/* ============================================================
   Платформа самообучения — оформление
   Палитра приходит из шаблона (переменные --c-*), здесь только
   раскладка, типографика и поведение компонентов.
   ============================================================ */

:root {
  --f-ui: ui-sans-serif, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --f-reading: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, "Times New Roman", serif;
  --f-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;

  --fs-base: 16.5px;
  --measure: 92ch;

  --sp-1: 4px;  --sp-2: 8px;  --sp-3: 12px; --sp-4: 16px;
  --sp-5: 24px; --sp-6: 32px; --sp-7: 48px; --sp-8: 72px;

  --shadow-1: 0 1px 2px rgba(16, 20, 40, .05);
  --shadow-2: 0 8px 30px -12px rgba(16, 20, 40, .22);
  --shadow-3: 0 24px 60px -28px rgba(16, 20, 40, .38);

  --ease: cubic-bezier(.2, .7, .3, 1);
  --dur: .22s;
  --dur-slow: .45s;
  --maxw: 1120px;
}

html[data-scale="s"] { --fs-base: 15px; }
html[data-scale="l"] { --fs-base: 18px; }
html[data-width="compact"], html[data-width="normal"] { --measure: 68ch; }
html[data-width="standard"], html[data-width="wide"] { --measure: 92ch; }
html[data-width="expanded"] { --measure: 120ch; }
html[data-reading="sans"] { --f-reading: var(--f-ui); }
html[data-motion="off"] * { animation: none !important; transition: none !important; }

*, *::before, *::after { box-sizing: border-box; }

html {
  font-size: var(--fs-base);
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--f-ui);
  background: var(--c-bg);
  color: var(--c-text);
  line-height: 1.55;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 { margin: 0; line-height: 1.2; letter-spacing: -.015em; font-weight: 650; }
p { margin: 0; }
a { color: inherit; }
img { max-width: 100%; height: auto; display: block; }
code, pre { font-family: var(--f-mono); }

:focus-visible {
  outline: 2px solid var(--c-primary);
  outline-offset: 2px;
  border-radius: 4px;
}

.muted { color: var(--c-muted); font-size: .9rem; }

.page {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: var(--sp-6) var(--sp-4) var(--sp-8);
}
.page--chapter { max-width: 1480px; }

/* ---------- Верхняя панель ---------- */

.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--c-surface) 88%, transparent);
  backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--c-border);
}

.topbar__inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: var(--sp-3) var(--sp-4);
  display: flex;
  align-items: center;
  gap: var(--sp-4);
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  text-decoration: none;
  margin-right: auto;
}

.brand__mark {
  width: 38px; height: 38px;
  display: grid; place-items: center;
  border-radius: calc(var(--radius) * .55);
  background: var(--c-primary);
  color: var(--c-on-primary);
  font-size: 1.05rem;
  box-shadow: var(--shadow-2);
}

.brand__text { display: flex; flex-direction: column; line-height: 1.15; }
.brand__text b { font-size: .98rem; }
.brand__text small { color: var(--c-muted); font-size: .74rem; }

.nav { display: flex; align-items: center; gap: var(--sp-1); }

.nav__link {
  text-decoration: none;
  padding: var(--sp-2) var(--sp-3);
  border-radius: 999px;
  font-size: .93rem;
  font-weight: 550;
  color: var(--c-muted);
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease);
}
.nav__link:hover { background: var(--c-surface-alt); color: var(--c-text); }
.nav__link.is-active { background: var(--c-primary-soft); color: var(--c-primary); }

.nav__user {
  display: flex; align-items: center; gap: var(--sp-2);
  margin-left: var(--sp-3);
  padding-left: var(--sp-3);
  border-left: 1px solid var(--c-border);
}

.chip {
  font-size: .85rem;
  font-weight: 600;
  padding: 4px 10px;
  border-radius: 999px;
  background: var(--c-surface-alt);
  border: 1px solid var(--c-border);
  white-space: nowrap;
}

.burger {
  display: none;
  width: 42px; height: 38px;
  border: 1px solid var(--c-border);
  background: var(--c-surface);
  border-radius: 10px;
  cursor: pointer;
  padding: 9px 10px;
  flex-direction: column;
  justify-content: space-between;
}
.burger span {
  display: block; height: 2px; width: 100%;
  background: var(--c-text); border-radius: 2px;
  transition: transform var(--dur) var(--ease), opacity var(--dur) var(--ease);
}
.burger[aria-expanded="true"] span:nth-child(1) { transform: translateY(8px) rotate(45deg); }
.burger[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.burger[aria-expanded="true"] span:nth-child(3) { transform: translateY(-8px) rotate(-45deg); }

/* ---------- Уведомления ---------- */

.flashes {
  position: fixed;
  right: var(--sp-4); bottom: var(--sp-4);
  z-index: 80;
  display: flex; flex-direction: column; gap: var(--sp-2);
  max-width: min(420px, calc(100vw - 32px));
}

.flash {
  display: flex; align-items: flex-start; gap: var(--sp-3);
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-left: 3px solid var(--c-success);
  border-radius: calc(var(--radius) * .6);
  box-shadow: var(--shadow-3);
  padding: var(--sp-3) var(--sp-4);
  font-size: .92rem;
  animation: flash-in var(--dur-slow) var(--ease) both;
}
.flash--warn { border-left-color: var(--c-warning); }
.flash--err { border-left-color: var(--c-danger); }
.flash__close {
  border: 0; background: none; cursor: pointer; font-size: 1.2rem;
  line-height: 1; color: var(--c-muted); margin-left: auto; padding: 0 2px;
}
@keyframes flash-in {
  from { opacity: 0; transform: translateY(12px) scale(.98); }
  to { opacity: 1; transform: none; }
}

/* ---------- Кнопки ---------- */

.btn {
  --btn-bg: var(--c-surface);
  --btn-fg: var(--c-text);
  display: inline-flex; align-items: center; justify-content: center;
  gap: var(--sp-2);
  font: inherit; font-weight: 600; font-size: .93rem;
  padding: 10px 18px;
  border-radius: 999px;
  border: 1px solid var(--c-border);
  background: var(--btn-bg);
  color: var(--btn-fg);
  cursor: pointer;
  text-decoration: none;
  transition: transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease),
              background var(--dur) var(--ease), border-color var(--dur) var(--ease);
}
.btn:hover { box-shadow: var(--shadow-2); }
.btn:active { transform: translateY(1px); }
.btn:disabled { opacity: .4; cursor: not-allowed; box-shadow: none; }

.btn--primary { --btn-bg: var(--c-primary); --btn-fg: var(--c-on-primary); border-color: transparent; }
.btn--ghost { --btn-bg: transparent; }
.btn--ghost:hover { background: var(--c-surface-alt); }
.btn--danger { --btn-fg: var(--c-danger); border-color: color-mix(in srgb, var(--c-danger) 35%, var(--c-border)); }
.btn--danger:hover { background: color-mix(in srgb, var(--c-danger) 10%, var(--c-surface)); }
.btn--sm { padding: 6px 12px; font-size: .84rem; }
.btn--lg { padding: 13px 26px; font-size: 1rem; }
.btn--block { width: 100%; }

/* отметка «прочитано / решено» — состояние важнее иконки */
.btn--mark { border-style: dashed; }
.btn__check {
  display: grid; place-items: center;
  width: 18px; height: 18px;
  border-radius: 50%;
  border: 1.5px solid var(--c-border);
  font-size: .68rem;
  color: transparent;
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease),
              border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}
.btn--mark.is-on {
  border-style: solid;
  border-color: color-mix(in srgb, var(--c-success) 45%, var(--c-border));
  background: color-mix(in srgb, var(--c-success) 10%, var(--c-surface));
  color: var(--c-success);
}
.btn--mark.is-on .btn__check {
  background: var(--c-success); border-color: var(--c-success); color: #fff;
  transform: scale(1.08);
}

