/* ==========================================================================
   Course page + sandbox
   ========================================================================== */

.course-page {
  min-height: 100vh;
  background: var(--bg);
}

.course-layout {
  display: grid;
  grid-template-columns: minmax(300px, 340px) minmax(0, 1fr);
  min-height: 100vh;
  padding-top: 78px;
}

.course-sidebar {
  position: fixed;
  top: 78px;
  left: 0;
  bottom: 0;
  width: clamp(300px, 22vw, 340px);
  height: calc(100vh - 78px);
  border-right: 1px solid var(--border);
  background: var(--bg-soft);
  display: flex;
  flex-direction: column;
  z-index: 20;
}

.course-sidebar__head {
  padding: 24px 22px 18px;
  border-bottom: 1px solid var(--border);
}

.course-sidebar__brand {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.course-sidebar__icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border);
  padding: 7px;
  flex-shrink: 0;
}

.course-sidebar__icon img {
  width: 100%;
  height: 100%;
  display: block;
  object-fit: contain;
}

.course-sidebar__icon:not(.lang-icon--ready) {
  visibility: hidden;
}

.course-back {
  display: inline-block;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-dimmer);
  margin-bottom: 14px;
  transition: color 0.25s ease;
}
.course-back:hover { color: var(--gold-bright); }

.course-sidebar__title {
  font-family: var(--font-serif);
  font-size: 26px;
  font-weight: 500;
  line-height: 1.15;
  margin-bottom: 4px;
}

.course-sidebar__meta {
  font-size: 13px;
  color: var(--text-dimmer);
  margin-bottom: 16px;
}

.course-progress {
  height: 4px;
  background: rgba(255,255,255,0.06);
  border-radius: 999px;
  overflow: hidden;
  margin-bottom: 8px;
}
.course-progress__bar {
  height: 100%;
  width: 0%;
  background: var(--accent);
  transition: width 0.35s ease;
}
.course-progress__label {
  font-size: 12px;
  color: var(--text-dimmer);
}

.course-sidebar__scroll {
  overflow-y: auto;
  padding: 18px 14px 28px;
  flex: 1;
}

.course-nav-label {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--gold);
  margin: 8px 8px 10px;
}

.lesson-nav {
  display: flex;
  flex-direction: column;
  gap: 4px;
  margin-bottom: 22px;
}

.lesson-nav button {
  display: flex;
  align-items: center;
  gap: 6px;
  text-align: left;
  padding: 10px 12px;
  border-radius: 10px;
  color: var(--text-dim);
  font-size: 13.5px;
  font-weight: 500;
  line-height: 1.35;
  transition: background 0.25s ease, color 0.25s ease;
  width: 100%;
}
.lesson-nav button:hover {
  background: rgba(255,255,255,0.04);
  color: var(--text);
}
.lesson-nav button.active {
  background: var(--accent-soft);
  color: var(--gold-bright);
}
.lesson-nav button .num {
  display: inline-block;
  min-width: 22px;
  color: var(--text-dimmer);
  font-weight: 700;
  font-size: 12px;
  margin-right: 6px;
}
.lesson-nav button.active .num { color: var(--gold); }

.lesson-nav button.is-done .num {
  color: #8fd48f;
}

.lesson-nav button.is-locked {
  opacity: 0.45;
  cursor: not-allowed;
  color: var(--text-dimmer);
}

.lesson-nav button.is-locked:hover {
  background: transparent;
  color: var(--text-dimmer);
}

.lesson-nav button.is-locked::after {
  content: 'закрыт';
  margin-left: auto;
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  opacity: 0.75;
  flex-shrink: 0;
}

.lesson-nav button.is-done::after {
  content: '✓';
  margin-left: auto;
  font-size: 12px;
  color: #8fd48f;
  flex-shrink: 0;
}

.lesson-theory-intro {
  padding: 14px 16px;
  margin-bottom: 22px;
  border-radius: 12px;
  border: 1px solid rgba(var(--accent-rgb), 0.22);
  background: rgba(var(--accent-rgb), 0.06);
  color: var(--text-dim);
  font-size: 15px;
  line-height: 1.6;
}

.lesson-theory {
  /* theory uses same styles as .lesson-body content */
}

.lesson-practice {
  margin-top: 44px;
  padding: 28px 26px 30px;
  border-radius: var(--radius);
  border: 1px solid rgba(var(--accent-rgb), 0.22);
  background: linear-gradient(165deg, rgba(var(--accent-rgb), 0.07), rgba(255, 255, 255, 0.02));
}

.lesson-practice__head {
  margin-bottom: 20px;
}

.lesson-practice__title {
  font-family: var(--font-serif);
  font-size: 26px;
  font-weight: 500;
  margin-bottom: 8px;
  color: var(--gold-bright);
}

.lesson-practice__lead {
  color: var(--text-dim);
  font-size: 15px;
  line-height: 1.65;
  margin: 0;
}

.lesson-practice__task-title {
  font-size: 18px;
  font-weight: 700;
  margin: 0 0 16px;
  color: var(--text);
}

.lesson-practice .task-tabs {
  margin-top: 0;
  margin-bottom: 24px;
}

.lesson-practice .task-card {
  margin-top: 0;
}

.lesson-practice .task-goal {
  margin-top: 0;
}

.lesson-practice__task {
  min-height: 220px;
}

.lesson-next-gate {
  margin: 0 0 12px;
  padding: 12px 14px;
  border-radius: 12px;
  border: 1px solid rgba(255, 160, 80, 0.35);
  background: rgba(255, 160, 80, 0.08);
  color: #ffc896;
  font-size: 14px;
  line-height: 1.55;
}

.lesson-nav-btns .btn.is-locked:disabled {
  opacity: 0.55;
}

.sidebar-toggle {
  display: none;
  position: fixed;
  bottom: 22px;
  left: 22px;
  z-index: 40;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: linear-gradient(165deg, #1a828a, var(--btn));
  color: #eef8f8;
  font-size: 18px;
  font-weight: 700;
  box-shadow: 0 10px 24px rgba(var(--btn-rgb), 0.35);
}

