:root {
  --navy: #202b40;
  --navy-deep: #111a2d;
  --slate: #58677d;
  --dusty: #8895a6;
  --taupe: #c5b9ad;
  --ivory: #f3eee8;
  --paper: #fffdf9;
  --white: #ffffff;
  --ink: #182238;
  --muted: #68758a;
  --line: rgba(32, 43, 64, .14);
  --shadow: 0 22px 60px rgba(32, 43, 64, .14);
  --serif: Georgia, "Times New Roman", serif;
  --sans: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

*, *::before, *::after { 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, a { font: inherit; }
button { color: inherit; }
a { color: inherit; text-decoration: none; }
img, video { display: block; max-width: 100%; }
.shell { width: min(1180px, calc(100% - 48px)); margin-inline: auto; }
.section { padding: 104px 0; }
.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: 20px; top: -80px; z-index: 100; padding: 12px 18px; background: var(--ivory); color: var(--navy); border-radius: 8px; font-weight: 800; transition: top .2s; }
.skip-link:focus { top: 20px; }

.site-header { position: fixed; inset: 0 0 auto; z-index: 50; padding: 18px 0; transition: background .25s, box-shadow .25s, padding .25s; }
.site-header.scrolled { padding: 10px 0; background: rgba(255, 253, 249, .94); box-shadow: 0 8px 30px rgba(17, 26, 45, .08); backdrop-filter: blur(16px); }
.nav-shell { width: min(1240px, calc(100% - 40px)); margin-inline: auto; display: flex; align-items: center; justify-content: space-between; }
.brand { display: inline-flex; align-items: center; gap: 11px; color: white; font-size: 1.48rem; letter-spacing: -.025em; }
.wordmark { display: inline-flex; align-items: baseline; gap: 6px; }
.wordmark b { font-family: "Aptos", "Segoe UI", var(--sans); font-weight: 650; letter-spacing: .025em; }
.wordmark strong { font-family: var(--serif); font-weight: 500; font-style: italic; color: #b8c5d3; letter-spacing: -.02em; }
.brand-mark { width: 42px; height: 36px; fill: none; stroke: currentColor; stroke-width: 2.3; stroke-linecap: round; stroke-linejoin: round; }
.site-header.scrolled .brand { color: var(--navy); }
.site-header.scrolled .wordmark strong { color: var(--slate); }
.primary-nav { display: flex; align-items: center; gap: 34px; color: white; font-size: .92rem; font-weight: 650; }
.primary-nav a:not(.nav-cta), .nav-link { transition: opacity .2s; }
.primary-nav a:not(.nav-cta):hover, .nav-link:hover { opacity: .68; }
.nav-link { border: 0; background: none; padding: 0; cursor: pointer; }
.site-header.scrolled .primary-nav { color: var(--navy); }
.nav-cta { padding: 12px 20px; border: 1px solid rgba(255,255,255,.45); border-radius: 8px; background: rgba(255,255,255,.1); }
.site-header.scrolled .nav-cta { color: white; background: var(--navy); border-color: var(--navy); }
.menu-toggle { display: none; width: 42px; height: 42px; border: 1px solid rgba(255,255,255,.35); border-radius: 9px; background: rgba(255,255,255,.08); align-items: center; justify-content: center; flex-direction: column; gap: 5px; }
.menu-toggle span:not(.sr-only) { width: 20px; height: 2px; background: currentColor; }

