/* ============================================================
   Full Stack Course — styles
   ============================================================ */

:root {
  --bg: #f6f7fb;
  --bg-alt: #eef0f7;
  --surface: #ffffff;
  --surface-2: #f8f9fc;
  --surface-3: #eef1f8;
  --border: #dde1ed;
  --border-strong: #c0c8de;
  --text: #1a1f2e;
  --text-2: #475069;
  --text-3: #7882a0;
  --primary: #4a3de0;
  --primary-strong: #3930c6;
  --primary-soft: #e8e6fc;
  --accent: #059688;
  --danger: #d93025;
  --danger-soft: #fce8e6;
  --success: #0e7a38;
  --success-soft: #e6f6ec;
  --warning: #a34808;
  --warning-soft: #fef2dc;
  --code-bg: #161b29;
  --code-text: #e8ecf8;
  --shadow: 0 1px 2px rgba(28, 35, 51, .06), 0 8px 24px rgba(28, 35, 51, .06);
  --radius: 12px;
  --radius-sm: 8px;
  --topbar-h: 60px;
  --sidebar-w: 340px;
}

[data-theme="dark"] {
  --bg: #0e1122;
  --bg-alt: #111528;
  --surface: #171d33;
  --surface-2: #1b2240;
  --surface-3: #222a4e;
  --border: #2d3558;
  --border-strong: #3e4872;
  --text: #e9edf9;
  --text-2: #bcc3e0;
  --text-3: #8890b0;
  --primary: #9384ff;
  --primary-strong: #b0a3ff;
  --primary-soft: #2c2656;
  --accent: #3ee8d3;
  --danger: #ff6b6b;
  --danger-soft: #3c2228;
  --success: #5ce08c;
  --success-soft: #153624;
  --warning: #ffcf44;
  --warning-soft: #3e3015;
  --code-bg: #111827;
  --code-text: #e8ecf8;
  --shadow: 0 1px 2px rgba(0, 0, 0, .35), 0 8px 24px rgba(0, 0, 0, .35);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

/* ---------- Bengali font: Hind Siliguri (body) + Noto Sans Bengali (digits) ---------- */
@font-face {
  font-family: "BengaliDigits";
  src: local("Noto Sans Bengali");
  unicode-range: U+09E6-U+09EF, U+0966-U+096F;
  font-display: swap;
}
html[lang="bn"] body {
  font-family: "Hind Siliguri", "BengaliDigits", sans-serif;
}
html[lang="bn"] .lesson-content,
html[lang="bn"] .home-hero,
html[lang="bn"] .module-hero,
html[lang="bn"] .sidebar-inner,
html[lang="bn"] .practice-box,
html[lang="bn"] .quiz-wrap,
html[lang="bn"] .toast,
html[lang="bn"] .lesson-header,
html[lang="bn"] .quiz-option,
html[lang="bn"] .def-box,
html[lang="bn"] .sec-tag,
html[lang="bn"] .lesson-nav,
html[lang="bn"] .home-grid .card,
html[lang="bn"] .module-list .card {
  font-family: "Hind Siliguri", "BengaliDigits", sans-serif;
}

/* ---------- Top bar ---------- */

.topbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--topbar-h);
  display: flex;
  justify-content: center;
  align-items: center;
  background: #e8ebf3;
  border-bottom: 1px solid #d6dce8;
  z-index: 60;
}

[data-theme="dark"] .topbar {
  background: #151b30;
  border-bottom-color: #2a3252;
}

.topbar-inner {
  display: flex;
  align-items: center;
  gap: 12px;
  width: 78%;
  padding: 0 40px 0 20px;
}

@media (max-width: 980px) {
  .topbar-inner {
    width: 100%;
    max-width: 1200px;
    padding: 0 16px;
  }
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--text);
  white-space: nowrap;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border-radius: 9px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #fff;
  font-weight: 800;
  font-size: 18px;
}

.brand-text {
  font-weight: 800;
  font-size: 15px;
  line-height: 1.2;
  display: flex;
  flex-direction: column;
}

