:root {
  --dbx-blue: #0061fe;
  --dbx-blue-hover: #004dc7;
  --dbx-blue-light: #b4d1ff;
  --dbx-blue-wash: #f2f7ff;
  --dbx-canvas: #f7f5f2;
  --dbx-ink: #1e1919;
  --dbx-ink-soft: #44403d;
  --dbx-muted: #736c64;
  --dbx-surface: #ffffff;
  --dbx-surface-soft: #ebe9e6;
  --dbx-border: #d3cec9;
  --dbx-dark: #1e1919;
  --dbx-dark-elevated: #2d2b29;
  --brand-lime: #b4dc19;
  --brand-yellow: #fad24b;
  --font-display: "Sharp Grotesk", SharpGrotesk, "Atlas Grotesk", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-body: "Atlas Grotesk Web", "Atlas Grotesk", AtlasGrotesk, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --r-card: 16px;
  --r-button: 16px;
  --r-xl: 24px;
  --space-section: 96px;
  --container: 1200px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.5;
  color: var(--dbx-ink-soft);
  background: var(--dbx-canvas);
  -webkit-font-smoothing: antialiased;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--dbx-blue);
  text-decoration: none;
}

a:hover {
  color: var(--dbx-blue-hover);
}

:focus-visible {
  outline: 2px solid var(--dbx-blue);
  outline-offset: 3px;
}

.container {
  width: min(100% - 32px, var(--container));
  margin-inline: auto;
}

/* Nav */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--dbx-surface);
  border-bottom: 1px solid var(--dbx-border);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  gap: 16px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 18px;
  color: var(--dbx-ink);
  text-decoration: none;
}

.logo-mark {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  background: var(--dbx-blue);
  display: grid;
  place-items: center;
  color: var(--dbx-canvas);
  font-size: 14px;
  font-weight: 600;
}

.nav-links {
  display: none;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: 28px;
}

.nav-links a {
  color: var(--dbx-ink);
  font-size: 16px;
}

.nav-links a:hover {
  color: var(--dbx-blue);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.menu-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 10px;
  border: none;
  background: transparent;
  cursor: pointer;
  border-radius: var(--r-card);
}

.menu-toggle span {
  display: block;
  height: 2px;
  background: var(--dbx-ink);
  border-radius: 1px;
}

.menu-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.menu-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}

.menu-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

.mobile-nav {
  display: none;
  padding: 16px 0 24px;
  border-top: 1px solid var(--dbx-border);
}

.mobile-nav.is-open {
  display: block;
}

.mobile-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.mobile-nav li {
  border-bottom: 1px solid var(--dbx-surface-soft);
}

.mobile-nav a {
  display: block;
  padding: 14px 0;
  color: var(--dbx-ink);
}

@media (min-width: 900px) {
  .menu-toggle {
    display: none;
  }

  .nav-links {
    display: flex;
  }

  .mobile-nav {
    display: none !important;
  }
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 500;
  line-height: 1;
  border-radius: var(--r-button);
  padding: 16px 24px;
  border: 2px solid transparent;
  cursor: pointer;
  text-decoration: none;
  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}

.btn-primary {
  background: var(--dbx-blue);
  color: var(--dbx-canvas);
  border-color: var(--dbx-blue);
}

.btn-primary:hover {
  background: var(--dbx-blue-hover);
  border-color: var(--dbx-blue-hover);
  color: var(--dbx-canvas);
}

.btn-secondary {
  background: transparent;
  color: var(--dbx-ink);
  border-color: var(--dbx-border);
}

.btn-secondary:hover {
  background: var(--dbx-surface-soft);
  color: var(--dbx-ink);
}

.btn-on-dark {
  background: var(--dbx-blue);
  color: var(--dbx-canvas);
}

.btn-on-dark:hover {
  background: var(--dbx-blue-hover);
  color: var(--dbx-canvas);
}

.btn-ghost-dark {
  background: transparent;
  color: var(--dbx-canvas);
  border-color: rgba(247, 245, 242, 0.35);
}

.btn-ghost-dark:hover {
  background: var(--dbx-dark-elevated);
  color: var(--dbx-canvas);
}

.btn-arrow::after {
  content: "→";
  font-size: 18px;
}

/* Hero */
.hero {
  padding: 64px 0 80px;
}

.hero-grid {
  display: grid;
  gap: 48px;
  align-items: center;
}

.hero-eyebrow {
  font-size: 13px;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--dbx-muted);
  margin: 0 0 16px;
}

.hero-title {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: clamp(48px, 8vw, 64px);
  line-height: 1.05;
  letter-spacing: -0.02em;
  color: var(--dbx-ink);
  margin: 0 0 20px;
}

.hero-title .brand-word {
  color: var(--dbx-blue);
  display: block;
}

.hero-lead {
  font-size: clamp(18px, 2.5vw, 20px);
  line-height: 1.5;
  max-width: 540px;
  margin: 0 0 28px;
  color: var(--dbx-muted);
}

