@import url('https://fonts.googleapis.com/css2?family=Heebo:wght@400;500;600;700;800;900&display=swap');

:root {
  --ink: #152238;
  --muted: #667085;
  --paper: #fffdf7;
  --surface: #ffffff;
  --cream: #fff5db;
  --navy: #17324d;
  --navy-2: #234d6f;
  --coral: #ff6b5e;
  --coral-dark: #d9473d;
  --cyan: #4bc3c8;
  --cyan-soft: #dff8f7;
  --yellow: #ffd45a;
  --green: #42b883;
  --green-soft: #e3f8ef;
  --purple: #7957d5;
  --purple-soft: #eee8ff;
  --line: #dbe2e8;
  --shadow: 0 14px 40px rgba(23, 50, 77, 0.11);
  --shadow-sm: 0 5px 0 rgba(23, 50, 77, 0.09);
  --radius: 24px;
  --radius-sm: 14px;
  --max: 1180px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 8% 18%, rgba(75, 195, 200, 0.09) 0 120px, transparent 121px),
    radial-gradient(circle at 95% 46%, rgba(255, 212, 90, 0.12) 0 170px, transparent 171px),
    var(--paper);
  font-family: "Heebo", Arial, sans-serif;
  line-height: 1.65;
  direction: rtl;
  min-height: 100vh;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: 0.3;
  background-image: radial-gradient(#17324d 0.65px, transparent 0.65px);
  background-size: 22px 22px;
  mask-image: linear-gradient(to bottom, black, transparent 40%);
  z-index: -1;
}

a { color: inherit; text-decoration: none; }
button, input, select { font: inherit; }
button { color: inherit; }
img, svg, canvas { max-width: 100%; }
[hidden] { display: none !important; }

.skip-link {
  position: fixed;
  top: 8px;
  right: 8px;
  transform: translateY(-150%);
  background: var(--navy);
  color: white;
  padding: 10px 16px;
  border-radius: 10px;
  z-index: 1000;
}
.skip-link:focus { transform: translateY(0); }

:focus-visible { outline: 4px solid rgba(75, 195, 200, 0.55); outline-offset: 3px; }

.shell { width: min(var(--max), calc(100% - 36px)); margin-inline: auto; }
.narrow { width: min(820px, calc(100% - 36px)); margin-inline: auto; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 253, 247, 0.91);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(23, 50, 77, 0.1);
}

.topbar {
  min-height: 74px;
  display: flex;
  align-items: center;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 900;
  font-size: 1.2rem;
  white-space: nowrap;
}

.brand-mark {
  width: 43px;
  height: 43px;
  display: grid;
  place-items: center;
  border: 2px solid var(--navy);
  border-radius: 13px 13px 18px 13px;
  color: var(--navy);
  background: var(--yellow);
  box-shadow: 3px 4px 0 var(--navy);
  font-size: 1.5rem;
  line-height: 1;
  transform: rotate(2deg);
}

.main-nav { display: flex; gap: 5px; align-items: center; margin-inline-start: auto; }
.main-nav a {
  padding: 9px 13px;
  border-radius: 12px;
  color: #415168;
  font-weight: 700;
  font-size: 0.96rem;
}
.main-nav a:hover, .main-nav a[aria-current="page"] { color: var(--navy); background: var(--cream); }

.header-progress {
  min-width: 160px;
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 4px 10px;
  align-items: center;
  font-size: 0.78rem;
  font-weight: 800;
}
.header-progress .track { grid-column: 1 / -1; }

.track { height: 8px; background: #e6e9ed; border-radius: 20px; overflow: hidden; }
.track > span {
  display: block;
  height: 100%;
  width: var(--progress, 0%);
  background: linear-gradient(90deg, var(--coral), var(--yellow));
  border-radius: inherit;
  transition: width 600ms cubic-bezier(.2,.8,.2,1);
}

