:root {
  --ink: #17243d;
  --muted: #627087;
  --paper: #fbfaf6;
  --white: #ffffff;
  --blue: #3759d7;
  --blue-dark: #2644b9;
  --blue-soft: #e9edff;
  --aqua: #dff6ef;
  --aqua-dark: #177d68;
  --coral: #f06f57;
  --coral-soft: #fff0eb;
  --gold: #f5c652;
  --line: #dfe3e9;
  --shadow: 0 18px 48px rgba(28, 43, 74, .10);
  --small-shadow: 0 8px 22px rgba(28, 43, 74, .09);
  --radius: 20px;
  --serif: Georgia, "Times New Roman", serif;
  --sans: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: var(--sans);
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

button, input { font: inherit; }
button { color: inherit; }
button:focus-visible, input:focus-visible, a:focus-visible {
  outline: 3px solid rgba(55, 89, 215, .35);
  outline-offset: 3px;
}

.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;
  left: 16px;
  top: -60px;
  z-index: 100;
  padding: 10px 16px;
  background: var(--ink);
  color: white;
  border-radius: 8px;
  transition: top .2s ease;
}

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

.site-header {
  height: 78px;
  padding: 0 clamp(22px, 5vw, 76px);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 36px;
  background: rgba(251, 250, 246, .96);
  border-bottom: 1px solid rgba(23, 36, 61, .08);
  position: sticky;
  top: 0;
  z-index: 40;
  backdrop-filter: blur(14px);
}

.brand {
  color: var(--ink);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 11px;
  font-size: 15px;
  letter-spacing: -.2px;
  white-space: nowrap;
}

.brand strong { color: var(--blue); font-weight: 750; }

.brand-mark {
  width: 38px;
  height: 38px;
  display: grid;
  place-items: center;
  border-radius: 11px;
  color: white;
  background: var(--blue);
}

.brand-mark svg {
  width: 25px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.main-nav { display: flex; gap: 36px; align-items: center; }

.nav-link {
  border: 0;
  background: transparent;
  padding: 10px 0;
  font-size: 13px;
  font-weight: 700;
  color: #657087;
  cursor: pointer;
  position: relative;
}

.nav-link:hover, .nav-link.is-active { color: var(--ink); }
.nav-link.is-active::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background: var(--coral);
}

.menu-button {
  display: none;
  width: 42px;
  height: 42px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--white);
  place-content: center;
  gap: 4px;
}

.menu-button span:not(.sr-only) { display: block; width: 18px; height: 2px; background: var(--ink); }
.mobile-menu { display: none; }

.view { display: none; }
.view.is-visible { display: block; animation: fade-in .25s ease both; }
@keyframes fade-in { from { opacity: .3; transform: translateY(4px); } }

.hero-shell {
  max-width: 1300px;
  min-height: 655px;
  padding: 70px clamp(28px, 6vw, 84px) 62px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1.02fr .98fr;
  gap: 7vw;
  align-items: center;
  overflow: hidden;
}

.hero-copy, .hero-visual { min-width: 0; }

.eyebrow {
  display: flex;
  align-items: center;
  gap: 9px;
  margin-bottom: 17px;
  color: var(--blue);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 1.8px;
  text-transform: uppercase;
}

.eyebrow span { width: 22px; height: 2px; background: var(--coral); }

.hero-copy h1, .page-intro h1 {
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(48px, 6.3vw, 82px);
  line-height: .98;
  letter-spacing: -3px;
  margin: 0;
  color: #13223c;
}

.hero-lede {
  max-width: 560px;
  margin: 26px 0 27px;
  font-size: 17px;
  line-height: 1.7;
  color: var(--muted);
}

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

.primary-button, .secondary-button {
  border: 0;
  border-radius: 10px;
  min-height: 48px;
  padding: 0 20px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 11px;
  font-weight: 750;
  font-size: 13px;
  cursor: pointer;
  transition: transform .16s ease, box-shadow .16s ease, background .16s ease;
}

.primary-button { background: var(--blue); color: white; box-shadow: 0 9px 20px rgba(55, 89, 215, .22); }
.primary-button:hover { background: var(--blue-dark); transform: translateY(-1px); box-shadow: 0 11px 24px rgba(55, 89, 215, .28); }
.primary-button svg { width: 17px; fill: none; stroke: currentColor; stroke-width: 2; }
.secondary-button { background: var(--white); color: var(--ink); border: 1px solid var(--line); }
.secondary-button:hover { border-color: #aeb6c3; transform: translateY(-1px); }