.course-main {
  grid-column: 2;
  width: 100%;
  min-width: 0;
  padding: 34px clamp(28px, 4vw, 72px) 72px;
  max-width: none;
}

.lesson-panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  width: 100%;
  padding: clamp(30px, 4vw, 56px) clamp(28px, 5vw, 76px);
  margin-bottom: 24px;
}

.lesson-kicker {
  display: inline-block;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--gold-bright);
  margin-bottom: 10px;
}

.lesson-title {
  font-family: var(--font-serif);
  font-size: clamp(28px, 3.5vw, 40px);
  font-weight: 500;
  letter-spacing: -0.02em;
  margin-bottom: 28px;
  line-height: 1.2;
  font-optical-sizing: auto;
}

.lesson-body {
  color: var(--text-dim);
  font-size: 17px;
  font-weight: 500;
  line-height: 1.8;
  letter-spacing: -0.01em;
  max-width: 88ch;
}
.lesson-body p { margin-bottom: 18px; }
.lesson-body h3 {
  font-family: var(--font-serif);
  font-size: 25px;
  font-weight: 500;
  color: var(--text);
  margin: 32px 0 12px;
  letter-spacing: -0.02em;
  line-height: 1.25;
  font-optical-sizing: auto;
}
.lesson-body ul, .lesson-body ol {
  margin: 0 0 18px 1.2em;
  list-style: disc;
}
.lesson-body ol { list-style: decimal; }
.lesson-body li { margin-bottom: 10px; }
.lesson-body strong { color: var(--text); font-weight: 700; }
.lesson-body code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  font-weight: 500;
  background: rgba(255,255,255,0.06);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 1px 6px;
  color: var(--gold-bright);
}
.lesson-body pre {
  background: #080a10;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 18px 20px;
  overflow-x: auto;
  margin: 18px 0 22px;
}
.lesson-body pre code {
  background: none;
  border: none;
  padding: 0;
  color: #d8d6cf;
  font-size: 13.5px;
  line-height: 1.65;
}

.task-goal {
  background: var(--accent-soft);
  border: 1px solid rgba(var(--accent-rgb), 0.28);
  border-radius: 14px;
  padding: 18px 20px;
  margin: 0 0 20px;
  color: var(--text);
}
.task-goal strong,
.task-steps strong,
.task-requirements strong,
.task-expected strong {
  display: block;
  color: var(--gold-bright);
  margin-bottom: 10px;
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-family: var(--font-mono);
}
.task-goal p {
  margin: 0;
  font-size: 16px;
  line-height: 1.65;
  color: var(--text);
}

.task-tabs {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 18px;
}
.task-tab {
  display: flex;
  align-items: center;
  gap: 12px;
  width: 100%;
  text-align: left;
  padding: 14px 16px;
  border-radius: 16px;
  border: 1px solid var(--border-strong);
  background: rgba(255, 255, 255, 0.03);
  color: var(--text-dim);
  font-size: 14px;
  font-weight: 600;
  transition: color 0.2s ease, background 0.2s ease, border-color 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
}
.task-tab:hover {
  color: var(--text);
  border-color: rgba(var(--accent-rgb), 0.4);
  background: rgba(var(--accent-rgb), 0.08);
  transform: translateY(-1px);
}
.task-tab.active {
  color: #f2fbfc;
  background: linear-gradient(145deg, rgba(24, 122, 130, 0.95), rgba(50, 112, 144, 0.92));
  border-color: transparent;
  box-shadow: 0 10px 28px -12px rgba(var(--btn-rgb), 0.55);
}
.task-tab__num {
  flex-shrink: 0;
  width: 36px;
  height: 36px;
  border-radius: 12px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.1);
  color: var(--gold-bright);
}
.task-tab.active .task-tab__num {
  background: rgba(255, 255, 255, 0.16);
  color: #fff;
  border-color: transparent;
}
.task-tab__text {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
  flex: 1;
}
.task-tab__label {
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.01em;
  color: inherit;
}
.task-tab__title {
  font-size: 12.5px;
  font-weight: 500;
  color: var(--text-dimmer);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.task-tab.active .task-tab__title {
  color: rgba(255, 255, 255, 0.78);
}
.task-tab__status {
  flex-shrink: 0;
  width: 22px;
  text-align: center;
  font-size: 14px;
  color: #8fd48f;
}
.task-tab.is-done:not(.active) {
  border-color: rgba(143, 212, 143, 0.4);
}
.task-tab.is-done:not(.active) .task-tab__label {
  color: #b7e3a1;
}

.task-card {
  display: grid;
  gap: 18px;
}
.task-steps,
.task-requirements,
.task-expected {
  padding: 16px 18px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--panel);
}
.task-steps ol,
.task-requirements ul {
  margin: 0;
  padding-left: 1.25em;
  color: var(--text-dim);
  font-size: 15px;
  line-height: 1.65;
}
.task-steps li + li,
.task-requirements li + li {
  margin-top: 8px;
}
.task-expected pre {
  margin: 0;
  padding: 14px 16px;
  border-radius: 10px;
  background: var(--bg-soft);
  border: 1px solid var(--border);
}
.task-expected code {
  font-family: var(--font-mono);
  font-size: 13.5px;
  color: var(--gold-bright);
  white-space: pre-wrap;
}
.task-hint {
  border: 1px dashed var(--border-strong);
  border-radius: 12px;
  padding: 12px 16px;
  background: rgba(var(--accent-rgb), 0.06);
}
.task-hint summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--gold-bright);
  font-size: 14px;
}
.task-hint p {
  margin: 10px 0 0;
  color: var(--text-dim);
  font-size: 14.5px;
  line-height: 1.6;
}