.hero-benefits {
  list-style: none;
  margin: 0 0 32px;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.hero-benefits li {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  font-size: 16px;
  color: var(--dbx-ink-soft);
}

.hero-benefits li::before {
  content: "";
  flex-shrink: 0;
  width: 22px;
  height: 22px;
  margin-top: 2px;
  border-radius: 50%;
  background: var(--dbx-blue-wash);
  border: 2px solid var(--dbx-blue-light);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 12'%3E%3Cpath fill='%230061FE' d='M4.5 8.5L2 6l1-1 1.5 1.5L9 3l1 1z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: center;
}

.hero-cta-group {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* Product mockup */
.mockup-stack {
  position: relative;
  min-height: 380px;
}

.mockup-desktop {
  background: var(--dbx-surface);
  border: 1px solid var(--dbx-border);
  border-radius: var(--r-xl);
  box-shadow: 0 24px 48px rgba(30, 25, 25, 0.08);
  overflow: hidden;
}

.mockup-toolbar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 16px;
  background: var(--dbx-surface-soft);
  border-bottom: 1px solid var(--dbx-border);
}

.mockup-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--dbx-border);
}

.mockup-dot:nth-child(1) {
  background: #fa551e;
}

.mockup-dot:nth-child(2) {
  background: var(--brand-yellow);
}

.mockup-dot:nth-child(3) {
  background: var(--brand-lime);
}

.mockup-title {
  margin-left: 8px;
  font-size: 13px;
  color: var(--dbx-muted);
}

.mockup-body {
  padding: 20px;
}

.chat-thread {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.chat-bubble {
  max-width: 85%;
  padding: 12px 16px;
  border-radius: 14px;
  font-size: 14px;
  line-height: 1.45;
}

.chat-bubble.tutor {
  align-self: flex-start;
  background: var(--dbx-blue-wash);
  color: var(--dbx-ink);
  border: 1px solid var(--dbx-blue-light);
}

.chat-bubble.user {
  align-self: flex-end;
  background: var(--dbx-blue);
  color: var(--dbx-canvas);
}

.chat-label {
  font-size: 11px;
  font-weight: 500;
  color: var(--dbx-muted);
  margin-bottom: 4px;
}

.mockup-mobile {
  position: absolute;
  right: -8px;
  bottom: -16px;
  width: 42%;
  max-width: 180px;
  background: var(--dbx-surface);
  border: 1px solid var(--dbx-border);
  border-radius: 20px;
  box-shadow: 0 16px 32px rgba(30, 25, 25, 0.12);
  padding: 12px;
}

.mockup-mobile-notch {
  width: 40%;
  height: 4px;
  background: var(--dbx-surface-soft);
  border-radius: 4px;
  margin: 0 auto 12px;
}

.mockup-mobile .chat-bubble {
  font-size: 12px;
  padding: 10px 12px;
}

.mockup-mobile-reply {
  margin-top: 8px;
}

.feedback-chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 12px;
  padding: 8px 12px;
  background: #0f503c;
  color: #e8f5f0;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 500;
}

@media (min-width: 900px) {
  .hero {
    padding: 96px 0 128px;
  }

  .hero-grid {
    grid-template-columns: 1fr 1fr;
    gap: 64px;
  }
}

/* Trust strip */
.trust-section {
  padding: 48px 0;
  background: var(--dbx-surface);
  border-top: 1px solid var(--dbx-border);
  border-bottom: 1px solid var(--dbx-border);
}

.trust-inner {
  text-align: center;
}

.trust-headline {
  font-family: var(--font-display);
  font-size: clamp(22px, 3vw, 26px);
  font-weight: 500;
  color: var(--dbx-ink);
  margin: 0 0 24px;
}

.trust-stats {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 32px 48px;
}

.trust-stat {
  text-align: center;
}

.trust-stat strong {
  display: block;
  font-family: var(--font-display);
  font-size: 28px;
  font-weight: 500;
  color: var(--dbx-blue);
  margin-bottom: 4px;
}

.trust-stat span {
  font-size: 14px;
  color: var(--dbx-muted);
}

/* Feature story */
.section {
  padding: var(--space-section) 0;
}

.section-label {
  font-size: 13px;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--dbx-blue);
  margin: 0 0 12px;
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(28px, 4vw, 40px);
  font-weight: 500;
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--dbx-ink);
  margin: 0 0 16px;
  max-width: 640px;
}

.section-lead {
  font-size: 18px;
  max-width: 560px;
  margin: 0 0 32px;
  color: var(--dbx-muted);
}

.steps-grid {
  display: grid;
  gap: 24px;
  margin-top: 48px;
}

.step-card {
  background: var(--dbx-surface);
  border: 1px solid var(--dbx-border);
  border-radius: var(--r-card);
  padding: 24px;
}

.step-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: var(--dbx-blue-wash);
  color: var(--dbx-blue);
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 16px;
  margin-bottom: 16px;
}

.step-card h3 {
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 500;
  color: var(--dbx-ink);
  margin: 0 0 10px;
}

