(20, 20, 20, 0.03) 2px,
    transparent 2px,
    transparent 4px
  );
}

.container { width: 100%; max-width: 1080px; margin: 0 auto; padding: 0 20px; }

a { color: var(--ink); text-decoration: none; }
a:hover { text-decoration: underline; }

main { flex: 1; }

/* ===== Type rules ===== */
.site-header h1, .section-title, .stat-value, .cell, .num-btn { text-transform: uppercase; letter-spacing: 0.5px; }

/* ===== Header ===== */
.site-header {
  background: var(--ink);
  color: var(--bg);
  border-bottom: 4px solid var(--accent);
  position: sticky;
  top: 0;
  z-index: 50;
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.logo {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--bg);
  letter-spacing: 1px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.logo::before {
  content: "▦";
  color: var(--accent);
  font-size: 1.1rem;
}
.logo:hover { text-decoration: none; }
.main-nav { display: flex; gap: 0; }
.nav-link {
  padding: 8px 14px;
  color: var(--bg);
  border: 1px solid transparent;
  font-weight: 700;
  letter-spacing: 0.5px;
}
.nav-link:hover { text-decoration: none; border-color: var(--accent); }
.nav-link.active { background: var(--accent); color: var(--white); }

/* ===== Buttons ===== */
.btn {
  display: inline-block;
  padding: 12px 22px;
  border: 2px solid var(--ink);
  background: var(--surface);
  color: var(--ink);
  border-radius: 0;
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  transition: none;
  font-family: inherit;
  box-shadow: var(--shadow-hard);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}
.btn:active { transform: translate(3px, 3px); box-shadow: 3px 3px 0 var(--ink); }
.btn-small { padding: 8px 14px; font-size: 0.85rem; box-shadow: 4px 4px 0 var(--ink); }
.btn-full { width: 100%; }

.btn-primary { background: var(--accent); color: var(--white); border-color: var(--ink); }
.btn-primary:hover { background: var(--accent-soft); text-decoration: none; }

.btn-outline { background: var(--white); border-color: var(--ink); }
.btn-outline:hover { background: var(--surface-strong); text-decoration: none; }

.btn-secondary { background: var(--surface); border-color: var(--ink); color: var(--ink); }
.btn-secondary:hover { background: var(--surface-strong); }

.btn-ghost { background: var(--surface); color: var(--ink); }
.btn-ghost:hover { background: var(--surface-strong); }

/* ===== Hero (index) ===== */
.hero { padding: 64px 0; }
.hero-inner { display: grid; grid-template-columns: 1.2fr 0.8fr; gap: 40px; align-items: center; }
.hero-text h1 {
  font-size: 2.6rem;
  line-height: 1.1;
  letter-spacing: 1px;
  margin-bottom: 16px;
  text-transform: uppercase;
}
.accent { color: var(--accent); }
.hero-subtitle { font-size: 1.05rem; color: var(--muted); max-width: 520px; margin-bottom: 28px; }
.hero-actions { display: flex; gap: 16px; flex-wrap: wrap; }

.hero-board { display: flex; justify-content: center; }
.mini-board {
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  width: 320px;
  aspect-ratio: 1;
  background: var(--line);
  gap: 2px;
  padding: 2px;
  box-shadow: var(--shadow-hard);
  border: 2px solid var(--ink);
}
.mini-cell {
  background: var(--surface);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--ink);
}
.mini-cell.empty { color: var(--accent); }
.mini-cell.bl { border-left: 3px solid var(--line-heavy); }
.mini-cell.bt { border-top: 3px solid var(--line-heavy); }
.mini-cell.br { border-right: 3px solid var(--line-heavy); }
.mini-cell.bb { border-bottom: 3px solid var(--line-heavy); }

@media (max-width: 800px) {
  .hero-inner { grid-template-columns: 1fr; }
  .mini-board { width: 240px; }
  .mini-cell { font-size: 0.85rem; }
}

/* ===== Cards ===== */
.section { padding: 48px 0; }
.section-alt { background: var(--surface); border-top: 3px solid var(--ink); border-bottom: 3px solid var(--ink); }
.section-title { font-size: 1.7rem; letter-spacing: 1px; margin-bottom: 28px; text-align: center; text-transform: uppercase; }
.section-title::after {
  content: " ////";
  color: var(--accent);
}

.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 24px; }
.card {
  background: var(--white);
  border: 2px solid var(--ink);
  border-bottom-width: 5px;
  padding: 22px;
  padding-top: 28px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  color: var(--ink);
  position: relative;
  box-shadow: var(--shadow-hard);
}
.card:hover { text-decoration: none; transform: translate(-2px, -2px); box-shadow: 8px 8px 0 var(--ink); }
.card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 6px;
  background: var(--line);
}
.card-easy.card::before { background: #3a7d44; }
.card-medium.card::before { background: var(--accent); }
.card-hard.card::before { background: #141414; }
.card-expert.card::before { background: #000; }
.card-icon { font-size: 1.8rem; }
.card h3 { font-size: 1.15rem; letter-spacing: 0.5px; }
.card p { color: var(--muted); font-size: 0.9rem; flex: 1; }
.card-link {
  color: var(--accent);
  font-weight: 700;
  text-transform: uppercase;
  font-size: 0.85rem;
  letter-spacing: 0.5px;
}
.card-link::after { content: " →"; }