.task-pass {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 14px 16px;
  border-radius: 12px;
  border: 1px solid rgba(120, 200, 120, 0.35);
  background: rgba(80, 160, 90, 0.12);
  color: #b7e3a1;
  font-size: 14.5px;
  line-height: 1.55;
}
.task-pass[hidden] { display: none; }

.lesson-panel.is-task-mode .lesson-kicker {
  color: var(--gold-bright);
}

.lesson-nav-btns {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin-top: 36px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  flex-wrap: wrap;
}
.lesson-nav-btns .btn:disabled {
  opacity: 0.35;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

/* ---------- Sandbox ---------- */
.sandbox {
  width: 100%;
  background: #fffdf8;
  border: 1px solid rgba(59, 48, 39, 0.12);
  border-radius: 16px;
  overflow: hidden;
  box-shadow: 0 12px 32px rgba(90, 71, 55, 0.06);
}

.sandbox__head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 18px;
  border-bottom: 1px solid rgba(59, 48, 39, 0.12);
  flex-wrap: wrap;
  background: #f3ebe0;
}

.sandbox__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: flex-end;
  max-width: 100%;
}

.sandbox__actions .btn {
  border-radius: 10px;
  min-height: 38px;
  padding: 0 14px;
  font-weight: 650;
  white-space: nowrap;
}

.sandbox__title {
  font-family: var(--font-serif);
  font-size: 20px;
  font-weight: 500;
  margin-bottom: 2px;
  color: #3b3027;
}
.sandbox__hint {
  font-size: 13px;
  color: #74685b;
  margin: 4px 0 0;
}
.sandbox__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.sandbox__title-row {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.sandbox__lang {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 4px 10px;
  border-radius: 999px;
  border: 1px solid rgba(182, 147, 99, 0.45);
  color: #5a4737;
  background: #fffdf8;
}

.sandbox__editor-wrap {
  display: grid;
  grid-template-columns: auto 1fr;
  background: #2f2924;
  border-bottom: 1px solid rgba(59, 48, 39, 0.18);
  min-height: 280px;
  overflow: hidden;
}

.sandbox__lines {
  margin: 0;
  padding: 18px 10px 18px 14px;
  text-align: right;
  font-family: var(--font-mono), "DM Mono", ui-monospace, monospace;
  font-size: 13px;
  line-height: 1.65;
  color: #a89884;
  background: #261f1b;
  user-select: none;
  overflow: hidden;
  min-width: 44px;
  border-right: 1px solid rgba(255, 248, 236, 0.08);
}

.sandbox__editor {
  display: block;
  width: 100%;
  min-height: 280px;
  max-height: 420px;
  resize: vertical;
  background: #2f2924;
  color: #fff8ec;
  caret-color: #d4b483;
  border: none;
  border-radius: 0;
  padding: 18px 20px;
  font-family: var(--font-mono), "DM Mono", ui-monospace, monospace;
  font-size: 13.5px;
  line-height: 1.65;
  outline: none;
  box-shadow: none;
  tab-size: 2;
  overflow: auto;
}

.sandbox__editor-wrap .sandbox__editor {
  border-bottom: none;
}

.sandbox__stdout {
  padding: 16px 18px 18px;
  background: #f3ebe0;
  border-top: 1px solid rgba(59, 48, 39, 0.1);
}
.sandbox__stdout-label {
  font-size: 11px;
  font-weight: 750;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: #765633;
  margin-bottom: 10px;
}
.sandbox__stdout pre {
  font-family: var(--font-mono), "DM Mono", ui-monospace, monospace;
  font-size: 13px;
  line-height: 1.6;
  color: #5a4737;
  background: #fffdf8;
  border: 1px solid rgba(59, 48, 39, 0.14);
  border-radius: 12px;
  padding: 12px 14px;
  white-space: pre-wrap;
  word-break: break-word;
  min-height: 56px;
  margin: 0;
}
.sandbox__stdout pre.is-error {
  color: #9a3428;
  background: rgba(180, 67, 50, 0.1);
  border-color: rgba(180, 67, 50, 0.28);
}
.sandbox__stdout pre.is-ok {
  color: #246640;
  background: rgba(61, 139, 90, 0.1);
  border-color: rgba(61, 139, 90, 0.3);
}
.sandbox__stdout pre.is-running {
  color: #765633;
  background: rgba(182, 147, 99, 0.14);
  border-color: rgba(182, 147, 99, 0.35);
}

.course-error {
  padding: 120px 32px;
  text-align: center;
}
.course-error h1 {
  font-family: var(--font-serif);
  font-size: 40px;
  margin-bottom: 12px;
}
.course-error p {
  color: var(--text-dim);
  margin-bottom: 28px;
}

.lesson-note {
  margin-top: 28px;
  padding: 16px 18px;
  border-radius: 14px;
  border: 1px solid rgba(var(--accent-rgb), 0.28);
  background: var(--accent-soft);
  color: var(--text);
  font-size: 15px;
  line-height: 1.6;
}
.lesson-note strong {
  color: var(--gold-bright);
}

/* ---------- Paywall ---------- */
.paywall {
  position: relative;
  min-height: calc(100vh - 78px);
  padding: 140px 0 80px;
  overflow: hidden;
}
.paywall[hidden], .course-layout[hidden] { display: none !important; }

.paywall__bg {
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
}
.paywall__inner {
  max-width: 720px;
  text-align: center;
}
.paywall__title {
  font-family: var(--font-serif);
  font-size: clamp(40px, 6vw, 64px);
  font-weight: 500;
  letter-spacing: -0.02em;
  margin-bottom: 18px;
}
.paywall__text {
  color: var(--text-dim);
  font-size: 17px;
  line-height: 1.7;
  margin: 0 auto 36px;
  max-width: 560px;
}
.paywall__card {
  text-align: left;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 30px 26px;
  margin: 0 auto 28px;
  max-width: 460px;
}
.paywall__row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
  color: var(--text-dim);
  font-size: 15px;
}
.paywall__check { color: var(--gold-bright); font-weight: 700; }
.paywall__price-block {
  display: flex;
  flex-direction: column;
  gap: 4px;
  margin: 22px 0 18px;
}
.paywall__price {
  font-family: var(--font-serif);
  font-size: 40px;
  color: var(--gold-bright);
}
.paywall__price-note {
  font-size: 13px;
  color: var(--text-dimmer);
}
.paywall__card .btn { width: 100%; }
.paywall__note {
  margin-top: 14px;
  font-size: 12.5px;
  color: var(--text-dimmer);
  line-height: 1.5;
  text-align: center;
}
.paywall__back {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-dim);
  transition: color 0.25s ease;
}
.paywall__back:hover { color: var(--gold-bright); }

