/* ============================================================
   LMS 1619 — дизайн-система в стиле Apple
   ============================================================ */

:root {
  /* Типографика */
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "SF Pro Text", "SF Pro Display",
    system-ui, "Segoe UI", "Helvetica Neue", Arial, "Apple Color Emoji",
    "Segoe UI Emoji", sans-serif;
  --font-mono: "SF Mono", ui-monospace, "Cascadia Code", "JetBrains Mono", Menlo, Consolas, monospace;

  /* Светлая тема (по умолчанию) — мягкая, как Apple.com */
  --bg: #FBFBFD;
  --bg-elevated: #FFFFFF;
  --bg-soft: #F5F5F7;

  --fill: rgba(20, 20, 30, 0.06);
  --fill-secondary: rgba(20, 20, 30, 0.1);

  --label: #1D1D1F;
  --label-secondary: rgba(29, 29, 31, 0.65);
  --label-tertiary: rgba(29, 29, 31, 0.34);

  --separator: rgba(0, 0, 0, 0.08);
  --separator-strong: rgba(0, 0, 0, 0.14);

  --accent: #0A84FF;
  --accent-pressed: #0066CC;
  --accent-soft: color-mix(in srgb, var(--accent) 14%, white);
  --success: #34C759;
  --success-soft: color-mix(in srgb, var(--success) 16%, white);
  --warning: #FF9F0A;
  --danger: #FF3B30;
  --danger-soft: color-mix(in srgb, var(--danger) 14%, white);

  --card-radius: 20px;
  --row-radius: 14px;
  --chip-radius: 999px;

  --shadow-sm: 0 1px 2px rgba(0,0,0,.04);
  --shadow: 0 10px 30px rgba(0,0,0,.08), 0 2px 6px rgba(0,0,0,.04);
  --shadow-lg: 0 24px 60px rgba(0,0,0,.12), 0 6px 14px rgba(0,0,0,.06);
  --shadow-card: 0 1px 0 rgba(0,0,0,.04), 0 2px 10px rgba(0,0,0,.05);

  /* hero-градиент — мягкий, как стартовый экран Apple */
  --hero-grad: linear-gradient(180deg,
                    rgba(10, 132, 255, 0.10) 0%,
                    rgba(191, 90, 242, 0.06) 45%,
                    rgba(255, 255, 255, 0) 100%);
  --accent-grad: linear-gradient(135deg, #0A84FF 0%, #5E5CE6 60%, #BF5AF2 100%);
  --accent-grad-2: linear-gradient(135deg, #34C759 0%, #30B0C7 100%);

  --ease: cubic-bezier(.2, .8, .2, 1);
  --ease-bounce: cubic-bezier(.34, 1.4, .64, 1);
}

@media (prefers-color-scheme: dark) {
  /* Сайт всегда белый (по запросу). Тёмный режим не включается. */
  :root { color-scheme: light; }
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--label);
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.45;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  min-height: 100%;
}

a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-pressed); }

button { font-family: inherit; }

#app { min-height: 100vh; }

/* ============================================================
   Переопределения под «белый Apple-дизайн» + плавные анимации
   ============================================================ */

html { scroll-behavior: smooth; }
html, body {
  background: var(--bg);
  background-image: radial-gradient(120% 60% at 50% -10%, rgba(10,132,255,.08), transparent 60%),
                    radial-gradient(80% 50% at 100% 0%, rgba(191,90,242,.05), transparent 60%);
  background-attachment: fixed, fixed;
}

/* ---------- Переходы экранов ---------- */
main.container { animation: screen-enter .45s var(--ease); }
@keyframes screen-enter { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: translateY(0); } }

/* переход между упражнениями — slide+fade */
.exercise { animation: ex-in .4s var(--ease); }
@keyframes ex-in {
  from { opacity: 0; transform: translateX(24px) scale(.99); }
  to   { opacity: 1; transform: none; }
}
.exercise .prompt { transition: transform .3s var(--ease); }
.exercise.swap-out { animation: ex-out .3s var(--ease) forwards; }
@keyframes ex-out {
  to { opacity: 0; transform: translateX(-32px) scale(.99); }
}