.brand-sub {
  font-size: 10px;
  font-weight: 600;
  color: var(--text-3);
  letter-spacing: .4px;
}

.search-wrap {
  position: relative;
  flex: 1;
  max-width: 520px;
  margin: 0 auto;
}

#searchInput {
  width: 100%;
  padding: 9px 14px 9px 38px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface-2) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%238b93a9' stroke-width='2'%3E%3Ccircle cx='11' cy='11' r='7'/%3E%3Cpath d='m21 21-4.3-4.3'/%3E%3C/svg%3E") no-repeat 14px center;
  color: var(--text);
  font-size: 14px;
  outline: none;
  transition: border-color .15s, box-shadow .15s;
}

#searchInput:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-soft);
}

.search-results {
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  right: 0;
  max-height: 420px;
  overflow: auto;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  z-index: 80;
}

.search-results .sr-item {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 10px 14px;
  cursor: pointer;
  border-bottom: 1px solid var(--border);
}

.search-results .sr-item:last-child {
  border-bottom: none;
}

.search-results .sr-item:hover,
.search-results .sr-item.active {
  background: var(--primary-soft);
}

.search-results .sr-item .sr-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
}

.search-results .sr-item .sr-meta {
  font-size: 12px;
  color: var(--text-3);
}

.search-results .sr-item mark {
  background: #fde68a;
  color: #78350f;
  border-radius: 3px;
  padding: 0 2px;
}

[data-theme="dark"] .search-results .sr-item mark {
  background: #fde68a;
  color: #451a03;
}

.progress-wrap {
  display: flex;
  align-items: center;
  gap: 8px;
  min-width: 110px;
}

.progress-track {
  width: 90px;
  height: 8px;
  background: #cfd5e5;
  border-radius: 999px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  border-radius: 999px;
  transition: width .4s ease;
}

.progress-text {
  font-size: 12px;
  font-weight: 700;
  color: #3a4460;
  min-width: 34px;
  text-align: right;
}

.icon-btn {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-2);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 17px;
  transition: background .15s, color .15s;
}

.icon-btn:hover {
  background: var(--surface-3);
  color: var(--text);
}

.lang-switch {
  display: flex;
  align-items: center;
  gap: 2px;
  background: rgba(15, 20, 45, .07);
  border: 1px solid #d6dce8;
  border-radius: var(--radius-sm);
  padding: 3px;
}

[data-theme="dark"] .lang-switch {
  background: rgba(255, 255, 255, .06);
  border-color: #2a3252;
}

.lang-btn {
  border: none;
  background: transparent;
  color: #5a6480;
  font-size: 12px;
  font-weight: 800;
  font-family: inherit;
  padding: 5px 12px;
  border-radius: 5px;
  cursor: pointer;
  transition: all .15s;
}

[data-theme="dark"] .lang-btn { color: #9aa3c8; }

.lang-btn.active {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #fff;
  box-shadow: 0 1px 4px rgba(20, 15, 90, .3);
}

/* ---------- Layout ---------- */

.layout {
  display: flex;
  padding-top: var(--topbar-h);
  min-height: calc(100vh - var(--topbar-h));
  max-width: min(1540px, 100%);
  margin: 0 auto;
}

.sidebar {
  position: fixed;
  top: var(--topbar-h);
  bottom: 0;
  left: calc(50vw - 740px);
  width: var(--sidebar-w);
  overflow-y: auto;
  background: var(--surface);
  border-right: 1px solid var(--border);
  padding: 14px 10px 60px;
  z-index: 50;
}

.nav-section {
  margin-bottom: 8px;
}

.nav-section-title {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 12px;
  font-size: 12px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: .6px;
  color: var(--text-3);
  cursor: pointer;
  user-select: none;
}

.nav-section-title:hover {
  color: var(--text-2);
}

.nav-section-title .sec-caret {
  transition: transform .2s;
  font-size: 10px;
}

