/* =========================================================
   LEARN — каталог курсов
   ========================================================= */

.learn {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 100px 24px 80px;
}

.learn-hero {
  text-align: center;
  padding: 40px 0 32px;
}
.learn-hero-inner {
  max-width: 720px;
  margin: 0 auto;
}
.learn-title {
  font-family: var(--f-serif);
  font-size: clamp(36px, 5vw, 64px);
  font-weight: 600;
  line-height: 1.1;
  color: var(--c-ink);
  margin-bottom: 12px;
}
.learn-sub {
  font-size: clamp(15px, 1.3vw, 18px);
  color: var(--c-ink-soft);
  line-height: 1.6;
}

/* =========================================================
   ФИЛЬТРЫ
   ========================================================= */

.learn-filters {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
  padding: 0 0 32px;
}
.learn-filters-inner {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  justify-content: center;
}
.filter-btn {
  padding: 10px 22px;
  border-radius: 100px;
  border: 1px solid var(--c-line-strong);
  background: transparent;
  font-family: var(--f-sans);
  font-size: 13px;
  font-weight: 500;
  color: var(--c-ink-soft);
  cursor: pointer;
  transition: all var(--t-fast);
  white-space: nowrap;
}
.filter-btn:hover {
  background: rgba(44, 24, 16, 0.05);
  color: var(--c-ink);
  border-color: var(--c-ink);
}
.filter-btn.active {
  background: var(--c-ink);
  color: var(--c-paper);
  border-color: var(--c-ink);
}

/* =========================================================
   СЕТКА КАРТОЧЕК
   ========================================================= */

.learn-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 20px;
}
.learn-empty {
  text-align: center;
  padding: 60px 24px;
  color: var(--c-ink-muted);
  font-size: 15px;
}
.learn-empty[hidden] { display: none; }

/* =========================================================
   КАРТОЧКА КУРСА
   ========================================================= */

.course-card {
  background: var(--c-paper);
  border: 1px solid var(--c-line);
  border-radius: var(--r-md);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  cursor: pointer;
  transition: transform var(--t-med), box-shadow var(--t-med), border-color var(--t-med);
}
.course-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--sh-card);
  border-color: var(--c-accent);
}
.course-card.done {
  border-color: var(--c-accent);
  box-shadow: 0 0 0 1px var(--c-accent) inset;
}

.course-card-body {
  padding: 24px 18px;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 10px;
}
.course-card-title {
  font-family: var(--f-sans);
  font-size: 17px;
  font-weight: 700;
  color: var(--c-ink);
  line-height: 1.25;
  margin: 0;
}
.course-card-sub {
  font-size: 13px;
  color: var(--c-ink-soft);
  line-height: 1.45;
  flex: 1;
}
.course-card-meta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  padding-top: 10px;
  border-top: 1px solid var(--c-line);
  font-size: 11px;
  color: var(--c-ink-muted);
  font-family: var(--f-mono);
  letter-spacing: 0.5px;
  width: 100%;
}
.course-card-meta i {
  color: var(--c-accent);
  margin-right: 4px;
}
.course-card-progress {
  height: 3px;
  background: var(--c-line);
  border-radius: 2px;
  overflow: hidden;
  width: 100%;
}
.course-card-progress-fill {
  height: 100%;
  width: 0;
  background: var(--c-accent);
  transition: width var(--t-med);
}

/* =========================================================
   СТРАНИЦА КУРСА
   ========================================================= */

.learn-course {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 100px 24px 80px;
}
.course-hero { padding: 20px 0 40px; }

.course-back {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--f-sans);
  font-size: 13px;
  font-weight: 500;
  color: var(--c-accent);
  text-decoration: none;
  margin-bottom: 28px;
  transition: color var(--t-fast);
}
.course-back:hover { color: var(--c-ink); }

.course-hero-grid {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 16px;
}

.course-title {
  font-family: var(--f-serif);
  font-size: clamp(32px, 4vw, 48px);
  font-weight: 600;
  line-height: 1.1;
  color: var(--c-ink);
  margin: 8px 0 12px;
  max-width: 720px;
}
.course-sub {
  font-size: 16px;
  color: var(--c-ink-soft);
  line-height: 1.6;
  margin-bottom: 20px;
  max-width: 720px;
}
.course-meta {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 20px;
  margin-bottom: 24px;
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: 0.5px;
  color: var(--c-ink-muted);
}
.course-meta-item {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.course-meta-item i { color: var(--c-accent); }