/* кнопки ”Дальше/Проверить” — мягкое касание */
.btn { transition: transform .15s var(--ease-bounce), background .25s var(--ease), box-shadow .25s var(--ease), opacity .2s; }

/* конфетти для верного ответа */
.confetti {
  position: fixed; inset: 0; pointer-events: none; z-index: 2000;
  overflow: hidden;
}
.confetti i {
  position: absolute; top: -10px; width: 8px; height: 14px;
  border-radius: 2px; opacity: 0;
  animation: confetti-fall 1.2s var(--ease) forwards;
}
@keyframes confetti-fall {
  0%  { opacity: 1; transform: translateY(0) rotate(0deg); }
  100%{ opacity: 0; transform: translateY(100vh) rotate(540deg); }
}

/* ---------- Верхняя панель — плавающая, прозрачная ---------- */
.appbar {
  padding: 10px 20px;
  background: color-mix(in srgb, var(--bg-elevated) 70%, transparent);
  border-bottom: 1px solid transparent;
  transition: border-color .3s var(--ease), background .3s var(--ease);
  box-shadow: 0 1px 0 rgba(0,0,0,0);
}
.appbar.scrolled {
  border-bottom-color: var(--separator);
  box-shadow: 0 8px 20px -12px rgba(0,0,0,.25);
}
.appbar .brand a {
  background: var(--accent-grad);
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent;
  font-weight: 800; letter-spacing: -.02em;
}
.appbar nav a, .appbar nav button {
  position: relative;
  transition: color .2s var(--ease), background .25s var(--ease), transform .15s var(--ease);
}
.appbar nav a:active, .appbar nav button:active { transform: scale(.94); }
.streak-chip {
  background: linear-gradient(135deg, rgba(255,159,10,.14), rgba(255,159,10,.06));
  border: 1px solid rgba(255,159,10,.2);
}

/* ---------- Кнопки ---------- */
.btn {
  border-radius: 14px;
  transition: transform .15s var(--ease-bounce), background .25s var(--ease),
              box-shadow .25s var(--ease), opacity .2s;
}
.btn:active { transform: scale(.97); }
.btn-primary {
  background: var(--accent-grad);
  background-size: 160% 160%;
  color: white;
  box-shadow: 0 8px 18px -8px color-mix(in srgb, var(--accent) 80%, transparent);
  transition: background-position .5s var(--ease), transform .15s var(--ease-bounce), box-shadow .25s;
}
.btn-primary:hover {
  background-position: 100% 0;
  box-shadow: 0 10px 22px -8px color-mix(in srgb, var(--accent) 90%, transparent);
}
.btn-primary:active { transform: scale(.97); }
.btn-lg { border-radius: 16px; }
.btn-block { border-radius: 16px; }

/* hero — главный экран */
.hero {
  position: relative; overflow: hidden;
  border-radius: 28px; padding: 56px 32px 48px;
  background: var(--bg-elevated);
  box-shadow: var(--shadow);
  border: 1px solid var(--separator);
  margin-bottom: 28px;
}
.hero::before {
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background: var(--hero-grad);
  background-size: 200% 200%;
  animation: hero-pan 10s var(--ease) infinite alternate;
  opacity: .9;
}
.hero > * { position: relative; z-index: 1; }
.hero h1 { font-size: 40px; font-weight: 800; letter-spacing: -.03em; margin-bottom: 14px;
  background: linear-gradient(180deg, var(--label), color-mix(in srgb, var(--label) 70%, var(--accent)));
  -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent;
}
.hero .lead { font-size: 19px; max-width: 56ch; margin-bottom: 22px; }
@keyframes hero-pan {
  from { background-position: 0% 0%; }
  to   { background-position: 100% 100%; }
}