.menu-button {
  display: none;
  border: 2px solid var(--navy);
  background: white;
  width: 44px;
  height: 44px;
  border-radius: 12px;
  cursor: pointer;
  font-weight: 900;
}

.hero { padding: 72px 0 46px; overflow: hidden; }
.hero-grid { display: grid; grid-template-columns: minmax(0, 1.06fr) minmax(340px, .94fr); align-items: center; gap: 56px; }
.eyebrow, .lesson-kicker {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 12px;
  border: 1px solid rgba(23,50,77,.15);
  background: white;
  border-radius: 99px;
  color: var(--navy-2);
  font-size: 0.86rem;
  font-weight: 800;
  box-shadow: var(--shadow-sm);
}
.eyebrow::before, .lesson-kicker::before { content: ""; width: 9px; height: 9px; border-radius: 50%; background: var(--coral); }

h1, h2, h3, p { margin-top: 0; }
h1 { font-size: clamp(2.75rem, 6vw, 5.4rem); letter-spacing: -0.055em; line-height: .98; margin: 22px 0 24px; color: var(--navy); }
h2 { color: var(--navy); font-size: clamp(1.85rem, 4vw, 3rem); line-height: 1.12; letter-spacing: -0.035em; margin-bottom: 15px; }
h3 { color: var(--navy); font-size: 1.25rem; line-height: 1.3; }
.hero h1 .scribble { color: var(--coral); position: relative; white-space: nowrap; }
.hero h1 .scribble::after {
  content: "";
  position: absolute;
  right: 3%; left: 0; bottom: -7px;
  height: 8px;
  background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='300' height='12' viewBox='0 0 300 12'%3E%3Cpath d='M2 8 C60 1 120 11 178 5 S250 3 298 7' fill='none' stroke='%23ff6b5e' stroke-width='4' stroke-linecap='round'/%3E%3C/svg%3E") center/100% 100% no-repeat;
}
.lead { font-size: 1.2rem; color: #4f5f72; max-width: 630px; line-height: 1.75; }
.hero-actions, .button-row { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; align-items: center; }

.btn {
  border: 2px solid var(--navy);
  border-radius: 14px;
  padding: 12px 20px;
  display: inline-flex;
  justify-content: center;
  align-items: center;
  gap: 9px;
  min-height: 49px;
  background: white;
  color: var(--navy);
  font-weight: 800;
  cursor: pointer;
  box-shadow: 3px 4px 0 var(--navy);
  transition: transform .15s, box-shadow .15s, background .15s;
}
.btn:hover { transform: translate(1px, 2px); box-shadow: 2px 2px 0 var(--navy); }
.btn:active { transform: translate(3px, 4px); box-shadow: 0 0 0 var(--navy); }
.btn-primary { background: var(--coral); color: white; }
.btn-secondary { background: var(--yellow); }
.btn-ghost { box-shadow: none; border-color: var(--line); }
.btn-small { min-height: 38px; padding: 7px 13px; border-width: 1.5px; box-shadow: 2px 2px 0 var(--navy); font-size: .9rem; }
.btn[disabled] { opacity: .45; cursor: not-allowed; transform: none; }