.text-button, .compare-button, .danger-text-button {
  border: 0;
  background: transparent;
  cursor: pointer;
  font-weight: 750;
}

.text-button { color: var(--blue); padding: 10px 0; font-size: 13px; border-bottom: 1px solid currentColor; }

.platform-picker {
  margin-top: 46px;
  max-width: 520px;
  padding-top: 27px;
  border-top: 1px solid var(--line);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
}

.picker-label { display: block; font-weight: 750; font-size: 12px; }
.picker-help { display: block; margin-top: 3px; color: var(--muted); font-size: 10px; }

.segmented-control {
  display: inline-flex;
  padding: 3px;
  border: 1px solid var(--line);
  background: #f0f1f2;
  border-radius: 10px;
}

.platform-option {
  min-height: 38px;
  min-width: 102px;
  border: 0;
  border-radius: 7px;
  background: transparent;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  font-size: 11px;
  font-weight: 750;
  color: #697386;
  cursor: pointer;
}

.platform-option svg { width: 15px; height: 15px; fill: currentColor; }
.platform-option.is-selected { color: var(--ink); background: white; box-shadow: 0 2px 6px rgba(22, 35, 57, .1); }

.hero-visual {
  min-height: 480px;
  position: relative;
  display: grid;
  place-items: center;
}

.visual-dots {
  position: absolute;
  inset: 9% 2% 2% 9%;
  opacity: .24;
  background-image: radial-gradient(#6176a4 1.1px, transparent 1.1px);
  background-size: 17px 17px;
  border-radius: 45% 55% 42% 58%;
}

.hero-visual::before {
  content: "";
  position: absolute;
  width: 390px;
  height: 390px;
  border-radius: 50%;
  background: var(--aqua);
  right: 5%;
  top: 8%;
}

.computer-card { position: relative; z-index: 2; transform: translate(5px, 15px); }
.monitor {
  width: min(36vw, 414px);
  aspect-ratio: 1.37;
  border: 11px solid #1e2d4c;
  border-radius: 19px;
  background: #fff;
  box-shadow: 17px 20px 0 rgba(32, 56, 93, .11), var(--shadow);
  overflow: hidden;
}

.monitor-bar { height: 29px; padding-left: 13px; display: flex; align-items: center; gap: 5px; background: #f3f4f6; border-bottom: 1px solid var(--line); }
.monitor-bar i { width: 6px; height: 6px; border-radius: 50%; background: #c9ced6; }
.monitor-content { min-height: calc(100% - 29px); display: flex; flex-direction: column; align-items: center; justify-content: center; }
.tiny-eyebrow { font-size: 8px; font-weight: 800; letter-spacing: 1.3px; color: var(--muted); }

.progress-ring {
  --progress: 0;
  width: 113px;
  height: 113px;
  margin: 12px 0 10px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  font-family: var(--serif);
  font-size: 25px;
  background: conic-gradient(var(--blue) calc(var(--progress) * 1%), #e8ebef 0);
  position: relative;
}

.progress-ring::before { content: ""; position: absolute; inset: 9px; background: white; border-radius: 50%; }
.progress-ring span { z-index: 1; }
.monitor-content strong { font-family: var(--serif); font-weight: 400; font-size: 16px; }
.monitor-content small { margin-top: 3px; color: var(--muted); font-size: 9px; }
.monitor-stand { width: 65px; height: 53px; margin: 0 auto; background: #1e2d4c; clip-path: polygon(29% 0, 71% 0, 85% 100%, 15% 100%); }
.monitor-base { width: 128px; height: 11px; margin: 0 auto; border-radius: 7px 7px 3px 3px; background: #1e2d4c; }

.floating-note {
  position: absolute;
  z-index: 4;
  min-width: 194px;
  padding: 13px 15px;
  display: flex;
  align-items: center;
  gap: 11px;
  background: white;
  border: 1px solid rgba(23, 36, 61, .08);
  border-radius: 12px;
  box-shadow: var(--small-shadow);
}

.floating-note strong, .floating-note small { display: block; }
.floating-note strong { font-size: 11px; }
.floating-note small { color: var(--muted); font-size: 8px; margin-top: 2px; }
.note-top { top: 6%; right: -2%; }
.note-bottom { left: 0; bottom: 6%; }
.mini-icon { width: 31px; height: 31px; display: grid; place-items: center; border-radius: 8px; font-size: 15px; font-weight: 800; }
.mini-icon.coral { color: var(--coral); background: var(--coral-soft); }
.mini-icon.blue { color: var(--blue); background: var(--blue-soft); }