.course-progress {
  margin-bottom: 24px;
  width: 100%;
  max-width: 480px;
}
.course-progress-label {
  display: flex;
  justify-content: space-between;
  font-family: var(--f-sans);
  font-size: 12px;
  color: var(--c-ink-muted);
  margin-bottom: 8px;
}
.course-progress-bar {
  height: 6px;
  background: var(--c-line);
  border-radius: 3px;
  overflow: hidden;
}
#courseProgressFill {
  height: 100%;
  width: 0;
  background: var(--c-accent);
  transition: width var(--t-med);
}

.course-actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  justify-content: center;
}
.course-btn {
  padding: 12px 22px;
  border-radius: 100px;
  border: 1px solid var(--c-line-strong);
  background: transparent;
  font-family: var(--f-sans);
  font-size: 13px;
  font-weight: 600;
  color: var(--c-ink);
  cursor: pointer;
  transition: all var(--t-fast);
}
.course-btn:hover {
  background: rgba(44, 24, 16, 0.05);
  border-color: var(--c-ink);
}
.course-btn-primary {
  background: var(--c-ink);
  color: var(--c-paper);
  border-color: var(--c-ink);
}
.course-btn-primary:hover {
  background: var(--c-accent-deep);
  border-color: var(--c-accent-deep);
}

/* =========================================================
   СПИСОК ШАГОВ
   ========================================================= */

.course-steps { padding: 40px 0 0; }
.course-steps-inner {
  max-width: 800px;
  margin: 0 auto;
}
.course-steps-title {
  font-family: var(--f-serif);
  font-size: 28px;
  font-weight: 600;
  color: var(--c-ink);
  margin: 0 0 24px;
  text-align: center;
}
.course-steps-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.step-item {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 16px 20px;
  background: var(--c-paper);
  border: 1px solid var(--c-line);
  border-radius: var(--r-md);
  cursor: pointer;
  transition: transform var(--t-fast), box-shadow var(--t-fast), border-color var(--t-fast);
}
.step-item:hover {
  transform: translateX(4px);
  border-color: var(--c-accent);
  box-shadow: var(--sh-card);
}
.step-item.done    { border-color: var(--c-accent); }
.step-item.current { border-color: var(--c-ink); }
.step-item.locked  { opacity: 0.45; cursor: not-allowed; pointer-events: none; }

.step-item-icon {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--c-line);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  color: var(--c-ink-soft);
  flex-shrink: 0;
}
.step-item.done .step-item-icon {
  background: var(--c-accent);
  color: var(--c-paper);
}
.step-item.current .step-item-icon {
  background: var(--c-ink);
  color: var(--c-paper);
}
.step-item-text {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.step-item-title {
  font-family: var(--f-sans);
  font-size: 15px;
  font-weight: 600;
  color: var(--c-ink);
}
.step-item-type {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  color: var(--c-ink-muted);
}
.step-item-arrow {
  color: var(--c-ink-muted);
  font-size: 13px;
  transition: color var(--t-fast);
}
.step-item:hover .step-item-arrow { color: var(--c-accent); }

/* =========================================================
   СТРАНИЦА ШАГА
   ========================================================= */

.learn-step {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 100px 24px 80px;
}
.step-hero { padding: 0 0 32px; }
.step-hero-inner {
  max-width: 800px;
  margin: 0 auto;
}
.step-breadcrumbs {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--f-sans);
  font-size: 13px;
  color: var(--c-ink-muted);
  margin-bottom: 20px;
  flex-wrap: wrap;
}
.step-breadcrumbs a {
  color: var(--c-accent);
  text-decoration: none;
  transition: color var(--t-fast);
}
.step-breadcrumbs a:hover { color: var(--c-ink); }
.step-breadcrumbs-sep { color: var(--c-ink-muted); }