.hero-visual { position: relative; min-height: 420px; display: grid; place-items: center; }
.plane-card {
  width: min(430px, 100%);
  aspect-ratio: 1.08;
  background-color: white;
  background-image:
    linear-gradient(rgba(23, 50, 77, .075) 1px, transparent 1px),
    linear-gradient(90deg, rgba(23, 50, 77, .075) 1px, transparent 1px);
  background-size: 34px 34px;
  border: 2px solid var(--navy);
  border-radius: 38px 38px 60px 32px;
  box-shadow: 11px 13px 0 var(--cyan), var(--shadow);
  position: relative;
  transform: rotate(-2deg);
  overflow: hidden;
}
.axis-x, .axis-y { position: absolute; background: var(--navy); opacity: .74; }
.axis-x { height: 2px; left: 9%; right: 9%; top: 53%; }
.axis-y { width: 2px; top: 9%; bottom: 9%; left: 48%; }
.axis-x::after, .axis-y::after { content: ""; position: absolute; border-style: solid; }
.axis-x::after { right: -1px; top: -5px; border-width: 6px 0 6px 9px; border-color: transparent transparent transparent var(--navy); }
.axis-y::after { left: -5px; top: -1px; border-width: 0 6px 9px; border-color: transparent transparent var(--navy); }
.complex-vector { position: absolute; left: 48%; top: 53%; width: 34%; height: 4px; transform: rotate(-37deg); transform-origin: left center; background: var(--coral); border-radius: 9px; }
.complex-vector::after { content: ""; position: absolute; left: calc(100% - 8px); top: -7px; width: 15px; height: 15px; background: var(--coral); border: 3px solid white; border-radius: 50%; box-shadow: 0 0 0 2px var(--navy); }
.vector-label { position: absolute; top: 24%; left: 72%; background: var(--yellow); border: 2px solid var(--navy); padding: 7px 11px; border-radius: 11px; font-weight: 900; direction: ltr; transform: rotate(2deg); }
.axis-label { position: absolute; font-size: .78rem; font-weight: 800; color: var(--navy); }
.axis-label.real { top: 48%; right: 4%; }
.axis-label.imag { top: 4%; left: 51%; }
.float-chip { position: absolute; padding: 10px 14px; border: 2px solid var(--navy); border-radius: 15px; font-weight: 900; background: white; box-shadow: 4px 5px 0 var(--navy); z-index: 2; }
.float-chip.one { top: 2%; right: 0; transform: rotate(5deg); }
.float-chip.two { bottom: 3%; left: -2%; background: var(--purple-soft); transform: rotate(-4deg); }
.mascot {
  position: absolute;
  bottom: 0; right: 7%;
  width: 86px; height: 86px;
  background: var(--yellow);
  border: 3px solid var(--navy);
  border-radius: 48% 52% 46% 54%;
  box-shadow: 5px 6px 0 var(--navy);
  transform: rotate(6deg);
  z-index: 3;
}
.mascot::before { content: "• ᴗ •"; white-space: pre; position: absolute; inset: 21px 0 0; text-align: center; direction: ltr; font-size: 1.25rem; font-weight: 900; }
.mascot::after { content: "i"; position: absolute; top: -31px; left: 29px; color: var(--coral); font-size: 2.8rem; font-weight: 900; }

.section { padding: 76px 0; }
.section-soft { background: rgba(223, 248, 247, .48); border-block: 1px solid rgba(23,50,77,.08); }
.section-head { display: flex; justify-content: space-between; gap: 24px; align-items: end; margin-bottom: 32px; }
.section-head > p { max-width: 520px; color: var(--muted); margin: 0; }
.section-label { color: var(--coral-dark); font-weight: 900; letter-spacing: .04em; font-size: .82rem; text-transform: uppercase; margin-bottom: 8px; }

.stat-row { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin-top: 30px; }
.stat {
  padding: 15px;
  border: 1px solid var(--line);
  border-radius: 15px;
  background: rgba(255,255,255,.75);
}
.stat strong { display: block; font-size: 1.35rem; color: var(--navy); }
.stat span { color: var(--muted); font-size: .86rem; }

