:root {
  --ink: #10233f;
  --muted: #5b6b7f;
  --line: #d9e3ef;
  --panel: #ffffff;
  --soft: #eef7fb;
  --blue: #0b73bb;
  --green: #25b28f;
  --yellow: #ffd166;
  --red: #de5b55;
  --navy: #102a43;
  --shadow: 0 18px 55px rgba(16, 35, 63, .12);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, sans-serif;
  color: var(--ink);
  background: #f8fbfe;
  line-height: 1.55;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
.wrap { width: min(1160px, 92vw); margin: 0 auto; }
.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(248, 251, 254, .94);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
}
.nav { display: flex; align-items: center; justify-content: space-between; gap: 18px; padding: 13px 0; }
.brand { display: flex; align-items: center; }
.brand-logo { width: 480px; height: auto; max-height: 124px; object-fit: contain; }
.navlinks { display: flex; gap: 5px; align-items: center; flex-wrap: wrap; justify-content: flex-end; }
.navlinks a { border-radius: 10px; padding: 9px 10px; font-size: 14px; font-weight: 800; color: #31506d; }
.navlinks a:hover, .navlinks a.active { background: #e8f4fc; color: var(--blue); }
.navlinks a.cta { background: var(--blue); color: #fff; }
.lang { display: flex; padding: 3px; gap: 3px; border: 1px solid var(--line); border-radius: 999px; background: #fff; }
.lang button, .menu-button {
  border: 0;
  background: transparent;
  font: inherit;
  cursor: pointer;
  font-weight: 900;
}
.lang button { padding: 7px 9px; border-radius: 999px; font-size: 13px; color: #35556f; }
.lang button.active { background: var(--blue); color: #fff; }
.menu-button { display: none; width: 42px; height: 42px; border-radius: 11px; background: #e8f4fc; color: var(--blue); }
.hero {
  background:
    radial-gradient(circle at 82% 18%, rgba(37, 178, 143, .16), transparent 28%),
    linear-gradient(180deg, #eef8ff 0%, #f8fbfe 76%);
  padding: 70px 0 44px;
}
.hero-grid { display: grid; grid-template-columns: minmax(0, 1.05fr) minmax(340px, .95fr); gap: 40px; align-items: center; }
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 11px;
  border-radius: 999px;
  background: #e9f8f4;
  color: #0e7462;
  border: 1px solid #c6ece4;
  font-weight: 900;
  font-size: 14px;
}
h1, h2, h3 { margin: 0; line-height: 1.08; letter-spacing: 0; }
h1 { margin-top: 18px; font-size: clamp(42px, 5.8vw, 72px); max-width: 850px; }
h2 { font-size: clamp(30px, 4vw, 46px); }
h3 { font-size: 22px; }
.lead { font-size: 20px; color: var(--muted); max-width: 760px; margin: 18px 0 0; }
.actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; }
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 13px 17px;
  border: 1px solid var(--line);
  border-radius: 11px;
  background: #fff;
  color: var(--ink);
  font-weight: 900;
  cursor: pointer;
}
.button.primary { background: var(--blue); border-color: var(--blue); color: #fff; }
.button.green { background: var(--green); border-color: var(--green); color: #073d33; }
.product-shell {
  border: 1px solid var(--line);
  background: rgba(255,255,255,.86);
  box-shadow: var(--shadow);
  border-radius: 8px;
  overflow: hidden;
}
.shell-top { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 13px 16px; border-bottom: 1px solid var(--line); background: #fff; }
.dots { display: flex; gap: 6px; }
.dots span { width: 9px; height: 9px; border-radius: 50%; background: var(--line); }
.screen { display: grid; gap: 13px; padding: 18px; }
.message { width: fit-content; max-width: 92%; border-radius: 16px; padding: 13px 15px; font-size: 15px; }
.message.student { justify-self: end; background: #e8f4fc; }
.message.tutor { background: #effaf6; border: 1px solid #ccefe5; }
.guardrail { border-left: 5px solid var(--yellow); background: #fff8df; padding: 14px 15px; border-radius: 8px; font-weight: 800; }
.section { padding: 62px 0; }