/* плитки курса — мягкий подъём + лёгкий shine */
.tile {
  position: relative; overflow: hidden;
  border-radius: 22px; border: 0;
  transition: transform .25s var(--ease), box-shadow .25s var(--ease), filter .25s;
  box-shadow: 0 14px 30px -16px rgba(0,0,0,.4);
}
.tile::after {
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background: linear-gradient(135deg, rgba(255,255,255,.25), rgba(255,255,255,0) 40%);
  opacity: .6;
}
.tile:hover { transform: translateY(-4px); box-shadow: 0 24px 50px -18px rgba(0,0,0,.45); }
.tile:active { transform: translateY(-1px) scale(.99); }

/* карточки */
.card {
  border-radius: var(--card-radius);
  border: 1px solid var(--separator);
  box-shadow: var(--shadow-card);
}
.list { border: 1px solid var(--separator); border-radius: var(--card-radius); overflow: hidden; }
.row {
  border-top: 1px solid var(--separator);
  transition: background .2s var(--ease), transform .15s var(--ease);
  animation: row-in .35s var(--ease) both;
}
.row:first-child { border-top: 0; }
.row:hover { background: var(--fill); }
.row:active { transform: scale(.995); }
.row .icon-circle {
  box-shadow: 0 6px 14px -6px color-mix(in srgb, var(--accent) 80%, transparent);
}
.row.done .icon-circle { box-shadow: 0 6px 14px -6px color-mix(in srgb, var(--success) 80%, transparent); }
@keyframes row-in { from { opacity: 0; transform: translateX(-6px); } to { opacity: 1; transform: none; } }

/* ---------- Упражнения: варианты ---------- */
.option {
  transition: transform .15s var(--ease-bounce), background .2s var(--ease),
              border-color .2s var(--ease), color .2s var(--ease);
  border-radius: var(--row-radius);
  background: var(--bg-elevated);
  border: 1.5px solid var(--separator-strong);
  position: relative; overflow: hidden;
}
.option:hover { background: var(--accent-soft); border-color: color-mix(in srgb, var(--accent) 40%, white); }
.option:active { transform: scale(.98); }
.option.selected {
  border-color: var(--accent); background: var(--accent-soft);
  transform: scale(1.0); animation: pop .3s var(--ease-bounce);
}
.option.correct {
  border-color: var(--success); background: var(--success-soft);
  animation: pop .35s var(--ease-bounce);
}
.option.wrong {
  border-color: var(--danger); background: var(--danger-soft);
  animation: shake .4s var(--ease);
}
@keyframes pop { 0% { transform: scale(.94); } 60% { transform: scale(1.03); } 100% { transform: scale(1); } }
@keyframes shake {
  0%,100% { transform: translateX(0); }
  25% { transform: translateX(-6px); } 75% { transform: translateX(6px); }
}

/* input */
.input, .textarea, .select { transition: border-color .2s var(--ease), box-shadow .2s var(--ease), background .2s; }
.input.correct, .textarea.correct { border-color: var(--success); background: var(--success-soft); animation: pop .35s var(--ease-bounce); }
.input.wrong { border-color: var(--danger); background: var(--danger-soft); animation: shake .4s var(--ease); }

/* match cards */
.mcard {
  border: 1.5px solid var(--separator-strong);
  transition: transform .15s var(--ease-bounce), background .2s var(--ease), border-color .2s var(--ease);
}
.mcard:active { transform: scale(.97); }
.mcard.active {
  border-color: var(--accent); background: var(--accent-soft);
  animation: pop .3s var(--ease-bounce); transform: scale(1.02);
}
.mcard.matched { border-color: var(--success); background: var(--success-soft); animation: pop .3s var(--ease-bounce); }
.mcard.wrong { border-color: var(--danger); animation: shake .4s var(--ease); }

/* feedback */
.feedback { border-radius: var(--row-radius); animation: feedback-in .35s var(--ease); }
.feedback.success { background: var(--success-soft); border: 1px solid color-mix(in srgb, var(--success) 30%, white); }
.feedback.danger { background: var(--danger-soft); border: 1px solid color-mix(in srgb, var(--danger) 30%, white); }
@keyframes feedback-in {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: none; }
}

/* прогресс-бар — плавная заливка */
.progress-bar .bar > i { transition: width .5s var(--ease); border-radius: inherit;
  background: var(--accent-grad); background-size: 200% 100%;
  animation: bar-shimmer 2s linear infinite;
}
@keyframes bar-shimmer {
  from { background-position: 0% 0; }
  to   { background-position: 200% 0; }
}

