*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: var(--font-body); color: var(--dark); background: var(--surface); }

.nav { position: sticky; top: 0; z-index: 100; background: var(--surface-blur); backdrop-filter: blur(12px); border-bottom: 1px solid var(--border); }
.nav-inner { max-width: 1140px; margin: 0 auto; padding: 0 24px; height: 64px; display: flex; align-items: center; justify-content: space-between; }
.nav-brand { display: flex; align-items: center; gap: 10px; text-decoration: none; }
.nav-logo {
  height: 50px; width: calc(50px * var(--logo-lockup-ratio));
  background: url('/img/brand/logo-lockup.png') left center/contain no-repeat;
  flex: none;
}
.nav-name { font-family: var(--font-sub); font-weight: 800; font-size: var(--fs-2xl); color: var(--dark); }
.nav-links { display: flex; align-items: center; gap: 16px; }
.nav-link { font-weight: 700; font-size: var(--fs-lg); color: var(--ink-soft); text-decoration: none; padding: 8px 12px; border-radius: var(--r-sm); transition: background .15s; }
.nav-link:hover { background: var(--status-info-bg); color: var(--blue); }
.btn-nav-join { font-weight: 800; font-size: var(--fs-lg); color: var(--on-accent); text-decoration: none; padding: 10px 20px; background: var(--accent-strong); border-radius: var(--r-md); transition: opacity .15s; }
.btn-nav-join:hover { opacity: .88; }

.hero { max-width: 1140px; margin: 0 auto; padding: 80px 24px 60px; display: grid; grid-template-columns: 1fr 420px; gap: 48px; align-items: center; }
.hero-inner { display: flex; flex-direction: column; gap: 20px; }
.hero-badge { display: inline-flex; align-items: center; gap: 8px; background: var(--status-info-bg); color: var(--blue); font-weight: 800; font-size: var(--fs-base); padding: 6px 14px; border-radius: var(--r-pill); width: fit-content; letter-spacing: .3px; }
.hero-title { font-family: var(--font-sub); font-weight: 800; font-size: clamp(38px, 6vw, 60px); line-height: 1.1; color: var(--dark); }
.hero-sub { font-size: var(--fs-xl); color: var(--ink-soft); line-height: 1.65; max-width: 480px; }
.hero-ctas { display: flex; align-items: center; gap: 14px; flex-wrap: wrap; }
.btn-hero-primary { display: inline-flex; align-items: center; gap: 8px; background: var(--accent-strong); color: var(--on-accent); text-decoration: none; font-weight: 800; font-size: var(--fs-lg); padding: 14px 28px; border-radius: var(--r-md); transition: opacity .15s; }
.btn-hero-primary:hover { opacity: .88; }
.btn-hero-secondary { font-weight: 800; font-size: var(--fs-lg); color: var(--blue); text-decoration: none; padding: 14px 20px; border-radius: var(--r-md); border: 2.5px solid var(--sub-sky-2); transition: background .15s; }
.btn-hero-secondary:hover { background: var(--status-info-bg); }
.hero-trust { display: flex; flex-wrap: wrap; gap: 10px 18px; list-style: none; margin: 0; padding: 0; }
.hero-trust li { display: inline-flex; align-items: center; gap: 7px; font-size: var(--fs-base); font-weight: 700; color: var(--ink-soft); }
.hero-trust svg { width: 15px; height: 15px; flex: none; color: var(--sub-green-text); }