/* ---------- Экран входа ---------- */

.gate {
  min-height: 100vh;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, .85fr);
  align-items: center;
  gap: var(--sp-8);
  max-width: 1040px;
  margin: 0 auto;
  padding: var(--sp-7) var(--sp-4);
}
.gate--single { grid-template-columns: minmax(0, 1fr); max-width: 480px; }

.gate__panel {
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: var(--sp-7) var(--sp-6);
  box-shadow: var(--shadow-3);
  animation: rise var(--dur-slow) var(--ease) both;
}
@keyframes rise { from { opacity: 0; transform: translateY(14px); } to { opacity: 1; transform: none; } }

.gate__mark {
  width: 52px; height: 52px;
  display: grid; place-items: center;
  border-radius: 16px;
  background: var(--c-primary); color: var(--c-on-primary);
  font-size: 1.4rem;
  margin-bottom: var(--sp-4);
}
.gate__mark--admin { background: var(--c-text); }
.gate__title { font-size: 1.75rem; }
.gate__sub { color: var(--c-muted); margin-top: var(--sp-2); font-size: .95rem; }
.gate__form { margin-top: var(--sp-5); display: flex; flex-direction: column; gap: var(--sp-4); }
.gate__error {
  color: var(--c-danger);
  background: color-mix(in srgb, var(--c-danger) 9%, var(--c-surface));
  border: 1px solid color-mix(in srgb, var(--c-danger) 28%, var(--c-border));
  border-radius: 10px;
  padding: var(--sp-3);
  font-size: .9rem;
  animation: shake .3s var(--ease);
}
@keyframes shake {
  0%, 100% { transform: none; }
  25% { transform: translateX(-5px); }
  75% { transform: translateX(5px); }
}
.gate__hint { margin-top: var(--sp-5); font-size: .86rem; color: var(--c-muted); }
.gate__hint a { color: var(--c-primary); }

.gate__aside h2 { font-size: 1.05rem; margin-bottom: var(--sp-4); }
.gate__steps { margin: 0; padding-left: 1.1rem; display: grid; gap: var(--sp-4); }
.gate__steps li { color: var(--c-muted); font-size: .93rem; }
.gate__steps b { color: var(--c-text); }

/* ---------- Поля ---------- */

.field { display: flex; flex-direction: column; gap: 6px; }
.field__label { font-size: .82rem; font-weight: 600; color: var(--c-muted); }
.field--grow { flex: 1 1 220px; }
.field--inline { margin-top: var(--sp-3); }

.input {
  font: inherit;
  padding: 11px 14px;
  border-radius: 12px;
  border: 1px solid var(--c-border);
  background: var(--c-surface-alt);
  color: var(--c-text);
  width: 100%;
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}
.input:focus { background: var(--c-surface); border-color: var(--c-primary); outline: none; }
.input--lg { padding: 14px 16px; font-size: 1.05rem; }
.input--color { padding: 4px; height: 44px; width: 84px; cursor: pointer; }

/* ---------- Обложка курса ---------- */

.cover {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius);
  border: 1px solid var(--c-border);
  background: var(--c-surface);
  padding: var(--sp-7) var(--sp-6);
  margin-bottom: var(--sp-6);
  box-shadow: var(--shadow-2);
}
.cover::before {
  content: "";
  position: absolute; inset: 0;
  opacity: .14;
  pointer-events: none;
}
.cover--gradient::before {
  background: radial-gradient(120% 140% at 12% 0%, var(--c-primary) 0%, transparent 58%),
              radial-gradient(90% 120% at 100% 0%, var(--c-accent) 0%, transparent 55%);
}
.cover--solid::before { background: var(--c-primary); opacity: .08; }
.cover--grid::before {
  background-image: linear-gradient(var(--c-primary) 1px, transparent 1px),
                    linear-gradient(90deg, var(--c-primary) 1px, transparent 1px);
  background-size: 28px 28px;
  opacity: .07;
}
.cover--rays::before {
  background: repeating-conic-gradient(from 0deg at 90% -10%,
              var(--c-primary) 0deg 6deg, transparent 6deg 16deg);
  opacity: .08;
}
.cover__image {
  position: absolute; inset: 0;
  width: 100%; height: 100%;
  object-fit: cover;
  opacity: .16;
}
.cover__body { position: relative; }
.cover__head { display: flex; gap: var(--sp-4); align-items: flex-start; }
.cover__icon {
  flex: none;
  width: 58px; height: 58px;
  display: grid; place-items: center;
  font-size: 1.7rem;
  border-radius: calc(var(--radius) * .6);
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  box-shadow: var(--shadow-1);
}
.cover__title { font-size: clamp(1.6rem, 4vw, 2.35rem); }
.cover__desc { color: var(--c-muted); margin-top: var(--sp-2); max-width: 62ch; }
.cover__meta {
  display: flex; flex-wrap: wrap; gap: var(--sp-2);
  margin-top: var(--sp-5);
}
.cover__meta span {
  font-size: .8rem;
  padding: 5px 11px;
  border-radius: 999px;
  background: var(--c-surface-alt);
  border: 1px solid var(--c-border);
  color: var(--c-muted);
}
.cover__progress {
  display: flex; align-items: center; gap: var(--sp-3);
  margin-top: var(--sp-5);
  max-width: 520px;
}
.cover__percent { font-variant-numeric: tabular-nums; font-size: .95rem; }
.cover__cta { margin-top: var(--sp-5); flex-direction: column; align-items: flex-start; gap: 2px; }
.cover__cta small { font-weight: 500; opacity: .8; font-size: .78rem; }

/* ---------- Прогресс ---------- */

.progress {
  flex: 1;
  height: 10px;
  border-radius: 999px;
  background: var(--c-surface-alt);
  border: 1px solid var(--c-border);
  overflow: hidden;
}
.progress--thin { height: 6px; }
.progress__fill {
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--c-primary), color-mix(in srgb, var(--c-accent) 60%, var(--c-primary)));
  transition: width var(--dur-slow) var(--ease);
}

/* ---------- Дорожная карта ---------- */

.roadmap { display: grid; gap: var(--sp-6); }

.sect {
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: var(--sp-5);
}
.sect__title-row { display: flex; align-items: center; gap: var(--sp-3); }
.sect__num {
  flex: none;
  width: 28px; height: 28px;
  display: grid; place-items: center;
  border-radius: 9px;
  background: var(--c-primary-soft);
  color: var(--c-primary);
  font-size: .85rem; font-weight: 700;
  font-variant-numeric: tabular-nums;
}
.sect__title { font-size: 1.2rem; display: flex; align-items: center; gap: var(--sp-2); flex-wrap: wrap; }
.sect__icon { font-size: 1.05rem; }
.sect__meta {
  display: flex; align-items: center; gap: var(--sp-3);
  margin-top: var(--sp-3);
  font-size: .82rem; color: var(--c-muted);
}
.sect__count { white-space: nowrap; }
.sect__percent { font-variant-numeric: tabular-nums; min-width: 34px; text-align: right; }
.sect__desc { color: var(--c-muted); font-size: .9rem; margin-top: var(--sp-3); }

