@font-face {
  font-family:Manrope;
  src:url('/assets/fonts/Manrope.ttf') format('truetype');
  font-style:normal;
  font-weight:200 800;
  font-display:swap
}

@font-face {
  font-family:Vazirmatn;
  src:url('/assets/fonts/Vazirmatn.ttf') format('truetype');
  font-style:normal;
  font-weight:100 900;
  font-display:swap
}

:root {
  --navy:#102f50;
  --blue:#086b9c;
  --orange:#c34b17;
  --ink:#213748;
  --muted:#597080;
  --line:#dce4e8;
  --pale:#f1f7fa;
  --warm:#faf6ef;
  --teal:#176f64;
  --font:Manrope,"Segoe UI",sans-serif;
  --radius:10px
}

* {
  box-sizing:border-box
}

html {
  scroll-padding-top:110px;
  scroll-behavior:smooth
}

body {
  margin:0;
  background:#fff;
  color:var(--ink);
  font-family:var(--font);
  font-size:16px;
  line-height:1.7;
  -webkit-font-smoothing:antialiased
}

html[lang=fa] {
  --font:Vazirmatn,Tahoma,sans-serif
}

html[lang=fa] body {
  line-height:1.95
}

a {
  color:inherit;
  text-decoration:none
}

button,input {
  font:inherit
}

button,a,input,summary {
  -webkit-tap-highlight-color:transparent
}

button {
  cursor:pointer
}

button:disabled {
  cursor:default
}

button {
  color:inherit
}

button,summary,a,input {
  touch-action:manipulation
}

button:focus-visible,a:focus-visible,summary:focus-visible,input:focus-visible,[tabindex]:focus-visible {
  outline:3px solid #0b78b1;
  outline-offset:5px
}

a:hover {
  color:var(--blue)
}

p,h1,h2,h3,figure,blockquote {
  margin:0
}

h1,h2,h3 {
  color:var(--navy);
  line-height:1.2
}

h1 {
  font-size:clamp(40px,5.3vw,68px);
  font-weight:750;
  letter-spacing:-2.8px
}

h2 {
  font-size:clamp(27px,2.6vw,36px);
  font-weight:750;
  letter-spacing:-1.2px
}

h3 {
  font-size:21px;
  font-weight:750;
  letter-spacing:-.5px
}

p+p {
  margin-top:18px
}

ul,ol {
  padding-inline-start:22px
}

svg {
  display:block
}

.icon {
  width:21px;
  height:21px;
  flex:none;
  display:inline-block;
  vertical-align:middle
}

.wrap {
  width:calc(100% - 112px);
  max-width:1280px;
  margin-inline:auto
}

.section-space {
  padding-block:78px
}

.eyebrow {
  font-size:11px;
  letter-spacing:1.65px;
  line-height:1.7;
  font-weight:800;
  color:var(--muted);
  text-transform:uppercase;
  margin-bottom:16px
}

.small-eyebrow {
  font-size:10px;
  letter-spacing:.75px;
  text-transform:uppercase;
  font-weight:750;
  color:var(--muted)
}

.lead {
  font-size:17px;
  line-height:1.9;
  color:#4f6575;
  max-width:610px
}

.section-intro {
  max-width:755px;
  margin-top:18px;
  margin-bottom:32px;
  color:var(--muted);
  line-height:1.85
}

.sr-only {
  position:absolute;
  width:1px;
  height:1px;
  padding:0;
  margin:-1px;
  overflow:hidden;
  clip:rect(0,0,0,0);
  white-space:nowrap;
  border:0
}

.skip-link {
  position:fixed;
  top:-100px;
  inset-inline-start:20px;
  z-index:100;
  background:var(--navy);
  color:white;
  padding:12px 22px;
  border-radius:5px
}

.skip-link:focus {
  top:12px
}

.loading {
  max-width:800px;
  margin:100px auto;
  padding:20px
}

.loading h1 {
  font-size:32px
}

.preview-bar {
  background:var(--navy);
  color:#d3e2ed;
  font-size:10px;
  letter-spacing:.25px;
  line-height:1.5
}

.preview-bar>.wrap {
  display:flex;
  justify-content:space-between;
  gap:15px;
  min-height:30px;
  align-items:center
}

.preview-bar span:first-child {
  display:flex;
  align-items:center;
  gap:9px
}

.status-dot {
  height:5px;
  width:5px;
  border-radius:50%;
  background:#f6b773;
  display:inline-block
}

.site-header {
  position:sticky;
  top:0;
  z-index:20;
  background:#fffefdf5;
  backdrop-filter:blur(16px);
  border-bottom:1px solid var(--line)
}

.header-inner {
  min-height:90px;
  display:flex;
  align-items:center;
  gap:45px
}

.brand {
  display:flex;
  align-items:center;
  gap:12px;
  color:var(--navy);
  font-weight:800;
  font-size:19px;
  letter-spacing:-.65px;
  margin-inline-end:auto;
  white-space:nowrap
}

.brand small {
  display:block;
  color:var(--muted);
  font-size:8px;
  letter-spacing:2px;
  font-weight:650;
  line-height:1.8;
  margin-top:3px
}

.primary-nav {
  align-self:stretch;
  display:flex;
  align-items:center;
  gap:30px;
  font-size:12px;
  font-weight:700;
  white-space:nowrap
}

.primary-nav a {
  display:flex;
  align-items:center;
  height:100%;
  border-bottom:2px solid transparent;
  padding-top:2px
}

.primary-nav a.active {
  color:var(--blue);
  border-color:var(--blue)
}

.header-tools {
  display:flex;
  align-items:center;
  gap:18px
}

.icon-button {
  border:0;
  background:transparent;
  min-height:44px;
  min-width:44px;
  display:inline-flex;
  align-items:center;
  justify-content:center;
  border-radius:6px;
  padding:9px
}

.icon-button:hover {
  background:var(--pale);
  color:var(--blue)
}

.tool-divider {
  width:1px;
  height:23px;
  background:var(--line)
}

.language-link {
  display:flex;
  align-items:center;
  gap:8px;
  font-size:13px;
  font-weight:650;
  min-height:44px
}

.language-link[lang=fa] {
  font-family:Vazirmatn,Tahoma,sans-serif
}

.mobile-menu {
  display:none
}

.button {
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:17px;
  border-radius:5px;
  min-height:50px;
  padding:13px 22px;
  font-weight:750;
  font-size:12px;
  line-height:1.7;
  text-decoration:none;
  border:1px solid transparent;
  transition:background .15s,box-shadow .15s
}

.button:hover {
  box-shadow:0 4px 16px #102f5015
}

.button-primary {
  background:var(--orange);
  color:white
}

.button-primary:hover {
  background:#a83d10;
  color:white
}

.button-dark {
  background:var(--navy);
  color:white
}

.button-dark:hover {
  background:#204b70;
  color:white
}

.button-small {
  font-size:11px;
  background:white;
  border:1px solid var(--line);
  min-height:42px;
  padding:8px 13px;
  gap:8px
}

.button-small:hover {
  background:var(--pale)
}

.text-link {
  display:inline-flex;
  align-items:center;
  gap:13px;
  font-size:12px;
  font-weight:750;
  text-decoration:underline;
  text-decoration-color:#bccbd5;
  text-underline-offset:6px
}

.text-link:hover {
  text-decoration-color:var(--blue)
}

.text-button {
  border:0;
  background:transparent;
  text-decoration:underline;
  text-underline-offset:4px;
  font-size:11px;
  min-height:44px;
  padding:4px 7px
}

.text-button:hover {
  color:var(--blue)
}

.course-hero {
  background:linear-gradient(105deg,#f4f8fa,#f7f9f9 70%,#fbf6ed);
  border-bottom:1px solid var(--line)
}

.hero-grid {
  display:grid;
  grid-template-columns:1.15fr 1fr;
  gap:40px;
  align-items:center;
  min-height:590px;
  padding-block:50px
}

.hero-copy {
  padding-block:16px
}

.hero-copy .eyebrow {
  color:var(--blue);
  font-size:10px;
  letter-spacing:1.5px;
  margin-bottom:22px
}

.hero-copy h1 {
  margin-bottom:26px;
  max-width:700px
}

.hero-copy h1>span {
  color:var(--blue)
}

.hero-copy .lead {
  max-width:525px;
  font-size:15px;
  line-height:1.95
}

.hero-actions {
  display:flex;
  flex-wrap:wrap;
  gap:24px;
  align-items:center;
  margin-top:30px
}

.hero-meta {
  display:flex;
  flex-wrap:wrap;
  column-gap:20px;
  row-gap:10px;
  font-size:10px;
  color:var(--muted);
  margin-top:34px
}

.hero-meta>span {
  display:flex;
  align-items:center;
  gap:7px
}

.hero-meta .icon {
  height:15px;
  width:15px
}

.hero-figure {
  min-width:0;
  position:relative;
  align-self:center;
  margin-top:-15px
}

.field-art {
  position:relative;
  min-width:0
}

.field-art svg {
  width:100%;
  height:auto;
  overflow:hidden
}

.art-label {
  position:absolute;
  font-size:7px;
  letter-spacing:1.3px;
  font-weight:750;
  color:#567384;
  line-height:1.8
}

.art-label-one {
  inset-inline-start:3%;
  top:34%;
  max-width:70px
}

.art-label-two {
  inset-inline-end:5%;
  top:11%;
  max-width:90px
}

.hero-figure figcaption {
  margin-top:10px;
  padding-inline-start:50px
}

.hero-figure figcaption>span {
  display:block;
  font-size:8px;
  letter-spacing:1.4px;
  color:var(--orange);
  font-weight:800
}

.hero-figure figcaption strong {
  font-size:15px;
  display:block;
  margin-top:4px;
  color:var(--navy)
}

.hero-figure figcaption small {
  font-size:9px;
  line-height:1.7;
  display:block;
  max-width:300px;
  color:var(--muted);
  margin-top:4px
}

.section-heading {
  display:flex;
  justify-content:space-between;
  gap:24px;
  align-items:flex-end
}

.section-heading .eyebrow {
  margin-bottom:10px
}

.outline-tag {
  font-size:10px;
  white-space:nowrap;
  color:var(--muted);
  padding:5px 11px;
  background:var(--warm);
  border:1px solid #e9dfd0;
  border-radius:4px;
  margin-bottom:3px
}