.course-map { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; counter-reset: lesson; }
.lesson-card {
  position: relative;
  min-height: 255px;
  padding: 25px;
  background: white;
  border: 1.5px solid var(--line);
  border-radius: var(--radius);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  transition: transform .2s, border-color .2s, box-shadow .2s;
}
.lesson-card:hover { transform: translateY(-5px); border-color: var(--navy); box-shadow: var(--shadow); }
.lesson-card::after { content: ""; position: absolute; width: 110px; height: 110px; left: -30px; bottom: -38px; border-radius: 50%; background: var(--accent-soft, var(--cream)); }
.lesson-number { display: flex; align-items: center; gap: 8px; color: var(--muted); font-weight: 800; font-size: .84rem; }
.lesson-number::before { counter-increment: lesson; content: "0" counter(lesson); color: var(--accent, var(--coral)); font-size: 1.15rem; }
.lesson-icon { width: 51px; height: 51px; display: grid; place-items: center; border-radius: 15px; background: var(--accent-soft, var(--cream)); color: var(--accent, var(--coral)); font-size: 1.5rem; font-weight: 900; margin: 17px 0 13px; direction: ltr; }
.lesson-card h3 { margin-bottom: 7px; }
.lesson-card p { color: var(--muted); font-size: .94rem; margin-bottom: 18px; }
.lesson-link { margin-top: auto; position: relative; z-index: 1; font-weight: 900; color: var(--accent, var(--coral-dark)); }
.lesson-link::after { content: " ←"; }
.lesson-status { position: absolute; left: 18px; top: 18px; width: 26px; height: 26px; border-radius: 50%; display: grid; place-items: center; border: 2px solid var(--line); background: white; color: white; font-size: .75rem; z-index: 2; }
.lesson-card.is-complete .lesson-status { background: var(--green); border-color: var(--green); }

.level-banner {
  background: var(--navy);
  color: white;
  border-radius: 32px;
  padding: 38px;
  display: grid;
  grid-template-columns: 1.1fr .9fr;
  gap: 40px;
  align-items: center;
  box-shadow: 9px 10px 0 var(--yellow);
}
.level-banner h2 { color: white; }
.level-banner p { color: #d5e2ec; }
.level-banner .track { height: 14px; background: rgba(255,255,255,.14); }
.level-data { display: flex; justify-content: space-between; margin-bottom: 10px; font-weight: 800; }
.badge-row { display: flex; gap: 10px; margin-top: 22px; flex-wrap: wrap; }
.badge { padding: 7px 11px; border-radius: 99px; background: rgba(255,255,255,.11); color: #dce8f2; font-size: .84rem; border: 1px solid rgba(255,255,255,.14); }
.badge.earned { color: var(--navy); background: var(--yellow); border-color: var(--yellow); font-weight: 900; }

.lesson-hero { padding: 52px 0 36px; }
.lesson-hero-grid { display: grid; grid-template-columns: 1fr 300px; gap: 48px; align-items: center; }
.lesson-hero h1 { font-size: clamp(2.45rem, 6vw, 4.8rem); }
.lesson-meta { display: flex; gap: 18px; flex-wrap: wrap; color: var(--muted); font-weight: 700; font-size: .92rem; }
.lesson-meta span { display: inline-flex; align-items: center; gap: 7px; }
.lesson-orb {
  aspect-ratio: 1;
  border-radius: 44% 56% 62% 38%;
  background: var(--lesson-soft, var(--cyan-soft));
  border: 2px solid var(--navy);
  box-shadow: 10px 11px 0 var(--lesson-color, var(--cyan));
  display: grid;
  place-items: center;
  font-size: 5rem;
  font-weight: 900;
  color: var(--navy);
  direction: ltr;
  transform: rotate(-3deg);
}

.lesson-layout { display: grid; grid-template-columns: minmax(0, 1fr) 260px; gap: 42px; align-items: start; }
.lesson-content > section { scroll-margin-top: 100px; margin-bottom: 62px; }
.lesson-content p { font-size: 1.06rem; }
.lesson-aside { position: sticky; top: 98px; }
.toc { background: white; border: 1px solid var(--line); border-radius: 18px; padding: 18px; box-shadow: var(--shadow-sm); }
.toc strong { display: block; margin-bottom: 9px; }
.toc a { display: block; padding: 7px 10px; border-radius: 9px; color: var(--muted); font-size: .92rem; }
.toc a:hover { background: var(--cream); color: var(--navy); }
.aside-tip { margin-top: 16px; background: var(--yellow); border: 1.5px solid var(--navy); border-radius: 18px; padding: 17px; transform: rotate(1deg); box-shadow: 4px 5px 0 var(--navy); }
.aside-tip strong { display: block; margin-bottom: 5px; }
.aside-tip p { font-size: .9rem; margin: 0; }