.chapters {
  list-style: none;
  margin: var(--sp-4) 0 0;
  padding: 0 0 0 14px;
  border-left: 2px solid var(--c-border);
  display: grid;
  gap: 2px;
}

.chapter__link {
  display: flex; align-items: center; gap: var(--sp-3);
  padding: var(--sp-3);
  border-radius: calc(var(--radius) * .55);
  text-decoration: none;
  transition: background var(--dur) var(--ease), transform var(--dur) var(--ease);
}
.chapter__link:hover { background: var(--c-surface-alt); transform: translateX(3px); }

.chapter__dot {
  flex: none;
  width: 30px; height: 30px;
  margin-left: -30px;
  display: grid; place-items: center;
  border-radius: 50%;
  background: var(--c-surface);
  border: 2px solid var(--c-border);
  font-size: .8rem; font-weight: 700;
  color: var(--c-muted);
}
.chapter--done .chapter__dot {
  background: var(--c-success); border-color: var(--c-success); color: #fff;
}
.chapter--active .chapter__dot { border-color: var(--c-primary); color: var(--c-primary); }

.chapter__body { display: flex; flex-direction: column; gap: 2px; min-width: 0; margin-left: var(--sp-3); }
.chapter__title { font-weight: 580; font-size: .98rem; }
.chapter__desc {
  color: var(--c-muted); font-size: .85rem;
  overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
}
.chapter__meta { display: flex; flex-wrap: wrap; gap: var(--sp-3); color: var(--c-muted); font-size: .78rem; }
.chapter__state { margin-left: auto; display: flex; align-items: center; gap: var(--sp-2); }

.pill {
  display: inline-block;
  font-size: .74rem; font-weight: 650;
  padding: 4px 10px;
  border-radius: 999px;
  background: var(--c-surface-alt);
  border: 1px solid var(--c-border);
  color: var(--c-muted);
  white-space: nowrap;
}
.pill--done { background: color-mix(in srgb, var(--c-success) 14%, var(--c-surface)); color: var(--c-success); border-color: transparent; }
.pill--active { background: var(--c-primary-soft); color: var(--c-primary); border-color: transparent; }
.pill--new { background: transparent; }
.pill--updated, .pill--fresh {
  color: var(--c-on-primary); border-color: transparent;
  background: var(--c-primary);
  box-shadow: 0 5px 14px color-mix(in srgb, var(--c-primary) 22%, transparent);
}
.pill--fresh { padding: 3px 8px; font-size: .72rem; }
.pill--easy { color: var(--c-success); }
.pill--medium { color: var(--c-warning); }
.pill--hard { color: var(--c-danger); }

.switcher { margin-top: var(--sp-6); }
.switcher h3 { font-size: 1rem; margin-bottom: var(--sp-3); }
.switcher__list { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: var(--sp-3); }
.switcher__item {
  display: flex; flex-direction: column; gap: 3px;
  padding: var(--sp-4);
  border-radius: calc(var(--radius) * .6);
  border: 1px solid var(--c-border);
  background: var(--c-surface);
  text-decoration: none;
  transition: border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}
.switcher__item:hover { border-color: var(--c-primary); transform: translateY(-2px); }
.switcher__item span { font-size: .8rem; color: var(--c-muted); }

/* ---------- Пустое состояние ---------- */

.empty {
  max-width: 520px; margin: var(--sp-8) auto; text-align: center;
  display: grid; gap: var(--sp-4); justify-items: center;
}
.empty--inline { margin: var(--sp-6) auto; }
.empty__mark {
  width: 64px; height: 64px; display: grid; place-items: center;
  border-radius: 20px; background: var(--c-primary-soft); color: var(--c-primary);
  font-size: 1.5rem; font-weight: 700;
}
.empty p { color: var(--c-muted); }
.empty__actions { display: flex; gap: var(--sp-3); flex-wrap: wrap; justify-content: center; }

/* ---------- Глава: подшапка ---------- */

.subbar {
  position: sticky; top: 62px; z-index: 30;
  margin: calc(var(--sp-6) * -1) calc(var(--sp-4) * -1) var(--sp-4);
  padding: 0 var(--sp-4);
  background: color-mix(in srgb, var(--c-bg) 85%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--c-border);
}
.subbar__inner {
  display: flex; align-items: center; gap: var(--sp-4);
  padding: var(--sp-3) 0;
  max-width: var(--maxw); margin: 0 auto;
}
.subbar__back {
  text-decoration: none; color: var(--c-muted); font-size: .86rem; white-space: nowrap;
  transition: color var(--dur) var(--ease);
}
.subbar__back:hover { color: var(--c-primary); }
.subbar__title { display: flex; flex-direction: column; min-width: 0; }
.subbar__title b { font-size: .95rem; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.subbar__title small { color: var(--c-muted); font-size: .76rem; }
.subbar__progress {
  margin-left: auto; display: flex; align-items: center; gap: var(--sp-2);
  min-width: 140px; font-size: .8rem; color: var(--c-muted);
  font-variant-numeric: tabular-nums;
}

@keyframes fade-in { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }

/* ---------- Текст курса ---------- */

.prose { font-family: var(--f-reading); font-size: 1.02rem; line-height: 1.72; }
.prose > * + * { margin-top: var(--sp-4); }
.prose__h { font-family: var(--f-ui); margin-top: var(--sp-6); }
h2.prose__h { font-size: 1.35rem; }
h3.prose__h { font-size: 1.15rem; }
h4.prose__h { font-size: 1rem; }
.prose__p { }
.prose__list { padding-left: 1.3rem; display: grid; gap: var(--sp-2); }
.prose__list--num { list-style: decimal; }
.prose__hr { border: 0; border-top: 1px solid var(--c-border); margin: var(--sp-6) 0; }
.prose a { color: var(--c-primary); text-decoration-thickness: 1px; text-underline-offset: 2px; }
.prose code {
  font-size: .88em;
  padding: 2px 6px;
  border-radius: 6px;
  background: var(--c-primary-soft);
  color: var(--c-primary);
}

.code {
  margin: var(--sp-5) 0;
  border-radius: calc(var(--radius) * .6);
  overflow: hidden;
  border: 1px solid var(--c-border);
  background: var(--c-code-bg);
}
.code__bar {
  display: flex; align-items: center; justify-content: space-between;
  padding: 8px 12px;
  background: color-mix(in srgb, var(--c-code-text) 8%, var(--c-code-bg));
  color: color-mix(in srgb, var(--c-code-text) 70%, transparent);
  font-family: var(--f-ui);
  font-size: .74rem;
}
.code__copy {
  font: inherit; font-size: .74rem;
  background: none; border: 1px solid color-mix(in srgb, var(--c-code-text) 25%, transparent);
  color: inherit; border-radius: 6px; padding: 3px 9px; cursor: pointer;
  transition: background var(--dur) var(--ease);
}
.code__copy:hover { background: color-mix(in srgb, var(--c-code-text) 14%, transparent); }
.code pre {
  margin: 0; padding: var(--sp-4);
  overflow-x: auto;
  color: var(--c-code-text);
  font-size: .86rem;
  line-height: 1.6;
}
.code pre code { background: none; padding: 0; color: inherit; }
.code figcaption {
  padding: 8px 12px; font-family: var(--f-ui); font-size: .78rem;
  color: color-mix(in srgb, var(--c-code-text) 62%, transparent);
  border-top: 1px solid color-mix(in srgb, var(--c-code-text) 12%, transparent);
}