.module-grid {
  display:grid;
  grid-template-columns:repeat(3,minmax(0,1fr));
  gap:24px
}

.module-card {
  border:1px solid var(--line);
  border-radius:var(--radius);
  overflow:hidden;
  display:flex;
  flex-direction:column;
  background:#fff
}

.module-card-top {
  display:flex;
  justify-content:space-between;
  align-items:center;
  gap:10px;
  padding:20px 22px 0
}

.module-no {
  font-size:21px;
  letter-spacing:-.5px;
  color:var(--navy);
  font-weight:650
}

.pill {
  display:inline-flex;
  align-items:center;
  min-height:22px;
  padding:2px 8px;
  font-size:8px;
  line-height:1.5;
  font-weight:700;
  letter-spacing:.1px;
  border-radius:3px;
  background:#f1f3f4;
  color:#667783
}

.pill-ready {
  background:#e9f3ed;
  color:#236246
}

.module-art {
  width:100%;
  height:140px;
  margin-block:5px 3px;
  color:#5f8c9f;
  background:linear-gradient(0deg,#edf5f8,white);
  stroke-width:1.3
}

.module-1 .module-art {
  color:#bc8a59;
  background:linear-gradient(0deg,#faf4eb,white)
}

.module-2 .module-art {
  color:#74928a;
  background:linear-gradient(0deg,#f0f5ef,white)
}

.module-card-copy {
  padding:23px 24px 22px;
  display:flex;
  flex-direction:column;
  flex:1
}

.module-card h3 {
  font-size:20px;
  line-height:1.35;
  letter-spacing:-.5px
}

.module-card p {
  margin-top:13px;
  font-size:12px;
  line-height:1.9;
  color:var(--muted)
}

.module-keywords {
  font-size:9px;
  color:var(--muted);
  margin-top:auto;
  padding-block:20px 18px
}

.card-link {
  display:flex;
  justify-content:space-between;
  align-items:center;
  border-top:1px solid var(--line);
  padding-top:16px;
  font-size:11px;
  font-weight:800;
  color:var(--blue)
}

.outline-details {
  border-top:1px solid var(--line);
  padding-top:15px
}

.outline-details summary {
  font-size:11px;
  font-weight:700;
  display:flex;
  justify-content:space-between;
  align-items:center;
  min-height:26px
}

.outline-details .icon {
  height:17px;
  width:17px
}

.outline-details p {
  font-size:11px;
  margin-bottom:6px
}

.approach-section {
  background:var(--navy);
  color:#d2e0ea;
  padding-block:65px
}

.approach-grid {
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:110px;
  align-items:center
}

.approach-section .eyebrow {
  color:#a8c3d8;
  font-size:9px
}

.approach-section h2 {
  color:white;
  max-width:460px;
  line-height:1.3;
  font-size:34px
}

.approach-section p:not(.eyebrow) {
  font-size:13px;
  line-height:1.95;
  margin-top:20px;
  max-width:480px;
  color:#b7ccda
}

.approach-section .text-link {
  color:#ffd1a3;
  margin-top:24px
}

.approach-steps {
  list-style:none;
  padding:0;
  margin:0;
  display:grid;
  gap:22px
}

.approach-steps>li {
  display:flex;
  gap:20px
}

.approach-steps h3 {
  color:white;
  font-size:17px
}

.approach-steps p {
  margin-top:5px!important;
  font-size:11px!important
}

.step-number {
  width:37px;
  height:37px;
  border:1px solid #62809a;
  color:#ffd1a3;
  display:flex;
  align-items:center;
  justify-content:center;
  border-radius:50%;
  font-size:10px;
  flex:none
}

.resource-grid {
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:22px;
  margin-top:28px
}

.resource-card {
  display:flex;
  align-items:center;
  gap:17px;
  padding:24px;
  border:1px solid var(--line);
  border-radius:7px;
  transition:border-color .15s,background .15s
}

.resource-card:hover {
  border-color:#a8bccb;
  background:var(--pale)
}

.resource-card>.icon:first-child {
  height:27px;
  width:27px;
  color:var(--blue)
}

.resource-card>.icon:last-child {
  height:16px;
  width:16px;
  margin-inline-start:auto;
  color:var(--muted)
}

.resource-card strong {
  font-size:12px;
  display:block;
  color:var(--navy)
}

.resource-card small {
  font-size:9px;
  color:var(--muted);
  display:block;
  margin-top:5px;
  line-height:1.8
}

.about-section {
  border-top:1px solid var(--line);
  padding-block:55px 80px;
  display:grid;
  grid-template-columns:1.3fr 1fr;
  gap:100px
}

.about-section h2 {
  font-size:27px;
  max-width:450px
}

.about-section p {
  font-size:12px;
  line-height:1.95;
  color:var(--muted);
  margin-top:18px;
  max-width:620px
}

.about-section aside {
  padding:28px 30px;
  background:var(--warm);
  border-radius:7px;
  align-self:center
}

.about-section h3 {
  font-size:17px
}

.about-section aside p {
  font-size:11px;
  margin-top:10px
}

.site-footer {
  background:#f5f7f8;
  border-top:1px solid var(--line);
  padding-block:36px 18px
}

.footer-top {
  display:flex;
  justify-content:space-between;
  align-items:center;
  gap:40px;
  padding-bottom:30px
}

.footer-brand {
  color:var(--navy);
  font-size:17px;
  font-weight:800;
  letter-spacing:-.5px
}

.footer-brand>span {
  display:block;
  font-size:10px;
  color:var(--muted);
  font-weight:400;
  letter-spacing:0;
  margin-top:8px
}

.footer-top>a:last-child {
  font-size:11px;
  display:flex;
  align-items:center;
  gap:15px;
  font-weight:700
}

.footer-bottom {
  border-top:1px solid var(--line);
  padding-top:18px;
  display:flex;
  justify-content:space-between;
  gap:20px;
  font-size:9px;
  color:var(--muted)
}

.breadcrumb {
  display:flex;
  flex-wrap:wrap;
  gap:12px;
  padding-block:22px;
  font-size:10px;
  line-height:1.8;
  color:var(--muted)
}

.breadcrumb>a {
  color:var(--blue)
}

.module-hero {
  background:var(--pale);
  border-block:1px solid var(--line)
}

.module-hero-grid {
  display:grid;
  grid-template-columns:1.4fr 1fr;
  gap:70px;
  align-items:center;
  padding-block:55px
}

.module-hero h1 {
  font-size:51px;
  letter-spacing:-2px;
  max-width:700px
}

.module-question {
  color:var(--blue);
  font-size:20px;
  line-height:1.5;
  margin-top:24px;
  font-weight:600;
  max-width:570px
}

.module-hero .lead {
  font-size:13px;
  margin-top:16px;
  line-height:1.9
}

.module-hero .button {
  margin-top:28px
}

.small-meta {
  font-size:10px;
  color:var(--muted);
  display:flex;
  align-items:center;
  gap:8px;
  margin-top:18px
}

.small-meta .icon {
  width:15px;
  height:15px
}

.module-body {
  display:grid;
  grid-template-columns:1.65fr 1fr;
  gap:65px
}

.module-body h2 {
  font-size:29px
}

.module-body .section-intro {
  font-size:12px;
  margin-top:12px
}

.lesson-list {
  display:grid;
  gap:18px
}

.lesson-row {
  border:1px solid var(--line);
  border-radius:8px;
  display:flex;
  align-items:start;
  gap:20px;
  padding:25px 22px;
  background:#fafbfc
}

.lesson-row-ready {
  background:white;
  border-color:#a8c3d6;
  box-shadow:0 3px 12px #102f5006
}

.lesson-index {
  font-size:16px;
  font-weight:700;
  color:var(--muted);
  padding-top:1px;
  min-width:25px
}

.lesson-row-ready .lesson-index {
  color:var(--blue)
}

.lesson-row h3 {
  font-size:20px;
  line-height:1.4;
  margin-top:7px
}

.lesson-row p {
  font-size:11px;
  color:var(--muted);
  line-height:1.9;
  margin-top:10px
}

.lesson-row .text-link {
  margin-top:18px;
  font-size:10px
}

.lesson-duration {
  font-size:9px;
  color:var(--muted);
  white-space:nowrap;
  padding-top:3px;
  margin-inline-start:auto
}

.lesson-row .small-eyebrow {
  font-size:8px
}

.objectives-panel {
  border:1px solid #e4e7df;
  border-radius:8px;
  background:#f8f9f3;
  padding:30px;
  align-self:start
}

.objective-icon {
  width:42px;
  height:42px;
  background:#edf0df;
  color:#637649;
  display:flex;
  align-items:center;
  justify-content:center;
  border-radius:50%;
  margin-bottom:18px
}

.objectives-panel h2 {
  font-size:23px;
  line-height:1.5
}

.objectives-panel ul {
  list-style:none;
  padding:0;
  margin-top:25px;
  display:grid;
  gap:18px
}

.objectives-panel li {
  display:flex;
  align-items:start;
  gap:12px;
  font-size:12px;
  line-height:1.9;
  color:#506348
}

.objectives-panel li>.icon {
  width:17px;
  height:17px;
  margin-top:4px
}

.prerequisite-box {
  border-top:1px solid #dde2d3;
  margin-top:28px;
  padding-top:24px
}

.prerequisite-box h3 {
  font-size:13px
}

.prerequisite-box p {
  font-size:10px;
  color:var(--muted);
  line-height:1.95;
  margin-top:10px
}

.module-resources {
  border-top:1px solid var(--line);
  padding-top:45px
}

.lesson-layout {
  display:grid;
  grid-template-columns:220px minmax(0,1fr);
  gap:65px;
  align-items:start
}

.lesson-sidebar {
  position:sticky;
  top:120px;
  padding-top:10px
}

.back-link {
  display:flex;
  align-items:center;
  gap:9px;
  font-size:11px;
  font-weight:700;
  color:var(--blue);
  margin-bottom:37px
}

.back-link .icon {
  height:16px;
  width:16px
}

.lesson-sidebar>.eyebrow {
  font-size:9px;
  margin-bottom:15px
}

.lesson-sidebar ol {
  list-style:none;
  padding:0;
  margin:0;
  border-inline-start:1px solid var(--line)
}