/* ===== Features ===== */
.features { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 24px; }
.feature {
  background: var(--white);
  border: 2px solid var(--ink);
  padding: 22px;
  box-shadow: var(--shadow-hard);
}
.feature-num { font-size: 2rem; font-weight: 700; color: var(--accent); }
.feature h3 { margin: 8px 0 6px; letter-spacing: 0.5px; }

/* ===== Page hero (instructions) ===== */
.page-hero { background: var(--ink); color: var(--bg); padding: 48px 0; border-bottom: 4px solid var(--accent); }
.page-hero h1 { font-size: 2.1rem; letter-spacing: 1px; text-transform: uppercase; }
.page-hero .subtitle { color: #b9b4a8; font-size: 1.05rem; max-width: 640px; margin-top: 8px; }

/* ===== Guide content ===== */
.content { max-width: 820px; }
.guide-block {
  background: var(--white);
  border: 2px solid var(--ink);
  box-shadow: var(--shadow-hard);
  padding: 28px;
  margin-bottom: 24px;
}
.guide-block h2 { display: flex; align-items: center; gap: 12px; font-size: 1.3rem; margin-bottom: 16px; letter-spacing: 0.5px; }
.guide-block h2::before { content: "#"; color: var(--accent); }
.guide-block p { color: var(--muted); margin-bottom: 10px; }
.rule-list { display: flex; flex-direction: column; gap: 12px; margin-top: 12px; }
.rule-item { display: flex; gap: 12px; align-items: flex-start; }
.rule-item strong { color: var(--ink); }
.rule-icon { font-size: 1.2rem; }

.badge {
  background: var(--accent);
  color: var(--white);
  min-width: 34px;
  height: 34px;
  border: 2px solid var(--ink);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  flex-shrink: 0;
  font-weight: 700;
  box-shadow: 3px 3px 0 var(--ink);
}
.tip {
  background: #f0ead6;
  color: #5a3a12;
  padding: 12px 16px;
  border-left: 6px solid var(--accent);
  border: 2px dashed var(--accent);
  margin-top: 8px;
}

.terms { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 14px; }
.term {
  background: var(--surface);
  border: 2px solid var(--ink);
  padding: 14px;
}

.technique { margin-bottom: 16px; }
.technique h3 { font-size: 1rem; margin-bottom: 4px; color: var(--accent); letter-spacing: 0.5px; text-transform: uppercase; }
.technique p { font-size: 0.95rem; }

.check-list { list-style: none; display: flex; flex-direction: column; gap: 10px; }
.check-list li { padding-left: 30px; position: relative; color: var(--muted); }
.check-list li::before { content: "[X]"; color: var(--accent); position: absolute; left: 0; font-weight: 700; }

.cta-block { text-align: center; padding: 24px 0 8px; }
.cta-block p { font-size: 1.2rem; font-weight: 700; margin-bottom: 12px; text-transform: uppercase; }

/* ===== Game ===== */
.game-main { padding: 32px 0; }
.game-layout { display: grid; grid-template-columns: minmax(0, 1fr) 280px; gap: 28px; align-items: start; }

.game-panel {
  background: var(--surface);
  border: 3px solid var(--ink);
  padding: 24px;
  box-shadow: var(--shadow-hard);
}
.game-top { display: flex; justify-content: space-between; align-items: center; margin-bottom: 14px; }
.difficulty-badge {
  background: var(--ink);
  color: var(--bg);
  font-weight: 700;
  padding: 6px 14px;
  font-size: 0.85rem;
  border-left: 6px solid var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.game-stats { display: flex; gap: 28px; margin-bottom: 16px; }
.stat-label {
  display: block;
  font-size: 0.75rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 1px;
}
.stat-value { font-size: 1.4rem; font-weight: 700; font-variant-numeric: tabular-nums; }