.hero { position: relative; min-height: 760px; height: min(880px, 100svh); display: flex; align-items: center; overflow: hidden; color: white; background: var(--navy-deep) url("assets/hero-poster.jpg") center/cover no-repeat; }
.hero-video { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; object-position: center; }
.hero-overlay { position: absolute; inset: 0; background: linear-gradient(90deg, rgba(12,20,36,.86) 0%, rgba(18,28,47,.70) 35%, rgba(24,34,55,.28) 61%, rgba(24,34,55,.06) 100%), linear-gradient(0deg, rgba(16,25,43,.35), transparent 42%); }
.hero-content { position: relative; z-index: 1; padding-top: 80px; }
.eyebrow, .kicker { margin: 0 0 18px; text-transform: uppercase; letter-spacing: .15em; font-size: .76rem; font-weight: 800; }
.eyebrow { display: inline-flex; align-items: center; gap: 9px; padding: 8px 13px; border-radius: 999px; color: var(--ivory); background: rgba(243,238,232,.13); border: 1px solid rgba(243,238,232,.3); }
.hero h1 { max-width: 720px; margin: 0; font-family: var(--serif); font-size: clamp(3.2rem, 6.2vw, 6.2rem); line-height: .98; font-weight: 600; letter-spacing: -.045em; }
.hero h1 span { display: block; color: #d8e1ea; font-style: italic; }
.hero-copy { max-width: 640px; margin: 26px 0 0; color: rgba(255,255,255,.82); font-size: clamp(1.04rem, 1.7vw, 1.22rem); }
.hero-actions { display: flex; align-items: center; gap: 28px; margin-top: 34px; }
.button { display: inline-flex; align-items: center; justify-content: center; gap: 28px; min-height: 52px; padding: 0 26px; border-radius: 9px; border: 1px solid transparent; cursor: pointer; text-transform: uppercase; letter-spacing: .05em; font-size: .83rem; font-weight: 800; transition: transform .2s, box-shadow .2s, background .2s; }
.button:hover { transform: translateY(-2px); }
.button:focus-visible, a:focus-visible, summary:focus-visible, button:focus-visible { outline: 3px solid #dce5ed; outline-offset: 3px; }
.button-primary { background: var(--ivory); color: var(--navy); box-shadow: 0 12px 26px rgba(0,0,0,.18); }
.button-light { background: var(--paper); color: var(--navy); }
.button-ivory { background: var(--ivory); color: var(--navy); }
.text-link { display: inline-flex; gap: 10px; align-items: center; color: white; font-size: .9rem; font-weight: 750; border-bottom: 1px solid rgba(255,255,255,.4); padding-bottom: 4px; }
.text-link.dark { color: var(--navy); border-color: var(--dusty); }
.hero-benefits { display: flex; gap: 42px; padding: 0; margin: 52px 0 0; list-style: none; color: rgba(255,255,255,.78); font-size: .8rem; line-height: 1.35; }
.hero-benefits li { display: flex; align-items: center; gap: 11px; }
.benefit-icon { display: grid; place-items: center; width: 36px; height: 36px; border: 1px solid rgba(255,255,255,.4); border-radius: 50%; color: white; font-size: 1.15rem; }
.scroll-note { position: absolute; z-index: 2; right: 34px; bottom: 40px; display: flex; align-items: center; gap: 12px; color: rgba(255,255,255,.58); text-transform: uppercase; letter-spacing: .16em; font-size: .66rem; writing-mode: vertical-rl; }
.scroll-note span { width: 1px; height: 42px; background: rgba(255,255,255,.5); }

.how { position: relative; background: var(--ivory); overflow: hidden; }
.how::before, .how::after { content: ""; position: absolute; width: 380px; height: 380px; border: 1px solid rgba(136,149,166,.25); border-radius: 50%; }
.how::before { left: -220px; top: -180px; }
.how::after { right: -260px; bottom: -230px; }
.split-heading { display: grid; grid-template-columns: 1.1fr .8fr; align-items: end; gap: 90px; }
.section-heading { margin-bottom: 54px; }
.kicker { color: var(--slate); }
.section h2 { margin: 0; font-family: var(--serif); font-size: clamp(2.4rem, 4.3vw, 4.35rem); line-height: 1.04; letter-spacing: -.035em; color: var(--navy-deep); }
.section h2 span { color: var(--slate); font-style: italic; }
.section-heading > p, .promise-copy > p, .faq-intro > p { margin: 0; color: var(--muted); font-size: 1.04rem; }
.steps { position: relative; z-index: 1; display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; padding: 0; margin: 0; list-style: none; counter-reset: steps; }
.step-card { min-height: 324px; padding: 30px; border: 1px solid rgba(255,255,255,.16); border-radius: 18px; box-shadow: 0 10px 28px rgba(32,43,64,.08); transition: transform .25s, box-shadow .25s; }
.step-card:nth-child(1) { background: #202b40; color: white; }
.step-card:nth-child(2) { background: #58677d; color: white; }
.step-card:nth-child(3) { background: #8895a6; color: #172137; }
.step-card:nth-child(4) { background: #c5b9ad; color: #202b40; }
.step-card:hover { transform: translateY(-3px); box-shadow: 0 18px 38px rgba(32,43,64,.17); }
.step-top { display: flex; align-items: center; justify-content: space-between; margin-bottom: 56px; }
.step-number { color: currentColor; opacity: .64; font-family: var(--serif); font-size: 1rem; font-weight: 700; }
.step-icon { display: grid; place-items: center; width: 64px; height: 64px; border-radius: 16px; background: rgba(255,255,255,.13); color: currentColor; }
.step-icon svg { width: 38px; height: 38px; fill: none; stroke: currentColor; stroke-width: 2.2; stroke-linecap: round; stroke-linejoin: round; }
.step-card:nth-child(n+3) .step-icon { background: rgba(255,255,255,.32); }
.step-card h3 { margin: 0 0 13px; color: currentColor; font-family: var(--serif); font-size: 1.48rem; line-height: 1.15; }
.step-card p { margin: 0; color: currentColor; opacity: .8; font-size: .9rem; }