.lesson-sidebar li>a {
  display:flex;
  gap:12px;
  font-size:10px;
  color:var(--muted);
  padding:12px 10px 12px 15px;
  line-height:1.6;
  border-inline-start:2px solid transparent;
  margin-inline-start:-1px
}

.lesson-sidebar li>a>span {
  font-size:9px;
  color:#7892a1;
  min-width:18px
}

.lesson-sidebar li>a:hover,.lesson-sidebar li>a.current-section {
  background:#f0f6fa;
  color:var(--blue);
  border-color:var(--blue)
}

.sidebar-module {
  margin-top:30px;
  padding:20px;
  background:var(--warm);
  border-radius:6px;
  display:flex;
  align-items:start;
  flex-direction:column;
  gap:10px;
  font-size:9px;
  color:var(--muted)
}

.sidebar-module strong {
  font-size:11px;
  color:var(--navy)
}

.lesson-header {
  padding-top:14px;
  padding-bottom:32px;
  border-bottom:1px solid var(--line)
}

.lesson-header .eyebrow {
  font-size:9px;
  margin-bottom:18px;
  letter-spacing:1px
}

.eyebrow-divider {
  padding-inline:8px;
  color:#a1adb7
}

.lesson-header h1 {
  font-size:52px;
  letter-spacing:-2px
}

.lesson-lead {
  font-size:17px;
  line-height:1.9;
  margin-top:20px;
  color:var(--muted);
  max-width:800px
}

.lesson-byline {
  display:flex;
  align-items:center;
  gap:8px;
  margin-top:22px;
  font-size:9px;
  color:var(--muted)
}

.lesson-byline .icon {
  width:14px;
  height:14px
}

.sample-notice {
  display:inline-block;
  margin-top:18px;
  font-size:9px;
  background:#faf5ea;
  border:1px solid #ece2c9;
  color:#7c5d27;
  padding:4px 9px;
  border-radius:3px
}

.lesson-section {
  padding-block:45px;
  border-bottom:1px solid var(--line);
  scroll-margin-top:15px
}

.lesson-section-head {
  display:flex;
  gap:16px;
  align-items:start;
  margin-bottom:20px
}

.section-index {
  font-size:12px;
  color:#7e96a5;
  border:1px solid var(--line);
  border-radius:50%;
  width:33px;
  height:33px;
  display:flex;
  align-items:center;
  justify-content:center;
  flex:none;
  margin-top:2px
}

.lesson-section-head .eyebrow {
  font-size:8px;
  letter-spacing:1.5px;
  margin-bottom:7px
}

.lesson-section h2 {
  font-size:28px;
  line-height:1.4;
  letter-spacing:-.9px
}

.lesson-section>p {
  font-size:14px;
  line-height:2;
  color:#4d6372
}

.thinking-prompt {
  display:flex;
  align-items:start;
  gap:15px;
  background:var(--warm);
  border-inline-start:3px solid #d8ac73;
  padding:22px 25px;
  margin-top:25px;
  border-radius:0 5px 5px 0
}

.thinking-prompt>.icon {
  color:#a36d2e;
  margin-top:3px
}

.thinking-prompt p {
  font-size:13px;
  line-height:1.9;
  color:#6c5941
}

.concept-grid {
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:18px;
  margin-top:25px
}

.concept-card {
  background:#f6f9fb;
  border:1px solid #e5edf2;
  border-radius:8px;
  padding:23px
}

.concept-card:last-child {
  background:#fcf7f1;
  border-color:#f1e5d7
}

.concept-marker {
  display:flex;
  align-items:center;
  justify-content:center;
  width:29px;
  height:29px;
  border-radius:4px;
  font-size:9px;
  color:#fff;
  margin-bottom:15px
}

.conduction-bg {
  background:#1674b7
}

.displacement-bg {
  background:#c34b17
}

.concept-card h3 {
  font-size:16px;
  line-height:1.5
}

.equation {
  font-family:"Cambria Math",Cambria,Georgia,serif;
  font-size:23px;
  line-height:1.8;
  color:var(--navy);
  white-space:normal;
  unicode-bidi:isolate
}

.concept-card .equation {
  margin-top:15px;
  font-size:23px
}

.concept-card:last-child .equation {
  font-size:20px
}

.concept-card p {
  font-size:11px;
  line-height:1.95;
  color:var(--muted);
  margin-top:12px
}

.lesson-section>p.equation-caption {
  font-size:10px;
  line-height:1.9;
  margin-top:15px
}

.quiz {
  border:1px solid #dce6ed;
  background:#fbfcfd;
  border-radius:8px;
  padding:25px
}

.quiz fieldset {
  border:0;
  padding:0;
  margin:0;
  min-width:0
}

.quiz legend {
  font-size:14px;
  line-height:1.95;
  font-weight:600;
  color:var(--navy);
  padding:0;
  margin-bottom:20px;
  float:none;
  width:100%
}

.quiz-options {
  display:grid;
  gap:10px;
  clear:both
}

.quiz-option {
  display:flex;
  align-items:center;
  gap:13px;
  cursor:pointer;
  padding:13px 16px;
  border:1px solid var(--line);
  border-radius:5px;
  min-height:53px;
  background:white;
  font-size:12px;
  line-height:1.7
}

.quiz-option:hover {
  border-color:#95b5ca
}

.quiz-option:has(input:checked) {
  background:#edf6fb;
  border-color:#578dad
}

.quiz-option:focus-within {
  outline:2px solid var(--blue);
  outline-offset:2px
}

.quiz-option input {
  margin:0;
  width:16px;
  height:16px;
  accent-color:var(--blue);
  flex:none
}

.choice-letter {
  font-size:9px;
  font-weight:700;
  color:#8195a1;
  border:1px solid var(--line);
  border-radius:3px;
  width:20px;
  height:22px;
  display:flex;
  align-items:center;
  justify-content:center;
  flex:none
}

.quiz-actions {
  display:flex;
  gap:20px;
  align-items:start;
  flex-wrap:wrap;
  margin-top:22px
}

.quiz-actions .button {
  min-height:44px;
  font-size:10px;
  padding:10px 16px
}

.feedback {
  margin-top:22px;
  padding:20px;
  border-radius:5px;
  line-height:1.95;
  font-size:12px
}

.feedback[hidden] {
  display:none
}

.feedback strong {
  display:flex;
  align-items:center;
  gap:9px;
  font-size:12px
}

.feedback strong .icon {
  height:17px;
  width:17px
}

.feedback p {
  margin-top:8px
}

.feedback>a {
  display:inline-flex;
  gap:10px;
  align-items:center;
  font-size:10px;
  font-weight:700;
  text-decoration:underline;
  text-underline-offset:4px;
  margin-top:10px
}

.feedback-correct {
  background:#eaf4ee;
  color:#225e40;
  border:1px solid #cbe2d4
}

.feedback-rethink {
  background:#fff5e6;
  color:#805518;
  border:1px solid #ead7b6
}

.feedback-neutral {
  background:#eef3f7;
  color:var(--navy)
}

.hint {
  font-size:11px;
  line-height:1.9;
  flex:1;
  min-width:130px;
  margin-top:8px
}

.hint>summary {
  text-decoration:underline;
  text-underline-offset:4px
}

.hint p {
  margin-top:10px
}

.activity {
  border:1px solid #bdcfdc;
  border-radius:9px;
  overflow:hidden;
  margin-top:25px
}

.activity-heading {
  background:var(--navy);
  color:#e4eff5;
  padding:14px 22px;
  display:flex;
  justify-content:space-between;
  align-items:center;
  gap:15px;
  font-size:10px;
  letter-spacing:1.2px
}

.activity-heading>span:first-child {
  display:flex;
  align-items:center;
  gap:10px
}

.activity-heading>span:last-child {
  font-family:Georgia,serif;
  color:#eabe8b;
  font-size:15px;
  letter-spacing:0
}

.activity-heading .icon {
  width:16px;
  height:16px
}

.activity-body {
  display:grid;
  grid-template-columns:1.7fr 1fr
}

.plot-panel {
  background:#f3f8fb;
  padding:23px 18px 17px;
  min-width:0
}

.plot-panel h3 {
  font-size:13px;
  letter-spacing:0
}

.plot-legend {
  display:flex;
  gap:12px;
  flex-wrap:wrap;
  margin-top:14px;
  font-size:8px;
  line-height:1.7
}

.plot-legend>span {
  display:flex;
  align-items:center;
  gap:5px
}

.plot-legend>span:before {
  content:"";
  display:inline-block;
  width:13px;
  height:2px;
  background:currentColor
}

.legend-c {
  color:#12679d
}

.legend-d {
  color:#b33f10
}

.legend-total {
  color:var(--navy)
}

.plot-legend>.legend-total:before {
  background:repeating-linear-gradient(90deg,currentColor 0 4px,transparent 4px 6px)
}

#current-plot {
  display:block;
  width:100%;
  height:auto;
  overflow:visible;
  margin-top:24px
}

.plot-grid {
  stroke:#d7e3eb;
  stroke-width:1;
  fill:none
}

.zero-axis {
  stroke:#9eb4c3;
  stroke-width:1.1
}

.plot-labels {
  font-size:11px;
  fill:#48677c;
  font-family:Manrope,sans-serif;
  direction:ltr;
  unicode-bidi:isolate
}

.curve {
  fill:none;
  stroke-width:2.6;
  stroke-linejoin:round;
  stroke-linecap:round
}

.curve-c {
  stroke:#1674b7
}

.curve-d {
  stroke:#c34b17
}

.curve-total {
  stroke:#102f50;
  stroke-dasharray:7 4;
  stroke-width:2.1
}

.time-marker {
  stroke:#7f97aa;
  stroke-width:1;
  stroke-dasharray:3 5
}

.dot-c {
  fill:#1674b7;
  stroke:white;
  stroke-width:1.2
}

.dot-d {
  fill:#c34b17;
  stroke:white;
  stroke-width:1.2
}

.dot-total {
  fill:#102f50;
  stroke:white;
  stroke-width:1.2
}

.axis-caption {
  text-align:center;
  font-size:8px;
  color:var(--muted);
  margin-top:0
}

.playback-controls {
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:3px;
  margin-top:17px
}

.playback-controls .icon-button {
  width:35px;
  min-width:35px
}

.playback-controls>.text-button {
  font-size:9px;
  line-height:1.6
}

.motion-note {
  font-size:8px;
  line-height:1.9;
  color:var(--muted);
  margin-top:10px
}