.nav-section-title.open .sec-caret {
  transform: rotate(90deg);
}

.nav-section-title .sec-prog {
  margin-left: auto;
  font-size: 10px;
  font-weight: 700;
}

.nav-section-body {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding-bottom: 8px;
}

.nav-section.collapsed .nav-section-body {
  display: none;
}

.nav-module {
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  overflow: hidden;
  margin-bottom: 4px;
  background: var(--surface-2);
}

.nav-module-title {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 9px 12px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text);
  cursor: pointer;
  user-select: none;
}

.nav-module-title .mod-caret {
  transition: transform .2s;
  font-size: 10px;
  color: var(--text-3);
}

.nav-module-title.open .mod-caret {
  transform: rotate(90deg);
}

.nav-module-title .mod-prog {
  margin-left: auto;
  font-size: 10px;
  font-weight: 700;
  color: var(--text-3);
}

.nav-module-title:hover {
  background: var(--surface-3);
}

.nav-module.collapsed .nav-lessons {
  display: none;
}

.nav-lessons {
  padding: 4px 6px 8px;
  display: flex;
  flex-direction: column;
}

.nav-lesson {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 7px 10px;
  border-radius: var(--radius-sm);
  font-size: 13px;
  color: var(--text-2);
  text-decoration: none;
  transition: background .12s, color .12s;
  border-left: 3px solid transparent;
}

.nav-lesson:hover {
  background: var(--surface-3);
  color: var(--text);
}

.nav-lesson.active {
  background: var(--primary-soft);
  color: var(--primary-strong);
  border-left-color: var(--primary);
  font-weight: 600;
}

.nav-lesson .lbl {
  flex: 1;
}

.nav-lesson .num {
  font-size: 11px;
  color: var(--text-3);
  font-weight: 600;
  min-width: 22px;
}

.lesson-state {
  font-size: 11px;
  min-width: 18px;
  text-align: center;
}

.lesson-state.done {
  color: var(--success);
}

.lesson-state.score {
  color: var(--primary);
  font-weight: 700;
}

/* ---------- Main ---------- */

.content-col {
  flex: 1;
  margin-left: var(--sidebar-w);
  max-width: 1200px;
  display: flex;
  flex-direction: column;
}

.main {
  flex: 1;
  padding: 34px clamp(20px, 5vw, 64px) 40px;
}

.footer {
  display: flex;
  justify-content: center;
  border-top: 1px solid #d6dce8;
  background: #e8ebf3;
  padding: 5px 16px 10px;
  z-index: 61;
  position: relative;
}

[data-theme="dark"] .footer {
  background: #151b30;
  border-top-color: #2a3252;
}

.footer-inner {
  width: 100%;
  max-width: 1200px;
  text-align: center;
  color: var(--text-2);
  font-size: 13.5px;
}

.footer-love {
  color: #e5484d;
  font-weight: 700;
}

/* Home */
.home-hero {
  background: linear-gradient(135deg, var(--primary) 0%, #7c3aed 45%, var(--accent) 100%);
  color: #fff;
  border-radius: 18px;
  padding: 42px 40px;
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
}

.home-hero::after {
  content: "";
  position: absolute;
  right: -60px;
  top: -60px;
  width: 240px;
  height: 240px;
  border-radius: 50%;
  background: rgba(255, 255, 255, .12);
}

.home-hero h1 {
  margin: 0 0 10px;
  font-size: clamp(26px, 4vw, 40px);
  line-height: 1.15;
  letter-spacing: -.5px;
}

.home-hero p {
  margin: 0;
  max-width: 640px;
  font-size: 16px;
  opacity: .92;
}

.home-hero .badges {
  display: flex;
  gap: 8px;
  margin-top: 18px;
  flex-wrap: wrap;
  position: relative;
  z-index: 1;
}

.home-hero .badge {
  background: rgba(255, 255, 255, .18);
  border: 1px solid rgba(255, 255, 255, .25);
  padding: 5px 12px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
}

.stats-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 14px;
  margin: 22px 0;
}