.section-shell { width: min(1170px, calc(100% - 48px)); margin: 0 auto; }
.learning-path { padding: 92px 0 110px; }
.section-heading { display: flex; justify-content: space-between; align-items: end; gap: 40px; margin-bottom: 38px; }
.section-heading h2 { font-family: var(--serif); font-size: clamp(34px, 4vw, 48px); font-weight: 400; letter-spacing: -1.5px; margin: 0; }
.section-heading p { max-width: 390px; color: var(--muted); font-size: 14px; margin: 0 0 4px; }

.lesson-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 17px; }
.lesson-card {
  min-height: 274px;
  padding: 27px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: #fff;
  display: flex;
  flex-direction: column;
  cursor: pointer;
  text-align: left;
  transition: transform .18s ease, box-shadow .18s ease, border-color .18s ease;
  position: relative;
  overflow: hidden;
}

.lesson-card:hover { transform: translateY(-4px); box-shadow: var(--small-shadow); border-color: #c8cfd9; }
.lesson-card.completed::after { content: "✓ Completed"; position: absolute; right: 18px; top: 18px; padding: 5px 8px; border-radius: 20px; color: var(--aqua-dark); background: var(--aqua); font-size: 9px; font-weight: 800; }
.lesson-card-top { display: flex; align-items: center; justify-content: space-between; }
.lesson-icon { width: 43px; height: 43px; display: grid; place-items: center; border-radius: 11px; color: var(--blue); background: var(--blue-soft); }
.lesson-icon svg { width: 23px; height: 23px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.lesson-number { font-family: var(--serif); font-size: 14px; color: #a0a8b5; }
.lesson-card h3 { margin: 22px 0 7px; font-family: var(--serif); font-size: 24px; font-weight: 400; letter-spacing: -.4px; }
.lesson-card p { margin: 0; color: var(--muted); font-size: 12px; line-height: 1.65; }
.lesson-meta { margin-top: auto; padding-top: 20px; display: flex; align-items: center; gap: 9px; color: #818b9b; font-size: 10px; font-weight: 700; }
.lesson-meta svg { width: 14px; fill: none; stroke: currentColor; stroke-width: 1.8; }

.confidence-strip { background: #182640; color: white; }
.confidence-inner { width: min(1170px, calc(100% - 48px)); min-height: 196px; margin: 0 auto; display: flex; align-items: center; gap: 26px; }
.quote-mark { font-family: var(--serif); font-size: 84px; line-height: .7; color: var(--coral); }
.confidence-inner p { margin: 0; font-family: var(--serif); font-size: 28px; }
.confidence-inner span { color: #aeb9cc; font-size: 12px; }
.confidence-decoration { margin-left: auto; display: flex; align-items: center; gap: 10px; transform: rotate(-7deg); opacity: .7; }
.confidence-decoration span, .confidence-decoration b { color: white; font-size: 9px; letter-spacing: 2px; }
.confidence-decoration i { width: 44px; height: 1px; background: var(--coral); }

.site-footer { min-height: 120px; padding: 30px clamp(24px, 5vw, 76px); display: flex; align-items: center; justify-content: space-between; color: var(--muted); font-size: 12px; border-top: 1px solid var(--line); }
.footer-brand .brand-mark { width: 30px; height: 30px; }
.footer-brand .brand-mark svg { width: 20px; }

