/* ============================================================================
 *  ФормулаЦТ — маршрут как «главы»: цветные обложки, таймлайн, арт-мотивы
 * ==========================================================================*/
.chapter {
  position: relative;
  margin-bottom: 22px;
  border-radius: 26px;
  background: var(--surface);
  border: 1px solid var(--line);
  box-shadow: var(--sh-2);
  overflow: hidden;
  isolation: isolate;
}

/* ------------------------------- обложка -------------------------------- */
.chapter__head {
  position: relative;
  padding: 18px 18px 16px;
  color: #fff;
  background:
    radial-gradient(320px 180px at 88% 8%, rgba(255,255,255,.22), transparent 62%),
    linear-gradient(135deg,
      color-mix(in srgb, var(--unit) 72%, #070b14),
      color-mix(in srgb, var(--unit-dark) 82%, #070b14) 72%,
      #070b14);
  overflow: hidden;
}
.chapter__head::after {
  content: "";
  position: absolute; inset: 0;
  background: linear-gradient(180deg, rgba(255,255,255,.10), transparent 46%);
  pointer-events: none;
}
.chapter__art {
  position: absolute; right: -16px; top: -18px;
  width: 158px; height: 158px;
  color: #fff; opacity: .16;
  transform: rotate(-6deg);
  pointer-events: none;
}
.chapter__art svg { width: 100%; height: 100%; }

.chapter__top { position: relative; display: flex; align-items: center; gap: 10px; }
.chapter__eyebrow {
  font-size: 9.5px; font-weight: 900; letter-spacing: .16em; text-transform: uppercase;
  color: rgba(255,255,255,.66);
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.chapter__count {
  margin-left: auto; flex: none;
  font-size: 10px; font-weight: 900;
  padding: 4px 9px; border-radius: 999px;
  background: rgba(255,255,255,.16);
  border: 1px solid rgba(255,255,255,.18);
  backdrop-filter: blur(6px);
}
.chapter__title {
  position: relative;
  display: flex; align-items: center; gap: 9px;
  margin-top: 8px;
  font-family: var(--font-display);
  font-size: clamp(17px, 4.4vw, 21px);
  font-weight: 700; letter-spacing: -.03em; line-height: 1.12;
  padding-right: 54px;
}
.chapter__emoji { font-size: 20px; line-height: 1; filter: drop-shadow(0 3px 6px rgba(0,0,0,.35)); }
.chapter__sub {
  position: relative;
  margin-top: 5px; font-size: 12px; font-weight: 600;
  color: rgba(255,255,255,.7);
  max-width: 74%;
}
.chapter__bar {
  position: relative;
  margin-top: 13px; height: 5px; border-radius: 999px;
  background: rgba(255,255,255,.16);
  overflow: hidden;
}
.chapter__bar i {
  display: block; height: 100%; border-radius: inherit;
  background: linear-gradient(90deg, rgba(255,255,255,.92), var(--unit-soft, #fff));
  box-shadow: 0 0 12px rgba(255,255,255,.45);
  transition: width .9s cubic-bezier(.2,.7,.2,1);
}

/* ------------------------------- таймлайн ------------------------------- */
.chapter__path {
  position: relative;
  padding: 12px 12px 14px;
  display: grid; gap: 8px;
  background:
    radial-gradient(320px 200px at 100% 0%, color-mix(in srgb, var(--unit) 7%, transparent), transparent 70%),
    var(--surface);
}
.chapter__path::before {
  content: "";
  position: absolute; top: 26px; bottom: 26px; left: 34px; width: 2px;
  border-radius: 2px;
  background: linear-gradient(180deg,
    color-mix(in srgb, var(--unit) 55%, transparent),
    color-mix(in srgb, var(--unit) 18%, transparent) 55%,
    transparent);
  pointer-events: none;
}

.lesson-row {
  position: relative;
  display: grid;
  grid-template-columns: 46px minmax(0, 1fr) 22px;
  align-items: center;
  gap: 10px;
  width: 100%;
  padding: 4px 2px;
  border: 0; background: none;
  font: inherit; color: inherit;
  text-align: left;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}
.lesson-row__rail { position: relative; display: grid; place-items: center; z-index: 1; }
.lesson-row__dot {
  width: 42px; height: 42px; border-radius: 50%;
  display: grid; place-items: center;
  border: 3px solid var(--surface);
  background: linear-gradient(150deg, color-mix(in srgb, var(--unit) 82%, #fff), color-mix(in srgb, var(--unit) 72%, #070b14));
  color: #fff;
  box-shadow: 0 8px 18px -10px color-mix(in srgb, var(--unit) 70%, transparent), inset 0 1px 0 rgba(255,255,255,.4);
  transition: transform .22s cubic-bezier(.34,1.56,.64,1), box-shadow .22s;
}
.lesson-row__ico { width: 19px; height: 19px; display: grid; place-items: center; }
.lesson-row__ico svg { width: 19px; height: 19px; }