.control-panel {
  padding:25px 20px;
  min-width:0;
  background:white;
  border-inline-start:1px solid var(--line)
}

.range-heading {
  display:flex;
  justify-content:space-between;
  align-items:baseline;
  gap:6px;
  font-size:10px;
  font-weight:700;
  line-height:1.7
}

.range-heading output {
  font-size:10px;
  color:var(--blue);
  white-space:nowrap
}

.control-panel input[type=range] {
  width:100%;
  display:block;
  margin:13px 0 5px;
  accent-color:var(--blue);
  height:28px;
  direction:ltr;
  cursor:pointer
}

.frequency-presets {
  display:flex;
  align-items:center;
  justify-content:space-between;
  direction:ltr;
  gap:4px
}

.preset {
  background:white;
  border:1px solid var(--line);
  border-radius:3px;
  font-size:8px;
  line-height:1.6;
  min-width:31px;
  min-height:28px;
  padding:3px 5px
}

.preset:hover,.preset.selected {
  background:var(--navy);
  border-color:var(--navy);
  color:white
}

.frequency-presets>span {
  font-size:7px;
  color:var(--muted)
}

.conductivity-heading {
  margin-top:27px
}

.fixed-settings {
  font-size:8px;
  color:var(--muted);
  line-height:1.8;
  margin-top:15px;
  padding-top:16px;
  border-top:1px solid var(--line)
}

.amplitude-box {
  margin-top:20px
}

.amplitude-box>.small-eyebrow {
  font-size:8px;
  letter-spacing:.5px;
  margin-bottom:13px
}

.amplitude-box>div {
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  column-gap:7px;
  row-gap:3px;
  font-size:9px;
  line-height:1.8;
  margin-top:6px
}

.amplitude-box strong {
  font-size:10px;
  font-weight:700
}

.conduction-text {
  color:#12679d
}

.displacement-text {
  color:#b33f10
}

.ratio-box {
  display:flex;
  justify-content:space-between;
  align-items:center;
  flex-wrap:wrap;
  gap:3px;
  font-size:9px;
  border-top:1px solid var(--line);
  margin-top:16px;
  padding-top:14px;
  line-height:1.7
}

.ratio-box>strong {
  font-size:23px;
  line-height:1.2;
  color:var(--navy);
  letter-spacing:-.7px
}

.dominance {
  font-size:8px;
  line-height:1.8;
  color:var(--muted);
  margin-top:9px
}

.activity-results {
  display:flex;
  flex-wrap:wrap;
  justify-content:space-between;
  column-gap:20px;
  row-gap:7px;
  padding:13px 20px;
  background:#eef4f8;
  border-top:1px solid var(--line);
  font-size:9px;
  color:var(--muted)
}

.activity-results strong {
  color:var(--navy);
  margin-inline-start:5px;
  display:inline-block
}

.guided-exploration {
  padding:24px 0 6px
}

.guided-exploration h3 {
  font-size:15px;
  letter-spacing:-.25px
}

.guided-exploration ol {
  font-size:12px;
  line-height:1.95;
  color:var(--muted);
  padding-inline-start:19px
}

.guided-exploration li {
  padding-inline-start:6px;
  margin-top:8px
}

.model-limits {
  background:#faf8f3;
  border:1px solid #e9e3d6;
  padding:15px 20px;
  border-radius:5px
}

.model-limits summary,.deeper-math summary,.code-activity>summary {
  font-size:12px;
  font-weight:750;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:10px;
  line-height:1.9
}

.model-limits p,.deeper-math p,.code-activity p {
  font-size:11px;
  line-height:2;
  color:var(--muted);
  margin-top:15px
}

.model-limits .icon,.deeper-math .icon,.code-activity .icon {
  width:16px;
  height:16px
}

details>summary {
  cursor:pointer;
  list-style:none
}

details>summary::-webkit-details-marker {
  display:none
}

details[open]>summary .icon {
  transform:rotate(45deg)
}

.formula-panel {
  display:flex;
  align-items:center;
  justify-content:space-around;
  flex-wrap:wrap;
  gap:20px;
  padding:20px;
  border:1px solid var(--line);
  border-radius:6px;
  margin-top:25px;
  background:#f6f9fb
}

.formula-panel .equation {
  font-size:21px
}

.worked-example {
  border-inline-start:3px solid #85a99f;
  padding:3px 0 3px 22px;
  padding-inline-start:22px;
  padding-inline-end:0;
  margin-top:25px
}

.worked-example h3 {
  font-size:14px
}

.worked-example p {
  font-size:12px;
  color:var(--muted);
  line-height:2;
  margin-top:10px
}

.deeper-math {
  border-block:1px solid var(--line);
  padding-block:18px;
  margin-top:28px
}

.deeper-math .equation {
  font-size:21px;
  margin-top:15px
}

.recap-section {
  background:#f4f8f6;
  border:1px solid #dce7df;
  border-radius:8px;
  padding:30px;
  margin-top:35px
}

.recap-list {
  list-style:none;
  padding:0;
  margin:26px 0;
  display:grid;
  gap:16px
}

.recap-list li {
  display:flex;
  align-items:start;
  gap:12px;
  font-size:12px;
  line-height:1.95;
  color:#3d6657
}

.recap-list .icon {
  width:18px;
  height:18px;
  margin-top:3px
}

.recall-prompt {
  border-top:1px solid #dce7df;
  padding-top:23px;
  margin-bottom:25px
}

.recall-prompt h3 {
  font-size:15px
}

.recall-prompt p {
  font-size:12px;
  line-height:2;
  color:var(--muted);
  margin-top:12px
}

.recap-section .button {
  font-size:11px
}

.recap-section .button.is-complete {
  background:var(--teal)
}

.lesson-section p.local-save-note {
  font-size:9px;
  color:var(--muted);
  line-height:1.9;
  margin-top:12px
}

.lesson-resources {
  padding-block:45px 30px
}

.lesson-resources>h2 {
  font-size:25px;
  letter-spacing:-.6px
}

.lesson-resources .resource-grid {
  gap:12px;
  margin-top:22px
}

.lesson-resources .resource-card {
  padding:18px 15px;
  gap:10px;
  align-items:start
}

.lesson-resources .resource-card strong {
  font-size:10px;
  line-height:1.8
}

.lesson-resources .resource-card small {
  font-size:8px
}

.lesson-resources .resource-card>.icon:first-child {
  height:20px;
  width:20px
}

.lesson-resources .resource-card>.icon:last-child {
  height:13px;
  width:13px;
  margin-top:4px
}

.code-activity {
  padding:18px 20px;
  background:#f5f8fa;
  border:1px solid var(--line);
  border-radius:5px;
  margin-top:20px;
  scroll-margin-top:120px
}

.code-toolbar {
  display:flex;
  justify-content:space-between;
  align-items:center;
  margin-top:15px;
  background:var(--navy);
  color:#d6e4ed;
  padding-inline:16px;
  font-size:10px;
  border-radius:5px 5px 0 0
}

.code-toolbar .text-button {
  color:white;
  font-size:10px
}

pre {
  margin:0;
  white-space:pre;
  overflow-x:auto;
  padding:20px;
  background:#152c40;
  color:#deebf3;
  font-size:11px;
  line-height:1.95;
  border-radius:0 0 5px 5px;
  text-align:left;
  max-width:100%
}

.code-activity>#copy-status:empty {
  display:none
}

.lesson-end {
  border-top:1px solid var(--line);
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:20px;
  padding-block:28px 60px
}

.lesson-end>a:first-child {
  display:flex;
  align-items:center;
  gap:8px;
  font-size:10px;
  color:var(--muted)
}

.lesson-end .button {
  font-size:10px;
  min-height:44px;
  padding:10px 18px
}

.lesson-end .icon {
  height:17px;
  width:17px
}

.search-dialog {
  width:min(600px,calc(100vw - 30px));
  border:1px solid var(--line);
  border-radius:12px;
  padding:25px;
  margin:15vh auto auto;
  color:var(--ink);
  background:#fff;
  box-shadow:0 15px 90px #102f5033;
  max-height:75vh;
  overflow-y:auto
}

.search-dialog::backdrop {
  background:#102f5070;
  backdrop-filter:blur(4px)
}

.search-dialog-heading {
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:20px
}

.search-dialog h2 {
  font-size:20px;
  letter-spacing:-.5px
}

.search-input-wrap {
  position:relative;
  margin-top:20px
}

.search-input-wrap>.icon {
  position:absolute;
  inset-inline-start:15px;
  top:15px;
  color:var(--muted)
}

.search-dialog input {
  width:100%;
  border:1px solid #afc2cf;
  background:#f6f9fb;
  border-radius:5px;
  padding:14px 15px;
  padding-inline-start:48px;
  font-size:13px;
  color:var(--navy);
  min-height:50px
}

.search-dialog ul {
  list-style:none;
  padding:0;
  margin:18px 0 0;
  display:grid;
  gap:5px
}

.search-dialog li>a {
  display:flex;
  align-items:center;
  gap:15px;
  min-height:45px;
  padding:10px 14px;
  border-radius:5px;
  font-size:12px
}