.concept-card, .worked-example, .note-card {
  background: white;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px;
  margin: 22px 0;
}
.concept-card { border-right: 6px solid var(--lesson-color, var(--cyan)); }
.worked-example { background: var(--cream); border-color: #ecd9a7; }
.worked-example .example-label { color: var(--coral-dark); font-weight: 900; font-size: .8rem; letter-spacing: .06em; }
.math {
  direction: ltr;
  unicode-bidi: isolate;
  display: inline-block;
  font-family: "Times New Roman", Georgia, serif;
  font-style: italic;
  font-size: 1.12em;
}
.math-block {
  direction: ltr;
  unicode-bidi: isolate;
  text-align: center;
  padding: 18px;
  margin: 17px 0;
  border-radius: 14px;
  background: rgba(255,255,255,.72);
  border: 1px dashed rgba(23,50,77,.27);
  font-family: "Times New Roman", Georgia, serif;
  font-size: clamp(1.25rem, 3vw, 1.65rem);
}
.formula-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 13px; }
.formula-tile { background: white; border: 1px solid var(--line); border-radius: 14px; padding: 15px; text-align: center; }
.formula-tile .math { display: block; font-size: 1.25rem; margin-bottom: 4px; }
.formula-tile small { color: var(--muted); }

.steps { list-style: none; padding: 0; counter-reset: step; }
.steps li { position: relative; padding: 0 50px 24px 0; counter-increment: step; }
.steps li::before { content: counter(step); position: absolute; right: 0; top: 0; width: 32px; height: 32px; display: grid; place-items: center; border-radius: 50%; background: var(--navy); color: white; font-weight: 900; }
.steps li:not(:last-child)::after { content: ""; position: absolute; right: 15px; top: 35px; bottom: 4px; width: 2px; background: var(--line); }

.check-card {
  padding: 22px;
  background: var(--purple-soft);
  border: 1px solid #cfc0fa;
  border-radius: 18px;
  margin: 24px 0;
}
.check-card summary { cursor: pointer; font-weight: 900; color: var(--navy); }
.check-card .answer { padding-top: 14px; color: #4f3d86; }

.practice-lab {
  background: var(--navy);
  color: white;
  border-radius: 30px;
  padding: clamp(23px, 5vw, 38px);
  box-shadow: 9px 10px 0 var(--lesson-color, var(--cyan));
  margin: 36px 0;
}
.practice-top { display: flex; justify-content: space-between; gap: 24px; align-items: start; }
.practice-lab h2, .practice-lab h3 { color: white; }
.practice-lab .muted { color: #bfd0dd; }
.quiz-score { white-space: nowrap; padding: 7px 12px; border-radius: 99px; background: rgba(255,255,255,.1); font-weight: 800; }
.question-count { font-size: .86rem; color: #bdd1df; font-weight: 700; }
.quiz-question { font-size: clamp(1.35rem, 3vw, 1.8rem); font-weight: 800; margin: 14px 0 18px; min-height: 52px; }
.quiz-options { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 11px; direction: ltr; }
.quiz-option {
  min-height: 58px;
  border: 2px solid rgba(255,255,255,.2);
  border-radius: 14px;
  background: rgba(255,255,255,.07);
  color: white;
  padding: 11px 15px;
  font-weight: 800;
  cursor: pointer;
  transition: background .15s, border .15s, transform .15s;
}
.quiz-option:hover { background: rgba(255,255,255,.14); transform: translateY(-2px); }
.quiz-option.selected { border-color: var(--yellow); background: rgba(255,212,90,.15); }
.quiz-option.correct { border-color: var(--green); background: rgba(66,184,131,.22); }
.quiz-option.wrong { border-color: var(--coral); background: rgba(255,107,94,.23); }
.quiz-option[disabled] { cursor: default; transform: none; }
.quiz-feedback { min-height: 55px; margin-top: 15px; padding: 12px 15px; border-radius: 12px; display: none; }
.quiz-feedback.show { display: block; }
.quiz-feedback.good { background: rgba(66,184,131,.18); color: #c7ffe6; }
.quiz-feedback.bad { background: rgba(255,107,94,.17); color: #ffe0dc; }
.quiz-actions { display: flex; gap: 10px; margin-top: 16px; }
.practice-lab .btn { box-shadow: 3px 4px 0 #0a1b2a; }
.quiz-finish { text-align: center; padding: 18px 0 4px; }
.quiz-finish .finish-icon { font-size: 3.7rem; display: block; }
.quiz-finish strong { font-size: 2rem; display: block; }