.figure { margin: var(--sp-5) 0; }
.figure img {
  border-radius: calc(var(--radius) * .6);
  border: 1px solid var(--c-border);
  width: 100%;
}
.figure--small img { max-width: 280px; }
.figure--medium img { max-width: 520px; }
.figure--large img { max-width: 100%; }
.figure--full { margin-left: calc(var(--sp-4) * -1); margin-right: calc(var(--sp-4) * -1); }
.figure figcaption {
  font-family: var(--f-ui);
  font-size: .82rem; color: var(--c-muted);
  margin-top: var(--sp-2);
}
.figure__missing {
  display: grid; gap: 6px;
  padding: var(--sp-5);
  border: 1px dashed color-mix(in srgb, var(--c-warning) 50%, var(--c-border));
  border-radius: calc(var(--radius) * .6);
  background: color-mix(in srgb, var(--c-warning) 8%, var(--c-surface));
  font-family: var(--f-ui); font-size: .85rem;
}
.figure__missing code { background: var(--c-surface); color: var(--c-text); }

.callout {
  border-radius: calc(var(--radius) * .6);
  padding: var(--sp-4) var(--sp-5);
  border: 1px solid var(--c-border);
  border-left: 3px solid var(--c-primary);
  background: var(--c-surface-alt);
  font-family: var(--f-ui);
  font-size: .95rem;
}
.callout__title { display: block; margin-bottom: 4px; }
.callout--info { border-left-color: var(--c-primary); }
.callout--tip { border-left-color: var(--c-accent); }
.callout--success { border-left-color: var(--c-success); }
.callout--warning { border-left-color: var(--c-warning); }
.callout--danger { border-left-color: var(--c-danger); }

.quote {
  margin: var(--sp-5) 0;
  padding-left: var(--sp-5);
  border-left: 3px solid var(--c-border);
  font-style: italic;
  color: var(--c-muted);
}
.quote cite { display: block; margin-top: var(--sp-2); font-size: .85rem; font-style: normal; }

.table-wrap { overflow-x: auto; margin: var(--sp-5) 0; }
.table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--f-ui);
  font-size: .9rem;
  min-width: 420px;
}
.table th, .table td {
  text-align: left;
  padding: 10px 14px;
  border-bottom: 1px solid var(--c-border);
  vertical-align: top;
}
.table th { font-weight: 650; color: var(--c-muted); font-size: .82rem; }
.table tbody tr:hover { background: var(--c-surface-alt); }
.table--admin td { vertical-align: middle; }

.kv { display: grid; grid-template-columns: minmax(120px, auto) 1fr; gap: var(--sp-2) var(--sp-4); margin: var(--sp-5) 0; }
.kv dt { font-weight: 650; font-family: var(--f-ui); font-size: .92rem; }
.kv dd { margin: 0; color: var(--c-muted); }

.page-nav {
  display: flex; align-items: center; gap: var(--sp-3);
  max-width: var(--measure);
  margin: var(--sp-7) auto 0;
  padding-top: var(--sp-5);
  border-top: 1px solid var(--c-border);
  flex-wrap: wrap;
}
.page-nav .btn--primary { margin-left: auto; }

/* ---------- Практика ---------- */

.tasks { display: grid; gap: var(--sp-5); }

.task {
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: var(--sp-5);
  transition: border-color var(--dur) var(--ease);
}
.task.is-solved { border-color: color-mix(in srgb, var(--c-success) 40%, var(--c-border)); }
.task__head { display: flex; align-items: center; gap: var(--sp-3); margin-bottom: var(--sp-4); }
.task__title { display: flex; align-items: center; gap: var(--sp-3); min-width: 0; }
.task__num {
  flex: none;
  width: 28px; height: 28px; display: grid; place-items: center;
  border-radius: 9px; background: var(--c-primary-soft); color: var(--c-primary);
  font-size: .85rem; font-weight: 700;
}
.task__head h2 { font-size: 1.1rem; }
.task__head .pill { margin-left: auto; }
.task__foot { margin-top: var(--sp-4); }
.prose--task { font-size: .98rem; }

.hint {
  margin-top: var(--sp-4);
  border: 1px solid var(--c-border);
  border-radius: calc(var(--radius) * .55);
  background: var(--c-surface-alt);
  padding: var(--sp-3) var(--sp-4);
  font-size: .92rem;
}
.hint summary { cursor: pointer; font-weight: 600; color: var(--c-muted); }
.hint summary::marker { color: var(--c-primary); }
.hint > div { margin-top: var(--sp-3); }

.answer { margin-top: var(--sp-4); }
.btn--answer {
  border-style: dashed;
  border-color: color-mix(in srgb, var(--c-primary) 40%, var(--c-border));
  color: var(--c-primary);
  background: transparent;
}
.btn--answer:hover { background: var(--c-primary-soft); }

.answer__body {
  overflow: hidden;
  max-height: 0;
  opacity: 0;
  transition: max-height var(--dur-slow) var(--ease), opacity var(--dur-slow) var(--ease),
              margin-top var(--dur-slow) var(--ease);
}
.answer__body.is-open { opacity: 1; margin-top: var(--sp-4); }
.answer__inner {
  position: relative;
  padding: var(--sp-4) var(--sp-5);
  border-radius: calc(var(--radius) * .6);
  background: var(--c-surface-alt);
  border: 1px solid var(--c-border);
}
.answer__inner::before {
  content: "";
  position: absolute; inset: 0;
  border-radius: inherit;
  background: linear-gradient(90deg,
              color-mix(in srgb, var(--c-accent) 55%, transparent),
              color-mix(in srgb, var(--c-accent) 5%, transparent));
  transform-origin: left;
  pointer-events: none;
  opacity: 0;
}
.answer__body.is-open .answer__inner::before { animation: sweep .55s var(--ease) forwards; }
@keyframes sweep {
  0% { opacity: .9; transform: scaleX(0); }
  55% { opacity: .75; transform: scaleX(1); }
  100% { opacity: 0; transform: scaleX(1); }
}

.chapter-nav {
  display: grid; grid-template-columns: 1fr 1fr; gap: var(--sp-3);
  margin-top: var(--sp-7);
}
.chapter-nav__item {
  display: flex; flex-direction: column; gap: 3px;
  padding: var(--sp-4);
  border: 1px solid var(--c-border);
  border-radius: calc(var(--radius) * .6);
  background: var(--c-surface);
  text-decoration: none;
  transition: border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}
.chapter-nav__item:hover { border-color: var(--c-primary); transform: translateY(-2px); }
.chapter-nav__item small { color: var(--c-muted); font-size: .76rem; }
.chapter-nav__item b { font-size: .92rem; }
.chapter-nav__item--next { text-align: right; }

/* ---------- Профиль и карточки ---------- */

.profile-head {
  display: flex; align-items: center; gap: var(--sp-4);
  flex-wrap: wrap;
  margin-bottom: var(--sp-6);
}
.profile-head__id { display: flex; align-items: center; gap: var(--sp-4); margin-right: auto; }
.profile-head h1 { font-size: 1.6rem; }
.profile-head p { color: var(--c-muted); font-size: .88rem; margin-top: 2px; }

.avatar {
  width: 54px; height: 54px;
  display: grid; place-items: center;
  border-radius: 18px;
  background: var(--c-primary); color: var(--c-on-primary);
  font-size: 1.4rem; font-weight: 700;
}
.avatar--admin { background: var(--c-text); }

.card {
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: var(--sp-5);
  margin-bottom: var(--sp-5);
}
.card__head {
  display: flex; align-items: baseline; gap: var(--sp-3);
  margin-bottom: var(--sp-4);
  flex-wrap: wrap;
}
.card__head h2 { font-size: 1.15rem; margin-right: auto; }
.card__head a { color: var(--c-primary); text-decoration: none; }

