:root {
  --ink: #172438;
  --muted: #68788a;
  --paper: #f7f5ef;
  --cream: #fffdf7;
  --lime: #c6f36b;
  --coral: #ff725e;
  --blue: #7fc5ff;
  --line: #dfe5e4;
  --shadow: 0 20px 55px rgba(23, 36, 56, .12);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: var(--paper); font-family: "Space Grotesk", system-ui, sans-serif; }
button, a { font: inherit; }
button { cursor: pointer; }
a { color: inherit; text-decoration: none; }
.site-shell { max-width: 1440px; margin: 0 auto; overflow: hidden; background: var(--paper); }
.topbar { min-height: 82px; padding: 18px 5.5%; display: flex; align-items: center; gap: 32px; border-bottom: 1px solid var(--line); background: rgba(247,245,239,.92); }
.brand { display: flex; align-items: center; gap: 10px; font-size: 24px; font-weight: 700; letter-spacing: -.08em; }
.brand > span:last-child > span, .footer > span:first-child > span { color: var(--coral); }
.brand-mark { display: grid; place-items: center; width: 32px; height: 32px; color: var(--ink); background: var(--lime); border-radius: 10px 10px 10px 3px; font-family: Georgia, serif; font-size: 25px; font-weight: 400; transform: rotate(-8deg); }
.main-nav { display: flex; gap: 26px; margin-left: 28px; color: var(--muted); font-size: 14px; }
.main-nav a:hover { color: var(--ink); }
.account-actions { display: flex; gap: 8px; margin-left: auto; }
.button { border: 1px solid transparent; border-radius: 999px; padding: 10px 16px; color: var(--ink); font-weight: 600; font-size: 13px; transition: transform .2s, box-shadow .2s, background .2s; }
.button:hover { transform: translateY(-2px); box-shadow: 0 6px 16px rgba(23,36,56,.12); }
.button-quiet { background: transparent; }
.button-quiet:hover { background: var(--cream); }
.button-bright { background: var(--lime); }
.button-large { padding: 15px 22px; font-size: 15px; }
.button-large span { margin-left: 15px; font-size: 20px; line-height: 0; }
.menu-toggle { display: none; border: 0; background: none; color: var(--ink); font-size: 22px; }
.placeholder-home { display: grid; min-height: calc(100vh - 155px); place-content: center; justify-items: center; padding: 80px 6%; text-align: center; }
.placeholder-home h1 { margin-bottom: 22px; }
.placeholder-home > p:last-child { max-width: 440px; margin-bottom: 0; color: var(--muted); font-size: 16px; line-height: 1.6; }
.hero { display: grid; grid-template-columns: 1.04fr .96fr; gap: 6%; padding: 96px 9% 110px; min-height: 590px; align-items: center; }
.eyebrow { margin: 0 0 18px; color: var(--muted); font-family: "DM Mono", monospace; font-size: 11px; letter-spacing: .1em; text-transform: uppercase; }
.eyebrow-dot { display: inline-block; width: 8px; height: 8px; margin-right: 8px; border-radius: 50%; background: var(--lime); }
.eyebrow-dot.coral { background: var(--coral); }
h1, h2, h3, p { margin-top: 0; }
h1 { max-width: 600px; margin-bottom: 22px; font-size: clamp(52px, 6vw, 86px); line-height: .98; letter-spacing: -.075em; }
h1 em { color: var(--coral); font-family: Georgia, serif; font-weight: 400; letter-spacing: -.08em; }
.hero-text { max-width: 470px; color: var(--muted); font-size: 17px; line-height: 1.6; }
.hero-cta { display: flex; align-items: center; gap: 20px; margin-top: 36px; }
.hero-cta p { max-width: 150px; margin: 0; color: var(--muted); font-size: 11px; line-height: 1.35; }
.hero-art { position: relative; min-height: 390px; border-radius: 46% 54% 55% 45% / 42% 44% 56% 58%; background: var(--blue); transform: rotate(4deg); isolation: isolate; }
.hero-art::before { content: ""; position: absolute; inset: 11px; z-index: -1; border: 1px solid rgba(23,36,56,.13); border-radius: inherit; }
.orbit { position: absolute; border: 1px solid rgba(23,36,56,.18); border-radius: 50%; transform: rotate(-20deg); }
.orbit-one { inset: 15% -5% 15% -5%; }
.orbit-two { inset: 29% -14% 29% -14%; transform: rotate(58deg); }
.orbit-three { inset: -7% 26% -7% 26%; transform: rotate(72deg); }