/* Lesson page */
.lesson-layout { display: grid; grid-template-columns: 270px minmax(0, 860px); max-width: 1180px; margin: 0 auto; gap: 65px; padding: 48px 32px 100px; align-items: start; }
.lesson-sidebar { position: sticky; top: 112px; }
.back-button { border: 0; background: transparent; padding: 5px 0; display: flex; align-items: center; gap: 8px; font-size: 11px; font-weight: 750; cursor: pointer; color: var(--blue); }
.back-button svg { width: 16px; fill: none; stroke: currentColor; stroke-width: 2; }
.course-progress { margin: 29px 0; padding-bottom: 26px; border-bottom: 1px solid var(--line); }
.progress-label { display: flex; justify-content: space-between; font-size: 10px; margin-bottom: 8px; }
.progress-label span { color: var(--muted); }
.progress-track { height: 6px; border-radius: 10px; background: #e4e7ec; overflow: hidden; }
.progress-track span { display: block; height: 100%; width: 0; border-radius: inherit; background: var(--blue); transition: width .3s ease; }
.lesson-list { margin: 0; padding: 0; list-style: none; }
.lesson-list li { margin-bottom: 7px; }
.sidebar-lesson {
  width: 100%;
  border: 0;
  border-radius: 10px;
  background: transparent;
  display: grid;
  grid-template-columns: 27px 1fr;
  align-items: center;
  gap: 10px;
  padding: 10px;
  text-align: left;
  cursor: pointer;
  color: var(--muted);
}
.sidebar-lesson.is-current { background: var(--blue-soft); color: var(--ink); }
.sidebar-lesson.is-complete .side-number { color: white; background: var(--aqua-dark); border-color: var(--aqua-dark); }
.side-number { width: 24px; height: 24px; display: grid; place-items: center; border: 1px solid #cbd1db; border-radius: 50%; font-size: 9px; font-weight: 800; }
.side-name { font-size: 10px; font-weight: 700; }

.lesson-topbar { display: flex; align-items: center; justify-content: space-between; padding-bottom: 22px; border-bottom: 1px solid var(--line); }
.lesson-count { font-size: 10px; font-weight: 800; color: var(--muted); letter-spacing: .5px; text-transform: uppercase; }
.segmented-control.compact .platform-option { min-width: 74px; min-height: 31px; font-size: 9px; }
.lesson-header { display: grid; grid-template-columns: 67px 1fr; gap: 21px; padding: 44px 0 45px; }
.lesson-icon-large { width: 63px; height: 63px; display: grid; place-items: center; border-radius: 16px; color: var(--blue); background: var(--blue-soft); }
.lesson-icon-large svg { width: 32px; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.lesson-header .eyebrow { margin: 3px 0 9px; font-size: 9px; }
.lesson-header h1 { margin: 0; font-family: var(--serif); font-size: clamp(38px, 5vw, 54px); font-weight: 400; letter-spacing: -1.7px; line-height: 1; }
.lesson-header p { margin: 15px 0 0; max-width: 690px; color: var(--muted); font-size: 14px; }

.lesson-block { display: grid; grid-template-columns: 48px 1fr; gap: 21px; padding: 42px 0; border-top: 1px solid var(--line); }
.block-number { width: 38px; height: 38px; display: grid; place-items: center; border: 1px solid var(--line); border-radius: 50%; font-family: var(--serif); font-size: 12px; color: var(--blue); }
.block-label { margin: 2px 0 7px; font-size: 9px; color: var(--blue); font-weight: 850; letter-spacing: 1.5px; }
.block-body h2 { margin: 0 0 9px; font-family: var(--serif); font-size: 29px; font-weight: 400; letter-spacing: -.6px; }
.block-body > p:not(.block-label) { margin: 0 0 23px; color: var(--muted); font-size: 13px; }

.instruction-card { border: 1px solid var(--line); border-radius: 15px; background: #fff; overflow: hidden; }
.instruction-title { min-height: 53px; padding: 14px 18px; display: flex; align-items: center; justify-content: space-between; background: #f5f6f8; border-bottom: 1px solid var(--line); }
.instruction-title span { display: inline-flex; align-items: center; gap: 9px; font-size: 11px; font-weight: 800; }
.os-badge { padding: 5px 9px; border-radius: 6px; color: var(--blue); background: var(--blue-soft); font-size: 8px; font-weight: 800; letter-spacing: .7px; text-transform: uppercase; }
.instruction-steps { margin: 0; padding: 6px 20px; list-style: none; }
.instruction-steps li { display: grid; grid-template-columns: 28px 1fr; gap: 10px; padding: 15px 0; border-bottom: 1px solid #eceef1; color: #46536a; font-size: 12px; }
.instruction-steps li:last-child { border: 0; }
.step-dot { width: 24px; height: 24px; display: grid; place-items: center; border-radius: 50%; background: var(--aqua); color: var(--aqua-dark); font-size: 9px; font-weight: 850; }
kbd { display: inline-block; min-width: 25px; padding: 2px 6px; margin: 0 2px; border: 1px solid #cbd1da; border-bottom-width: 2px; border-radius: 5px; background: white; font: 700 10px var(--sans); color: var(--ink); text-align: center; }