.search-dialog li>a:hover {
  background:var(--pale)
}

.search-dialog li .icon {
  width:16px;
  height:16px;
  color:var(--blue)
}

.search-empty {
  font-size:13px;
  color:var(--muted);
  margin-top:20px
}

html[dir=rtl] .directional {
  transform:scaleX(-1)
}

html[lang=fa] h1,html[lang=fa] h2,html[lang=fa] h3 {
  letter-spacing:0;
  line-height:1.65
}

html[lang=fa] .eyebrow,html[lang=fa] .small-eyebrow,html[lang=fa] .art-label {
  letter-spacing:0
}

html[lang=fa] .brand {
  font-size:21px;
  letter-spacing:0
}

html[lang=fa] .brand small {
  font-size:9px;
  letter-spacing:0
}

html[lang=fa] .hero-copy h1 {
  font-size:clamp(35px,3.6vw,54px);
  line-height:1.75;
  margin-bottom:18px
}

html[lang=fa] .hero-copy .lead {
  font-size:16px;
  line-height:2.1
}

html[lang=fa] .hero-meta {
  font-size:10px
}

html[lang=fa] .module-hero h1 {
  font-size:43px
}

html[lang=fa] .lesson-header h1 {
  font-size:48px
}

html[lang=fa] .lesson-section>p {
  font-size:16px;
  line-height:2.1
}

html[lang=fa] .lesson-section h2 {
  font-size:26px
}

html[lang=fa] .quiz legend {
  font-size:15px
}

html[lang=fa] .module-card p {
  font-size:13px
}

html[lang=fa] .concept-card p {
  font-size:13px
}

html[lang=fa] .concept-card h3 {
  font-size:16px
}

html[lang=fa] .hero-figure figcaption {
  margin-top:10px
}

html[lang=fa] .art-label-one {
  inset-inline-start:auto;
  left:3%
}

html[lang=fa] .art-label-two {
  inset-inline-end:auto;
  right:5%
}

html[lang=fa] .field-art text {
  direction:ltr
}

html[lang=fa] .activity-heading {
  letter-spacing:0
}

html[lang=fa] .range-heading {
  font-size:11px
}

html[lang=fa] .fixed-settings {
  font-size:9px
}

html[lang=fa] .module-keywords {
  font-size:10px
}

html[lang=fa] .language-link[lang=en] {
  font-family:Manrope,sans-serif;
  font-size:12px
}

@media(min-width:1500px) {
  .hero-grid {
    min-height:630px
  }
  .hero-copy h1 {
    font-size:71px
  }
  .hero-copy .lead {
    font-size:16px
  }
}

@media(max-width:1200px) {
  .wrap {
    width:calc(100% - 72px)
  }
  .header-inner {
    gap:26px
  }
  .primary-nav {
    gap:22px
  }
  .brand {
    font-size:17px
  }
  .brand img {
    width:38px;
    height:38px
  }
  .hero-grid {
    gap:20px;
    min-height:550px
  }
  .hero-copy h1 {
    font-size:57px
  }
  .hero-meta {
    column-gap:12px;
    font-size:9px
  }
  .hero-actions {
    gap:18px
  }
  .hero-actions .button {
    font-size:11px;
    padding-inline:18px
  }
  .hero-actions .text-link {
    font-size:11px
  }
  .module-grid {
    gap:18px
  }
  .module-card-copy {
    padding-inline:20px
  }
  .module-card h3 {
    font-size:18px
  }
  .approach-grid {
    gap:70px
  }
  .about-section {
    gap:65px
  }
  .lesson-layout {
    grid-template-columns:185px minmax(0,1fr);
    gap:38px
  }
  .lesson-sidebar li>a {
    font-size:9px;
    padding-inline-start:10px
  }
  .lesson-sidebar li>a>span {
    font-size:8px
  }
  .lesson-header h1 {
    font-size:46px
  }
  .control-panel {
    padding-inline:15px
  }
  .activity-body {
    grid-template-columns:1.55fr 1fr
  }
  .playback-controls>.text-button {
    font-size:8px
  }
  .playback-controls .button-small {
    font-size:9px;
    padding-inline:8px;
    gap:5px
  }
  .module-hero-grid {
    gap:35px
  }
  .module-hero h1 {
    font-size:43px
  }
  .module-body {
    gap:35px
  }
  .objectives-panel {
    padding:25px
  }
  html[lang=fa] .hero-copy h1 {
    font-size:43px
  }
  html[lang=fa] .brand {
    font-size:18px
  }
  html[lang=fa] .primary-nav {
    font-size:11px
  }
  html[lang=fa] .lesson-header h1 {
    font-size:43px
  }
}

@media(max-width:980px) {
  .wrap {
    width:calc(100% - 48px)
  }
  .header-inner {
    gap:20px;
    min-height:80px
  }
  .brand {
    font-size:15px
  }
  .brand small {
    font-size:7px;
    letter-spacing:1.5px
  }
  .primary-nav {
    gap:18px;
    font-size:10px
  }
  .header-tools {
    gap:8px
  }
  .language-link {
    font-size:11px
  }
  .language-link>.icon {
    height:17px;
    width:17px
  }
  .tool-divider {
    margin-inline:3px
  }
  .hero-grid {
    grid-template-columns:1.2fr 1fr;
    min-height:520px
  }
  .hero-copy h1 {
    font-size:46px;
    letter-spacing:-1.9px
  }
  .hero-copy .lead {
    font-size:13px
  }
  .hero-copy .eyebrow {
    font-size:8px;
    letter-spacing:1.2px
  }
  .hero-actions .text-link {
    font-size:10px
  }
  .hero-actions {
    gap:18px;
    margin-top:25px
  }
  .hero-actions .button {
    font-size:10px;
    gap:12px;
    min-height:45px;
    padding-inline:16px
  }
  .hero-meta {
    font-size:8px;
    column-gap:13px;
    margin-top:25px
  }
  .hero-meta .icon {
    height:13px;
    width:13px
  }
  .hero-figure figcaption {
    padding-inline-start:20px
  }
  .hero-figure figcaption strong {
    font-size:12px
  }
  .hero-figure figcaption small {
    font-size:8px
  }
  .art-label {
    font-size:6px;
    letter-spacing:0
  }
  .section-space {
    padding-block:60px
  }
  .module-card h3 {
    font-size:17px
  }
  .module-card p {
    font-size:11px
  }
  .module-keywords {
    font-size:8px
  }
  .module-art {
    height:110px
  }
  .module-card-top {
    padding-inline:17px
  }
  .module-card-copy {
    padding:18px
  }
  .module-card .pill {
    font-size:7px
  }
  .module-grid {
    gap:15px
  }
  .approach-grid {
    gap:45px
  }
  .approach-section h2 {
    font-size:28px
  }
  .approach-section p:not(.eyebrow) {
    font-size:12px
  }
  .resource-card {
    padding:20px;
    gap:12px
  }
  .resource-card strong {
    font-size:11px
  }
  .resource-card small {
    font-size:8px
  }
  .about-section {
    gap:35px
  }
  .about-section h2 {
    font-size:24px
  }
  .about-section aside {
    padding:25px
  }
  .module-hero h1 {
    font-size:39px
  }
  .module-question {
    font-size:17px
  }
  .module-hero-grid {
    gap:25px;
    padding-block:40px;
    grid-template-columns:1.5fr 1fr
  }
  .module-body {
    grid-template-columns:1.5fr 1fr;
    gap:25px
  }
  .module-body h2 {
    font-size:25px
  }
  .objectives-panel h2 {
    font-size:20px
  }
  .lesson-row {
    padding:20px 17px;
    gap:13px
  }
  .lesson-row h3 {
    font-size:18px
  }
  .lesson-duration {
    display:none
  }
  .lesson-row .small-eyebrow {
    font-size:7px
  }
  .lesson-layout {
    grid-template-columns:150px minmax(0,1fr);
    gap:28px
  }
  .lesson-sidebar li>a {
    gap:6px;
    font-size:8px;
    line-height:1.8;
    padding-inline-start:8px
  }
  .lesson-sidebar .back-link {
    font-size:9px
  }
  .lesson-sidebar .eyebrow {
    font-size:8px
  }
  .sidebar-module {
    padding:15px
  }
  .sidebar-module strong {
    font-size:10px
  }
  .lesson-header h1 {
    font-size:40px
  }
  .lesson-lead {
    font-size:15px
  }
  .lesson-header .eyebrow {
    font-size:8px
  }
  .lesson-section h2 {
    font-size:25px
  }
  .concept-card {
    padding:18px
  }
  .concept-card h3 {
    font-size:14px
  }
  .concept-card .equation {
    font-size:21px
  }
  .concept-card:last-child .equation {
    font-size:17px
  }
  .concept-card p {
    font-size:10px
  }
  .activity-body {
    grid-template-columns:1fr
  }
  .control-panel {
    display:grid;
    grid-template-columns:1fr 1fr;
    column-gap:25px;
    border-inline-start:0;
    border-top:1px solid var(--line);
    padding:23px
  }
  .control-panel>.range-heading {
    grid-column:1;
    grid-row:1
  }
  .control-panel>#frequency {
    grid-column:1;
    grid-row:2
  }
  .control-panel>.frequency-presets {
    grid-column:1;
    grid-row:3
  }
  .control-panel>.conductivity-heading {
    grid-column:2;
    grid-row:1;
    margin-top:0
  }
  .control-panel>#conductivity {
    grid-column:2;
    grid-row:2
  }
  .control-panel>.fixed-settings {
    grid-column:2;
    grid-row:3;
    border:0;
    padding-top:0;
    margin:0;
    font-size:8px
  }
  .control-panel>.amplitude-box {
    grid-column:1;
    grid-row:4 / 6
  }
  .control-panel>.ratio-box {
    grid-column:2;
    grid-row:4;
    margin-top:22px;
    padding-top:0;
    border:0
  }
  .control-panel>.dominance {
    grid-column:2;
    grid-row:5;
    margin-top:0
  }
  .plot-panel {
    padding:23px
  }
  .plot-panel h3 {
    font-size:15px
  }
  .plot-legend {
    font-size:9px
  }
  .playback-controls {
    justify-content:flex-start;
    gap:18px
  }
  .playback-controls .button-small {
    font-size:10px;
    padding-inline:13px
  }
  .playback-controls>.text-button {
    font-size:10px
  }
  .motion-note {
    font-size:9px
  }
  .lesson-resources .resource-grid {
    grid-template-columns:1fr
  }
  .lesson-resources .resource-card {
    align-items:center
  }
  html[lang=fa] .hero-copy h1 {
    font-size:36px
  }
  html[lang=fa] .hero-copy .lead {
    font-size:14px
  }
  html[lang=fa] .brand {
    font-size:16px
  }
  html[lang=fa] .brand small {
    font-size:8px
  }
  html[lang=fa] .primary-nav {
    font-size:10px
  }
  html[lang=fa] .module-hero h1 {
    font-size:34px
  }
  html[lang=fa] .lesson-header h1 {
    font-size:36px
  }
  html[lang=fa] .lesson-sidebar li>a {
    font-size:9px
  }
  html[lang=fa] .lesson-section h2 {
    font-size:23px
  }
}