.stat-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 18px;
}

.stat-card .val {
  font-size: 26px;
  font-weight: 800;
  color: var(--primary);
  line-height: 1.1;
}

.stat-card .lab {
  font-size: 12.5px;
  color: var(--text-3);
  font-weight: 600;
  margin-top: 4px;
}

.home-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  margin-top: 8px;
}

.sec-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  text-decoration: none;
  color: inherit;
  display: flex;
  flex-direction: column;
  transition: transform .15s, box-shadow .15s, border-color .15s;
}

.sec-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow);
  border-color: var(--primary);
}

.sec-card .sec-tag {
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 1px;
  color: var(--primary);
  text-transform: uppercase;
}

.sec-card h3 {
  margin: 8px 0 8px;
  font-size: 16px;
  line-height: 1.35;
}

.sec-card p {
  margin: 0 0 12px;
  font-size: 13px;
  color: var(--text-2);
  flex: 1;
}

.sec-card .sec-meta {
  font-size: 12px;
  color: var(--text-3);
  font-weight: 600;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.sec-card .mini-track {
  width: 80px;
  height: 6px;
  background: var(--surface-3);
  border-radius: 999px;
  overflow: hidden;
}

.sec-card .mini-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--primary), var(--accent));
}

.home-section-title {
  font-size: 18px;
  font-weight: 800;
  margin: 34px 0 12px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.home-section-title .idx {
  display: grid;
  place-items: center;
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: var(--primary-soft);
  color: var(--primary);
  font-size: 13px;
}

.module-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 12px;
  margin-top: 14px;
}

.module-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 14px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  text-decoration: none;
  color: inherit;
  transition: border-color .15s, transform .15s;
}

.module-item:hover {
  border-color: var(--primary);
  transform: translateY(-2px);
}

.module-item .mod-id {
  font-size: 12px;
  font-weight: 800;
  color: var(--primary);
  background: var(--primary-soft);
  border-radius: 7px;
  padding: 4px 8px;
}

.module-item .mod-name {
  font-size: 13.5px;
  font-weight: 600;
  flex: 1;
}

.module-item .mod-count {
  font-size: 11px;
  color: var(--text-3);
}

/* ---------- Lesson ---------- */

.crumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 12.5px;
  color: var(--text-3);
  font-weight: 600;
  margin-bottom: 10px;
  flex-wrap: wrap;
}

.crumb a {
  color: var(--primary);
  text-decoration: none;
}

.crumb a:hover {
  text-decoration: underline;
}

.lesson-header {
  margin-bottom: 26px;
}

.lesson-header h1 {
  font-size: clamp(24px, 3.4vw, 34px);
  line-height: 1.2;
  letter-spacing: -.4px;
  margin: 0 0 12px;
}

.lesson-meta {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  align-items: center;
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-2);
  background: var(--surface-2);
  border: 1px solid var(--border);
  padding: 4px 11px;
  border-radius: 999px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 16px;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  font-size: 13.5px;
  font-weight: 600;
  cursor: pointer;
  text-decoration: none;
  transition: background .15s, border-color .15s, transform .1s;
}

.btn:active {
  transform: scale(.98);
}

.btn-primary {
  background: var(--primary);
  color: #fff;
}

.btn-primary:hover {
  background: var(--primary-strong);
}

.btn-outline {
  background: transparent;
  border-color: var(--border-strong);
  color: var(--text-2);
}

.btn-outline:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.btn-success {
  background: var(--success);
  color: #fff;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 22px;
  margin: 18px 0;
  box-shadow: var(--shadow);
}

.def-block {
  border-left: 4px solid var(--primary);
  background: var(--primary-soft);
  padding: 16px 20px;
  border-radius: 0 var(--radius) var(--radius) 0;
  margin: 0 0 22px;
}

.def-block .def-label {
  font-size: 11px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--primary-strong);
  margin-bottom: 6px;
}