.math-card { position: absolute; padding: 15px 19px; background: var(--cream); box-shadow: var(--shadow); transform: rotate(-7deg); }
.math-card span { display: block; margin-bottom: 4px; color: var(--muted); font-family: "DM Mono", monospace; font-size: 10px; text-transform: uppercase; }
.math-card strong { font-family: Georgia, serif; font-size: 29px; font-weight: 400; }
.card-top { top: 13%; left: 9%; border-radius: 14px 5px 14px 14px; }
.card-bottom { right: 7%; bottom: 14%; transform: rotate(7deg); border-radius: 5px 14px 14px 14px; }
.hero-equation { position: absolute; top: 43%; left: 19%; color: var(--ink); font-family: Georgia, serif; font-size: clamp(34px, 4vw, 60px); letter-spacing: -.07em; transform: rotate(-4deg); }
.hero-badge { position: absolute; right: 8%; top: 12%; display: grid; place-items: center; width: 92px; height: 92px; padding-top: 10px; border-radius: 50%; color: var(--cream); background: var(--coral); font-family: "DM Mono", monospace; font-size: 10px; line-height: 1.15; text-align: center; transform: rotate(11deg); }
.hero-badge strong { font-size: 11px; }
.hero-badge span { position: absolute; right: -5px; bottom: 4px; color: var(--ink); font-size: 17px; }
.mission-section { padding: 94px 9% 100px; color: var(--cream); background: var(--ink); }
.section-heading { display: flex; align-items: end; justify-content: space-between; gap: 30px; margin-bottom: 30px; }
.section-heading .eyebrow { color: #9aaabc; }
h2 { margin-bottom: 0; font-size: clamp(36px, 5vw, 63px); line-height: 1; letter-spacing: -.07em; }
.lesson-meta { display: flex; gap: 12px; color: #9aaabc; font-family: "DM Mono", monospace; font-size: 10px; text-transform: uppercase; }
.lesson-meta span { padding-left: 12px; border-left: 1px solid #405065; }
.lesson-card { display: grid; grid-template-columns: .86fr 1.14fr; min-height: 475px; overflow: hidden; border: 1px solid #334257; border-radius: 22px; background: #202f44; box-shadow: 0 25px 60px rgba(0,0,0,.2); }
.lesson-intro { padding: 44px; border-right: 1px solid #334257; }
.mission-number { color: var(--lime); font-family: "DM Mono", monospace; font-size: 30px; }
.mission-number span { color: #718197; font-size: 13px; }
.lesson-kicker { margin-top: 70px; margin-bottom: 12px; color: var(--coral); font-family: "DM Mono", monospace; font-size: 11px; text-transform: uppercase; }
.lesson-intro h3 { max-width: 400px; font-size: 30px; line-height: 1.08; letter-spacing: -.06em; }
.lesson-description { max-width: 400px; color: #a7b4c2; font-size: 14px; line-height: 1.55; }
.tip { display: flex; gap: 12px; margin-top: 28px; padding: 15px 17px; border: 1px solid #46556a; border-radius: 13px; color: #c0ccd7; font-size: 12px; line-height: 1.4; }
.tip span { color: var(--lime); font-size: 20px; }
.tip p { margin: 0; }
.tip strong { color: var(--cream); }
.lesson-play { padding: 42px 44px; background: #f1f4ed; color: var(--ink); }
.graph-wrap { position: relative; height: 210px; margin-bottom: 26px; overflow: hidden; border-bottom: 1px solid #9aa9aa; border-left: 1px solid #9aa9aa; }
.graph-grid { position: absolute; inset: 0; background-image: linear-gradient(#d9e1df 1px, transparent 1px), linear-gradient(90deg, #d9e1df 1px, transparent 1px); background-size: 11% 20%; }
.graph-axis-y, .graph-axis-x { position: absolute; background: #53646d; }
.graph-axis-y { left: 12%; top: 7%; bottom: 0; width: 2px; }
.graph-axis-x { left: 12%; right: 3%; bottom: 13%; height: 2px; }
.graph-line { position: absolute; left: 13%; bottom: 13%; width: 78%; height: 3px; background: var(--coral); transform: rotate(-27deg); transform-origin: left center; }
.graph-point { position: absolute; display: grid; place-items: center; width: 11px; height: 11px; border: 3px solid #f1f4ed; border-radius: 50%; background: var(--coral); box-shadow: 0 0 0 1px var(--coral); }