@media(max-width:760px) {
  html {
    scroll-padding-top:90px
  }
  .wrap {
    width:calc(100% - 40px)
  }
  .preview-bar {
    font-size:8px
  }
  .preview-bar>.wrap {
    min-height:29px;
    gap:8px
  }
  .header-inner {
    min-height:75px;
    gap:7px;
    flex-wrap:wrap;
    position:relative
  }
  .brand {
    font-size:15px;
    gap:9px
  }
  .brand small {
    font-size:6px;
    letter-spacing:1.5px;
    margin-top:3px
  }
  .brand img {
    width:34px;
    height:34px
  }
  .header-tools {
    gap:2px;
    margin-inline-start:0
  }
  .header-tools .icon-button {
    width:36px;
    min-width:36px
  }
  .tool-divider {
    display:none
  }
  .language-link {
    font-size:10px;
    gap:5px;
    padding-inline:5px
  }
  .language-link>.icon {
    display:none
  }
  .mobile-menu {
    display:inline-flex;
    width:36px;
    min-width:36px;
    order:3;
    margin-inline-start:2px
  }
  .mobile-menu .icon {
    width:20px;
    height:20px
  }
  .primary-nav {
    display:none;
    position:absolute;
    inset-inline:0;
    top:100%;
    border:1px solid var(--line);
    background:white;
    box-shadow:0 10px 20px #102f5010;
    padding:12px 20px;
    align-items:stretch;
    gap:0;
    z-index:2;
    border-radius:0 0 6px 6px
  }
  .primary-nav.is-open {
    display:flex;
    flex-direction:column
  }
  .primary-nav a {
    min-height:44px;
    font-size:13px;
    border:0;
    padding-block:10px
  }
  .hero-grid {
    display:flex;
    flex-direction:column;
    gap:8px;
    align-items:stretch;
    padding-block:39px 30px;
    min-height:0
  }
  .hero-copy {
    padding:0
  }
  .hero-copy .eyebrow {
    font-size:8px;
    letter-spacing:1.25px;
    margin-bottom:18px
  }
  .hero-copy h1 {
    font-size:clamp(39px,7vw,60px);
    letter-spacing:-1.9px;
    margin-bottom:20px
  }
  .hero-copy .lead {
    max-width:590px;
    font-size:13px;
    line-height:1.95
  }
  .hero-actions {
    gap:22px;
    margin-top:23px
  }
  .hero-actions .button {
    font-size:10px;
    min-height:47px;
    padding:11px 16px
  }
  .hero-actions .text-link {
    font-size:10px
  }
  .hero-meta {
    font-size:8px;
    gap:13px;
    margin-top:25px
  }
  .hero-figure {
    margin-top:7px;
    width:100%;
    max-width:480px;
    margin-inline:auto;
    align-self:center
  }
  .hero-figure .field-art {
    max-width:400px;
    margin-inline:auto
  }
  .hero-figure figcaption {
    margin-top:10px;
    padding-inline-start:15px;
    position:relative;
    max-width:360px;
    margin-inline:auto;
    border-inline-start:2px solid #deb783
  }
  .hero-figure figcaption strong {
    font-size:13px
  }
  .hero-figure figcaption small {
    font-size:8px;
    max-width:none
  }
  .hero-figure figcaption>span {
    font-size:7px
  }
  .art-label {
    font-size:6px
  }
  .section-space {
    padding-block:45px
  }
  .section-heading {
    align-items:start;
    gap:13px;
    flex-direction:column
  }
  .section-heading .eyebrow {
    font-size:9px;
    margin-bottom:8px
  }
  h2 {
    font-size:28px;
    letter-spacing:-1px
  }
  .section-intro {
    font-size:12px;
    line-height:1.95;
    margin-top:17px;
    margin-bottom:25px
  }
  .outline-tag {
    font-size:8px;
    padding:3px 8px
  }
  .module-grid {
    grid-template-columns:1fr;
    gap:20px
  }
  .module-card {
    position:relative
  }
  .module-card-top {
    padding:18px 22px 0
  }
  .module-no {
    font-size:22px
  }
  .module-card .pill {
    font-size:8px
  }
  .module-art {
    height:120px;
    max-width:none
  }
  .module-card-copy {
    padding:20px 23px
  }
  .module-card h3 {
    font-size:21px
  }
  .module-card p {
    font-size:12px;
    line-height:1.85;
    margin-top:11px
  }
  .module-keywords {
    font-size:9px;
    padding-block:18px
  }
  .card-link,.outline-details summary {
    font-size:11px
  }
  .module-card .outline-details p {
    font-size:11px
  }
  .approach-section {
    padding-block:45px
  }
  .approach-grid {
    grid-template-columns:1fr;
    gap:35px
  }
  .approach-section h2 {
    font-size:30px
  }
  .approach-section p:not(.eyebrow) {
    font-size:12px
  }
  .approach-steps {
    gap:24px
  }
  .approach-steps h3 {
    font-size:17px
  }
  .approach-steps p {
    font-size:11px!important
  }
  .resource-grid {
    grid-template-columns:1fr;
    gap:15px
  }
  .resource-card {
    padding:22px 19px
  }
  .resource-card strong {
    font-size:12px
  }
  .resource-card small {
    font-size:9px
  }
  .about-section {
    grid-template-columns:1fr;
    gap:25px;
    padding-block:35px 45px
  }
  .about-section h2 {
    font-size:26px
  }
  .about-section p {
    font-size:12px
  }
  .about-section aside {
    padding:23px
  }
  .about-section aside p {
    font-size:11px
  }
  .footer-top {
    align-items:start;
    gap:25px;
    flex-direction:column;
    padding-bottom:25px
  }
  .site-footer {
    padding-top:30px
  }
  .footer-bottom {
    font-size:8px;
    flex-direction:column;
    gap:10px
  }
  .footer-brand {
    font-size:16px
  }
  .footer-brand>span {
    font-size:9px
  }
  .footer-top>a:last-child {
    font-size:10px
  }
  .breadcrumb {
    font-size:9px;
    gap:8px;
    padding-block:18px
  }
  .module-hero-grid {
    display:flex;
    flex-direction:column;
    gap:0;
    padding-block:35px
  }
  .module-hero h1 {
    font-size:39px;
    letter-spacing:-1.5px
  }
  .module-hero .eyebrow {
    font-size:9px
  }
  .module-question {
    font-size:19px;
    margin-top:20px
  }
  .module-hero .lead {
    font-size:13px
  }
  .module-hero .compact {
    width:100%;
    max-width:350px;
    margin-top:15px
  }
  .module-body {
    grid-template-columns:1fr;
    gap:35px
  }
  .objectives-panel {
    grid-row:1;
    padding:24px
  }
  .objectives-panel h2 {
    font-size:22px
  }
  .objectives-panel li {
    font-size:12px
  }
  .objective-icon {
    margin-bottom:12px
  }
  .objectives-panel ul {
    gap:13px;
    margin-top:18px
  }
  .module-body h2 {
    font-size:27px
  }
  .prerequisite-box {
    margin-top:22px;
    padding-top:20px
  }
  .lesson-row {
    padding:22px 18px;
    gap:17px
  }
  .lesson-row h3 {
    font-size:20px
  }
  .lesson-row .small-eyebrow {
    font-size:8px
  }
  .lesson-row p {
    font-size:12px
  }
  .lesson-row .text-link {
    font-size:11px
  }
  .lesson-index {
    font-size:16px
  }
  .module-resources {
    padding-top:35px
  }
  .lesson-layout {
    grid-template-columns:1fr;
    gap:0
  }
  .lesson-sidebar {
    position:static;
    padding-top:0
  }
  .lesson-sidebar>.back-link {
    display:none
  }
  .lesson-sidebar>.eyebrow,.sidebar-module {
    display:none
  }
  .lesson-sidebar nav {
    margin-bottom:25px;
    border:1px solid var(--line);
    background:#f6f9fb;
    border-radius:6px;
    padding:12px 15px
  }
  .lesson-sidebar ol {
    display:flex;
    flex-wrap:wrap;
    gap:5px 14px;
    border:0
  }
  .lesson-sidebar li>a {
    padding:3px 0;
    gap:5px;
    line-height:1.7;
    font-size:9px;
    border:0;
    margin:0
  }
  .lesson-sidebar li>a>span {
    font-size:8px;
    min-width:13px
  }
  .lesson-sidebar li>a.current-section {
    background:transparent;
    text-decoration:underline;
    text-underline-offset:4px
  }
  .lesson-header {
    padding-top:0;
    padding-bottom:27px
  }
  .lesson-header .eyebrow {
    font-size:8px;
    line-height:1.9;
    margin-bottom:13px;
    letter-spacing:.7px
  }
  .lesson-header h1 {
    font-size:41px;
    line-height:1.25;
    letter-spacing:-1.7px
  }
  .lesson-lead {
    font-size:15px;
    line-height:1.95;
    margin-top:18px
  }
  .lesson-byline {
    font-size:8px;
    line-height:1.8;
    margin-top:20px
  }
  .sample-notice {
    font-size:8px;
    margin-top:14px
  }
  .lesson-section {
    padding-block:35px
  }
  .lesson-section h2 {
    font-size:25px;
    line-height:1.45;
    letter-spacing:-.65px
  }
  .lesson-section-head {
    gap:11px;
    margin-bottom:20px
  }
  .lesson-section-head .eyebrow {
    font-size:7px;
    letter-spacing:1.1px;
    margin-bottom:6px
  }
  .section-index {
    height:28px;
    width:28px;
    font-size:10px;
    margin-top:3px
  }
  .lesson-section>p {
    font-size:14px;
    line-height:2
  }
  .thinking-prompt {
    padding:18px 17px;
    gap:12px
  }
  .thinking-prompt p {
    font-size:12px
  }
  .thinking-prompt>.icon {
    height:18px;
    width:18px
  }
  .concept-grid {
    grid-template-columns:1fr;
    gap:16px
  }
  .concept-card {
    padding:23px
  }
  .concept-card h3 {
    font-size:18px
  }
  .concept-card p {
    font-size:12px
  }
  .concept-card .equation {
    font-size:25px
  }
  .concept-card:last-child .equation {
    font-size:24px
  }
  .lesson-section>p.equation-caption {
    font-size:10px
  }
  .quiz {
    padding:21px 17px
  }
  .quiz legend {
    font-size:14px;
    line-height:1.95
  }
  .quiz-option {
    padding:13px 11px;
    gap:9px;
    font-size:12px
  }
  .quiz-actions {
    gap:12px
  }
  .quiz-actions .button {
    font-size:10px
  }
  .feedback {
    font-size:12px;
    padding:17px
  }
  .feedback strong {
    font-size:12px
  }
  .activity-heading {
    font-size:8px;
    padding:13px 15px;
    letter-spacing:.6px
  }
  .plot-panel {
    padding:21px 13px 15px
  }
  .plot-panel h3 {
    font-size:13px;
    padding-inline:4px
  }
  .plot-legend {
    gap:10px;
    font-size:8px;
    padding-inline:4px
  }
  .plot-legend>span:before {
    width:12px
  }
  .playback-controls {
    gap:5px;
    justify-content:space-between
  }
  .playback-controls .button-small {
    font-size:9px;
    gap:5px;
    padding-inline:10px
  }
  .playback-controls>.text-button {
    font-size:9px
  }
  .motion-note {
    font-size:8px;
    line-height:1.9;
    padding-inline:3px
  }
  .control-panel {
    padding:21px 17px;
    column-gap:18px
  }
  .range-heading {
    font-size:9px;
    gap:4px;
    flex-wrap:wrap
  }
  .range-heading output {
    font-size:9px
  }
  .preset {
    font-size:7px;
    min-width:24px;
    min-height:30px;
    padding-inline:3px
  }
  .frequency-presets {
    gap:3px
  }
  .frequency-presets>span {
    font-size:6px
  }
  .control-panel>.fixed-settings {
    font-size:7px;
    line-height:1.9
  }
  .amplitude-box>div {
    font-size:8px;
    gap:3px
  }
  .amplitude-box strong {
    font-size:9px
  }
  .ratio-box {
    font-size:8px
  }
  .ratio-box>strong {
    font-size:22px
  }
  .control-panel>.dominance {
    font-size:7px
  }
  .activity-results {
    font-size:8px;
    padding:13px 15px;
    row-gap:8px
  }
  .guided-exploration h3 {
    font-size:15px
  }
  .guided-exploration ol {
    font-size:12px;
    line-height:2
  }
  .model-limits summary,.deeper-math summary,.code-activity>summary {
    font-size:11px;
    line-height:1.9
  }
  .model-limits p,.deeper-math p,.code-activity p {
    font-size:12px;
    line-height:2
  }
  .model-limits {
    padding:16px
  }
  .formula-panel {
    gap:13px;
    padding:20px 12px;
    flex-direction:column;
    align-items:center
  }
  .formula-panel .equation {
    font-size:22px
  }
  .worked-example {
    padding-inline-start:18px
  }
  .worked-example p {
    font-size:12px
  }
  .deeper-math .equation {
    font-size:20px
  }
  .recap-section {
    padding:24px 18px;
    margin-top:25px
  }
  .recap-list li {
    font-size:12px
  }
  .recall-prompt p {
    font-size:12px
  }
  .recap-section .button {
    font-size:10px;
    min-height:45px;
    padding:11px 17px
  }
  .lesson-section p.local-save-note {
    font-size:9px
  }
  .lesson-resources {
    padding-top:35px
  }
  .lesson-resources>h2 {
    font-size:24px
  }
  .lesson-resources .resource-card strong {
    font-size:11px
  }
  .lesson-resources .resource-card small {
    font-size:9px
  }
  .lesson-end {
    padding-block:25px 45px
  }
  .lesson-end>a:first-child {
    font-size:9px
  }
  .lesson-end .button {
    font-size:9px;
    padding-inline:13px
  }
  .search-dialog {
    padding:20px;
    margin-top:8vh
  }
  .search-dialog h2 {
    font-size:19px
  }
  .search-dialog input {
    font-size:12px
  }
  .search-dialog li>a {
    font-size:12px;
    padding-inline:8px
  }
  pre {
    font-size:10px;
    padding:15px
  }
  .code-activity {
    padding:16px
  }
  .code-activity p {
    font-size:11px
  }
  html[lang=fa] .brand {
    font-size:16px
  }
  html[lang=fa] .brand small {
    font-size:7px
  }
  html[lang=fa] .hero-copy h1 {
    font-size:clamp(33px,6.3vw,49px);
    line-height:1.8
  }
  html[lang=fa] .hero-copy .lead {
    font-size:15px;
    line-height:2.1
  }
  html[lang=fa] h2 {
    font-size:27px;
    line-height:1.8
  }
  html[lang=fa] .module-card h3 {
    font-size:21px
  }
  html[lang=fa] .module-card p {
    font-size:14px
  }
  html[lang=fa] .module-hero h1 {
    font-size:35px
  }
  html[lang=fa] .lesson-header h1 {
    font-size:39px
  }
  html[lang=fa] .lesson-section h2 {
    font-size:24px
  }
  html[lang=fa] .lesson-sidebar li>a {
    font-size:9px
  }
  html[lang=fa] .lesson-section>p {
    font-size:15px
  }
  html[lang=fa] .concept-card p {
    font-size:14px
  }
  html[lang=fa] .quiz-option {
    font-size:13px
  }
  html[lang=fa] .quiz legend {
    font-size:14px
  }
  html[lang=fa] .control-panel>.fixed-settings {
    font-size:8px
  }
  html[lang=fa] .range-heading {
    font-size:10px
  }
  html[lang=fa] .activity-results {
    font-size:9px
  }
  html[lang=fa] .model-limits p,html[lang=fa] .deeper-math p {
    font-size:13px
  }
}