.step-progress { margin-top: 8px; }
.step-progress-label {
  display: flex;
  justify-content: space-between;
  font-family: var(--f-sans);
  font-size: 12px;
  color: var(--c-ink-muted);
  margin-bottom: 8px;
}
.step-progress-bar {
  height: 5px;
  background: var(--c-line);
  border-radius: 3px;
  overflow: hidden;
}
#stepProgressFill {
  height: 100%;
  width: 0;
  background: var(--c-accent);
  transition: width var(--t-med);
}
.step-content {
  max-width: 800px;
  margin: 0 auto;
  padding: 20px 0 48px;
  min-height: 200px;
  font-family: var(--f-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--c-ink);
}
.step-loading {
  text-align: center;
  padding: 40px 0;
  color: var(--c-ink-muted);
  font-family: var(--f-sans);
  font-size: 14px;
}
.step-nav {
  max-width: 800px;
  margin: 0 auto;
  padding: 24px 0;
  display: flex;
  justify-content: space-between;
  gap: 12px;
  border-top: 1px solid var(--c-line);
}
.step-btn {
  padding: 12px 22px;
  border-radius: 100px;
  border: 1px solid var(--c-line-strong);
  background: transparent;
  font-family: var(--f-sans);
  font-size: 13px;
  font-weight: 600;
  color: var(--c-ink);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  transition: all var(--t-fast);
}
.step-btn:hover:not(:disabled) {
  background: rgba(44, 24, 16, 0.05);
  border-color: var(--c-ink);
}
.step-btn:disabled {
  opacity: 0.35;
  cursor: not-allowed;
}
.step-btn-primary {
  background: var(--c-ink);
  color: var(--c-paper);
  border-color: var(--c-ink);
}
.step-btn-primary:hover:not(:disabled) {
  background: var(--c-accent-deep);
  border-color: var(--c-accent-deep);
}

/* =========================================================
   SOLVE — доска с pointer-драгом
   ========================================================= */

.solve {
  display: grid;
  grid-template-columns: minmax(280px, 480px) 1fr;
  gap: var(--gap-lg);
  align-items: start;
}
.solve-board-wrap {
  position: relative;
  width: 100%;
  aspect-ratio: 1 / 1;
  border-radius: var(--r-md);
  overflow: hidden;
  border: 1px solid var(--c-line);
  user-select: none;
  touch-action: none;
  container-type: inline-size;
}

.solve-board {
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  grid-template-rows: repeat(8, 1fr);
  width: 100%;
  height: 100%;
}

.solve-board .sq {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  line-height: 1;
  transition: box-shadow .12s, background .12s;
  -webkit-tap-highlight-color: transparent;
}

.solve-board .sq .piece {
  font-size: 28px;
  font-size: 7cqw;
  line-height: 1;
  pointer-events: none;
  user-select: none;
}
.solve-board .sq.light { background: var(--c-board-light); }
.solve-board .sq.dark  { background: var(--c-board-dark); }
.solve-board .sq.has-piece { cursor: grab; }
.solve-board .sq.has-piece:active { cursor: grabbing; }
.solve-board .sq.selected {
  box-shadow: inset 0 0 0 3px var(--c-accent);
}
.solve-board .sq.valid-move::after {
  content: '';
  position: absolute;
  width: 26%;
  height: 26%;
  border-radius: 50%;
  background: rgba(44, 24, 16, 0.35);
  pointer-events: none;
}
.solve-board .sq.valid-capture::after {
  content: '';
  position: absolute;
  inset: 0;
  box-shadow: inset 0 0 0 3px rgba(44, 24, 16, 0.35);
  pointer-events: none;
}
.solve-board .sq .piece.white { color: #fafafa; text-shadow: 0 1px 2px rgba(0,0,0,.6); }
.solve-board .sq .piece.black { color: #111;    text-shadow: 0 1px 1px rgba(255,255,255,.35); }

.solve-ghost {
  position: fixed;
  top: 0;
  left: 0;
  width: 64px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 44px;
  pointer-events: none;
  opacity: 0;
  transform: translate(-50%, -50%);
  z-index: 9999;
  transition: opacity .1s;
}
.solve-ghost.visible { opacity: 0.9; }
.solve-ghost .piece.white { color: #fafafa; text-shadow: 0 1px 2px rgba(0,0,0,.6); }
.solve-ghost .piece.black { color: #111;    text-shadow: 0 1px 1px rgba(255,255,255,.35); }