.promise { background: var(--ivory); }
.promise-grid { display: grid; grid-template-columns: 1fr 1fr; align-items: center; gap: 70px; }
.promise-copy > p { margin-top: 26px; max-width: 590px; }
.promise-copy .button { margin-top: 32px; }
.button-navy { background: var(--navy); color: white; box-shadow: 0 12px 26px rgba(32,43,64,.18); }
.subject-video-wrap { position: relative; overflow: hidden; aspect-ratio: 4 / 3; border-radius: 20px; background: #ded6cc url("assets/navi-learn-subjects-poster.jpg") center/cover no-repeat; box-shadow: var(--shadow); }
.subject-video-wrap::after { content: ""; position: absolute; inset: 0; pointer-events: none; box-shadow: inset 0 0 0 1px rgba(255,255,255,.25); border-radius: inherit; }
.subject-video-wrap video { width: 100%; height: 100%; object-fit: cover; object-position: center; }
.subject-video-label { position: absolute; z-index: 2; left: 20px; right: 20px; bottom: 20px; display: grid; gap: 2px; padding: 14px 17px; border: 1px solid rgba(255,255,255,.35); border-radius: 11px; background: rgba(32,43,64,.78); color: white; backdrop-filter: blur(12px); }
.subject-video-label span { text-transform: uppercase; letter-spacing: .13em; font-size: .62rem; opacity: .72; }
.subject-video-label strong { font-family: var(--serif); font-size: 1.05rem; }
.check-list { margin: 34px 0 0; padding: 0; list-style: none; display: grid; gap: 16px; }
.check-list li { display: flex; align-items: center; gap: 13px; color: var(--slate); font-weight: 650; }
.check-list span { display: grid; place-items: center; width: 27px; height: 27px; flex: 0 0 auto; border-radius: 50%; background: var(--navy); color: white; font-size: .75rem; }
.paper-stack { position: relative; min-height: 470px; display: grid; place-items: center; }
.paper { position: absolute; width: min(390px, 88%); height: 470px; border-radius: 8px; border: 1px solid rgba(32,43,64,.12); }
.paper-back { transform: rotate(6deg) translate(18px, 5px); background: #e3e8ed; box-shadow: var(--shadow); }
.paper-front { transform: rotate(-3deg); padding: 34px; background: white; box-shadow: 0 26px 60px rgba(32,43,64,.18); }
.mini-brand { color: var(--navy); font-size: .72rem; font-weight: 800; }
.paper-label { display: inline-block; margin: 46px 0 12px; padding: 5px 9px; border-radius: 4px; color: white; background: var(--slate); font-size: .62rem; letter-spacing: .12em; font-weight: 800; }
.paper h3 { margin: 0; color: var(--navy); font-family: var(--serif); font-size: 2.2rem; }
.paper > p:not(.paper-label) { margin: 3px 0 0; color: var(--slate); }
.paper-rule { height: 1px; margin: 26px 0 22px; background: var(--line); }
.paper h4 { margin: 0 0 16px; color: var(--navy); }
.paper-line { height: 6px; width: 62%; margin: 10px 0; border-radius: 10px; background: #dfe4e9; }
.paper-line.wide { width: 95%; }.paper-line.medium { width: 79%; }
.paper-diagram { position: absolute; right: 32px; bottom: 34px; width: 116px; height: 116px; border-radius: 50%; border: 1px solid #d6dde4; background: radial-gradient(circle, #eef1f4 0 35%, transparent 36%), repeating-radial-gradient(circle, transparent 0 14px, rgba(136,149,166,.16) 15px 16px); }
.paper-diagram span { position: absolute; width: 10px; height: 10px; background: var(--slate); border-radius: 50%; }.paper-diagram span:nth-child(1){left:20px;top:48px}.paper-diagram span:nth-child(2){right:22px;top:30px}.paper-diagram span:nth-child(3){right:35px;bottom:20px}