@media (max-width: 980px) {
  .course-layout {
    grid-template-columns: 1fr;
    padding-top: calc(68px + env(safe-area-inset-top, 0px));
  }
  .course-main {
    grid-column: 1;
  }
  .course-sidebar {
    position: fixed;
    left: 0;
    top: 0;
    bottom: 0;
    width: min(320px, 88vw);
    height: 100dvh;
    padding-top: calc(68px + env(safe-area-inset-top, 0px));
    transform: translateX(-105%);
    transition: transform 0.35s cubic-bezier(0.22, 1, 0.36, 1);
    box-shadow: 20px 0 60px rgba(0,0,0,0.45);
    z-index: 90;
    overflow: hidden;
  }
  .course-sidebar.open { transform: translateX(0); }
  .sidebar-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    bottom: calc(18px + env(safe-area-inset-bottom, 0px));
    left: calc(18px + env(safe-area-inset-left, 0px));
    width: 52px;
    height: 52px;
    z-index: 95;
  }
  .course-main { padding: 16px 16px calc(88px + env(safe-area-inset-bottom, 0px)); }
  .lesson-panel { padding: 22px 18px; }
  .lesson-practice { padding: 20px 16px 22px; margin-top: 32px; }
  .lesson-practice__title { font-size: 22px; }
  .lesson-title { font-size: clamp(24px, 6vw, 32px); }
  .lesson-body pre { overflow-x: auto; -webkit-overflow-scrolling: touch; }
  .lesson-body pre code { font-size: 12.5px; }
  .sandbox__head {
    flex-direction: column;
    align-items: stretch;
    gap: 12px;
    padding: 16px 18px;
  }
  .task-tabs {
    margin-top: 14px;
    grid-template-columns: 1fr;
  }
  .task-tab {
    width: 100%;
    text-align: left;
    border-radius: 14px;
  }
  .sandbox__actions {
    width: 100%;
  }
  .sandbox__actions .btn {
    flex: 1;
    min-height: 44px;
  }
  .sandbox__editor-wrap {
    grid-template-columns: 32px 1fr;
  }
  .sandbox__lines {
    padding: 16px 0 16px 6px;
    min-width: 32px;
    font-size: 11px;
  }
  .sandbox__editor {
    min-height: 200px;
    font-size: 16px;
    padding: 16px;
  }
  .lesson-nav-btns {
    flex-direction: column;
  }
  .lesson-nav-btns .btn {
    width: 100%;
    min-height: 44px;
  }
  .paywall {
    padding: 120px 0 60px;
    min-height: calc(100dvh - 68px);
  }
  .paywall__card { padding: 20px 18px; }
}

@media (max-width: 640px) {
  .course-sidebar__title { font-size: 22px; }
  .course-sidebar__head { padding: 18px 16px 14px; }
  .lesson-panel h3 { font-size: 16px; }
}

/* Light editorial course workspace */
html:not([data-theme="dark"]) {
  .course-page { background: var(--bg); }
  .course-layout { background: transparent; }
  .course-sidebar {
    background: rgba(255, 253, 248, 0.98);
    border-right-color: rgba(59, 48, 39, 0.1);
    box-shadow: 8px 0 28px rgba(90, 71, 55, 0.04);
  }
  .course-sidebar__head,
  .course-sidebar__scroll { border-color: rgba(59, 48, 39, 0.1); }
  .course-sidebar__icon {
    background: #f3ebe0;
    border-radius: 50%;
    border-color: rgba(59, 48, 39, 0.12);
  }
  .course-back,
  .course-sidebar__meta { color: #74685b; }
  .course-sidebar__title,
  .lesson-title,
  .paywall__title { color: #3b3027; }

  .lesson-nav button {
    color: #5a4737;
    border-radius: 10px;
  }
  .lesson-nav button:hover {
    background: #f0e6d6;
    color: #3b3027;
  }
  .lesson-nav button.active {
    background: #5a4737;
    color: #fffdf8;
  }
  .lesson-nav button.active .num { color: #d4b483; }
  .lesson-nav button.is-locked { color: #9e9488; }

  .course-main { background: transparent; }
  .lesson-panel,
  .sandbox,
  .paywall__card {
    background: #fffdf8;
    border: 1px solid rgba(59, 48, 39, 0.12);
    box-shadow: 0 12px 32px rgba(90, 71, 55, 0.06);
    border-radius: 16px;
  }
  .sandbox {
    overflow: hidden !important;
    display: flex;
    flex-direction: column;
    gap: 0;
  }
  .lesson-kicker,
  .lesson-practice__title { color: #9f7e52; }
  .lesson-practice__lead,
  .lesson-theory { color: #5a4737; }
  .lesson-theory h2,
  .lesson-theory h3,
  .lesson-theory h4 {
    color: #3b3027;
    font-family: var(--font-serif);
  }
  .lesson-theory pre,
  .lesson-theory code,
  .task-expected pre {
    background: #3b3027 !important;
    color: #fff8ec !important;
    border-color: transparent !important;
    border-radius: 10px !important;
  }
  .lesson-practice {
    border-top: 1px solid rgba(59, 48, 39, 0.12);
    margin-top: 28px;
    padding-top: 24px;
  }