.tool-card { background: white; border: 1.5px solid var(--line); border-radius: var(--radius); padding: 25px; box-shadow: var(--shadow-sm); margin: 24px 0; }
.input-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; }
.field label { display: block; font-size: .84rem; font-weight: 800; margin-bottom: 5px; color: var(--muted); }
.field input, .field select {
  width: 100%; min-height: 47px; border: 1.5px solid var(--line); border-radius: 11px; padding: 8px 11px; background: var(--paper); color: var(--ink); direction: ltr;
}
.field input:focus { border-color: var(--cyan); outline: 3px solid rgba(75,195,200,.18); }
.tool-result { margin-top: 18px; padding: 18px; border-radius: 14px; background: var(--cyan-soft); border: 1px solid #a5dfdc; }
.result-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 10px; direction: ltr; }
.result-grid span { background: white; border-radius: 10px; padding: 10px; text-align: center; }

.canvas-wrap { display: grid; grid-template-columns: minmax(280px, 520px) 1fr; gap: 24px; align-items: center; }
.math-canvas { width: 100%; aspect-ratio: 1; background: #fff; border: 2px solid var(--navy); border-radius: 22px; box-shadow: 6px 7px 0 var(--lesson-color, var(--cyan)); touch-action: none; }
.canvas-panel { padding: 20px; background: var(--cream); border-radius: 18px; border: 1px solid #ead8a8; }
.canvas-target { font-size: 1.5rem; font-weight: 900; direction: ltr; text-align: center; margin: 15px 0; }
.canvas-message { min-height: 50px; font-weight: 700; }

.pill-list { display: flex; flex-wrap: wrap; gap: 9px; padding: 0; list-style: none; }
.pill-list li { padding: 6px 11px; background: var(--cyan-soft); border: 1px solid #b3e5e2; border-radius: 99px; font-size: .9rem; font-weight: 700; }

.callout { display: flex; gap: 15px; padding: 19px; background: var(--green-soft); border: 1px solid #b6e9d3; border-radius: 17px; margin: 22px 0; }
.callout-icon { flex: 0 0 38px; width: 38px; height: 38px; display: grid; place-items: center; border-radius: 11px; background: var(--green); color: white; font-weight: 900; }
.callout p { margin: 0; font-size: .96rem; }

.page-hero { padding: 58px 0 34px; text-align: center; }
.page-hero h1 { font-size: clamp(2.6rem, 7vw, 5rem); }
.page-hero .lead { margin-inline: auto; }
.arena-grid { display: grid; grid-template-columns: 1.3fr .7fr; gap: 24px; align-items: start; }
.mission-list { display: grid; gap: 12px; }
.mission { display: flex; gap: 14px; align-items: center; padding: 15px; border: 1px solid var(--line); border-radius: 15px; background: white; }
.mission-icon { width: 42px; height: 42px; flex: 0 0 42px; display: grid; place-items: center; border-radius: 12px; background: var(--purple-soft); }
.mission strong { display: block; }
.mission small { color: var(--muted); }

.reference-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; }
.reference-card { background: white; border: 1px solid var(--line); border-radius: 20px; padding: 23px; }
.reference-card h2 { font-size: 1.35rem; }
.reference-card ul { padding-right: 19px; margin-bottom: 0; }
.reference-card li { margin-bottom: 8px; }