@media(max-width:370px) {
  .wrap {
    width:calc(100% - 30px)
  }
  .brand {
    font-size:13px
  }
  .brand img {
    width:30px;
    height:30px
  }
  .brand small {
    font-size:5px;
    letter-spacing:1.2px
  }
  .header-tools .icon-button {
    width:30px;
    min-width:30px;
    padding:6px
  }
  .mobile-menu {
    width:30px;
    min-width:30px
  }
  .header-inner {
    gap:2px
  }
  .hero-copy h1 {
    font-size:36px
  }
  .hero-actions {
    gap:18px
  }
  .hero-actions .button {
    font-size:9px;
    padding-inline:13px
  }
  .hero-actions .text-link {
    font-size:9px
  }
  .hero-meta {
    font-size:7px;
    gap:10px
  }
  .preview-bar {
    font-size:7px
  }
  .lesson-header h1 {
    font-size:35px
  }
  .control-panel {
    column-gap:12px;
    padding-inline:13px
  }
  .frequency-presets>span {
    display:none
  }
  .activity-heading>span:last-child {
    font-size:13px
  }
  .activity-heading {
    font-size:7px
  }
  .range-heading {
    font-size:8px
  }
  .range-heading output {
    font-size:8px
  }
  html[lang=fa] .brand {
    font-size:14px
  }
  html[lang=fa] .brand small {
    font-size:6px
  }
  html[lang=fa] .hero-copy h1 {
    font-size:31px
  }
  html[lang=fa] .hero-copy .lead {
    font-size:14px
  }
}

@media(prefers-reduced-motion:reduce) {
  html {
    scroll-behavior:auto
  }
  *,*:before,*:after {
    animation:none!important;
    transition:none!important
  }
}

/* Contrast holds on white, highlighted navigation, and the recap panel. */
.pill {
  color:#506575
}

.pill-ready {
  color:#236246
}

.section-index,.lesson-sidebar li>a>span {
  color:#526d80
}

/* Reading content stays comfortably sized; controls and metadata are compact. */
.lesson-section>p {
  font-size:16px
}

.concept-card p {
  font-size:13px
}

.quiz legend {
  font-size:16px
}

.quiz-option {
  font-size:14px
}

.thinking-prompt p,.guided-exploration ol,.worked-example p,.recap-list li,.recall-prompt p {
  font-size:14px
}

.model-limits p,.deeper-math p,.code-activity p {
  font-size:13px
}

.lesson-header .lesson-byline {
  font-size:11px
}

.lesson-section p.local-save-note {
  font-size:10px
}

.module-card p {
  font-size:14px
}

.module-keywords {
  font-size:10px
}

.hero-copy .lead {
  font-size:16px
}

.resource-card strong {
  font-size:14px
}

.resource-card small {
  font-size:11px
}

.about-section p {
  font-size:14px
}

.about-section aside p {
  font-size:13px
}

.module-hero .lead {
  font-size:15px
}

.lesson-row p {
  font-size:13px
}

.module-body .section-intro {
  font-size:14px
}

.objectives-panel li {
  font-size:14px
}

.prerequisite-box p {
  font-size:12px
}

.lesson-sidebar li>a {
  font-size:11px
}

.lesson-sidebar li>a>span {
  font-size:9px
}

.feedback,.feedback strong {
  font-size:14px
}

.feedback>a {
  font-size:12px
}

.lesson-section>p.equation-caption {
  font-size:12px
}

.section-intro {
  font-size:15px
}

.approach-section p:not(.eyebrow) {
  font-size:14px
}

.approach-steps p {
  font-size:13px!important
}

.primary-nav {
  font-size:13px
}

@media(max-width:980px) {
  .primary-nav {
    font-size:11px
  }
  .lesson-sidebar li>a {
    font-size:9px
  }
  .hero-copy .lead {
    font-size:14px
  }
  .resource-card strong {
    font-size:12px
  }
  .resource-card small {
    font-size:10px
  }
  .module-card p {
    font-size:12px
  }
  .module-keywords {
    font-size:9px
  }
  .objectives-panel li {
    font-size:12px
  }
}

@media(max-width:760px) {
  .hero-copy .lead {
    font-size:15px
  }
  .primary-nav {
    font-size:13px
  }
  .module-card p,.section-intro,.about-section p {
    font-size:14px
  }
  .module-keywords {
    font-size:10px
  }
  .resource-card strong {
    font-size:13px
  }
  .resource-card small {
    font-size:10px
  }
  .lesson-sidebar li>a {
    font-size:10px
  }
  .lesson-header .lesson-byline {
    font-size:10px
  }
  .lesson-section>p {
    font-size:16px
  }
  .concept-card p {
    font-size:14px
  }
  .quiz legend {
    font-size:15px
  }
  .quiz-option {
    font-size:14px
  }
  .feedback,.feedback strong {
    font-size:13px
  }
  .thinking-prompt p,.guided-exploration ol,.worked-example p,.recap-list li,.recall-prompt p {
    font-size:14px
  }
  .model-limits p,.deeper-math p,.code-activity p {
    font-size:13px
  }
  .approach-section p:not(.eyebrow) {
    font-size:14px
  }
  .approach-steps p {
    font-size:13px!important
  }
  .lesson-row p {
    font-size:14px
  }
  .objectives-panel li {
    font-size:14px
  }
  .module-body .section-intro {
    font-size:14px
  }
}