/* результат — всплывание */
.result { animation: result-in .5s var(--ease-bounce); }
@keyframes result-in { from { opacity: 0; transform: translateY(20px) scale(.96); } to { opacity: 1; transform: none; } }
.result .emoji { animation: emoji-pop .7s var(--ease-bounce); }
@keyframes emoji-pop { 0% { transform: scale(0) rotate(-20deg); } 60% { transform: scale(1.2) rotate(5deg); } 100% { transform: scale(1); } }

/* toast slide-in */
.toast { animation: toast-in .3s var(--ease-bounce); }
.toast.hidden { animation: toast-out .25s var(--ease) forwards; }
@keyframes toast-in { from { opacity: 0; transform: translateX(-50%) translateY(16px); } to { opacity: 1; transform: translateX(-50%) translateY(0); } }
@keyframes toast-out { to { opacity: 0; transform: translateX(-50%) translateY(8px); } }

/* админ: статистические плитки */
.stat { border: 1px solid var(--separator); transition: transform .2s var(--ease), box-shadow .2s var(--ease); }
.stat:hover { transform: translateY(-2px); box-shadow: var(--shadow); }

/* страницы теории */
.theory-step { animation: screen-enter .45s var(--ease); }
.theory-figure {
  margin: 18px 0; padding: 18px; border-radius: var(--card-radius);
  background: var(--bg-soft); border: 1px solid var(--separator);
  display: grid; gap: 10px; place-items: center; overflow-x: auto;
}
.theory-figure svg { max-width: 100%; height: auto; }
.theory-body { font-size: 17px; line-height: 1.6; color: var(--label-secondary); }
.theory-body strong { color: var(--label); font-weight: 700; }
.theory-body em { color: var(--label); font-style: normal; background: linear-gradient(transparent 60%, color-mix(in srgb, var(--accent) 30%, transparent) 60%); padding: 0 2px; }
.theory-body code { background: var(--fill); padding: 1px 6px; border-radius: 6px; font-family: var(--font-mono); color: var(--accent); font-size: .94em; }
.theory-body b { color: var(--label); }
.theory-body ul, .theory-body ol { margin: 10px 0 10px 22px; padding: 0; }
.theory-body li { margin: 6px 0; }
.theory-body blockquote { border-left: 3px solid var(--accent); margin: 12px 0; padding: 8px 16px; background: var(--accent-soft); border-radius: 0 12px 12px 0; color: var(--label); }
.callout {
  padding: 16px 18px; border-radius: var(--row-radius);
  background: linear-gradient(135deg, color-mix(in srgb, var(--accent) 12%, white), color-mix(in srgb, var(--accent) 6%, white));
  border: 1px solid color-mix(in srgb, var(--accent) 28%, white);
  color: var(--label); margin: 16px 0;
}
.callout .c-title { font-weight: 800; margin-bottom: 6px; display: flex; gap: 8px; align-items: center; }
.callout.warn { background: linear-gradient(135deg, color-mix(in srgb, var(--warning) 14%, white), color-mix(in srgb, var(--warning) 6%, white)); border-color: color-mix(in srgb, var(--warning) 30%, white); }
.callout.warn .c-title::before { content: "⚠"; }
.callout.success { background: linear-gradient(135deg, color-mix(in srgb, var(--success) 14%, white), color-mix(in srgb, var(--success) 6%, white)); border-color: color-mix(in srgb, var(--success) 30%, white); }
.callout.success .c-title::before { content: "✓"; }
.callout.info .c-title::before { content: "💡"; }

/* нумерованные шаги-бейджи внутри теории */
.step-badge { display: inline-flex; align-items: center; justify-content: center; min-width: 26px; height: 26px; border-radius: 50%;
  background: var(--accent-grad); color: white; font-weight: 800; font-size: 14px; margin-right: 8px; flex: 0 0 26px; }