.def-block p {
  margin: 0;
  font-size: 15.5px;
  color: var(--text);
}

[data-theme="dark"] .def-block .def-label {
  color: var(--primary);
}

.lesson-section {
  margin: 26px 0;
}

.lesson-section h2 {
  font-size: 21px;
  font-weight: 800;
  letter-spacing: -.2px;
  margin: 0 0 12px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--border);
  display: flex;
  align-items: center;
  gap: 10px;
}

.lesson-section h2 .h-ico {
  color: var(--primary);
}

.lesson-section h3 {
  font-size: 16.5px;
  font-weight: 700;
  margin: 20px 0 8px;
  color: var(--text);
}

.md-body p {
  margin: 0 0 12px;
  color: var(--text);
}

.md-body ul,
.md-body ol {
  margin: 0 0 14px;
  padding-left: 24px;
  color: var(--text);
}

.md-body li {
  margin: 4px 0;
  color: var(--text);
}

.md-body code {
  font-family: "JetBrains Mono", Consolas, monospace;
  font-size: 12.5px;
  background: #ffecd9;
  border: 1px solid #f4cf9e;
  padding: 2px 7px;
  border-radius: 5px;
  color: #9a3412;
  white-space: nowrap;
}

[data-theme="dark"] .md-body code {
  background: #3a2b1c;
  border-color: #5c4525;
  color: #ffd9a3;
}

.md-body p code,
.md-body li code,
.md-body td code,
.md-body th code {
  font-size: 12.5px;
}

.md-body pre code {
  background: var(--code-bg);
  color: var(--code-text);
  border: none;
  padding: 0;
  font-size: 13.5px;
  white-space: pre;
  border-radius: 0;
}

.md-body blockquote {
  margin: 14px 0;
  padding: 10px 16px;
  border-left: 3px solid var(--accent);
  background: var(--surface-2);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--text-2);
}

.md-body blockquote p {
  margin: 0;
  color: var(--text-2);
}

.md-body table {
  border-collapse: collapse;
  width: 100%;
  margin: 14px 0;
  font-size: 14px;
}

.md-body th,
.md-body td {
  border: 1px solid var(--border);
  padding: 8px 12px;
  text-align: left;
}

.md-body th {
  background: var(--surface-3);
  font-weight: 700;
}

.md-body hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 22px 0;
}

.md-body strong {
  font-weight: 700;
  color: var(--text);
}

.md-body a {
  color: var(--primary);
  font-weight: 500;
}

.md-body a:hover {
  color: var(--primary-strong);
  text-decoration: underline;
}

/* code blocks inside markdown */
.md-body pre {
  margin: 16px 0;
  border-radius: var(--radius-sm);
  border: 1px solid #303650;
  box-shadow: 0 2px 6px rgba(0, 0, 0, .15);
}

.md-body pre code {
  display: block;
  padding: 16px 18px;
  background: #1a1f35;
  color: #e8ecf8;
  border: none;
  font-family: "JetBrains Mono", Consolas, monospace;
  font-size: 13.5px;
  line-height: 1.7;
  overflow-x: auto;
}

/* ---------- Examples ---------- */

.examples-tabs {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  margin-bottom: 12px;
}

.ex-tab {
  padding: 8px 14px;
  border-radius: 999px;
  border: 1px solid var(--border-strong);
  background: var(--surface);
  color: var(--text-2);
  font-size: 12.5px;
  font-weight: 600;
  cursor: pointer;
  transition: all .15s;
}

.ex-tab:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.ex-tab.active {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
}

.ex-panel {
  display: none;
}

.ex-panel.active {
  display: block;
  animation: fadeIn .25s ease;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(4px);
  }

  to {
    opacity: 1;
    transform: none;
  }
}

.code-frame {
  margin: 12px 0 22px;
  border-radius: var(--radius-sm);
  border: 1px solid #303650;
  background: #1a1f35;
  box-shadow: 0 2px 8px rgba(0, 0, 0, .2);
}

.code-frame .code-head {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  background: #141830;
  border-bottom: 1px solid #2a2f4a;
}