.lesson-row__body {
  display: grid; gap: 2px;
  padding: 10px 12px;
  border-radius: 16px;
  border: 1px solid var(--line);
  background: color-mix(in srgb, var(--surface) 88%, transparent);
  min-width: 0;
  transition: transform .22s cubic-bezier(.34,1.56,.64,1), border-color .22s, box-shadow .22s, background .22s;
}
.lesson-row__meta {
  font-size: 8.5px; font-weight: 900; letter-spacing: .12em; text-transform: uppercase;
  color: var(--fg-3);
}
.lesson-row__title {
  font-size: 13.5px; font-weight: 800; letter-spacing: -.015em; line-height: 1.25;
  overflow: hidden; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical;
}
.lesson-row__foot { margin-top: 2px; }
.lesson-row__hint { font-size: 10.5px; font-weight: 700; color: var(--fg-3); }
.lesson-row__stars { display: inline-flex; gap: 2px; }
.lesson-row__stars i { font-style: normal; font-size: 12px; color: var(--line-2); line-height: 1; }
.lesson-row__stars i.on { color: var(--gold); text-shadow: 0 0 10px color-mix(in srgb, var(--gold) 55%, transparent); }
.lesson-row__state { width: 20px; height: 20px; color: var(--fg-3); display: grid; place-items: center; }
.lesson-row__state svg { width: 18px; height: 18px; }

/* состояния */
.lesson-row.is-current .lesson-row__dot {
  background: linear-gradient(150deg, var(--gold-2), var(--gold));
  color: #3a2600;
  box-shadow: 0 0 0 5px color-mix(in srgb, var(--unit) 14%, transparent), 0 12px 24px -10px color-mix(in srgb, var(--unit) 60%, transparent);
  animation: nodePulse 3.4s ease-in-out infinite;
}
.lesson-row.is-current .lesson-row__body {
  border-color: color-mix(in srgb, var(--unit) 45%, var(--line));
  background: linear-gradient(120deg, color-mix(in srgb, var(--unit) 9%, var(--surface)), var(--surface));
  box-shadow: 0 10px 24px -16px color-mix(in srgb, var(--unit) 55%, transparent);
}
.lesson-row.is-current .lesson-row__hint { color: var(--brand-700); }
html[data-theme="dark"] .lesson-row.is-current .lesson-row__hint { color: var(--brand-300); }
.lesson-row.is-current .lesson-row__state { color: var(--brand-700); }
html[data-theme="dark"] .lesson-row.is-current .lesson-row__state { color: var(--brand-300); }

.lesson-row.is-done .lesson-row__dot {
  background: linear-gradient(150deg, var(--brand-300), var(--brand));
  color: #042414;
}
.lesson-row.is-done .lesson-row__state { color: var(--brand-600); }

.lesson-row.is-locked { cursor: default; }
.lesson-row.is-locked .lesson-row__dot {
  background: var(--surface-3);
  color: var(--fg-3);
  box-shadow: none;
}
.lesson-row.is-locked .lesson-row__body { opacity: .62; background: var(--surface-2); }
.lesson-row.is-locked .lesson-row__title { color: var(--fg-2); }

.lesson-row:not(.is-locked):hover .lesson-row__dot { transform: scale(1.06); }
.lesson-row:not(.is-locked):hover .lesson-row__body { transform: translateX(3px); border-color: color-mix(in srgb, var(--unit) 35%, var(--line)); }
.lesson-row:not(.is-locked):active .lesson-row__dot { transform: scale(.94); }
.lesson-row:not(.is-locked):active .lesson-row__body { transform: scale(.995); }

/* первая/последняя строка таймлайна */
.lesson-row:last-child .lesson-row__rail::after { display: none; }

@media (max-width: 380px) {
  .chapter__head { padding: 15px 14px 14px; }
  .chapter__path { padding: 10px 9px 12px; }
  .chapter__path::before { left: 31px; }
  .lesson-row { grid-template-columns: 42px minmax(0, 1fr) 18px; gap: 8px; }
  .lesson-row__dot { width: 38px; height: 38px; }
  .lesson-row__body { padding: 9px 10px; }
  .lesson-row__title { font-size: 12.5px; }
  .chapter__sub { max-width: 72%; }
}

@media (prefers-reduced-motion: reduce) {
  .lesson-row__dot, .lesson-row__body { transition: none !important; animation: none !important; }
  .lesson-row.is-current .lesson-row__dot { animation: none !important; }
}