/* буква-плитка для подсветки букв в теории */
.letter-chip {
  display: inline-flex; align-items: center; justify-content: center;
  width: 34px; height: 34px; border-radius: 9px;
  background: var(--bg-soft); border: 1px solid var(--separator);
  font-weight: 800; font-size: 18px; color: var(--label);
  box-shadow: var(--shadow-sm);
}
.letter-chip.l1 { background: #0A84FF; color: white; border-color: transparent; }
.letter-chip.l2 { background: #5E5CE6; color: white; border-color: transparent; }
.letter-chip.l3 { background: #BF5AF2; color: white; border-color: transparent; }
.letter-chip.l4 { background: #34C759; color: white; border-color: transparent; }
.letter-chip.l5 { background: #FF9F0A; color: white; border-color: transparent; }
.table-codes {
  width: 100%; border-collapse: collapse;
  font-family: var(--font-mono); font-size: 15px;
}
.table-codes th, .table-codes td {
  padding: 10px 14px; border-bottom: 1px solid var(--separator); text-align: left;
}
.table-codes th { color: var(--label-secondary); font-weight: 600; }
.table-codes tr:last-child td { border-bottom: 0; }

/* дерево Фано (интерактив) */
.fano-tree {
  position: relative; width: 100%; min-height: 340px;
  background:
    radial-gradient(circle at 50% 0, color-mix(in srgb, var(--accent) 4%, var(--bg-elevated)), var(--bg-elevated) 70%);
  border: 1px solid var(--separator); border-radius: var(--card-radius);
  overflow: hidden;
}
.fano-tree svg { display: block; width: 100%; height: auto; min-height: 260px; max-height: 420px; }
.fano-node circle { transition: transform .2s var(--ease); cursor: pointer; }
.fano-node:hover circle { transform: scale(1.06); transform-box: fill-box; transform-origin: center; }
.fano-controls { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; margin-top: 12px; }
.fano-legend { color: var(--label-secondary); font-size: 14px; }

/* ---------- Верхняя панель ---------- */
.appbar {
  position: sticky; top: 0; z-index: 50;
  display: flex; align-items: center; gap: 12px;
  padding: 12px 20px;
  background: color-mix(in srgb, var(--bg-elevated) 80%, transparent);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: .5px solid var(--separator);
}
.appbar .brand {
  font-weight: 700; letter-spacing: -.01em; font-size: 19px;
}
.appbar .brand a { color: var(--label); }
.appbar .spacer { flex: 1; }
.appbar nav { display: flex; gap: 8px; align-items: center; }
.appbar nav a, .appbar nav button {
  color: var(--label-secondary);
  background: transparent; border: 0;
  padding: 8px 12px; border-radius: var(--chip-radius);
  font-size: 15px; cursor: pointer;
}
.appbar nav a:hover, .appbar nav button:hover { color: var(--label); background: var(--fill); }
.streak-chip {
  display: inline-flex; align-items: center; gap: 6px;
  background: var(--fill); color: var(--label);
  padding: 6px 12px; border-radius: var(--chip-radius); font-weight: 600; font-size: 14px;
}
.streak-chip .flame { color: var(--warning); }

/* ---------- Контейнер ---------- */
.container { max-width: 880px; margin: 0 auto; padding: 24px 20px 80px; }
.container.narrow { max-width: 620px; }

h1, h2, h3 { letter-spacing: -.02em; line-height: 1.2; margin: 0 0 .4em; }
h1 { font-size: 34px; font-weight: 800; }
h2 { font-size: 26px; font-weight: 700; }
h3 { font-size: 20px; font-weight: 600; }
.muted { color: var(--label-secondary); }
.lead { color: var(--label-secondary); font-size: 17px; }

/* ---------- Кнопки ---------- */
.btn {
  appearance: none;
  border: 1px solid transparent;
  padding: 14px 20px;
  border-radius: var(--chip-radius);
  background: var(--fill);
  color: var(--label);
  font-size: 17px; font-weight: 600;
  cursor: pointer;
  transition: transform .15s ease, background .2s ease, opacity .2s;
}
.btn:hover { background: var(--fill-secondary); }
.btn:active { transform: scale(.98); }
.btn:disabled { opacity: .45; cursor: not-allowed; transform: none; }
.btn-primary { background: var(--accent); color: white; }
.btn-primary:hover { background: var(--accent-pressed); }
.btn-ghost { background: transparent; }
.btn-ghost:hover { background: var(--fill); }
.btn-danger { background: var(--danger); color: white; }
.btn-block { display: block; width: 100%; }
.btn-lg { padding: 16px 22px; font-size: 19px; }