  /* Next-lesson gate — must stay readable on cream */
  .lesson-next-gate {
    background: #efe2cf !important;
    border: 1.5px solid rgba(182, 147, 99, 0.55) !important;
    color: #3b3027 !important;
    border-radius: 14px !important;
    padding: 14px 16px !important;
    font-weight: 650;
    font-size: 14.5px !important;
    line-height: 1.55 !important;
  }

  /* Task switcher */
  .task-tabs {
    gap: 10px !important;
    margin: 18px 0 8px !important;
  }
  .task-tab {
    color: #3b3027 !important;
    background: #fffdf8 !important;
    border: 1.5px solid rgba(59, 48, 39, 0.18) !important;
    border-radius: 14px !important;
    box-shadow: 0 1px 2px rgba(59, 48, 39, 0.04) !important;
  }
  .task-tab:hover {
    color: #3b3027 !important;
    background: #efe2cf !important;
    border-color: rgba(182, 147, 99, 0.55) !important;
    transform: translateY(-1px);
  }
  .task-tab.active {
    color: #fffdf8 !important;
    background: #5a4737 !important;
    border-color: #5a4737 !important;
    box-shadow: 0 8px 20px rgba(90, 71, 55, 0.18) !important;
  }
  .task-tab__num {
    background: #f3ebe0 !important;
    border-color: rgba(59, 48, 39, 0.12) !important;
    color: #3b3027 !important;
    border-radius: 10px !important;
    font-weight: 800 !important;
  }
  .task-tab.active .task-tab__num {
    background: rgba(255, 253, 248, 0.18) !important;
    color: #fffdf8 !important;
    border-color: transparent !important;
  }
  .task-tab__label {
    color: inherit !important;
    font-weight: 750 !important;
  }
  .task-tab__title {
    color: #74685b !important;
  }
  .task-tab.active .task-tab__title {
    color: rgba(255, 253, 248, 0.8) !important;
  }
  .task-tab.is-done:not(.active) {
    border-color: rgba(61, 139, 90, 0.4) !important;
    background: rgba(61, 139, 90, 0.08) !important;
  }
  .task-tab.is-done:not(.active) .task-tab__label,
  .task-tab.is-done:not(.active) .task-tab__status {
    color: #2f7a4a !important;
  }

  .lesson-practice__task-title {
    color: #3b3027 !important;
    margin: 16px 0 12px;
  }

  /* Task content cards — rounded, warm, readable */
  .task-card {
    display: grid;
    gap: 14px;
    background: transparent !important;
    border: none !important;
    box-shadow: none !important;
    padding: 0 !important;
    border-radius: 0 !important;
  }

  .task-goal,
  .task-steps,
  .task-requirements,
  .task-expected,
  .task-hint {
    background: #f7f1e6 !important;
    border: 1.5px solid rgba(59, 48, 39, 0.14) !important;
    border-radius: 16px !important;
    overflow: hidden !important;
    color: #3b3027 !important;
    box-shadow: 0 1px 3px rgba(59, 48, 39, 0.05);
  }

  .task-goal {
    background: #efe2cf !important;
    border-color: rgba(182, 147, 99, 0.5) !important;
    padding: 18px 20px !important;
  }

  .task-steps,
  .task-requirements,
  .task-expected {
    padding: 16px 18px !important;
  }

  .task-goal strong,
  .task-steps strong,
  .task-requirements strong,
  .task-expected strong {
    color: #765633 !important;
    font-weight: 700;
  }

  .task-goal p,
  .task-steps ol,
  .task-requirements ul,
  .task-expected p {
    color: #3b3027 !important;
  }

  .task-steps li,
  .task-requirements li {
    color: #5a4737 !important;
  }

  .task-hint {
    border-style: dashed !important;
    border-color: rgba(182, 147, 99, 0.45) !important;
  }
  .task-hint summary {
    color: #5a4737 !important;
  }
  .task-hint p {
    color: #5a4737 !important;
  }

  .task-pass {
    background: rgba(61, 139, 90, 0.12) !important;
    border: 1px solid rgba(61, 139, 90, 0.35) !important;
    color: #246640 !important;
    border-radius: 12px !important;
  }

  .sandbox__head,
  .sandbox__header {
    background: #f3ebe0 !important;
    border-bottom: 1px solid rgba(59, 48, 39, 0.12) !important;
    padding: 16px 18px !important;
    gap: 14px !important;
    align-items: flex-start !important;
  }
  .sandbox__title,
  .sandbox__meta {
    color: #3b3027 !important;
    font-size: 20px !important;
    margin: 0 !important;
  }
  .sandbox__hint {
    color: #74685b !important;
    margin: 4px 0 0 !important;
  }
  .sandbox__lang {
    color: #5a4737 !important;
    background: #fffdf8 !important;
    border: 1px solid rgba(182, 147, 99, 0.45) !important;
    border-radius: 999px !important;
    padding: 4px 10px !important;
    font-size: 11px !important;
    letter-spacing: 0.06em !important;
  }
  .sandbox__actions {
    display: flex !important;
    flex-wrap: wrap !important;
    gap: 8px !important;
    justify-content: flex-end !important;
    flex: 1 1 280px !important;
  }
  .sandbox__actions .btn {
    border-radius: 10px !important;
    min-height: 38px !important;
    font-weight: 650 !important;
    white-space: nowrap !important;
  }
  .sandbox__actions .btn--outline {
    background: #fffdf8 !important;
    border-color: rgba(59, 48, 39, 0.18) !important;
    color: #5a4737 !important;
  }
  .sandbox__actions .btn--outline:hover {
    background: #efe2cf !important;
    border-color: rgba(182, 147, 99, 0.5) !important;
  }
  .sandbox__actions .btn--gold {
    background: #5a4737 !important;
    color: #fffdf8 !important;
    border: none !important;
  }
  .sandbox__actions .btn--gold:hover {
    background: #3b3027 !important;
  }