.code-frame .code-title {
  color: #9aa3c8;
  font-size: 12px;
  font-weight: 600;
  font-family: "JetBrains Mono", monospace;
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.code-frame .lang-badge {
  color: #3ee8d3;
  font-size: 10.5px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .6px;
  background: rgba(62, 232, 211, .1);
  padding: 2px 7px;
  border-radius: 4px;
}

.copy-btn {
  background: rgba(255, 255, 255, .06);
  border: 1px solid rgba(255, 255, 255, .1);
  color: #9aa3c8;
  font-size: 11.5px;
  font-weight: 600;
  padding: 5px 12px;
  border-radius: 6px;
  cursor: pointer;
  transition: all .15s;
}

.copy-btn:hover {
  background: rgba(255, 255, 255, .14);
  color: #e8ecf8;
}

.code-frame pre {
  margin: 0;
  overflow-x: auto;
}

.code-frame pre code {
  padding: 16px 18px;
  font-size: 13.5px;
  line-height: 1.7;
  background: transparent;
  color: #e8ecf8;
  border: none;
}

.ex-note {
  font-size: 13px;
  color: var(--text-2);
  background: var(--warning-soft);
  border: 1px solid rgba(180, 83, 9, .2);
  padding: 9px 14px;
  border-radius: var(--radius-sm);
  margin: 4px 0 16px;
}

.ex-note strong {
  color: var(--warning);
}

[data-theme="dark"] .ex-note {
  border-color: rgba(255, 207, 68, .2);
}

/* ---------- Practice ---------- */

.task-item {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  padding: 10px 4px;
  border-bottom: 1px dashed var(--border);
}

.task-item:last-child {
  border-bottom: none;
}

.task-item input[type="checkbox"] {
  width: 18px;
  height: 18px;
  margin-top: 3px;
  accent-color: var(--primary);
  cursor: pointer;
  flex-shrink: 0;
}

.task-item.done label {
  text-decoration: line-through;
  color: var(--text-3);
}

.task-item label {
  font-size: 14.5px;
  cursor: pointer;
}

details.solution {
  margin-top: 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  overflow: hidden;
  background: var(--surface-2);
}

details.solution summary {
  padding: 12px 16px;
  cursor: pointer;
  font-weight: 700;
  font-size: 14px;
  color: var(--primary);
  user-select: none;
}

details.solution .solution-body {
  padding: 4px 16px 16px;
}

/* ---------- Quiz ---------- */

.quiz-q {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 20px;
  margin: 14px 0;
}

.quiz-q .q-num {
  font-size: 11px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--primary);
}

.quiz-q .q-text {
  font-size: 15.5px;
  font-weight: 600;
  margin: 8px 0 12px;
}

.q-options {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.q-opt {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  padding: 10px 14px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  background: var(--surface);
  cursor: pointer;
  font-size: 14px;
  transition: all .15s;
}

.q-opt:hover {
  border-color: var(--primary);
  background: var(--primary-soft);
}

.q-opt .opt-key {
  font-weight: 800;
  color: var(--text-3);
  min-width: 20px;
}

.q-opt.selected {
  border-color: var(--primary);
  background: var(--primary-soft);
}

.q-opt.correct {
  border-color: var(--success);
  background: var(--success-soft);
}

.q-opt.wrong {
  border-color: var(--danger);
  background: var(--danger-soft);
}

.q-feedback {
  display: none;
  margin-top: 12px;
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  font-size: 13.5px;
}

.q-feedback.show {
  display: block;
}

.q-feedback.good {
  background: var(--success-soft);
  color: var(--success);
  border: 1px solid rgba(18, 135, 63, .3);
}

.q-feedback.bad {
  background: var(--danger-soft);
  color: var(--danger);
  border: 1px solid rgba(229, 72, 77, .3);
}

.quiz-score {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  background: var(--primary-soft);
  border: 1px solid rgba(91, 75, 240, .3);
  border-radius: var(--radius);
  padding: 14px 18px;
  margin-top: 18px;
}