.board-wrap { display: flex; justify-content: center; }
.board {
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  width: 100%;
  max-width: 480px;
  aspect-ratio: 1;
  background: var(--line-heavy);
  gap: 2px;
  padding: 2px;
  border: 4px solid var(--ink);
  user-select: none;
}
.cell {
  background: var(--white);
  border: none;
  padding: 0;
  font-family: inherit;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  position: relative;
  cursor: pointer;
  font-size: var(--fluid);
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  outline: none;
}
.cell.given { color: var(--ink); }
.cell.user { color: var(--accent); font-weight: 700; }
.cell.editable { cursor: pointer; }
.cell.selected { background: #c9c4b4; }
.cell.same { background: #d4cfc0; }
.cell.highlight { background: #dcd7c8; }
.cell.conflict { background: #c13b1d !important; color: var(--white) !important; }
.cell.correct { color: #3a7d44; font-weight: 700; }
.cell.bl { border-left: 3px solid var(--line-heavy); }
.cell.bt { border-top: 3px solid var(--line-heavy); }
.cell.br { border-right: 3px solid var(--line-heavy); }
.cell.bb { border-bottom: 3px solid var(--line-heavy); }
.cell .notes {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  width: 100%;
  height: 100%;
  padding: 1px;
}
.cell .note-num {
  font-size: clamp(8px, 1vw, 0.65rem);
  font-weight: 600;
  color: var(--muted);
  display: flex;
  align-items: center;
  justify-content: center;
}
.cell .note-num.active { color: var(--accent); font-weight: 800; }
.cell .main-num { position: absolute; inset: 0; display: flex; align-items: center; justify-content: center; }

.num-pad { display: grid; grid-template-columns: repeat(9, 1fr); gap: 6px; max-width: 480px; margin: 18px auto 0; }
.num-btn {
  aspect-ratio: 1;
  border: 2px solid var(--ink);
  background: var(--white);
  font-size: 1.1rem;
  font-weight: 700;
  font-family: inherit;
  cursor: pointer;
  box-shadow: 3px 3px 0 var(--ink);
}
.num-btn:hover { background: var(--surface-strong); }
.num-btn:active { transform: translate(2px, 2px); box-shadow: 1px 1px 0 var(--ink); }
.num-btn.dim { opacity: 0.3; }

.controls { display: flex; gap: 12px; margin-top: 16px; justify-content: center; flex-wrap: wrap; }
.controls .btn { flex: 1; max-width: 200px; }
.btn.on { background: var(--accent); color: var(--white); }

/* ===== Side panel ===== */
.side-panel { display: flex; flex-direction: column; gap: 20px; }
.side-box {
  background: var(--white);
  border: 2px solid var(--ink);
  padding: 20px;
  box-shadow: var(--shadow-hard);
}
.side-box h3 { font-size: 0.95rem; margin-bottom: 12px; text-transform: uppercase; letter-spacing: 1px; }
.side-box h3::before { content: "▸ "; color: var(--accent); }
.side-text { font-size: 0.85rem; color: var(--muted); margin-bottom: 14px; }

.difficulty-options { display: flex; flex-direction: column; gap: 6px; margin-bottom: 14px; }
.opt { display: flex; align-items: center; gap: 8px; cursor: pointer; padding: 8px 10px; transition: background 0.12s; }
.opt:hover { background: var(--surface); }
.opt input { accent-color: var(--accent); width: 16px; height: 16px; }

.keys { list-style: none; display: flex; flex-direction: column; gap: 6px; font-size: 0.85rem; color: var(--muted); }
.keys kbd {
  background: var(--surface);
  border: 2px solid var(--ink);
  border-bottom-width: 3px;
  padding: 1px 7px;
  font-family: inherit;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--ink);
  display: inline-block;
  margin-right: 4px;
}

/* ===== Modal ===== */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(20, 20, 20, 0.7);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  padding: 20px;
}
.modal {
  background: var(--white);
  border: 4px solid var(--ink);
  box-shadow: 10px 10px 0 var(--ink);
  padding: 32px;
  max-width: 380px;
  width: 100%;
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.modal h2 { font-size: 1.5rem; letter-spacing: 1px; text-transform: uppercase; }
.modal p { color: var(--muted); }

/* ===== Footer ===== */
.site-footer { background: var(--ink); color: var(--bg); border-top: 4px solid var(--accent); margin-top: 48px; }
.footer-inner { display: flex; justify-content: space-between; align-items: center; min-height: 60px; font-size: 0.85rem; flex-wrap: wrap; gap: 8px; }
.footer-inner nav { display: flex; gap: 16px; }
.footer-inner a { color: var(--bg); }
.footer-inner a:hover { color: var(--accent); }
.footer-inner::before { content: "© 2026 — МОНО™"; color: var(--muted); }

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .game-layout { grid-template-columns: 1fr; }
  .side-panel { order: -1; flex-direction: row; flex-wrap: wrap; }
  .side-box { flex: 1; min-width: 240px; }
}
@media (max-width: 600px) {
  .hero-text h1 { font-size: 1.7rem; }
  .num-pad { max-width: 100%; }
  .controls .btn { font-size: 0.8rem; }
  .btn { box-shadow: 4px 4px 0 var(--ink); }
}

/* ===== Scanline texture ===== */
body::after {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 9999;
  background: repeating-linear-gradient(
    0deg,
    rgba(20, 20, 20, 0.015) 0px,
    rgba(20, 20, 20, 0.015) 1px,
    transparent 1px,
    transparent 3px
  );
}