/* Instructor outline: chapter overviews and reusable section plans. */
.brand.brand-wordmark {
  flex-direction:column;
  align-items:center;
  gap:0;
  padding-block:6px;
}
.brand.brand-wordmark img {
  width:190px;
  height:auto;
  display:block;
  mix-blend-mode:multiply;
}
.brand-wordmark .brand-course {
  font-size:11px;
  font-weight:650;
  letter-spacing:0;
  line-height:1.4;
  margin-top:-4px;
}
.footer-wordmark img {
  display:block;
  width:180px;
  height:auto;
  mix-blend-mode:multiply;
}
@media(max-width:760px) {
  .brand.brand-wordmark img { width:145px; }
  .brand-wordmark .brand-course { font-size:9px; }
}
@media(max-width:370px) {
  .brand.brand-wordmark img { width:125px; }
  .brand-wordmark .brand-course { font-size:8px; }
}

.curriculum-grid .chapter-card .card-link {
  margin-top:auto;
}
.curriculum-grid .chapter-card p {
  padding-bottom:24px;
}
.chapter-card .chapter-art {
  width:100%;
  height:125px;
  margin-top:12px;
  color:var(--blue);
  background:linear-gradient(0deg,var(--pale),white);
}
.chapter-card:nth-child(3n + 2) .chapter-art {
  color:var(--teal);
  background:linear-gradient(0deg,#f0f6f2,white);
}
.chapter-card:nth-child(3n) .chapter-art {
  color:var(--orange);
  background:linear-gradient(0deg,var(--warm),white);
}
.chapter-card-core {
  border-color:#b98060;
}
.chapter-card-core .pill {
  background:var(--warm);
  color:#89411f;
}
.chapter-hero h1 {
  font-size:clamp(30px,3.8vw,52px);
  line-height:1.2;
  letter-spacing:-1.4px;
  overflow-wrap:anywhere;
}
.chapter-hero .module-hero-grid {
  grid-template-columns:minmax(0,1.6fr) minmax(0,1fr);
  gap:60px;
}
.chapter-status {
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:15px;
  margin-top:24px;
  font-size:13px;
  color:var(--muted);
}
.chapter-illustration {
  align-self:center;
  text-align:center;
  border:1px solid var(--line);
  border-radius:50% 50% 12px 12px;
  padding:25px 18px;
  color:var(--blue);
  background:linear-gradient(145deg,#fff,var(--pale));
}
.chapter-illustration .chapter-art {
  width:100%;
  height:auto;
}
.chapter-illustration>span {
  font-size:12px;
  color:var(--muted);
}
.chapter-body {
  display:grid;
  grid-template-columns:minmax(0,1fr) 290px;
  gap:60px;
  align-items:start;
}
.chapter-body .lesson-row {
  grid-template-columns:42px minmax(0,1fr);
}
.chapter-body .lesson-row p {
  font-size:14px;
}
.chapter-aside {
  display:grid;
  gap:24px;
}
.chapter-map {
  border:1px solid var(--line);
  border-radius:var(--radius);
  padding:24px 20px;
  background:var(--pale);
}
.chapter-map h2 {
  font-size:18px;
}
.chapter-map ol {
  list-style:none;
  margin:18px 0 0;
  padding:0;
}
.chapter-map a {
  display:flex;
  align-items:baseline;
  gap:10px;
  padding:11px 8px;
  font-size:13px;
  line-height:1.6;
  border-radius:4px;
}
.chapter-map a>span {
  color:var(--blue);
  min-width:1em;
  font-weight:800;
}
.chapter-map a[aria-current] {
  background:white;
  box-shadow:0 0 0 1px var(--line);
  font-weight:750;
}
.priority-note {
  border-inline-start:3px solid var(--orange);
  padding:24px;
  background:var(--warm);
  border-radius:4px;
}
.priority-note h2 {
  font-size:23px;
  margin-block:10px 14px;
}
.priority-note p {
  font-size:14px;
}
.priority-note .text-link {
  margin-top:16px;
}
.topic-priority {
  border-inline-start:3px solid var(--orange);
  background:var(--warm);
}
.outline-note {
  padding:16px 20px;
  margin-bottom:24px;
  border-inline-start:3px solid #9caeba;
  background:var(--pale);
  font-size:14px;
  line-height:1.8;
}
.outline-note strong {
  display:block;
  margin-bottom:5px;
}
.section-plan h1 {
  overflow-wrap:anywhere;
}
.priority-banner {
  padding:16px 20px;
  background:var(--warm);
  font-size:14px;
  border-inline-start:3px solid var(--orange);
}
.section-plan .sample-notice {
  font-size:13px;
  line-height:1.9;
}
.section-plan .lesson-section>h2 {
  margin-top:10px;
}
.template-intro {
  margin-bottom:24px;
}
.template-intro h2 {
  font-size:27px;
  margin-bottom:12px;
}
.template-intro p {
  font-size:14px;
  color:var(--muted);
}
.planned-step {
  margin-block:12px;
  border:1px solid var(--line);
  border-radius:var(--radius);
  background:white;
  scroll-margin-top:110px;
}
.planned-step summary {
  display:flex;
  align-items:center;
  gap:18px;
  padding:20px;
  cursor:pointer;
  color:var(--navy);
  font-weight:750;
  list-style:none;
}
.planned-step summary::-webkit-details-marker {
  display:none;
}
.planned-step summary>.icon:last-child {
  margin-inline-start:auto;
}
.planned-step summary small {
  display:block;
  font-size:11px;
  font-weight:500;
  color:var(--muted);
  margin-top:3px;
}
.planned-step[open] {
  background:var(--pale);
}
.planned-step[open] summary>.icon:last-child {
  transform:rotate(45deg);
}
.planned-step .step-number {
  color:var(--blue);
  background:var(--pale);
  border:1px solid var(--line);
}
.planned-step>p {
  padding:0 24px 24px;
  font-size:15px;
}
.deeper-plan {
  margin-top:26px;
}
.sample-callout {
  padding:30px;
  background:var(--pale);
  border-radius:var(--radius);
  border:1px solid var(--line);
  margin-block:36px;
}
.sample-callout h2 {
  font-size:26px;
  margin-block:14px;
}
.sample-callout p {
  max-width:780px;
  font-size:15px;
  margin-bottom:20px;
}
.curriculum-pagination {
  display:grid;
  grid-template-columns:repeat(2,minmax(0,1fr));
  gap:25px;
  padding-block:28px 60px;
  border-top:1px solid var(--line);
}
.curriculum-pagination>a {
  padding:16px;
  border:1px solid var(--line);
  border-radius:var(--radius);
}
.curriculum-pagination>a:last-child {
  text-align:end;
}
.curriculum-pagination strong {
  display:block;
  font-size:15px;
  margin-top:8px;
}
.curriculum-pagination .small-eyebrow {
  font-size:10px;
  color:var(--muted);
}
.curriculum-pagination .icon {
  width:16px;
  height:16px;
}
html[lang=fa] .chapter-hero h1 {
  letter-spacing:0;
  line-height:1.5;
}
@media(max-width:980px) {
  .chapter-body { grid-template-columns:minmax(0,1fr) 240px; gap:30px; }
  .chapter-hero .module-hero-grid { gap:25px; }
}
@media(max-width:760px) {
  .chapter-body { grid-template-columns:minmax(0,1fr); gap:36px; }
  .chapter-hero .module-hero-grid { grid-template-columns:minmax(0,1fr); }
  .chapter-illustration { max-width:320px; width:100%; justify-self:center; padding:15px; }
  .chapter-hero h1 { font-size:34px; letter-spacing:-.8px; }
  .chapter-body .lesson-row { grid-template-columns:35px minmax(0,1fr); padding:20px 12px; }
  .curriculum-pagination { gap:12px; }
  .curriculum-pagination>a { padding:12px; }
  .curriculum-pagination strong { font-size:13px; }
  .planned-step summary { gap:12px; padding:18px 14px; font-size:15px; }
  .planned-step>p { padding-inline:18px; }
  .sample-callout { padding:24px 20px; }
  .sample-callout h2 { font-size:24px; }
}

@media print {
  .preview-bar,.site-header,.lesson-sidebar,.site-footer,.quiz-actions,.playback-controls,.lesson-end,.header-tools,.button,.search-dialog {
    display:none!important
  }
  .wrap {
    width:100%;
    max-width:none
  }
  .lesson-layout,.module-body {
    display:block
  }
  .lesson-section {
    break-inside:avoid
  }
  .lesson-section h2 {
    font-size:22px
  }
  .lesson-header h1 {
    font-size:36px
  }
  body {
    font-size:12px
  }
  .activity {
    break-inside:avoid
  }
  .lesson-resources pre {
    white-space:pre-wrap
  }
  .hero-grid {
    min-height:0
  }
}

/* Font pairing shared with metasurface.ir. */
@font-face { font-family: Inter; src: url('/assets/fonts/inter.ttf') format('truetype'); font-style: normal; font-weight: 400; font-display: swap; }
@font-face { font-family: 'Playpen Sans Arabic'; src: url('/assets/fonts/playpen-sans-arabic.ttf') format('truetype'); font-style: normal; font-weight: 100 800; font-display: swap; }
html[lang=en] { --font: Inter, 'Segoe UI', sans-serif; }
html[lang=fa] main :is(h1,h2,h3) { font-family: 'Playpen Sans Arabic', Vazirmatn, Tahoma, sans-serif; font-weight: 500; letter-spacing: 0; line-height: 1.6; }
html[lang=fa] main h1 { font-weight: 800; }

@font-face { font-family: Inter; src: url('/assets/fonts/inter-semibold.ttf') format('truetype'); font-style: normal; font-weight: 600 900; font-display: swap; }

.numbered-equation {
  display: inline-flex;
  align-items: center;
  gap: .65rem;
  max-width: 100%;
  overflow-x: auto;
  vertical-align: middle;
}
.numbered-equation math { margin: 0; }
.equation-number { color: var(--muted); font: 600 .75rem var(--font); }