.tutor { background: var(--ivory); }
.tutor-card { display: grid; grid-template-columns: 1.12fr .88fr; min-height: 600px; overflow: hidden; border-radius: 22px; background: var(--navy); box-shadow: var(--shadow); }
.tutor-media { position: relative; min-height: 500px; overflow: hidden; }
.tutor-media::after { content: ""; position: absolute; inset: 0; background: linear-gradient(90deg, transparent 58%, rgba(32,43,64,.7)); }
.tutor-media video { width: 100%; height: 100%; object-fit: cover; }
.coming-badge { position: absolute; z-index: 2; left: 26px; top: 26px; padding: 8px 13px; border-radius: 999px; background: rgba(243,238,232,.93); color: var(--navy); text-transform: uppercase; letter-spacing: .12em; font-size: .7rem; font-weight: 800; }
.tutor-copy { display: flex; flex-direction: column; justify-content: center; padding: 58px; color: white; }
.tutor-copy .kicker { color: var(--taupe); }
.tutor-copy h2 { color: white; font-size: clamp(2.5rem, 4vw, 4rem); }
.tutor-copy > p:not(.kicker) { margin: 24px 0 30px; color: rgba(255,255,255,.74); }
.tutor-copy .button { align-self: flex-start; }
.pro-note { display: flex; gap: 14px; margin-top: 42px; padding-top: 28px; border-top: 1px solid rgba(255,255,255,.15); }
.pro-note div { display: grid; gap: 4px; }.pro-note strong { font-family: var(--serif); font-size: 1rem; }.pro-note span:not(.pro-icon) { color: rgba(255,255,255,.6); font-size: .78rem; }

.faq { background: var(--paper); }
.faq-grid { display: grid; grid-template-columns: .7fr 1.3fr; gap: 100px; align-items: start; }
.faq-intro { position: sticky; top: 120px; }
.faq-intro > p { margin: 24px 0 30px; }
.accordion { border-top: 1px solid var(--line); }
.accordion details { border-bottom: 1px solid var(--line); }
.accordion summary { position: relative; list-style: none; cursor: pointer; padding: 24px 50px 24px 0; color: var(--navy); font-family: var(--serif); font-size: 1.18rem; font-weight: 700; }
.accordion summary::-webkit-details-marker { display: none; }
.accordion summary span::before, .accordion summary span::after { content: ""; position: absolute; right: 8px; top: 50%; width: 17px; height: 1.5px; background: var(--navy); transition: transform .2s; }
.accordion summary span::after { transform: rotate(90deg); }
.accordion details[open] summary span::after { transform: rotate(0); }
.accordion details p { margin: -6px 54px 24px 0; color: var(--muted); font-size: .93rem; }

.final-cta { padding: 74px 0; background: var(--slate); color: white; }
.final-cta-inner { display: flex; align-items: center; justify-content: space-between; gap: 50px; }
.final-cta .eyebrow { margin-bottom: 14px; }
.final-cta h2 { max-width: 800px; margin: 0; color: white; font-family: var(--serif); font-size: clamp(2.3rem, 4vw, 4rem); line-height: 1.05; letter-spacing: -.03em; }.final-cta h2 span { color: var(--ivory); font-style: italic; }
.site-footer { padding: 48px 0; background: var(--navy-deep); color: rgba(255,255,255,.68); }
.footer-grid { display: grid; grid-template-columns: 1fr auto auto; gap: 80px; align-items: end; }
.footer-brand { color: white; }.footer-grid > div > p { margin: 10px 0 0; font-size: .84rem; }
.footer-grid nav { display: flex; gap: 28px; color: white; font-size: .82rem; font-weight: 700; }
.copyright { margin: 0; text-align: right; font-size: .76rem; }