.quiz-score .qs-text {
  font-size: 14.5px;
  font-weight: 700;
  color: var(--primary-strong);
}

[data-theme="dark"] .quiz-score .qs-text {
  color: var(--primary);
}

/* ---------- Footer nav ---------- */

.pager {
  display: flex;
  justify-content: space-between;
  gap: 14px;
  margin-top: 40px;
  padding-top: 22px;
  border-top: 2px solid var(--border);
}

.pager .p-btn {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 14px 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  text-decoration: none;
  color: var(--text);
  transition: border-color .15s, background .15s;
  max-width: 48%;
}

.pager .p-btn:hover {
  border-color: var(--primary);
  background: var(--primary-soft);
}

.pager .p-btn .dir {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .8px;
  color: var(--text-3);
}

.pager .p-btn .t {
  font-size: 13.5px;
  font-weight: 600;
}

.pager .p-btn.next {
  align-items: flex-end;
  text-align: right;
}

/* ---------- Toast ---------- */

.toast {
  position: fixed;
  bottom: 26px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--text);
  color: var(--bg);
  padding: 11px 20px;
  border-radius: 999px;
  font-size: 13.5px;
  font-weight: 600;
  box-shadow: var(--shadow);
  opacity: 0;
  transition: opacity .25s, transform .25s;
  z-index: 100;
  pointer-events: none;
}

.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ---------- Misc ---------- */

.hidden {
  display: none !important;
}

.empty-state {
  text-align: center;
  padding: 60px 20px;
  color: var(--text-3);
}

.empty-state .big {
  font-size: 44px;
  margin-bottom: 12px;
}

.complete-banner {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--success-soft);
  border: 1px solid rgba(18, 135, 63, .3);
  color: var(--success);
  padding: 12px 18px;
  border-radius: var(--radius);
  font-weight: 700;
  font-size: 14px;
  margin: 18px 0;
}

.overlay {
  position: fixed;
  inset: 0;
  background: rgba(10, 12, 24, .5);
  z-index: 55;
}

/* ---------- Scrollbar ---------- */

::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: var(--border-strong);
  border-radius: 999px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-3);
}

/* ---------- Responsive ---------- */

@media (max-width: 980px) {
  .layout {
    max-width: 100%;
  }

  .content-col {
    margin-left: 0;
    max-width: 100%;
  }

  .home-grid {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: fixed;
    left: 0;
    transform: translateX(-100%);
    transition: transform .25s ease;
    box-shadow: var(--shadow);
    width: min(86vw, 340px);
  }

  .sidebar.open {
    transform: translateX(0);
  }

  .main {
    padding: 24px 18px 40px;
  }

  .footer {
    padding: 14px 16px 16px;
  }

  .progress-wrap {
    display: none;
  }

  .brand-sub {
    display: none;
  }
}

@media (max-width: 600px) {
  .pager {
    flex-direction: column;
  }

  .pager .p-btn {
    max-width: 100%;
  }

  .home-hero {
    padding: 28px 22px;
  }
}

/* ============================================================
   HIGHLIGHT.JS TOKEN OVERRIDES
   Force readable syntax colors on dark code backgrounds
   ============================================================ */