/* ---------- Карточки/списки ---------- */
.card {
  background: var(--bg-elevated);
  border-radius: var(--card-radius);
  box-shadow: var(--shadow-sm);
  padding: 20px;
}
.list {
  background: var(--bg-elevated);
  border-radius: var(--card-radius);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}
.row {
  display: flex; align-items: center; gap: 14px;
  padding: 16px 18px; cursor: pointer;
  border-top: .5px solid var(--separator);
  background: transparent; width: 100%; text-align: left;
  color: var(--label); border-left: 0; border-right: 0; border-bottom: 0;
}
.row:first-child { border-top: 0; }
.row:hover { background: var(--fill); }
.row .chev { color: var(--label-tertiary); margin-left: auto; }
.row .sub { color: var(--label-secondary); font-size: 14px; margin-top: 2px; }
.row .icon-circle {
  width: 40px; height: 40px; border-radius: 50%;
  display: inline-flex; align-items: center; justify-content: center;
  background: var(--accent); color: white; font-weight: 700;
}
.row.done .icon-circle { background: var(--success); }

/* tile-курс */
.tile {
  display: block; text-align: left;
  border: 0; width: 100%; cursor: pointer;
  padding: 22px; border-radius: var(--card-radius);
  color: white;
  box-shadow: var(--shadow);
  transition: transform .15s ease, box-shadow .2s ease;
  margin-bottom: 14px;
}
.tile:hover { transform: translateY(-2px); }
.tile h3 { color: white; font-size: 22px; margin-bottom: 6px; }
.tile p { color: rgba(255,255,255,.9); margin: 0; }
.tile .badge {
  display: inline-block; padding: 4px 10px;
  background: rgba(255,255,255,.2); border-radius: var(--chip-radius);
  font-size: 13px; font-weight: 600; margin-top: 12px;
}

/* ---------- Форма ---------- */
.form { display: grid; gap: 14px; }
.field label { display: block; margin-bottom: 6px; color: var(--label-secondary); font-size: 14px; }
.input, .textarea, .select {
  appearance: none; width: 100%;
  padding: 14px 16px; border-radius: var(--row-radius);
  border: 1px solid var(--separator); background: var(--bg-elevated);
  color: var(--label); font-size: 17px; font-family: inherit;
}
.input:focus, .textarea:focus, .select:focus {
  outline: none; border-color: var(--accent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 25%, transparent);
}
.input.error { border-color: var(--danger); }
.fieldmsg { font-size: 13px; color: var(--danger); margin-top: 6px; }
.textarea { font-family: var(--font-mono); resize: vertical; min-height: 200px; }

/* ---------- Toast ---------- */
.toast {
  position: fixed; left: 50%; bottom: 28px; transform: translateX(-50%) translateY(0);
  background: color-mix(in srgb, var(--label) 92%, transparent);
  color: var(--bg-elevated);
  padding: 12px 18px; border-radius: var(--chip-radius);
  box-shadow: var(--shadow-lg);
  font-weight: 600; z-index: 1000;
  transition: opacity .25s ease, transform .25s ease;
}
.toast.hidden { opacity: 0; transform: translateX(-50%) translateY(20px); pointer-events: none; }
.toast.danger { background: var(--danger); color: white; }
.toast.success { background: var(--success); color: white; }

/* ---------- Урок: прогресс-бар ---------- */
.progress-bar {
  display: flex; align-items: center; gap: 14px;
  padding: 8px 4px; margin-bottom: 8px;
}
.progress-bar .head { font-weight: 700; min-width: 110px; color: var(--label-secondary); }
.bar { flex: 1; height: 12px; border-radius: var(--chip-radius); background: var(--fill); overflow: hidden; }
.bar > i { display: block; height: 100%; background: var(--accent); border-radius: inherit; transition: width .3s ease; }
.progress-bar .pct { min-width: 42px; text-align: right; font-weight: 600; }