.compare-button { margin-top: 12px; padding: 8px 0; display: inline-flex; align-items: center; gap: 7px; color: var(--blue); font-size: 10px; }
.compare-button svg { width: 14px; fill: none; stroke: currentColor; stroke-width: 2; transition: transform .2s; }
.compare-button[aria-expanded="true"] svg { transform: rotate(180deg); }
.comparison-panel { margin-top: 10px; padding: 18px; border: 1px solid var(--line); border-radius: 12px; background: #f8f9fb; }
.comparison-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.comparison-grid h3 { margin: 0 0 8px; font-size: 11px; }
.comparison-grid ol { margin: 0; padding-left: 18px; color: var(--muted); font-size: 10px; }
.comparison-grid li + li { margin-top: 6px; }

.practice-lab { min-height: 270px; border: 1px solid #cad2de; border-radius: 15px; background: #eef1f6; overflow: hidden; box-shadow: inset 0 0 0 4px rgba(255,255,255,.45); }
.lab-toolbar { height: 37px; padding: 0 12px; display: flex; align-items: center; gap: 6px; background: #dbe0e7; border-bottom: 1px solid #cad0d8; }
.lab-toolbar i { width: 7px; height: 7px; border-radius: 50%; background: #b1b8c4; }
.lab-label { margin-left: 7px; font-size: 8px; font-weight: 800; color: #687387; letter-spacing: .6px; text-transform: uppercase; }
.lab-stage { min-height: 230px; padding: 24px; position: relative; }
.task-prompt { display: flex; justify-content: space-between; gap: 16px; align-items: start; margin-bottom: 22px; }
.task-prompt strong { font-family: var(--serif); font-size: 17px; font-weight: 400; }
.task-prompt small { display: block; color: var(--muted); font-size: 9px; margin-top: 3px; }
.task-counter { padding: 5px 10px; border-radius: 20px; background: white; color: var(--blue); font-size: 9px; font-weight: 800; }

.click-arena { height: 130px; position: relative; border: 1px dashed #b7c0cd; border-radius: 10px; background: rgba(255,255,255,.6); }
.click-target { position: absolute; left: 45%; top: 31%; width: 58px; height: 58px; border: 8px solid rgba(240,111,87,.3); border-radius: 50%; background: var(--coral); color: white; font-size: 9px; font-weight: 800; cursor: pointer; box-shadow: 0 5px 12px rgba(240,111,87,.25); transition: left .18s, top .18s, transform .1s; }
.click-target:active { transform: scale(.9); }

.typing-sample { margin: 4px 0 14px; padding: 11px 13px; border-radius: 8px; background: white; color: var(--ink); font-family: ui-monospace, SFMono-Regular, Consolas, monospace; font-size: 12px; }
.typing-input { width: 100%; height: 44px; padding: 0 13px; border: 2px solid #c4ccd8; border-radius: 8px; background: white; color: var(--ink); }
.typing-input.is-correct { border-color: var(--aqua-dark); background: #f1fcf8; }
.typing-feedback { min-height: 22px; margin-top: 8px; font-size: 10px; color: var(--muted); }

.desktop-practice { height: 145px; padding: 17px; display: flex; align-items: center; justify-content: center; border-radius: 9px; background: #cbd9e8; overflow: hidden; }
.practice-window { width: 74%; height: 104px; border: 1px solid #9da9b9; border-radius: 7px; background: white; box-shadow: 0 8px 15px rgba(30, 45, 76, .14); transition: width .22s ease, height .22s ease, opacity .22s ease, transform .22s ease; overflow: hidden; }
.practice-window.is-maximized { width: 100%; height: 100%; }
.practice-window.is-minimized { opacity: 0; transform: translateY(100px) scale(.7); }
.practice-window-bar { height: 31px; padding-left: 10px; display: flex; align-items: center; justify-content: space-between; background: #eef1f5; border-bottom: 1px solid #d6dbe2; font-size: 9px; font-weight: 700; }
.window-controls { height: 100%; display: flex; }
.window-controls button { width: 30px; height: 100%; border: 0; border-left: 1px solid #d8dde4; background: transparent; cursor: pointer; font-size: 11px; }
.window-controls button:hover { background: #dde3eb; }
.window-controls button:last-child:hover { color: white; background: var(--coral); }
.practice-window-body { height: calc(100% - 31px); display: grid; place-items: center; color: var(--muted); font-size: 9px; }