.solve-side { display: flex; flex-direction: column; gap: 16px; }
.solve-meta {
  display: flex;
  justify-content: space-between;
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: 0.5px;
  color: var(--c-ink-muted);
}
.solve-rating i { color: var(--c-accent); margin-right: 4px; }
.solve-feedback {
  min-height: 44px;
  padding: 12px 16px;
  border-radius: var(--r-md);
  font-family: var(--f-sans);
  font-size: 14px;
  line-height: 1.4;
  background: rgba(44, 24, 16, 0.04);
  color: var(--c-ink-soft);
}
.solve-feedback.ok   { color: #2e7d32; background: rgba(76, 175, 80, 0.1); }
.solve-feedback.bad  { color: #c62828; background: rgba(220, 80, 80, 0.1); }
.solve-feedback.hint { color: var(--c-accent); background: rgba(240, 180, 41, 0.12); }
.solve-actions { display: flex; gap: 8px; flex-wrap: wrap; }

/* =========================================================
   CONFIRM MODAL
   ========================================================= */

.confirm-overlay {
  position: fixed;
  inset: 0;
  background: rgba(44, 24, 16, 0.45);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 2000;
  padding: 24px;
}
.confirm-overlay[hidden] { display: none; }
.confirm-modal {
  background: var(--c-paper);
  border-radius: var(--r-md);
  padding: 28px 28px 20px;
  max-width: 420px;
  width: 100%;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.35);
  font-family: var(--f-sans);
}
.confirm-text {
  font-size: 16px;
  line-height: 1.5;
  color: var(--c-ink);
  margin: 0 0 24px;
}
.confirm-actions {
  display: flex;
  gap: 10px;
  justify-content: flex-end;
}

/* =========================================================
   QUIZ
   ========================================================= */

.quiz { max-width: 640px; margin: 0 auto; }
.quiz-head {
  display: flex;
  justify-content: space-between;
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: 0.5px;
  color: var(--c-ink-muted);
  margin-bottom: 16px;
}
.quiz-prompt {
  font-family: var(--f-serif);
  font-size: 22px;
  font-weight: 600;
  margin: 0 0 20px;
  color: var(--c-ink);
  line-height: 1.4;
}
.quiz-choices { display: flex; flex-direction: column; gap: 8px; }
.quiz-choice {
  padding: 14px 18px;
  border-radius: var(--r-md);
  border: 1px solid var(--c-line);
  background: var(--c-paper);
  font-family: var(--f-sans);
  font-size: 15px;
  color: var(--c-ink);
  cursor: pointer;
  text-align: left;
  transition: all var(--t-fast);
}
.quiz-choice:hover:not(:disabled) {
  border-color: var(--c-accent);
  background: rgba(44, 24, 16, 0.03);
}
.quiz-choice:disabled { opacity: 0.65; cursor: default; }
.quiz-feedback {
  margin-top: 16px;
  font-family: var(--f-sans);
  font-size: 14px;
  font-weight: 600;
  min-height: 20px;
}
.quiz-feedback.ok  { color: #2e7d32; }
.quiz-feedback.bad { color: #c62828; }
.quiz-result { text-align: center; padding: 40px 0; }
.quiz-result h3 {
  font-family: var(--f-serif);
  font-size: 32px;
  font-weight: 600;
  color: var(--c-ink);
  margin: 0 0 12px;
}
.quiz-result p {
  font-family: var(--f-sans);
  color: var(--c-ink-soft);
  font-size: 16px;
  margin: 4px 0;
}
.quiz-result-verdict.ok  { color: #2e7d32; font-weight: 700; }
.quiz-result-verdict.bad { color: #c62828; font-weight: 700; }

/* =========================================================
   RESPONSIVE
   ========================================================= */

@media (max-width: 900px) {
  .course-hero-grid { grid-template-columns: 1fr; }
}

@media (max-width: 720px) {
  .solve { grid-template-columns: 1fr; }
}

@media (max-width: 600px) {
  .learn,
  .learn-course,
  .learn-step {
    padding: 90px 16px 60px;
  }
  .course-steps-inner,
  .step-hero-inner,
  .step-content,
  .step-nav {
    max-width: 100%;
  }
}