.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: var(--sp-3); }
.stat {
  display: flex; flex-direction: column; gap: 4px;
  padding: var(--sp-4);
  border-radius: calc(var(--radius) * .6);
  background: var(--c-surface-alt);
  border: 1px solid var(--c-border);
}
.stat--wide { grid-column: 1 / -1; }
.stat__label { font-size: .8rem; color: var(--c-muted); font-weight: 600; }
.stat__value { font-size: 1.7rem; font-variant-numeric: tabular-nums; line-height: 1.1; }
.stat__value small { font-size: .95rem; color: var(--c-muted); font-weight: 500; }
.stat__hint { font-size: .78rem; color: var(--c-muted); }
.stat__bar { display: flex; align-items: center; gap: var(--sp-3); margin-top: 6px; }

.activity { margin-top: var(--sp-5); }
.activity__head { display: flex; align-items: baseline; gap: var(--sp-3); flex-wrap: wrap; }
.activity__head h3 { font-size: .95rem; margin-right: auto; }
.activity__chart {
  display: flex; align-items: flex-end; gap: 3px;
  height: 90px; margin-top: var(--sp-3);
  padding: var(--sp-3);
  background: var(--c-surface-alt);
  border: 1px solid var(--c-border);
  border-radius: calc(var(--radius) * .6);
}
.activity__col { flex: 1; height: 100%; display: flex; align-items: flex-end; }
.activity__bar {
  width: 100%;
  border-radius: 3px;
  background: var(--c-border);
  transition: height var(--dur-slow) var(--ease);
}
.activity__bar.is-filled { background: var(--c-primary); }

.section-progress { display: grid; gap: var(--sp-3); margin-top: var(--sp-5); }
.section-progress__row { display: flex; align-items: center; gap: var(--sp-3); font-size: .88rem; }
.section-progress__name { flex: 0 0 auto; max-width: 40%; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.section-progress__val { font-variant-numeric: tabular-nums; color: var(--c-muted); min-width: 36px; text-align: right; }

.course-list { display: grid; gap: var(--sp-3); }
.course-item {
  display: flex; align-items: center; gap: var(--sp-4);
  padding: var(--sp-4);
  border: 1px solid var(--c-border);
  border-radius: calc(var(--radius) * .6);
  background: var(--c-surface-alt);
  flex-wrap: wrap;
}
.course-item.is-active {
  border-color: var(--c-primary);
  background: var(--c-primary-ghost);
  box-shadow: inset 3px 0 0 var(--c-primary);
}
.course-item__body { flex: 1 1 260px; min-width: 0; }
.course-item__title-row { display: flex; align-items: center; gap: var(--sp-2); flex-wrap: wrap; }
.course-item__body p { color: var(--c-muted); font-size: .88rem; margin-top: 2px; }
.course-item__meta { display: block; color: var(--c-muted); font-size: .78rem; margin-top: 6px; }
.course-item__actions { display: flex; gap: var(--sp-2); flex-wrap: wrap; align-items: center; }

.errors {
  border: 1px solid color-mix(in srgb, var(--c-danger) 35%, var(--c-border));
  background: color-mix(in srgb, var(--c-danger) 7%, var(--c-surface));
  border-radius: calc(var(--radius) * .6);
  padding: var(--sp-4);
  margin-bottom: var(--sp-4);
  font-size: .9rem;
}
.errors ul { margin: var(--sp-2) 0 0; padding-left: 1.2rem; display: grid; gap: 4px; }

.upload { display: grid; gap: var(--sp-4); }
.drop {
  position: relative; display: grid; gap: var(--sp-2); padding: var(--sp-3);
  border: 2px dashed var(--c-border);
  border-radius: var(--radius);
  background: var(--c-surface-alt);
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}
.drop:hover, .drop.is-over { border-color: var(--c-primary); background: var(--c-primary-ghost); }
.drop input[type="file"] { position: absolute; width: 1px; height: 1px; opacity: 0; }
.drop input[type="file"]:focus-visible + .drop__picker {
  outline: 2px solid var(--c-primary); outline-offset: 2px;
}
.drop__picker {
  display: grid; gap: 4px; justify-items: center; text-align: center;
  padding: var(--sp-4); border-radius: calc(var(--radius) * .7); cursor: pointer;
}
.drop__icon { font-size: 1.5rem; }
.drop__title { font-weight: 650; }
.drop__title small { color: var(--c-muted); font-weight: 500; }
.drop__hint { font-size: .84rem; color: var(--c-muted); }
.drop__files { width: 100%; display: grid; gap: var(--sp-2); }
.drop__empty {
  display: block; padding: var(--sp-2); text-align: center;
  color: var(--c-muted); font-size: .8rem;
}
.drop-file {
  min-width: 0; display: grid; grid-template-columns: auto minmax(0, 1fr) auto auto;
  align-items: center; gap: var(--sp-3); padding: 9px var(--sp-3);
  border: 1px solid var(--c-border); border-radius: calc(var(--radius) * .55);
  background: var(--c-surface); box-shadow: var(--shadow-1); text-align: left;
}
.file-type {
  display: inline-grid; place-items: center; min-width: 42px; padding: 3px 7px;
  border-radius: 7px; background: var(--c-primary-soft); color: var(--c-primary);
  font: 700 .67rem/1.4 var(--f-mono); letter-spacing: .04em;
}
.drop-file__name {
  overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
  color: var(--c-text); font: 600 .82rem/1.4 var(--f-mono);
}
.drop-file__size { color: var(--c-muted); font-size: .76rem; white-space: nowrap; }
.drop-file__remove {
  appearance: none; border: 0; background: transparent; color: var(--c-danger);
  padding: 5px 7px; border-radius: 7px; font: inherit; font-size: .78rem;
  cursor: pointer; transition: background var(--dur) var(--ease);
}
.drop-file__remove:hover { background: color-mix(in srgb, var(--c-danger) 10%, transparent); }
.drop__status { color: var(--c-muted); font-size: .78rem; text-align: center; }
.drop__status.is-error { color: var(--c-danger); }

.samples-rows { display: grid; gap: var(--sp-3); }
.samples-row { display: grid; gap: var(--sp-3); }
.samples-row--1 { grid-template-columns: minmax(0, 1fr); }
.samples-row--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.samples-row--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.sample {
  display: flex; flex-direction: column; gap: 3px;
  padding: var(--sp-4);
  border: 1px solid var(--c-border);
  border-radius: calc(var(--radius) * .6);
  background: var(--c-surface-alt);
  text-decoration: none;
  transition: border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}
.sample:hover { border-color: var(--c-primary); transform: translateY(-2px); }
.sample span { font-size: .78rem; color: var(--c-muted); font-family: var(--f-mono); }

.settings { display: grid; gap: var(--sp-5); }
.settings__group { border: 0; margin: 0; padding: 0; display: grid; gap: var(--sp-3); }
.settings__group--compact { gap: var(--sp-2); }
.settings__group legend { font-size: .82rem; font-weight: 650; color: var(--c-muted); padding: 0; margin-bottom: var(--sp-2); }
.field-note { color: var(--c-muted); font-size: .82rem; }
.choices { display: flex; gap: var(--sp-2); flex-wrap: wrap; }
.choice { position: relative; }
.choice input { position: absolute; opacity: 0; }
.choice span {
  display: inline-block;
  padding: 8px 16px;
  border-radius: 999px;
  border: 1px solid var(--c-border);
  background: var(--c-surface-alt);
  font-size: .88rem;
  cursor: pointer;
  transition: background-color var(--dur) var(--ease), color var(--dur) var(--ease),
              border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}
.choice input:checked + span { background: var(--c-primary); color: var(--c-on-primary); border-color: transparent; }
.choice input:focus-visible + span { outline: 2px solid var(--c-primary); outline-offset: 2px; }