  /* Editor: cohesive dark chocolate panel */
  .sandbox .sandbox__editor-wrap,
  .sandbox__editor-wrap,
  .code-editor-wrap {
    background: #2f2924 !important;
    border: none !important;
    border-top: 1px solid rgba(59, 48, 39, 0.18) !important;
    border-bottom: 1px solid rgba(59, 48, 39, 0.18) !important;
    border-radius: 0 !important;
    min-height: 280px !important;
    overflow: hidden !important;
  }
  .sandbox .sandbox__lines,
  .sandbox__lines,
  .code-lines {
    margin: 0 !important;
    padding: 18px 10px 18px 14px !important;
    min-width: 44px !important;
    background: #261f1b !important;
    color: #a89884 !important;
    border-right: 1px solid rgba(255, 248, 236, 0.08) !important;
    font-family: var(--font-mono), "DM Mono", ui-monospace, monospace !important;
    font-size: 13px !important;
    line-height: 1.65 !important;
  }
  .sandbox .sandbox__editor,
  .sandbox__editor,
  .code-editor {
    color: #fff8ec !important;
    background: #2f2924 !important;
    caret-color: #d4b483 !important;
    padding: 18px 20px !important;
    font-family: var(--font-mono), "DM Mono", ui-monospace, monospace !important;
    font-size: 16px !important;
    line-height: 1.65 !important;
    min-height: 280px !important;
    border: none !important;
    outline: none !important;
    box-shadow: none !important;
    border-radius: 0 !important;
  }

  /* Output panel */
  .sandbox .sandbox__stdout,
  .sandbox__stdout,
  .sandbox-output {
    background: #f3ebe0 !important;
    color: #3b3027 !important;
    border: none !important;
    border-top: 1px solid rgba(59, 48, 39, 0.1) !important;
    border-radius: 0 !important;
    padding: 16px 18px 18px !important;
  }
  .sandbox .sandbox__stdout-label,
  .sandbox__stdout-label {
    color: #765633 !important;
    font-size: 11px !important;
    font-weight: 750 !important;
    letter-spacing: 0.1em !important;
    margin-bottom: 10px !important;
  }
  .sandbox .sandbox__stdout pre,
  .sandbox__stdout pre,
  .sandbox #codeOutput,
  #codeOutput {
    display: block !important;
    color: #5a4737 !important;
    background: #fffdf8 !important;
    border: 1px solid rgba(59, 48, 39, 0.14) !important;
    border-radius: 12px !important;
    padding: 12px 14px !important;
    min-height: 56px !important;
    margin: 0 !important;
    font-family: var(--font-mono), "DM Mono", ui-monospace, monospace !important;
    font-size: 13px !important;
    line-height: 1.6 !important;
    white-space: pre-wrap !important;
    word-break: break-word !important;
  }
  .sandbox #codeOutput.is-ok,
  .sandbox__stdout pre.is-ok,
  #codeOutput.is-ok {
    color: #246640 !important;
    background: rgba(61, 139, 90, 0.1) !important;
    border-color: rgba(61, 139, 90, 0.3) !important;
  }
  .sandbox #codeOutput.is-error,
  .sandbox__stdout pre.is-error,
  #codeOutput.is-error {
    color: #9a3428 !important;
    background: rgba(180, 67, 50, 0.1) !important;
    border-color: rgba(180, 67, 50, 0.28) !important;
  }
  .sandbox #codeOutput.is-running,
  .sandbox__stdout pre.is-running,
  #codeOutput.is-running {
    color: #765633 !important;
    background: rgba(182, 147, 99, 0.14) !important;
    border-color: rgba(182, 147, 99, 0.35) !important;
  }

  .paywall { background: transparent; }
  .paywall__bg {
    opacity: 0.42;
    background: radial-gradient(circle at 50% 35%, var(--accent-soft), transparent 52%);
  }

  @media (max-width: 980px) {
    .course-sidebar { background: #fffdf8; }
  }

  @media (max-width: 860px) {
    .sandbox__actions .btn {
      flex: 1 1 calc(50% - 8px);
      min-height: 44px !important;
    }
    .sandbox__editor-wrap,
    .sandbox__editor {
      min-height: 220px !important;
    }
  }

  /* Responsive final pass */
  @media (max-width: 980px) {
    .course-layout {
      min-height: 100dvh;
    }

    .course-sidebar {
      overscroll-behavior: contain;
      padding-bottom: env(safe-area-inset-bottom, 0px);
    }

    .course-sidebar__scroll {
      -webkit-overflow-scrolling: touch;
    }

    .sidebar-toggle {
      background: #5a4737;
      box-shadow: 0 8px 20px rgba(59, 48, 39, 0.22);
    }

    .lesson-body {
      max-width: none;
    }

    .lesson-body table {
      display: block;
      width: 100%;
      overflow-x: auto;
      -webkit-overflow-scrolling: touch;
    }

    .sandbox__editor {
      font-size: 16px !important;
    }
  }

  @media (max-width: 640px) {
    .course-main {
      padding: 12px 12px calc(82px + env(safe-area-inset-bottom, 0px));
    }

    .lesson-panel {
      padding: 20px 16px;
      margin-bottom: 16px;
    }

    .lesson-title {
      margin-bottom: 20px;
    }

    .lesson-body {
      font-size: 16px;
      line-height: 1.7;
    }

    .lesson-body h3 {
      font-size: 22px;
      margin-top: 28px;
    }

    .sandbox__head,
    .sandbox__header {
      padding: 14px 16px !important;
    }

    .sandbox__actions {
      flex-basis: 100% !important;
    }

    .sandbox__stdout {
      padding: 14px 16px 16px !important;
    }
  }

  @media (max-width: 380px) {
    .sandbox__actions .btn {
      flex-basis: 100%;
    }