.fake-window { border: 1px solid #bbc4d1; border-radius: 9px; background: white; overflow: hidden; }
.window-nav { height: 36px; padding: 0 11px; display: flex; align-items: center; gap: 8px; background: #edf0f4; border-bottom: 1px solid #d9dee5; font-size: 9px; font-weight: 700; }
.window-nav .crumb { flex: 1; padding: 5px 9px; border-radius: 4px; background: white; color: var(--muted); }
.file-area { min-height: 110px; display: flex; align-items: start; gap: 18px; padding: 18px; }
.file-item { width: 75px; border: 1px solid transparent; background: transparent; border-radius: 6px; padding: 6px; text-align: center; font-size: 9px; cursor: pointer; }
.file-item:hover, .file-item.is-selected { background: var(--blue-soft); border-color: #b7c3ef; }
.folder-shape { width: 36px; height: 27px; margin: 0 auto 6px; border-radius: 3px; background: var(--gold); position: relative; }
.folder-shape::before { content: ""; position: absolute; left: 0; top: -5px; width: 17px; height: 7px; border-radius: 3px 3px 0 0; background: var(--gold); }
.file-controls { display: flex; gap: 8px; margin-top: 12px; }
.lab-button { min-height: 32px; padding: 0 11px; border: 1px solid #b9c1cc; border-radius: 6px; background: white; font-size: 9px; font-weight: 750; cursor: pointer; }
.lab-button.primary { color: white; background: var(--blue); border-color: var(--blue); }
.lab-button:disabled { opacity: .45; cursor: not-allowed; }
.folder-name-input { width: 100%; min-width: 62px; padding: 2px 3px; border: 1px solid var(--blue); border-radius: 3px; font-size: 8px; text-align: center; }

.browser-shell { border: 1px solid #b9c2ce; border-radius: 9px; background: white; overflow: hidden; }
.browser-tabs { height: 31px; padding: 6px 9px 0; display: flex; gap: 4px; background: #dce1e8; }
.browser-tab { min-width: 115px; padding: 5px 9px; border-radius: 5px 5px 0 0; background: white; font-size: 8px; }
.new-tab-button { border: 0; background: transparent; font-size: 15px; line-height: 1; cursor: pointer; }
.address-row { display: flex; gap: 7px; padding: 7px; border-bottom: 1px solid #e3e6ea; }
.address-bar { flex: 1; min-width: 0; height: 27px; padding: 0 10px; border: 1px solid #ced4dd; border-radius: 14px; font-size: 9px; }
.browser-go { width: 42px; border: 0; border-radius: 14px; background: var(--blue); color: white; font-size: 9px; font-weight: 800; cursor: pointer; }
.browser-page { min-height: 88px; padding: 20px; text-align: center; color: var(--muted); font-size: 10px; }
.browser-page strong { display: block; color: var(--ink); font-family: var(--serif); font-size: 18px; font-weight: 400; }

.email-shell { display: grid; grid-template-columns: 120px 1fr; min-height: 184px; border: 1px solid #bdc5cf; border-radius: 9px; overflow: hidden; background: white; }
.email-sidebar { padding: 13px; background: #e9edf2; color: var(--muted); font-size: 9px; }
.email-sidebar b { display: block; margin-bottom: 12px; color: var(--ink); }
.email-sidebar span { display: block; padding: 5px; }
.email-sidebar span:first-of-type { background: white; border-radius: 4px; color: var(--blue); }
.email-message { padding: 17px; }
.email-message h4 { margin: 0 0 6px; font-size: 13px; }
.email-meta { color: var(--muted); font-size: 8px; border-bottom: 1px solid #edf0f3; padding-bottom: 8px; }
.email-body { font-size: 9px; color: #4e5a6e; }
.danger-chip { display: inline-block; margin: 2px; padding: 3px 6px; border: 1px solid transparent; border-radius: 4px; background: transparent; cursor: pointer; font-size: 9px; color: inherit; }
.danger-chip:hover { border-color: var(--coral); }
.danger-chip.is-found { color: #a23b28; background: var(--coral-soft); border-color: #f2b4a8; }

.safety-choice-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 9px; }
.safety-choice { padding: 13px; border: 1px solid #c7ced8; border-radius: 8px; background: white; text-align: left; cursor: pointer; font-size: 10px; }
.safety-choice:hover { border-color: var(--blue); }
.safety-choice.is-good { border-color: var(--aqua-dark); background: var(--aqua); }
.safety-choice.is-bad { border-color: var(--coral); background: var(--coral-soft); }