.switch { display: flex; align-items: center; gap: var(--sp-3); font-size: .93rem; cursor: pointer; }
.switch input { width: 18px; height: 18px; accent-color: var(--c-primary); cursor: pointer; }

.row-form { display: flex; gap: var(--sp-3); align-items: flex-end; flex-wrap: wrap; }
.row-actions { display: flex; gap: var(--sp-2); justify-content: flex-end; flex-wrap: wrap; }

.doc-head { margin-bottom: var(--sp-6); display: grid; gap: var(--sp-4); }
.doc-head h1 { font-size: clamp(1.6rem, 4vw, 2.2rem); }
.doc-head p { color: var(--c-muted); max-width: 70ch; }

.rules { margin: var(--sp-4) 0 0; padding-left: 1.2rem; display: grid; gap: var(--sp-2); font-size: .92rem; }
.rules code { font-size: .86em; padding: 2px 6px; border-radius: 6px; background: var(--c-surface-alt); }

/* ---------- Общие заголовки и магазин ---------- */

.page-head {
  display: flex; align-items: flex-end; justify-content: space-between; gap: var(--sp-5);
  margin-bottom: var(--sp-6);
}
.page-head--compact { align-items: center; }
.page-head h1 { font-size: clamp(1.65rem, 4vw, 2.25rem); }
.page-head p { color: var(--c-muted); margin-top: var(--sp-2); max-width: 66ch; }
.back-link {
  display: inline-block; color: var(--c-primary); text-decoration: none;
  font-size: .86rem; margin-bottom: var(--sp-3);
}

.store-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 290px), 1fr));
  gap: var(--sp-4);
}
.store-card {
  display: flex; flex-direction: column; gap: var(--sp-4);
  min-height: 310px;
  padding: var(--sp-5);
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-1);
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease),
              box-shadow var(--dur) var(--ease);
}
.store-card:hover { transform: translateY(-3px); border-color: var(--c-primary); box-shadow: var(--shadow-2); }
.store-card.is-added { box-shadow: inset 0 3px 0 var(--c-primary), var(--shadow-1); }
.store-card__top { display: flex; align-items: center; justify-content: space-between; }
.store-card__icon {
  width: 42px; height: 42px; display: grid; place-items: center;
  border-radius: 13px; color: var(--c-primary); background: var(--c-primary-soft);
}
.store-card__body h2 { font-size: 1.2rem; }
.store-card__body p {
  color: var(--c-muted); font-size: .9rem; margin-top: var(--sp-2);
  display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden;
}
.store-card__facts { display: flex; flex-wrap: wrap; gap: 6px; }
.store-card__facts span {
  padding: 4px 8px; border-radius: 8px; background: var(--c-surface-alt);
  border: 1px solid var(--c-border); color: var(--c-muted); font-size: .76rem;
}
.store-card__meta { display: grid; gap: 2px; color: var(--c-muted); font-size: .78rem; margin-top: auto; }
.store-card__actions { display: flex; flex-wrap: wrap; gap: var(--sp-2); }
.format-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--sp-4); }
.format-grid .card { margin-bottom: 0; }
.format-page { display: grid; gap: var(--sp-6); }
.format-page > .doc-head,
.format-page > .update-warning,
.format-page > .card { margin-bottom: 0; }
.samples-card { margin-top: 0; }

/* ---------- Последовательность материалов главы ---------- */

.lesson-layout {
  width: min(100%, calc(var(--measure) + 244px));
  margin: 0 auto;
  display: grid;
  grid-template-columns: 220px minmax(0, 1fr);
  gap: var(--sp-5);
  align-items: start;
}
.lesson-layout--single { grid-template-columns: minmax(0, 1fr); max-width: var(--measure); }
.lesson-main { min-width: 0; }
.lesson-rail {
  position: sticky; top: 132px;
  display: grid; gap: var(--sp-2);
  max-height: calc(100vh - 156px); overflow-y: auto;
  padding: 2px var(--sp-2) var(--sp-2) 2px;
  scrollbar-width: thin;
}
.lesson-step {
  min-width: 0; min-height: 54px;
  display: grid; grid-template-columns: 30px minmax(0, 1fr); align-items: center; gap: var(--sp-2);
  padding: 8px 10px; border: 1px solid var(--c-border); border-radius: 12px;
  background: var(--c-surface); color: var(--c-muted); text-decoration: none;
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease),
              background var(--dur) var(--ease);
}
.lesson-step__mark {
  width: 30px; height: 30px; display: grid; place-items: center;
  border-radius: 9px; background: var(--c-surface-alt);
  font-weight: 750; font-size: .78rem;
}
.lesson-step__text { min-width: 0; display: grid; gap: 1px; }
.lesson-step__text b { font-size: .78rem; }
.lesson-step__text small {
  font-size: .72rem; opacity: .78; overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
}
.lesson-step:hover { transform: translateX(2px); border-color: var(--c-primary); color: var(--c-primary); }
.lesson-step.is-current { background: var(--c-primary); border-color: var(--c-primary); color: var(--c-on-primary); box-shadow: var(--shadow-2); }
.lesson-step.is-current .lesson-step__mark { background: color-mix(in srgb, var(--c-on-primary) 14%, transparent); }
.lesson-step.is-done:not(.is-current) {
  color: var(--c-success);
  background: color-mix(in srgb, var(--c-success) 10%, var(--c-surface));
  border-color: color-mix(in srgb, var(--c-success) 35%, var(--c-border));
}
.lesson-step--task:not(.is-current, .is-done) { border-style: dashed; }
.lesson-step--quiz:not(.is-current, .is-done) { color: var(--c-warning); }

.learning-page {
  max-width: var(--measure); margin: 0 auto;
  animation: fade-in var(--dur-slow) var(--ease) both;
}
.learning-page.task, .learning-page--quiz {
  padding: clamp(var(--sp-4), 4vw, var(--sp-6));
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
}
.learning-page__head { margin-bottom: var(--sp-5); }
.learning-page__head h1 { font-size: clamp(1.45rem, 3.5vw, 2rem); margin-top: 5px; }
.learning-page__head p { color: var(--c-muted); margin-top: var(--sp-2); }
.learning-page__head--row { display: flex; align-items: flex-start; justify-content: space-between; gap: var(--sp-4); }
.content-kind {
  display: inline-block; color: var(--c-primary); font-size: .75rem; font-weight: 750;
  letter-spacing: .08em; text-transform: uppercase;
}