    .course-sidebar {
      width: min(304px, 92vw);
    }
  }

}

/* Dark editorial course workspace */
html[data-theme="dark"] .course-page {
  background: var(--bg);
}
html[data-theme="dark"] .course-sidebar {
  background: rgba(31, 35, 34, 0.98);
  border-right-color: var(--border);
  box-shadow: 8px 0 28px rgba(0, 0, 0, 0.28);
}
html[data-theme="dark"] .course-sidebar__head,
html[data-theme="dark"] .course-sidebar__scroll {
  border-color: var(--border);
}
html[data-theme="dark"] .course-sidebar__icon {
  background: var(--panel-2);
  border-color: var(--border);
}
html[data-theme="dark"] .course-back,
html[data-theme="dark"] .course-sidebar__meta,
html[data-theme="dark"] .course-progress__label,
html[data-theme="dark"] .lesson-nav button.is-locked {
  color: var(--text-dimmer);
}
html[data-theme="dark"] .course-sidebar__title,
html[data-theme="dark"] .lesson-title,
html[data-theme="dark"] .paywall__title,
html[data-theme="dark"] .lesson-theory h2,
html[data-theme="dark"] .lesson-theory h3,
html[data-theme="dark"] .lesson-theory h4,
html[data-theme="dark"] .lesson-practice__task-title,
html[data-theme="dark"] .sandbox__title,
html[data-theme="dark"] .sandbox__meta {
  color: var(--text) !important;
}
html[data-theme="dark"] .course-progress {
  background: rgba(255, 255, 255, 0.08);
}
html[data-theme="dark"] .lesson-nav button {
  color: var(--text-dim);
}
html[data-theme="dark"] .lesson-nav button:hover {
  background: rgba(143, 201, 176, 0.1);
  color: var(--text);
}
html[data-theme="dark"] .lesson-nav button.active {
  background: var(--accent-soft);
  color: var(--gold-bright);
}
html[data-theme="dark"] .lesson-nav button.active .num {
  color: var(--gold);
}
html[data-theme="dark"] .lesson-nav button.is-done .num,
html[data-theme="dark"] .lesson-nav button.is-done::after,
html[data-theme="dark"] .task-tab__status {
  color: #8fd48f;
}
html[data-theme="dark"] .lesson-panel,
html[data-theme="dark"] .sandbox,
html[data-theme="dark"] .paywall__card {
  background: var(--panel) !important;
  border: 1px solid var(--border) !important;
  box-shadow: 0 16px 36px rgba(0, 0, 0, 0.28) !important;
}
html[data-theme="dark"] .lesson-kicker,
html[data-theme="dark"] .lesson-practice__title,
html[data-theme="dark"] .course-nav-label {
  color: var(--accent) !important;
}
html[data-theme="dark"] .lesson-practice__lead,
html[data-theme="dark"] .lesson-theory,
html[data-theme="dark"] .lesson-body {
  color: var(--text-dim);
}
html[data-theme="dark"] .lesson-body strong,
html[data-theme="dark"] .lesson-body h3 {
  color: var(--text);
}
html[data-theme="dark"] .lesson-body code {
  background: rgba(143, 201, 176, 0.1);
  border-color: var(--border);
  color: var(--gold-bright);
}
html[data-theme="dark"] .lesson-body pre,
html[data-theme="dark"] .lesson-theory pre,
html[data-theme="dark"] .lesson-theory code,
html[data-theme="dark"] .task-expected pre {
  background: #0f1211 !important;
  color: #dceee6 !important;
  border-color: var(--border) !important;
}
html[data-theme="dark"] .lesson-practice {
  border-color: rgba(var(--accent-rgb), 0.22);
  background: linear-gradient(165deg, rgba(var(--accent-rgb), 0.08), rgba(255, 255, 255, 0.02));
  border-top-color: var(--border);
}
html[data-theme="dark"] .lesson-next-gate {
  background: rgba(255, 160, 80, 0.1) !important;
  border: 1px solid rgba(255, 160, 80, 0.35) !important;
  color: #ffc896 !important;
}
html[data-theme="dark"] .task-tab {
  color: var(--text) !important;
  background: var(--panel-2) !important;
  border: 1px solid var(--border-strong) !important;
  box-shadow: none !important;
}
html[data-theme="dark"] .task-tab:hover {
  color: var(--text) !important;
  background: rgba(143, 201, 176, 0.1) !important;
  border-color: rgba(var(--accent-rgb), 0.4) !important;
}
html[data-theme="dark"] .task-tab.active {
  color: #121413 !important;
  background: linear-gradient(135deg, #a8d9c4, #6eae96) !important;
  border-color: transparent !important;
  box-shadow: 0 10px 28px -12px rgba(var(--btn-rgb), 0.55) !important;
}
html[data-theme="dark"] .task-tab__num {
  background: rgba(255, 255, 255, 0.06) !important;
  border-color: var(--border) !important;
  color: var(--gold-bright) !important;
}
html[data-theme="dark"] .task-tab.active .task-tab__num {
  background: rgba(18, 20, 19, 0.18) !important;
  color: #121413 !important;
  border-color: transparent !important;
}
html[data-theme="dark"] .task-tab__title {
  color: var(--text-dimmer) !important;
}
html[data-theme="dark"] .task-tab.active .task-tab__title {
  color: rgba(18, 20, 19, 0.72) !important;
}
html[data-theme="dark"] .task-tab.is-done:not(.active) {
  border-color: rgba(143, 212, 143, 0.4) !important;
  background: rgba(80, 160, 90, 0.12) !important;
}
html[data-theme="dark"] .task-tab.is-done:not(.active) .task-tab__label,
html[data-theme="dark"] .task-tab.is-done:not(.active) .task-tab__status {
  color: #8fd48f !important;
}
html[data-theme="dark"] .task-goal,
html[data-theme="dark"] .task-steps,
html[data-theme="dark"] .task-requirements,
html[data-theme="dark"] .task-expected,
html[data-theme="dark"] .task-hint {
  background: var(--panel-2) !important;