.lab-success { min-height: 185px; padding: 30px; display: grid; place-items: center; text-align: center; }
.success-mark { width: 53px; height: 53px; display: grid; place-items: center; border-radius: 50%; background: var(--aqua); color: var(--aqua-dark); font-size: 24px; }
.lab-success h3 { margin: 12px 0 4px; font-family: var(--serif); font-size: 22px; font-weight: 400; }
.lab-success p { margin: 0; color: var(--muted); font-size: 10px; }
.retry-button { margin-top: 12px; border: 0; background: transparent; color: var(--blue); font-size: 9px; font-weight: 800; cursor: pointer; }

.quiz-card { padding: 21px; border-radius: 14px; background: #fff8e9; border: 1px solid #f0dfb8; }
.quiz-question { margin: 0 0 14px; font-size: 13px; font-weight: 750; }
.quiz-options { display: grid; gap: 8px; }
.quiz-option { padding: 11px 13px; border: 1px solid #e2d6bb; border-radius: 8px; background: white; text-align: left; cursor: pointer; font-size: 11px; }
.quiz-option:hover { border-color: var(--blue); }
.quiz-option.is-correct { color: #166452; border-color: #72b8a9; background: #e7f7f2; }
.quiz-option.is-wrong { color: #9b3c2b; border-color: #e4a294; background: var(--coral-soft); }
.quiz-feedback { min-height: 22px; margin: 11px 0 0; font-size: 10px; font-weight: 700; }

.lesson-footer { display: flex; justify-content: space-between; align-items: center; padding-top: 30px; border-top: 1px solid var(--line); }
.lesson-footer .primary-button:disabled { opacity: .45; cursor: not-allowed; transform: none; }

/* Shortcuts and teacher pages */
.shortcuts-view, .teacher-view { padding: 83px 0 100px; min-height: 75vh; }
.page-intro { max-width: 750px; }
.page-intro h1 { font-size: clamp(48px, 6vw, 72px); }
.page-intro p { max-width: 600px; color: var(--muted); font-size: 15px; }
.shortcut-toolbar { margin-top: 48px; display: flex; align-items: center; justify-content: space-between; color: var(--muted); font-size: 11px; }
.shortcut-table-wrap { margin-top: 15px; border: 1px solid var(--line); border-radius: 16px; overflow: hidden; background: white; }
.shortcut-table { width: 100%; border-collapse: collapse; }
.shortcut-table th { padding: 16px 21px; color: var(--muted); background: #f0f2f5; text-align: left; font-size: 10px; letter-spacing: .6px; text-transform: uppercase; }
.shortcut-table td { padding: 18px 21px; border-top: 1px solid #eaedf0; font-size: 12px; }
.shortcut-table td:first-child { font-weight: 750; }
.shortcut-note { margin-top: 16px; padding: 16px; border-left: 3px solid var(--coral); color: var(--muted); background: var(--coral-soft); font-size: 11px; }

.teacher-grid { display: grid; grid-template-columns: 1.15fr .85fr; gap: 18px; margin-top: 52px; }
.teacher-card { padding: 30px; border: 1px solid var(--line); border-radius: 16px; background: white; }
.teacher-card.featured { grid-row: span 2; }
.card-number { display: grid; place-items: center; width: 31px; height: 31px; border-radius: 50%; background: var(--blue-soft); color: var(--blue); font-family: var(--serif); font-size: 11px; }
.teacher-card h2 { margin: 18px 0; font-family: var(--serif); font-size: 26px; font-weight: 400; }
.teacher-card p, .teacher-card li { color: var(--muted); font-size: 12px; }
.teacher-card ul { margin: 0; padding-left: 18px; }
.teacher-card li + li { margin-top: 10px; }
.session-timeline { margin-top: 25px; }
.session-timeline div { display: grid; grid-template-columns: 75px 1fr; gap: 15px; align-items: center; padding: 18px 0; border-top: 1px solid var(--line); }
.session-timeline b { color: var(--blue); font-family: var(--serif); font-size: 18px; font-weight: 400; }
.session-timeline span { color: var(--muted); font-size: 12px; }
.progress-track.large { height: 9px; margin: 18px 0; }
.danger-text-button { padding: 6px 0; color: #ac4532; font-size: 10px; border-bottom: 1px solid currentColor; }