/* ---------- Экран упражнения ---------- */
.exercise { display: grid; gap: 22px; }
.exercise .prompt {
  background: var(--bg-elevated); padding: 22px;
  border-radius: var(--card-radius); box-shadow: var(--shadow-sm);
}
.exercise .prompt .label { color: var(--label-secondary); text-transform: uppercase; font-size: 12px; letter-spacing: .05em; margin-bottom: 8px; }
.options { display: grid; gap: 10px; }
.option {
  text-align: left; padding: 16px 18px;
  border-radius: var(--row-radius);
  border: 1px solid var(--separator); background: var(--bg-elevated);
  color: var(--label); font-size: 17px; cursor: pointer;
  transition: background .15s, transform .1s, border-color .15s;
}
.option:hover { background: var(--fill); }
.option.selected { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 12%, var(--bg-elevated)); }
.option.correct { border-color: var(--success); background: color-mix(in srgb, var(--success) 18%, var(--bg-elevated)); }
.option.wrong { border-color: var(--danger); background: color-mix(in srgb, var(--danger) 12%, var(--bg-elevated)); }

.match-cols { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.mcard {
  padding: 16px; border-radius: var(--row-radius);
  border: 1px solid var(--separator); background: var(--bg-elevated);
  cursor: pointer; transition: background .15s, border-color .15s, transform .1s;
}
.mcard.active { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 12%, var(--bg-elevated)); }
.mcard.matched { border-color: var(--success); background: color-mix(in srgb, var(--success) 16%, var(--bg-elevated)); }
.mcard.wrong { border-color: var(--danger); }

.foot {
  display: flex; gap: 12px; flex-wrap: wrap; align-items: center;
  margin-top: 8px;
}
.foot .spacer { flex: 1; }

.feedback {
  padding: 14px 16px; border-radius: var(--row-radius);
  background: var(--fill); margin-top: 4px;
}
.feedback.success { background: color-mix(in srgb, var(--success) 18%, transparent); }
.feedback.danger { background: color-mix(in srgb, var(--danger) 14%, transparent); color: var(--label); }
.feedback .title { font-weight: 700; margin-bottom: 4px; }
.feedback .explain { color: var(--label-secondary); }

/* ---------- Результат урока ---------- */
.result { text-align: center; display: grid; gap: 18px; justify-items: center; padding: 40px 20px; }
.result .emoji { font-size: 64px; }
.result .xp { font-size: 24px; font-weight: 800; color: var(--accent); }

/* ---------- Прелоадер ---------- */
.center { display: grid; place-items: center; height: 60vh; }
.spinner {
  width: 28px; height: 28px; border-radius: 50%;
  border: 3px solid var(--fill); border-top-color: var(--accent);
  animation: spin .8s linear infinite; margin: 0 auto 14px;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ---------- Админка ---------- */
.stat-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(180px,1fr)); gap: 14px; margin-bottom: 24px; }
.stat {
  background: var(--bg-elevated); border-radius: var(--card-radius);
  padding: 18px; box-shadow: var(--shadow-sm);
}
.stat .v { font-size: 30px; font-weight: 800; letter-spacing: -.02em; }
.stat .l { color: var(--label-secondary); font-size: 14px; }
.editor-actions { display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 14px; }

.activity svg { width: 100%; height: 120px; }

/* код-урок редактор */
.codeeditor {
  background: #0b1021; color: #E6E6E6;
  font-family: var(--font-mono); font-size: 15px;
  padding: 18px; border-radius: var(--row-radius); border: 1px solid var(--separator);
  min-height: 220px; tab-size: 4; white-space: pre; resize: vertical; overflow: auto;
}
.codeout {
  font-family: var(--font-mono); font-size: 14px;
  background: var(--fill); padding: 14px 16px; border-radius: var(--row-radius);
  white-space: pre-wrap; min-height: 80px;
  border: 1px solid var(--separator);
}