.hero-visual { display: flex; justify-content: center; }
.phone-mockup { width: 260px; background: var(--ink-panel); border-radius: var(--r-xl); overflow: hidden; box-shadow: 0 32px 80px rgba(0,0,0,.28); }
.pm-bar { display: flex; justify-content: space-between; padding: 10px 20px 6px; font-size: var(--fs-xs); font-weight: 700; color: rgba(255,255,255,.7); }
.pm-body { background: var(--surface-2); padding: 20px 16px 24px; }
.pm-wave { display: flex; justify-content: center; margin-bottom: 12px; }
.pm-title { font-family: var(--font-sub); font-weight: 800; font-size: var(--fs-2xl); color: var(--dark); margin-bottom: 4px; }
.pm-sub { font-size: var(--fs-sm); color: var(--ink-soft); font-weight: 600; margin-bottom: 14px; line-height: 1.4; }
.pm-field-label { font-size: var(--fs-2xs); font-weight: 800; color: var(--ink-soft); letter-spacing: .7px; margin-bottom: 4px; }
.pm-field { background: var(--surface); border: 2px solid var(--border); border-radius: var(--r-sm); padding: 8px 12px; font-weight: 800; font-size: var(--fs-md); color: var(--dark); }
.pm-code-boxes { display: flex; gap: 6px; margin-bottom: 14px; }
.pm-box { width: 32px; height: 36px; background: var(--surface); border: 2px solid var(--blue); border-radius: var(--r-sm); display: flex; align-items: center; justify-content: center; font-family: var(--font-sub); font-weight: 800; font-size: var(--fs-lg); color: var(--blue); }
.pm-btn { background: var(--accent-strong); color: var(--on-accent); text-align: center; padding: 10px; border-radius: var(--r-md); font-weight: 800; font-size: var(--fs-md); margin-bottom: 12px; }
.pm-chips { display: flex; gap: 6px; flex-wrap: wrap; }
.chip { font-size: var(--fs-2xs); font-weight: 800; padding: 3px 8px; border-radius: var(--r-pill); }
.chip.blue { background: var(--sub-sky-2); color: var(--status-info); }
.chip.green { background: var(--status-good-bg); color: var(--status-good); }
.chip.yellow { background: var(--status-warn-bg); color: var(--status-warn); }

.section-label { font-size: var(--fs-xs); font-weight: 800; letter-spacing: 1.2px; color: var(--blue); text-transform: uppercase; margin-bottom: 10px; }
.section-title { font-family: var(--font-sub); font-weight: 800; font-size: clamp(26px,4vw,40px); color: var(--dark); margin-bottom: 40px; line-height: 1.15; }

.roles { background: var(--surface-2); padding: 80px 24px; }
.roles-inner { max-width: 1140px; margin: 0 auto; }
.roles-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.role-card { background: var(--surface); border-radius: var(--r-xl); padding: 32px 28px; border: 2px solid var(--border); display: flex; flex-direction: column; gap: 14px; transition: box-shadow .2s; }
.role-card:hover { box-shadow: 0 12px 40px rgba(var(--main-rgb),.12); }
.role-icon { font-size: 36px; }
.role-card h3 { font-family: var(--font-sub); font-weight: 800; font-size: var(--fs-2xl); color: var(--dark); }
.role-card p { font-size: var(--fs-md); color: var(--ink-soft); line-height: 1.6; }
.role-features { list-style: none; display: flex; flex-direction: column; gap: 6px; flex: 1; }
.role-features li { font-size: var(--fs-base); font-weight: 700; color: var(--ink-soft); }
.role-btn { display: inline-block; text-align: center; text-decoration: none; font-weight: 800; font-size: var(--fs-md); padding: 11px 20px; border-radius: var(--r-md); transition: opacity .15s; margin-top: 4px; }
.role-btn-student { background: var(--status-good-bg); color: var(--green); }
.role-btn-teacher { background: var(--status-info-bg); color: var(--blue); }
.role-btn-admin { background: var(--status-bad-bg); color: var(--purple); }
.role-btn:hover { opacity: .8; }

.how { padding: 80px 24px; }
.how-inner { max-width: 1140px; margin: 0 auto; }
.steps { display: grid; grid-template-columns: 1fr auto 1fr auto 1fr auto 1fr; gap: 0; align-items: start; }
.step { padding: 0 8px; }
.step-num { font-family: var(--font-sub); font-weight: 800; font-size: 36px; color: var(--sub-sky-2); margin-bottom: 10px; }
.step h4 { font-family: var(--font-sub); font-weight: 800; font-size: var(--fs-xl); color: var(--dark); margin-bottom: 8px; }
.step p { font-size: var(--fs-md); color: var(--ink-soft); line-height: 1.6; }
.step-arrow { font-size: var(--fs-2xl); color: var(--canvas-ink-soft); align-self: center; padding: 0 8px; margin-top: -20px; }

.about-hero { padding: 80px 24px 40px; }
.about-hero-inner { max-width: 1140px; margin: 0 auto; display: flex; flex-direction: column; gap: 20px; }
.about-blurb { font-size: var(--fs-lg); color: var(--ink-soft); line-height: 1.7; max-width: 640px; margin: -20px auto 40px; text-align: center; }