  border: 1px solid var(--border) !important;
  color: var(--text) !important;
  box-shadow: none !important;
}
html[data-theme="dark"] .task-goal {
  background: rgba(var(--accent-rgb), 0.12) !important;
  border-color: rgba(var(--accent-rgb), 0.28) !important;
}
html[data-theme="dark"] .task-goal strong,
html[data-theme="dark"] .task-steps strong,
html[data-theme="dark"] .task-requirements strong,
html[data-theme="dark"] .task-expected strong,
html[data-theme="dark"] .task-hint summary {
  color: var(--gold-bright) !important;
}
html[data-theme="dark"] .task-goal p,
html[data-theme="dark"] .task-steps ol,
html[data-theme="dark"] .task-requirements ul,
html[data-theme="dark"] .task-expected p,
html[data-theme="dark"] .task-steps li,
html[data-theme="dark"] .task-requirements li,
html[data-theme="dark"] .task-hint p {
  color: var(--text-dim) !important;
}
html[data-theme="dark"] .task-hint {
  border-style: dashed !important;
  border-color: rgba(var(--accent-rgb), 0.35) !important;
  background: rgba(var(--accent-rgb), 0.08) !important;
}
html[data-theme="dark"] .task-pass {
  background: rgba(80, 160, 90, 0.14) !important;
  border: 1px solid rgba(120, 200, 120, 0.35) !important;
  color: #b7e3a1 !important;
}
html[data-theme="dark"] .sandbox__head,
html[data-theme="dark"] .sandbox__header {
  background: var(--panel-2) !important;
  border-bottom-color: var(--border) !important;
}
html[data-theme="dark"] .sandbox__hint,
html[data-theme="dark"] .sandbox__stdout-label {
  color: var(--text-dim) !important;
}
html[data-theme="dark"] .sandbox__lang {
  color: var(--accent) !important;
  background: var(--panel) !important;
  border-color: var(--border-strong) !important;
}
html[data-theme="dark"] .sandbox__actions .btn--outline {
  background: var(--panel) !important;
  border-color: var(--border-strong) !important;
  color: var(--accent) !important;
}
html[data-theme="dark"] .sandbox__actions .btn--outline:hover {
  background: var(--accent-soft) !important;
  border-color: var(--accent) !important;
}
html[data-theme="dark"] .sandbox__actions .btn--gold {
  background: var(--btn) !important;
  color: #121413 !important;
}
html[data-theme="dark"] .sandbox__actions .btn--gold:hover {
  background: var(--btn-hover) !important;
}
html[data-theme="dark"] .sandbox .sandbox__editor-wrap,
html[data-theme="dark"] .sandbox__editor-wrap,
html[data-theme="dark"] .code-editor-wrap,
html[data-theme="dark"] .sandbox .sandbox__editor,
html[data-theme="dark"] .sandbox__editor,
html[data-theme="dark"] .code-editor {
  background: #101412 !important;
  color: #e8f2ee !important;
  caret-color: #8fc9b0 !important;
  border-color: var(--border) !important;
}
html[data-theme="dark"] .sandbox .sandbox__lines,
html[data-theme="dark"] .sandbox__lines,
html[data-theme="dark"] .code-lines {
  background: #0c0f0e !important;
  color: var(--text-dimmer) !important;
  border-right-color: rgba(190, 220, 208, 0.1) !important;
}
html[data-theme="dark"] .sandbox .sandbox__stdout,
html[data-theme="dark"] .sandbox__stdout,
html[data-theme="dark"] .sandbox-output {
  background: var(--panel-2) !important;
  color: var(--text) !important;
  border-top-color: var(--border) !important;
}
html[data-theme="dark"] .sandbox .sandbox__stdout pre,
html[data-theme="dark"] .sandbox__stdout pre,
html[data-theme="dark"] .sandbox #codeOutput,
html[data-theme="dark"] #codeOutput {
  color: var(--text) !important;
  background: var(--panel) !important;
  border-color: var(--border) !important;
}
html[data-theme="dark"] .sandbox #codeOutput.is-ok,
html[data-theme="dark"] .sandbox__stdout pre.is-ok,
html[data-theme="dark"] #codeOutput.is-ok {
  color: #8fd48f !important;
  background: rgba(80, 160, 90, 0.14) !important;
  border-color: rgba(143, 212, 143, 0.35) !important;
}
html[data-theme="dark"] .sandbox #codeOutput.is-error,
html[data-theme="dark"] .sandbox__stdout pre.is-error,
html[data-theme="dark"] #codeOutput.is-error {
  color: #f0a8a0 !important;
  background: rgba(180, 67, 50, 0.16) !important;
  border-color: rgba(180, 67, 50, 0.35) !important;
}
html[data-theme="dark"] .sandbox #codeOutput.is-running,
html[data-theme="dark"] .sandbox__stdout pre.is-running,
html[data-theme="dark"] #codeOutput.is-running {
  color: var(--accent) !important;
  background: rgba(var(--accent-rgb), 0.12) !important;
  border-color: rgba(var(--accent-rgb), 0.35) !important;
}
html[data-theme="dark"] .sidebar-toggle {
  background: linear-gradient(165deg, #4a8a74, var(--btn));
  color: #121413;
  box-shadow: 0 10px 24px rgba(0, 0, 0, 0.35);
}
html[data-theme="dark"] .lesson-note {
  background: var(--accent-soft);
  border-color: rgba(var(--accent-rgb), 0.28);
  color: var(--text);
}
html[data-theme="dark"] .paywall__text,
html[data-theme="dark"] .paywall__row,
html[data-theme="dark"] .paywall__back {
  color: var(--text-dim);
}
html[data-theme="dark"] .paywall__check,
html[data-theme="dark"] .paywall__price {
  color: var(--accent);
}

@media (max-width: 980px) {
  html[data-theme="dark"] .course-sidebar {
    background: var(--panel);
  }
  html[data-theme="dark"] .sidebar-toggle {
    background: var(--btn);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.35);
  }
}