.toast { position: fixed; right: 22px; bottom: 22px; z-index: 90; max-width: 330px; padding: 13px 17px; border-radius: 10px; color: white; background: var(--ink); box-shadow: var(--shadow); font-size: 11px; font-weight: 700; opacity: 0; pointer-events: none; transform: translateY(10px); transition: .22s ease; }
.toast.is-visible { opacity: 1; transform: translateY(0); }

@media (max-width: 900px) {
  .main-nav { display: none; }
  .menu-button { display: grid; }
  .mobile-menu { position: fixed; z-index: 39; top: 78px; left: 0; right: 0; padding: 13px 24px 18px; background: var(--paper); border-bottom: 1px solid var(--line); box-shadow: var(--small-shadow); }
  .mobile-menu:not([hidden]) { display: grid; }
  .mobile-menu .nav-link { text-align: left; }
  .mobile-menu .nav-link.is-active::after { display: none; }
  .hero-shell { grid-template-columns: 1fr; padding-top: 55px; gap: 25px; }
  .hero-copy { max-width: 670px; }
  .hero-visual { min-height: 470px; }
  .monitor { width: min(72vw, 420px); }
  .lesson-grid { grid-template-columns: repeat(2, 1fr); }
  .lesson-layout { grid-template-columns: 1fr; padding-top: 28px; }
  .lesson-sidebar { position: static; }
  .course-progress { margin-bottom: 15px; }
  .lesson-list { display: flex; overflow-x: auto; gap: 5px; padding-bottom: 8px; }
  .lesson-list li { min-width: 145px; }
  .sidebar-lesson { grid-template-columns: 25px 1fr; }
}

@media (max-width: 650px) {
  .site-header { height: 68px; padding: 0 18px; }
  .mobile-menu { top: 68px; }
  .hero-shell { min-height: auto; padding: 43px 23px 50px; }
  .hero-copy h1 { font-size: clamp(43px, 12.8vw, 50px); letter-spacing: -2px; overflow-wrap: break-word; }
  .hero-lede { font-size: 15px; }
  .platform-picker { align-items: stretch; flex-direction: column; margin-top: 35px; }
  .segmented-control { width: 100%; }
  .platform-option { flex: 1; }
  .hero-visual { min-height: 390px; }
  .hero-visual::before { width: 300px; height: 300px; }
  .monitor { width: min(82vw, 360px); }
  .note-top { right: -2%; }
  .note-bottom { left: -2%; bottom: 0; }
  .floating-note { min-width: 170px; }
  .section-shell { width: min(100% - 36px, 1170px); }
  .learning-path { padding: 65px 0 75px; }
  .section-heading { align-items: start; flex-direction: column; gap: 14px; }
  .lesson-grid { grid-template-columns: 1fr; }
  .confidence-inner { min-height: 220px; }
  .confidence-decoration { display: none; }
  .site-footer { align-items: start; flex-direction: column; gap: 12px; }
  .lesson-layout { padding: 22px 18px 70px; gap: 34px; }
  .lesson-topbar { gap: 15px; }
  .lesson-topbar .segmented-control { width: auto; }
  .lesson-header { grid-template-columns: 1fr; }
  .lesson-block { grid-template-columns: 1fr; gap: 12px; }
  .comparison-grid { grid-template-columns: 1fr; }
  .email-shell { grid-template-columns: 75px 1fr; }
  .safety-choice-grid { grid-template-columns: 1fr; }
  .lesson-footer { gap: 10px; }
  .lesson-footer button { flex: 1; }
  .shortcuts-view, .teacher-view { padding-top: 55px; }
  .page-intro h1 { font-size: 48px; letter-spacing: -2px; }
  .shortcut-toolbar { align-items: stretch; flex-direction: column; gap: 14px; }
  .shortcut-table th, .shortcut-table td { padding: 14px 9px; }
  .shortcut-table td:first-child { width: 42%; }
  .teacher-grid { grid-template-columns: 1fr; }
  .teacher-card.featured { grid-row: auto; }
}

@media print {
  body { background: white; }
  .site-header, .site-footer, .shortcut-toolbar, .shortcut-note, .home-view, .lesson-view, .teacher-view { display: none !important; }
  .shortcuts-view { display: block !important; padding: 20px 0; }
  .shortcut-table-wrap { border: 1px solid #aaa; }
}

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