/* утилиты */
.row-actions { display: flex; gap: 8px; }
.row-actions button { padding: 8px 12px; font-size: 14px; }
.empty { text-align: center; color: var(--label-secondary); padding: 60px 20px; }

@media (max-width: 600px) {
  h1 { font-size: 28px; }
  h2 { font-size: 22px; }
  .container { padding: 14px 12px 80px; }
  .container.narrow { max-width: 100%; }
  .match-cols { grid-template-columns: 1fr; }
  .hero { padding: 32px 18px 28px; border-radius: 20px; margin-bottom: 18px; }
  .hero h1 { font-size: 28px; }
  .hero .lead { font-size: 16px; }
  .theory-figure { padding: 10px; margin: 12px 0; overflow-x: auto; -webkit-overflow-scrolling: touch; }
  .theory-figure svg { max-width: none; width: auto; min-width: 280px; }
  .stat-grid { grid-template-columns: repeat(auto-fill, minmax(140px,1fr)); gap: 10px; }
  .fano-tree { min-height: 200px; }
  .fano-tree .fano-controls { flex-direction: column; align-items: stretch; }
  .exercise .prompt { padding: 16px; }
  .appbar { padding: 8px 12px; gap: 6px; }
  .appbar .brand { font-size: 16px; }
  .appbar nav a, .appbar nav button { padding: 6px 10px; font-size: 14px; }
  .row { padding: 12px 14px; gap: 10px; }
  .options { gap: 8px; }
  .option { padding: 12px 14px; font-size: 15px; }
  .foot { flex-direction: column; align-items: stretch; }
  .foot .btn { width: 100%; }
}

/* ---------- Ссылка на главный сайт ---------- */
.site-link {
  display: inline-flex; align-items: center; gap: 4px;
  color: var(--label-secondary); text-decoration: none;
  padding: 8px 14px; border-radius: var(--chip-radius);
  border: 1px solid var(--separator); font-size: 14px; font-weight: 600;
  transition: all .2s var(--ease); white-space: nowrap;
}
.site-link:hover { color: var(--label); border-color: color-mix(in srgb, var(--label) 30%, transparent); background: var(--fill); }

/* ---------- Достижения ---------- */
.ach-rank { display: flex; gap: 18px; align-items: center; }
.ach-rank-emoji { font-size: 52px; line-height: 1; }
.ach-rank-title { font-size: 26px; font-weight: 800; letter-spacing: -.02em; }
.ach-bar {
  margin-top: 10px; height: 10px; border-radius: 999px;
  background: var(--fill); overflow: hidden;
}
.ach-bar-fill {
  height: 100%; border-radius: 999px;
  background: var(--accent-grad, linear-gradient(135deg,#0A84FF,#5E5CE6));
  transition: width .6s var(--ease);
}
.ach-bar-label { margin-top: 6px; font-size: 13px; color: var(--label-secondary); }
.ach-stats {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
  gap: 12px; margin-top: 18px;
}
.ach-stat {
  background: var(--bg-elevated); border: 1px solid var(--separator);
  border-radius: var(--card-radius); padding: 14px 16px;
}
.ach-stat-v { font-size: 24px; font-weight: 800; letter-spacing: -.02em; }
.ach-medals {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(210px, 1fr));
  gap: 12px; margin-top: 8px;
}
.ach-medal {
  background: var(--bg-elevated); border: 1px solid var(--separator);
  border-radius: var(--card-radius); padding: 16px;
  display: flex; flex-direction: column; gap: 6px;
}
.ach-medal.open { border-color: color-mix(in srgb, var(--accent) 35%, transparent); }
.ach-medal.locked { opacity: .55; }
.ach-medal-emoji { font-size: 30px; line-height: 1; }
.ach-medal-title { font-weight: 700; font-size: 15px; }
.ach-medal-desc { font-size: 13px; color: var(--label-secondary); flex: 1; }
.ach-medal-prog .ach-bar { margin-top: 6px; height: 6px; }
.ach-medal-nums { margin-top: 4px; font-size: 12px; color: var(--label-secondary); font-variant-numeric: tabular-nums; }