.devs { padding: 80px 24px; background: var(--surface-2); }
.devs-inner { max-width: 1140px; margin: 0 auto; text-align: center; }
.devs .section-label, .devs .section-title { text-align: left; }
.devs-grid { display: flex; justify-content: center; gap: 32px; flex-wrap: wrap; }
.dev-card { display: flex; flex-direction: column; align-items: center; gap: 6px; width: 200px; }
.dev-photo { width: 120px; height: 120px; border-radius: 50%; object-fit: cover; border: 3px solid var(--sub-sky-2); margin-bottom: 8px; }
.dev-name { font-family: var(--font-sub); font-weight: 800; font-size: var(--fs-xl); color: var(--dark); }
.dev-role { font-size: var(--fs-base); font-weight: 700; color: var(--ink-soft); }

.partners { padding: 80px 24px; }
.partners-inner { max-width: 1140px; margin: 0 auto; }
.partners-grid { display: flex; justify-content: center; align-items: flex-start; gap: 56px; flex-wrap: wrap; }
.partner-item { display: flex; flex-direction: column; align-items: center; gap: 12px; }
.partner-logo { width: 120px; height: 120px; object-fit: contain; }

.partner-logo--wide { width: 165px; }
.partner-caption { display: flex; flex-direction: column; gap: 2px; text-align: center; }
.partner-name { font-size: var(--fs-md); font-weight: 800; color: var(--dark); }
.partner-role { font-size: var(--fs-sm); font-weight: 700; color: var(--ink-soft); }

.footer { background: var(--ink-panel); color: rgba(255,255,255,.7); padding: 40px 24px; }
.footer-inner { max-width: 1140px; margin: 0 auto; display: flex; align-items: center; gap: 24px; flex-wrap: wrap; }
.footer-brand { display: flex; align-items: center; gap: 8px; color: #fff; font-weight: 800; flex: 1; }
.footer-links { display: flex; gap: 20px; }
.footer-links a { font-size: var(--fs-md); font-weight: 700; color: rgba(255,255,255,.6); text-decoration: none; }
.footer-links a:hover { color: #fff; }
.footer-copy { font-size: var(--fs-base); color: rgba(255,255,255,.4); width: 100%; }

@media (max-width: 900px) {
  .hero { grid-template-columns: 1fr; }
  .hero-visual { display: none; }
  .roles-grid { grid-template-columns: 1fr; }
  .steps { grid-template-columns: 1fr; }
  .step-arrow { display: none; }
}

@media (max-width: 600px) {
  .nav-inner { padding: 0 16px; }
  .nav-links { gap: 8px; }
  .nav-link { display: none; }
  .btn-nav-join { font-size: var(--fs-md); padding: 9px 16px; }
  .nav-name { font-size: var(--fs-xl); }
  .hero { padding: 40px 20px 40px; }
}

.nav-name, .footer-brand, .hero-title, .section-title { font-family: var(--font-display) !important; letter-spacing: .5px; }

.promo { background: var(--surface-2); padding: 80px 24px; }
.promo-inner { max-width: 1140px; margin: 0 auto; display: grid; grid-template-columns: 380px 1fr; gap: 48px; align-items: center; }
.promo-poster { width: 100%; border-radius: var(--r-xl); box-shadow: var(--shadow-lg); }
.promo-copy p { font-size: var(--fs-lg); color: var(--ink-soft); line-height: 1.7; max-width: 520px; margin-bottom: 24px; }
.btn-promo { display: inline-flex; align-items: center; gap: 8px; background: var(--accent-strong); color: var(--on-accent); text-decoration: none; font-weight: 800; font-size: var(--fs-lg); padding: 14px 28px; border-radius: var(--r-md); transition: opacity .15s; }
.btn-promo:hover { opacity: .88; }

.tutorial { padding: 80px 24px; }
.tutorial-inner { max-width: 860px; margin: 0 auto; text-align: center; }
.tutorial video { width: 100%; border-radius: var(--r-xl); box-shadow: var(--shadow-lg); background: var(--canvas); }

@media (max-width: 900px) {
  .promo-inner { grid-template-columns: 1fr; }
  .promo-poster { max-width: 320px; margin: 0 auto; }
}

.promo-inner--book {
  display: block;
  max-width: 1140px;
  margin: 0 auto;
  padding: 0 var(--sp-6);
}
.promo-copy--wide {
  max-width: 62ch;
  margin: 0 auto var(--sp-9);
  text-align: center;
}

.poster { background: var(--surface-2); padding: var(--sp-9) var(--sp-6); }
.poster-inner { max-width: 1140px; margin: 0 auto; display: flex; justify-content: center; }
.poster-img {
  display: block;
  width: 100%;
  max-width: 520px;
  height: auto;
  border-radius: var(--r-lg);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-lg);
}
@media (max-width: 640px) {
  .poster { padding: var(--sp-7) var(--sp-4); }
}