/* ---------- Тесты ---------- */

.quiz { display: grid; gap: var(--sp-5); }
.question {
  min-width: 0; margin: 0; padding: var(--sp-5);
  border: 1px solid var(--c-border); border-radius: calc(var(--radius) * .7);
  background: var(--c-surface-alt);
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}
/* Браузер по умолчанию выносит legend на линию рамки fieldset, из-за чего номер
   вопроса вылезал за блок. float возвращает его в обычный поток внутрь padding
   (это работает во всех движках, в отличие от display на legend). */
.question legend {
  float: left; width: 100%; margin-bottom: var(--sp-3);
  display: flex; align-items: center; gap: var(--sp-2);
  padding: 0; font-size: .82rem; color: var(--c-muted);
}
.question legend + * { clear: both; }
.question legend span {
  width: 22px; height: 22px; display: grid; place-items: center;
  border-radius: 7px; background: var(--c-primary-soft); color: var(--c-primary); font-weight: 700;
}
.question__prompt { font-size: 1rem; }
.question__options { display: grid; gap: var(--sp-2); margin-top: var(--sp-4); }
.quiz-option {
  display: flex; align-items: flex-start; gap: var(--sp-3); cursor: pointer;
  padding: 11px 13px; border: 1px solid var(--c-border); border-radius: 12px;
  background: var(--c-surface); font-size: .93rem;
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease),
              transform var(--dur) var(--ease);
}
.quiz-option:hover { border-color: var(--c-primary); transform: translateX(2px); }
/* Скрытому переключателю нужен позиционированный родитель, иначе фокус
   и прокрутка к нему считаются от постороннего блока. */
.quiz-option { position: relative; }
.quiz-option input { position: absolute; inset: 0; opacity: 0; pointer-events: none; }
.quiz-option__mark {
  flex: none; width: 18px; height: 18px; margin-top: 2px;
  border: 1.5px solid var(--c-border); border-radius: 50%; background: var(--c-surface);
  box-shadow: inset 0 0 0 4px var(--c-surface);
}
.quiz-option:has(input[type="checkbox"]) .quiz-option__mark { border-radius: 5px; }
.quiz-option:has(input:checked) {
  border-color: var(--c-primary); background: color-mix(in srgb, var(--c-primary) 8%, var(--c-surface));
}
.quiz-option:has(input:checked) .quiz-option__mark { background: var(--c-primary); border-color: var(--c-primary); }
.quiz-option.is-correct { border-color: var(--c-success); background: color-mix(in srgb, var(--c-success) 9%, var(--c-surface)); }
.quiz-option.is-correct .quiz-option__mark { background: var(--c-success); border-color: var(--c-success); }
.quiz-option.is-wrong { border-color: var(--c-danger); background: color-mix(in srgb, var(--c-danger) 9%, var(--c-surface)); }
.question.is-missing { border-color: var(--c-warning); }
.question.is-correct { border-color: color-mix(in srgb, var(--c-success) 55%, var(--c-border)); }
.question.is-incorrect { border-color: color-mix(in srgb, var(--c-danger) 55%, var(--c-border)); }
.question__explanation {
  margin-top: var(--sp-4); padding: var(--sp-4); border-radius: 12px;
  border-left: 3px solid var(--c-primary); background: var(--c-surface);
  font-size: .93rem;
}
.quiz__footer { display: flex; align-items: center; justify-content: space-between; gap: var(--sp-4); flex-wrap: wrap; }
.quiz__summary { color: var(--c-muted); font-size: .9rem; }
.quiz__summary.is-success { color: var(--c-success); font-weight: 650; }
.quiz__summary.is-error { color: var(--c-danger); }

/* ---------- Подсветка кода ---------- */

.tok-comment { color: #7f8a9d; font-style: italic; }
.tok-string { color: #a8dc76; }
.tok-number { color: #e7a96b; }
.tok-keyword { color: #82aaff; font-weight: 600; }
.tok-literal { color: #c792ea; }

/* ---------- Обновление курса ---------- */

.update-warning {
  display: grid; gap: 5px; margin-bottom: var(--sp-5); padding: var(--sp-4) var(--sp-5);
  border: 1px solid color-mix(in srgb, var(--c-warning) 40%, var(--c-border));
  border-left: 3px solid var(--c-warning); border-radius: calc(var(--radius) * .65);
  background: color-mix(in srgb, var(--c-warning) 7%, var(--c-surface));
}
.update-warning p { color: var(--c-muted); font-size: .9rem; }
.update-warning code, .source-list code {
  font-family: var(--f-mono); padding: 2px 6px; border-radius: 6px;
  background: var(--c-surface-alt); color: var(--c-text);
}
.source-list { display: flex; flex-wrap: wrap; gap: var(--sp-2); margin-bottom: var(--sp-4); }
.source-list code { border: 1px solid var(--c-border); font-size: .78rem; padding: 5px 8px; }
.source-manager { display: grid; gap: var(--sp-2); margin-bottom: var(--sp-4); }
.source-file {
  display: grid; grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center; gap: var(--sp-3); padding: var(--sp-3);
  border: 1px solid var(--c-border); border-radius: calc(var(--radius) * .6);
  background: var(--c-surface-alt);
}
.source-file.is-active { border-color: var(--c-primary); box-shadow: inset 3px 0 0 var(--c-primary); }
.source-file code {
  min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
  color: var(--c-text); font-size: .82rem;
}
.source-file__actions { display: flex; align-items: center; gap: var(--sp-2); }
.json-editor-panel {
  display: grid; gap: var(--sp-4); margin: 0 0 var(--sp-5); padding: var(--sp-4);
  border: 1px solid var(--c-border); border-radius: var(--radius);
  background: var(--c-surface); scroll-margin-top: 90px;
}
.json-editor-panel__head {
  display: flex; align-items: center; justify-content: space-between; gap: var(--sp-4);
}
.json-editor-panel__head h3 { margin-top: 2px; font-family: var(--f-mono); font-size: 1rem; }
.eyebrow {
  color: var(--c-primary); font-size: .72rem; font-weight: 750;
  letter-spacing: .08em; text-transform: uppercase;
}
.json-editor-form { display: grid; gap: var(--sp-3); }
.json-editor {
  position: relative; min-height: 440px; height: min(62vh, 680px); resize: vertical;
  overflow: hidden; border: 1px solid var(--c-border); border-radius: calc(var(--radius) * .6);
  background: var(--c-code-bg); box-shadow: inset 0 1px 8px rgba(0, 0, 0, .16);
}
.json-editor__highlight, .json-editor__input {
  position: absolute; inset: 0; width: 100%; height: 100%; margin: 0;
  padding: var(--sp-4); border: 0; tab-size: 2; white-space: pre;
  font: 400 .84rem/1.55 var(--f-mono); letter-spacing: 0;
}
.json-editor__highlight {
  display: none; overflow: hidden; color: var(--c-code-text); background: transparent;
  pointer-events: none;
}
.json-editor__highlight code { display: block; min-width: max-content; font: inherit; }
.json-editor__input {
  z-index: 1; overflow: auto; resize: none; outline: none;
  color: var(--c-code-text); caret-color: var(--c-code-text); background: transparent;
}
.json-editor.is-enhanced .json-editor__highlight { display: block; }
.json-editor.is-enhanced .json-editor__input {
  color: transparent;
  -webkit-text-fill-color: transparent;
}
.json-editor__input::selection {
  background: color-mix(in srgb, var(--c-primary) 38%, transparent);
  -webkit-text-fill-color: transparent;
}
.json-editor__message { color: var(--c-muted); font-size: .82rem; }
.json-editor__message.is-error { color: var(--c-danger); }
.json-editor__message.is-success { color: var(--c-success); }
.part-status-list { display: flex; flex-wrap: wrap; gap: var(--sp-2); margin-bottom: var(--sp-4); }
.part-status {
  display: inline-flex; align-items: center; gap: 7px; padding: 5px 9px;
  border: 1px solid var(--c-border); border-radius: 9px; background: var(--c-surface-alt);
}
.part-status code { font-size: .77rem; }
.part-status small { color: var(--c-muted); font-size: .72rem; }
.part-status.is-loaded { border-color: color-mix(in srgb, var(--c-success) 35%, var(--c-border)); }
.part-status.is-expected { border-style: dashed; border-color: color-mix(in srgb, var(--c-warning) 45%, var(--c-border)); }
.page-head__badges { display: flex; gap: var(--sp-2); flex-wrap: wrap; }
.publish-panel {
  display: flex; align-items: center; justify-content: space-between; gap: var(--sp-5);
  margin-bottom: var(--sp-5); padding: var(--sp-5);
  border: 1px solid color-mix(in srgb, var(--c-primary) 35%, var(--c-border));
  border-radius: var(--radius); background: var(--c-primary-ghost);
}
.publish-panel p { color: var(--c-muted); font-size: .86rem; margin-top: 3px; }
.switch--boxed {
  align-items: flex-start; padding: var(--sp-4); border: 1px solid var(--c-border);
  border-radius: calc(var(--radius) * .6); background: var(--c-surface-alt);
}
.switch--boxed span { display: grid; gap: 2px; }
.switch--boxed small { color: var(--c-muted); font-size: .8rem; }
.drop.is-disabled { opacity: .5; cursor: not-allowed; filter: grayscale(.3); }
.form-actions { display: flex; justify-content: flex-end; gap: var(--sp-3); flex-wrap: wrap; }
.danger-zone {
  display: flex; align-items: center; justify-content: space-between; gap: var(--sp-5);
  padding: var(--sp-5); border: 1px solid color-mix(in srgb, var(--c-danger) 35%, var(--c-border));
  border-radius: var(--radius); background: color-mix(in srgb, var(--c-danger) 5%, var(--c-surface));
}
.danger-zone p { color: var(--c-muted); font-size: .86rem; margin-top: 3px; }