.section.alt { background: #fff; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.section-head { display: flex; justify-content: space-between; gap: 24px; align-items: end; margin-bottom: 24px; }
.section-head p { color: var(--muted); max-width: 650px; margin: 0; font-size: 18px; }
.cards { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; }
.card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 22px;
  box-shadow: 0 10px 30px rgba(16, 35, 63, .06);
}
.card-icon { width: 44px; height: 44px; display: grid; place-items: center; border-radius: 8px; background: #e8f4fc; color: var(--blue); font-weight: 900; margin-bottom: 14px; }
.card p, .feature-list li { color: var(--muted); }
.feature-list { padding-left: 20px; margin: 16px 0 0; }
.feature-list li { margin: 8px 0; }
.two-col { display: grid; grid-template-columns: minmax(0, .95fr) minmax(0, 1.05fr); gap: 28px; align-items: start; }
.demo-tabs { display: grid; grid-template-columns: 220px minmax(0, 1fr); gap: 18px; }
.tab-list { display: grid; gap: 8px; align-content: start; }
.tab-list button { text-align: left; }
.tab-list button.active { background: var(--blue); color: #fff; border-color: var(--blue); }
.demo-panel { display: none; }
.demo-panel.active { display: block; }
.dashboard { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-top: 14px; }
.metric { background: #f5f9fd; border: 1px solid var(--line); border-radius: 8px; padding: 14px; }
.metric b { display: block; font-size: 26px; }
.bar { height: 11px; border-radius: 999px; background: #e5edf6; overflow: hidden; margin-top: 10px; }
.bar span { display: block; height: 100%; background: linear-gradient(90deg, var(--green), var(--blue)); }
.pricing { display: grid; grid-template-columns: .95fr 1.05fr; gap: 18px; align-items: stretch; }
.price { font-size: 46px; font-weight: 900; margin: 12px 0 0; }
table { width: 100%; border-collapse: collapse; margin-top: 10px; }
th, td { text-align: left; padding: 12px; border-bottom: 1px solid var(--line); }
th { color: #31506d; background: #f1f7fc; }
.form { display: grid; gap: 12px; }
.form label { display: grid; gap: 6px; font-weight: 800; color: #31506d; }
.form input, .form select, .form textarea {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 13px 14px;
  font: inherit;
  background: #fff;
  color: var(--ink);
}
.form textarea { min-height: 126px; resize: vertical; }
.alert { border-radius: 8px; padding: 13px 15px; border: 1px solid var(--line); margin-bottom: 14px; }
.alert.ok { background: #edf9f5; border-color: #bfe9dd; }
.alert.error { background: #fff0ef; border-color: #f4c1bd; }
.faq { display: grid; gap: 12px; }
.faq details { background: #fff; border: 1px solid var(--line); border-radius: 8px; padding: 17px; }
.faq summary { cursor: pointer; font-weight: 900; }
.footer { background: var(--navy); color: #d9e9f7; padding: 34px 0; }
.footer .wrap { display: flex; justify-content: space-between; gap: 20px; flex-wrap: wrap; }
.footer a { color: #fff; font-weight: 900; }
.small { color: var(--muted); font-size: 14px; }
.badge { display: inline-flex; padding: 5px 9px; border-radius: 999px; background: #e8f4fc; color: var(--blue); font-weight: 900; font-size: 12px; }

@media (max-width: 920px) {
  .menu-button { display: inline-grid; place-items: center; }
  .nav { align-items: flex-start; }
  .navlinks {
    display: none;
    position: absolute;
    left: 4vw;
    right: 4vw;
    top: 74px;
    background: #fff;
    border: 1px solid var(--line);
    box-shadow: var(--shadow);
    border-radius: 8px;
    padding: 10px;
  }
  body.nav-open .navlinks { display: grid; }
  .navlinks a { padding: 12px; }
  .hero { padding-top: 40px; }
  .hero-grid, .two-col, .pricing, .demo-tabs { grid-template-columns: 1fr; }
  .cards, .dashboard { grid-template-columns: 1fr; }
  .section-head { display: block; }
  h1 { font-size: 42px; }
}

@media (max-width: 520px) {
  .brand-logo { width: 320px; max-height: 96px; }
  .actions .button { width: 100%; }
  .price { font-size: 38px; }
}