.modal { width: min(480px, calc(100% - 32px)); padding: 42px; border: 0; border-radius: 18px; color: var(--ink); background: var(--paper); box-shadow: 0 30px 100px rgba(0,0,0,.38); text-align: center; }
.modal::backdrop { background: rgba(17,26,45,.68); backdrop-filter: blur(5px); }
.modal-close { position: absolute; right: 16px; top: 12px; border: 0; background: none; font-size: 1.8rem; color: var(--slate); cursor: pointer; }
.modal-icon { display: grid; place-items: center; width: 58px; height: 58px; margin: 0 auto 22px; border-radius: 50%; color: white; background: var(--navy); font-size: 1.4rem; }
.modal .kicker { margin-bottom: 10px; }.modal h2 { margin: 0; color: var(--navy); font-family: var(--serif); font-size: 2rem; }.modal p:not(.kicker) { color: var(--muted); }.modal .button { margin-top: 12px; background: var(--navy); color: white; }

@media (max-width: 980px) {
  .section { padding: 82px 0; }
  .steps { grid-template-columns: repeat(2, 1fr); }
  .split-heading { grid-template-columns: 1fr; gap: 22px; }
  .promise-grid { gap: 44px; }
  .tutor-card { grid-template-columns: 1fr; }
  .tutor-media { min-height: 440px; }
  .tutor-media::after { background: linear-gradient(0deg, rgba(32,43,64,.42), transparent 44%); }
  .faq-grid { gap: 54px; }
  .footer-grid { grid-template-columns: 1fr 1fr; }.copyright { grid-column: 1 / -1; text-align: left; }
}

@media (max-width: 760px) {
  .shell { width: min(100% - 34px, 620px); }
  .site-header { padding: 12px 0; }.nav-shell { width: calc(100% - 28px); }
  .brand { font-size: 1.2rem; }.brand-mark { width: 36px; height: 31px; }
  .menu-toggle { display: flex; color: white; cursor: pointer; }.site-header.scrolled .menu-toggle { color: var(--navy); border-color: var(--line); }
  .primary-nav { position: absolute; left: 14px; right: 14px; top: calc(100% + 4px); display: none; flex-direction: column; align-items: stretch; gap: 0; padding: 14px; color: var(--navy); background: var(--paper); border-radius: 12px; box-shadow: var(--shadow); }
  .primary-nav.open { display: flex; }.primary-nav > a, .primary-nav .nav-link { padding: 14px; text-align: left; }.primary-nav .nav-cta { margin-top: 6px; color: white; background: var(--navy); text-align: center; }
  .hero { min-height: 760px; height: 100svh; align-items: flex-end; }.hero-video { object-position: 58% center; }.hero-overlay { background: linear-gradient(0deg, rgba(12,20,36,.93) 0%, rgba(18,28,47,.74) 58%, rgba(18,28,47,.15) 100%); }
  .hero-content { padding: 120px 0 48px; }.hero h1 { font-size: clamp(3rem, 14vw, 4.7rem); }.hero-copy { font-size: 1rem; }.hero-actions { align-items: stretch; flex-direction: column; gap: 18px; }.button { width: 100%; }.text-link { align-self: flex-start; }
  .hero-benefits { display: none; }.scroll-note { display: none; }
  .section { padding: 70px 0; }.section-heading { margin-bottom: 34px; }.section h2 { font-size: clamp(2.35rem, 11vw, 3.6rem); }
  .steps { grid-template-columns: 1fr; }.step-card { min-height: auto; }.step-top { margin-bottom: 34px; }
  .promise-grid { grid-template-columns: 1fr; }.subject-video-wrap { margin-top: 12px; aspect-ratio: 4 / 3; }
  .tutor-card { width: calc(100% - 24px); border-radius: 16px; }.tutor-media { min-height: 320px; }.tutor-copy { padding: 38px 26px; }.tutor-copy .button { width: 100%; }
  .faq-grid { grid-template-columns: 1fr; }.faq-intro { position: static; }.accordion summary { font-size: 1.08rem; }
  .final-cta-inner { flex-direction: column; align-items: flex-start; }.final-cta .button { width: 100%; }
  .footer-grid { grid-template-columns: 1fr; gap: 30px; }.footer-grid nav { flex-wrap: wrap; }.copyright { grid-column: auto; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: .01ms !important; animation-duration: .01ms !important; animation-iteration-count: 1 !important; }
  video { display: none; }
  .tutor-media { background: url("assets/ai-tutor-poster.jpg") center/cover no-repeat; }
}