/* ---------- Адаптив ---------- */

@media (max-width: 860px) {
  .gate { grid-template-columns: 1fr; gap: var(--sp-6); min-height: auto; padding-top: var(--sp-6); }
  .gate__aside { order: -1; }
  .chapter-nav { grid-template-columns: 1fr; }
  .chapter-nav__item--next { text-align: left; }
  .format-grid { grid-template-columns: 1fr; }
  .samples-row--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .lesson-layout { width: 100%; grid-template-columns: minmax(0, 1fr); gap: var(--sp-4); }
  .lesson-rail {
    position: static; display: flex; max-height: none; overflow-x: auto; overflow-y: hidden;
    padding: 2px 2px var(--sp-2);
  }
  .lesson-step { flex: 0 0 190px; }
  .lesson-step:hover { transform: translateY(-2px); }
}

@media (max-width: 720px) {
  .page { padding: var(--sp-5) var(--sp-4) var(--sp-8); }

  .burger { display: flex; }

  .nav {
    position: fixed;
    inset: 62px 0 auto;
    flex-direction: column;
    align-items: stretch;
    gap: var(--sp-1);
    padding: var(--sp-4);
    background: var(--c-surface);
    border-bottom: 1px solid var(--c-border);
    box-shadow: var(--shadow-3);
    transform: translateY(-8px);
    opacity: 0;
    visibility: hidden;
    transition: transform var(--dur) var(--ease), opacity var(--dur) var(--ease), visibility var(--dur);
  }
  .nav.is-open { transform: none; opacity: 1; visibility: visible; }
  .nav__link { padding: var(--sp-3); border-radius: 12px; font-size: 1rem; }
  .nav__user {
    margin: var(--sp-2) 0 0;
    padding: var(--sp-3) 0 0;
    border-left: 0;
    border-top: 1px solid var(--c-border);
    justify-content: space-between;
  }

  .subbar { top: 58px; }
  .subbar__progress { display: none; }
  .subbar__back span { font-size: 1.1rem; }

  .cover { padding: var(--sp-5) var(--sp-4); }
  .cover__icon { width: 46px; height: 46px; font-size: 1.3rem; }
  .cover__cta { width: 100%; }

  .sect { padding: var(--sp-4) var(--sp-3); }
  .chapter__link { padding: var(--sp-3) var(--sp-2); gap: var(--sp-2); }
  .chapter__desc { display: none; }
  .chapter__state { margin-left: 0; }
  .chapter__body { flex: 1; }

  .stat__value { font-size: 1.45rem; }
  .course-item__actions { width: 100%; }
  .course-item__actions form { flex: 1 1 auto; }
  .course-item__actions .btn { width: 100%; }
  .drop-file { grid-template-columns: auto minmax(0, 1fr) auto; gap: var(--sp-2); }
  .drop-file__size { display: none; }
  .source-file { grid-template-columns: auto minmax(0, 1fr); }
  .source-file__actions { grid-column: 1 / -1; }
  .source-file__actions .btn { flex: 1; }
  .json-editor { min-height: 360px; height: 58vh; }
  .json-editor-panel__head { align-items: flex-start; }
  .row-actions { justify-content: flex-start; }
  .page-nav { flex-direction: column; align-items: stretch; }
  .page-nav .btn { width: 100%; margin-left: 0; }
  .flashes { left: var(--sp-4); right: var(--sp-4); max-width: none; }
  .kv { grid-template-columns: 1fr; gap: 2px var(--sp-4); }
  .kv dd { margin-bottom: var(--sp-3); }
  .page-head { align-items: stretch; flex-direction: column; gap: var(--sp-4); }
  .page-head > .btn { width: 100%; }
  .learning-page.task, .learning-page--quiz { padding: var(--sp-4); }
  .learning-page__head--row { align-items: flex-start; }
  .question { padding: var(--sp-4) var(--sp-3); }
  .quiz__footer { align-items: stretch; flex-direction: column; }
  .quiz__footer .btn { width: 100%; }
  .danger-zone { align-items: stretch; flex-direction: column; }
  .danger-zone .btn { width: 100%; }
  .form-actions { flex-direction: column-reverse; }
  .form-actions .btn { width: 100%; }
  .choices--stack-mobile { display: grid; grid-template-columns: 1fr; }
  .choices--stack-mobile .choice span { width: 100%; text-align: center; }
  .publish-panel { align-items: stretch; flex-direction: column; }
  .publish-panel .btn { width: 100%; }
  .samples-row--2, .samples-row--4 { grid-template-columns: minmax(0, 1fr); }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
    scroll-behavior: auto !important;
  }
}

@media print {
  .topbar, .subbar, .lesson-rail, .page-nav, .chapter-nav, .flashes { display: none !important; }
}

/* ---------- Запасные цвета для браузеров без color-mix() ---------- */

@supports not (color: color-mix(in srgb, red, blue)) {
  .topbar, .subbar { background: var(--c-surface); }
  .code__bar { background: var(--c-code-bg); color: var(--c-code-text); }
  .code__copy { border-color: var(--c-muted); }
  .pill--done { background: var(--c-primary-soft); color: var(--c-success); }
  .pill--active { background: var(--c-primary-soft); color: var(--c-primary); }
  .btn--mark.is-on { background: var(--c-surface-alt); border-color: var(--c-success); }
  .btn--danger { border-color: var(--c-danger); }
  .btn--answer { border-color: var(--c-primary); }
  .callout, .figure__missing, .errors, .gate__error { background: var(--c-surface-alt); }
  .figure__missing { border-color: var(--c-warning); }
  .errors, .gate__error { border-color: var(--c-danger); }
  .answer__inner::before { background: var(--c-accent); }
  .table tbody tr:hover { background: var(--c-surface-alt); }
  .drop:hover, .drop.is-over { background: var(--c-surface-alt); }
  .course-item.is-active { background: var(--c-surface-alt); }
}

/* Очень высокие картинки из курса не должны выталкивать текст за экран. */
.figure img { max-height: 70vh; object-fit: contain; background: var(--c-surface-alt); }