.hljs {
  color: #e8ecf8;
}

.hljs-keyword,
.hljs-selector-tag,
.hljs-literal {
  color: #c678dd;
}

.hljs-type,
.hljs-built_in {
  color: #e5c07b;
}

.hljs-number {
  color: #d19a66;
}

.hljs-string,
.hljs-attr {
  color: #98c379;
}

.hljs-template-variable {
  color: #e06c75;
}

.hljs-variable {
  color: #e06c75;
}

.hljs-title,
.hljs-title.function_ {
  color: #61afef;
}

.hljs-title.class_ {
  color: #e5c07b;
}

.hljs-params {
  color: #e8ecf8;
}

.hljs-comment {
  color: #5c6370;
  font-style: italic;
}

.hljs-doctag,
.hljs-section {
  color: #c678dd;
}

.hljs-meta {
  color: #61afef;
}

.hljs-tag {
  color: #e06c75;
}

.hljs-name {
  color: #e06c75;
}

.hljs-attribute {
  color: #d19a66;
}

.hljs-symbol,
.hljs-bullet {
  color: #56b6c2;
}

.hljs-addition {
  color: #98c379;
}

.hljs-deletion {
  color: #e06c75;
}

.hljs-link {
  color: #61afef;
  text-decoration: underline;
}

.hljs-emphasis {
  font-style: italic;
}

.hljs-strong {
  font-weight: 700;
}

.hljs-selector-class {
  color: #d19a66;
}

.hljs-selector-id {
  color: #61afef;
}

.hljs-property {
  color: #e06c75;
}

.hljs-built_in,
.hljs-type {
  color: #e5c07b;
}

.hljs-regex {
  color: #98c379;
}

.hljs-punctuation {
  color: #abb2bf;
}

/* ============================================================
   DARK MODE — explicit overrides for all text elements
   ============================================================ */

/* Quiz — force light text on dark backgrounds */
[data-theme="dark"] .quiz-q,
[data-theme="dark"] .quiz-q * {
  color: var(--text) !important;
}

[data-theme="dark"] .quiz-q .q-num {
  color: var(--primary) !important;
}

[data-theme="dark"] .q-opt {
  background: var(--surface) !important;
  border-color: var(--border-strong) !important;
}

[data-theme="dark"] .q-opt:hover {
  background: var(--primary-soft) !important;
}

[data-theme="dark"] .q-opt .opt-key {
  color: var(--text-3) !important;
}

[data-theme="dark"] .q-opt.selected {
  background: var(--primary-soft) !important;
  color: var(--text) !important;
}

[data-theme="dark"] .q-opt.correct {
  background: var(--success-soft) !important;
  border-color: var(--success) !important;
  color: var(--text) !important;
}

[data-theme="dark"] .q-opt.wrong {
  background: var(--danger-soft) !important;
  border-color: var(--danger) !important;
  color: var(--text) !important;
}

[data-theme="dark"] .q-feedback {
  background: transparent !important;
}

[data-theme="dark"] .q-feedback.good {
  background: var(--success-soft) !important;
  color: var(--success) !important;
  border-color: var(--success) !important;
}

[data-theme="dark"] .q-feedback.bad {
  background: var(--danger-soft) !important;
  color: var(--danger) !important;
  border-color: var(--danger) !important;
}

[data-theme="dark"] .quiz-score {
  background: var(--primary-soft) !important;
}

[data-theme="dark"] .quiz-score .qs-text {
  color: var(--primary) !important;
}

/* Headings and sections */
[data-theme="dark"] .lesson-header h1 {
  color: var(--text) !important;
}

[data-theme="dark"] .lesson-section h2 {
  color: var(--text) !important;
  border-color: var(--border) !important;
}

[data-theme="dark"] .lesson-section h3 {
  color: var(--text) !important;
}

/* Cards, chips, definitions */
[data-theme="dark"] .card {
  background: var(--surface) !important;
  border-color: var(--border) !important;
  color: var(--text) !important;
}

[data-theme="dark"] .chip {
  color: var(--text-2) !important;
  background: var(--surface-2) !important;
  border-color: var(--border) !important;
}

[data-theme="dark"] .def-block p {
  color: var(--text) !important;
}

/* Practice tasks and solutions */
[data-theme="dark"] .task-item label {
  color: var(--text) !important;
}

[data-theme="dark"] .task-item.done label {
  color: var(--text-3) !important;
}

[data-theme="dark"] details.solution summary {
  color: var(--primary) !important;
}

[data-theme="dark"] details.solution .solution-body {
  color: var(--text) !important;
}

/* Tables */
[data-theme="dark"] .md-body table th {
  color: var(--text) !important;
  background: var(--surface-3) !important;
}

[data-theme="dark"] .md-body table td {
  color: var(--text) !important;
}