.graph-point span { position: absolute; top: -24px; color: var(--ink); font-family: "DM Mono", monospace; font-size: 10px; }
.point-a { left: 17%; bottom: 26%; }.point-b { left: 48%; bottom: 48%; }.point-c { left: 79%; bottom: 70%; }
.graph-label { position: absolute; color: #68788a; font-family: "DM Mono", monospace; font-size: 10px; text-transform: uppercase; }.y-label { top: 0; left: 13%; }.x-label { right: 1%; bottom: 0; }
.answer-label { margin-bottom: 12px; font-size: 13px; font-weight: 600; }
.answer-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 9px; }
.answer-choice { padding: 13px 12px; border: 1px solid #cdd8d5; border-radius: 9px; color: var(--ink); background: var(--cream); font-family: "DM Mono", monospace; font-size: 12px; transition: .2s; }
.answer-choice:hover, .answer-choice:focus-visible { border-color: var(--coral); background: #fff; transform: translateY(-2px); }
.answer-choice.correct { border-color: #6ca21b; background: var(--lime); }.answer-choice.wrong { border-color: var(--coral); background: #ffd9d1; }
.answer-feedback { min-height: 20px; margin: 15px 0 0; color: #58716e; font-size: 12px; font-weight: 600; }
.principles { display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px; padding: 55px 9%; }
.principle { display: flex; gap: 15px; }.principle-icon { display: grid; flex: 0 0 38px; place-items: center; height: 38px; border-radius: 12px; color: var(--ink); background: var(--lime); font-size: 20px; }.principle:nth-child(2) .principle-icon { background: var(--coral); }.principle:nth-child(3) .principle-icon { background: var(--blue); }
.principle h3 { margin-bottom: 5px; font-size: 16px; }.principle p { color: var(--muted); font-size: 12px; line-height: 1.45; }
.footer { display: flex; justify-content: space-between; padding: 30px 9%; border-top: 1px solid var(--line); color: var(--muted); font-family: "DM Mono", monospace; font-size: 10px; text-transform: uppercase; }.footer > span:first-child { color: var(--ink); font-family: "Space Grotesk", sans-serif; font-size: 18px; font-weight: 700; letter-spacing: -.08em; text-transform: none; }
.modal-backdrop { position: fixed; inset: 0; z-index: 5; display: grid; place-items: center; padding: 20px; background: rgba(23,36,56,.55); }.modal-backdrop[hidden] { display: none; }.modal { position: relative; max-width: 430px; padding: 42px; border-radius: 22px; background: var(--cream); box-shadow: var(--shadow); }.modal h2 { margin-bottom: 18px; font-size: 40px; }.modal-copy { margin-bottom: 28px; color: var(--muted); font-size: 14px; line-height: 1.55; }.modal-close { position: absolute; top: 14px; right: 17px; border: 0; background: transparent; color: var(--muted); font-size: 26px; }
@media (max-width: 900px) { .main-nav { display: none; }.topbar { padding: 16px 5%; }.account-actions { display: flex; flex-wrap: wrap; justify-content: flex-end; }.menu-toggle { display: none; }.hero { grid-template-columns: 1fr; padding: 70px 8% 85px; }.hero-art { min-height: 320px; max-width: 610px; width: 100%; margin: 0 auto; }.lesson-card { grid-template-columns: 1fr; }.lesson-intro { border-right: 0; border-bottom: 1px solid #334257; }.lesson-kicker { margin-top: 40px; }.section-heading { align-items: start; flex-direction: column; }.lesson-meta { flex-wrap: wrap; }.principles { grid-template-columns: 1fr; gap: 12px; }.footer { flex-wrap: wrap; gap: 12px; } }
@media (max-width: 520px) { h1 { font-size: 54px; }.hero { padding-right: 6%; padding-left: 6%; }.hero-cta { align-items: start; flex-direction: column; }.hero-art { min-height: 260px; }.hero-equation { font-size: 31px; }.math-card { padding: 10px 12px; }.math-card strong { font-size: 21px; }.hero-badge { width: 72px; height: 72px; font-size: 8px; }.lesson-section, .mission-section { padding-right: 6%; padding-left: 6%; }.lesson-intro, .lesson-play { padding: 28px 22px; }.answer-grid { grid-template-columns: 1fr; }.footer { padding-right: 6%; padding-left: 6%; } }