.next-lesson {
  margin: 70px 0 20px;
  padding: 28px;
  background: var(--lesson-soft, var(--cyan-soft));
  border-radius: 24px;
  border: 1.5px solid var(--navy);
  display: flex;
  gap: 20px;
  align-items: center;
  justify-content: space-between;
}
.next-lesson p { margin: 0; color: var(--muted); }

.site-footer { margin-top: 80px; background: var(--navy); color: #d8e4ed; padding: 42px 0 28px; }
.footer-grid { display: grid; grid-template-columns: 1fr auto; gap: 30px; align-items: start; }
.site-footer .brand { color: white; }
.site-footer p { max-width: 480px; margin: 14px 0 0; color: #b7c8d6; }
.footer-links { display: flex; gap: 17px; flex-wrap: wrap; }
.footer-links a:hover { color: var(--yellow); }
.footer-bottom { border-top: 1px solid rgba(255,255,255,.12); margin-top: 26px; padding-top: 18px; color: #91a8ba; font-size: .85rem; }
.toast { position: fixed; left: 22px; bottom: 22px; z-index: 200; max-width: 330px; padding: 14px 17px; border-radius: 15px; color: white; background: var(--navy); box-shadow: var(--shadow); transform: translateY(140%); opacity: 0; transition: .25s; }
.toast.show { transform: translateY(0); opacity: 1; }
.toast strong { color: var(--yellow); }

@media (max-width: 980px) {
  .header-progress { display: none; }
  .hero-grid, .lesson-hero-grid { grid-template-columns: 1fr; }
  .hero-visual { width: min(480px, 94%); margin-inline: auto; }
  .course-map { grid-template-columns: repeat(2, 1fr); }
  .lesson-orb { width: 230px; justify-self: center; }
  .lesson-layout { grid-template-columns: 1fr; }
  .lesson-aside { display: none; }
  .canvas-wrap, .arena-grid { grid-template-columns: 1fr; }
}

@media (max-width: 760px) {
  .shell, .narrow { width: min(100% - 24px, var(--max)); }
  .topbar { min-height: 66px; }
  .menu-button { display: grid; place-items: center; margin-inline-start: auto; }
  .main-nav {
    position: absolute;
    display: none;
    top: calc(100% + 1px);
    right: 12px; left: 12px;
    padding: 10px;
    background: var(--paper);
    border: 1px solid var(--line);
    border-radius: 0 0 18px 18px;
    box-shadow: var(--shadow);
    flex-direction: column;
    align-items: stretch;
  }
  .main-nav.open { display: flex; }
  .main-nav a { padding: 11px 14px; }
  .hero { padding-top: 48px; }
  .hero-grid { gap: 30px; }
  .hero-visual { min-height: 330px; }
  .plane-card { width: 330px; max-width: 94%; }
  .float-chip { font-size: .82rem; }
  .section { padding: 58px 0; }
  .section-head { align-items: start; flex-direction: column; }
  .course-map, .reference-grid { grid-template-columns: 1fr; }
  .stat-row { grid-template-columns: repeat(2, 1fr); }
  .level-banner { grid-template-columns: 1fr; padding: 28px 23px; }
  .lesson-hero { padding-top: 38px; }
  .lesson-orb { width: 180px; font-size: 4rem; }
  .formula-grid, .quiz-options, .result-grid { grid-template-columns: 1fr; }
  .input-grid { grid-template-columns: repeat(2, 1fr); }
  .practice-top { flex-direction: column; gap: 8px; }
  .next-lesson { align-items: stretch; flex-direction: column; }
  .footer-grid { grid-template-columns: 1fr; }
}

@media (max-width: 420px) {
  h1 { font-size: 2.65rem; }
  .brand span:last-child { font-size: 1rem; }
  .input-grid { grid-template-columns: 1fr; }
  .hero-actions .btn { width: 100%; }
}

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