.step-card p {
  margin: 0;
  font-size: 16px;
  color: var(--dbx-muted);
}

@media (min-width: 768px) {
  .steps-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* Alternating features */
.feature-block {
  display: grid;
  gap: 40px;
  align-items: center;
  padding: 64px 0;
  border-bottom: 1px solid var(--dbx-border);
}

.feature-block:last-child {
  border-bottom: none;
}

.feature-panel {
  background: var(--dbx-surface);
  border: 1px solid var(--dbx-border);
  border-radius: var(--r-xl);
  padding: 28px;
}

.phrase-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.phrase-list li {
  padding: 12px 16px;
  background: var(--dbx-canvas);
  border-radius: var(--r-card);
  border: 1px solid var(--dbx-border);
  font-size: 15px;
  color: var(--dbx-ink);
}

.phrase-list li.highlight {
  background: var(--dbx-blue-wash);
  border-color: var(--dbx-blue-light);
}

.repeat-meter {
  height: 8px;
  background: var(--dbx-surface-soft);
  border-radius: 999px;
  overflow: hidden;
  margin: 16px 0;
}

.repeat-meter span {
  display: block;
  height: 100%;
  width: 78%;
  background: var(--dbx-blue);
  border-radius: 999px;
}

@media (min-width: 900px) {
  .feature-block {
    grid-template-columns: 1fr 1fr;
    gap: 64px;
  }

  .feature-block.reverse .feature-copy {
    order: 2;
  }

  .feature-block.reverse .feature-panel {
    order: 1;
  }
}

/* Dark trust panel */
.dark-panel {
  background: var(--dbx-dark);
  color: var(--dbx-canvas);
  padding: var(--space-section) 0;
  margin: var(--space-section) 0;
}

.dark-panel .section-label {
  color: var(--dbx-blue-light);
}

.dark-panel .section-title {
  color: var(--dbx-canvas);
}

.dark-panel .section-lead {
  color: rgba(247, 245, 242, 0.75);
}

.expert-grid {
  display: grid;
  gap: 24px;
  margin-top: 40px;
}

.expert-card {
  background: var(--dbx-dark-elevated);
  border: 1px solid rgba(211, 206, 201, 0.15);
  border-radius: var(--r-xl);
  padding: 32px;
}

.expert-card h3 {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 500;
  color: var(--dbx-canvas);
  margin: 0 0 12px;
}

.expert-card p {
  margin: 0;
  color: rgba(247, 245, 242, 0.72);
  font-size: 16px;
}

.dark-panel-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 40px;
}

@media (min-width: 768px) {
  .expert-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* FAQ */
.faq-list {
  max-width: 720px;
  margin-top: 40px;
}

.faq-item {
  border-bottom: 1px solid var(--dbx-border);
}

.faq-item summary {
  list-style: none;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 20px 0;
  background: none;
  border: none;
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 500;
  color: var(--dbx-ink);
  text-align: left;
  cursor: pointer;
}

.faq-question:hover {
  color: var(--dbx-blue);
}

.faq-icon {
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  border: 1px solid var(--dbx-border);
  display: grid;
  place-items: center;
  font-size: 18px;
  line-height: 1;
  color: var(--dbx-muted);
}

.faq-item[open] .faq-icon {
  background: var(--dbx-blue-wash);
  border-color: var(--dbx-blue-light);
  color: var(--dbx-blue);
}

.faq-answer {
  padding: 0 0 20px;
  color: var(--dbx-muted);
  font-size: 16px;
  line-height: 1.6;
}

.faq-answer p {
  margin: 0;
}

/* Final CTA */
.cta-final {
  padding: var(--space-section) 0;
  background: var(--dbx-blue-wash);
  border-top: 1px solid var(--dbx-blue-light);
}

.cta-final-inner {
  text-align: center;
  max-width: 640px;
  margin-inline: auto;
}

.cta-final .hero-title {
  font-size: clamp(36px, 5vw, 48px);
}

.cta-final .hero-lead {
  margin-inline: auto;
}

/* Footer */
.site-footer {
  background: var(--dbx-dark);
  color: rgba(247, 245, 242, 0.72);
  padding: 64px 0 32px;
}

.footer-grid {
  display: grid;
  gap: 32px;
  margin-bottom: 48px;
}

.footer-brand {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 500;
  color: var(--dbx-canvas);
  margin-bottom: 12px;
}

.footer-note {
  font-size: 14px;
  max-width: 320px;
  line-height: 1.5;
}

.footer-col h4 {
  font-family: var(--font-display);
  font-size: 14px;
  font-weight: 500;
  color: var(--dbx-canvas);
  margin: 0 0 16px;
}

.footer-col ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.footer-col li {
  margin-bottom: 10px;
}

.footer-col a {
  color: rgba(247, 245, 242, 0.72);
  font-size: 14px;
}

.footer-col a:hover {
  color: var(--dbx-canvas);
}

.footer-bottom {
  padding-top: 24px;
  border-top: 1px solid rgba(211, 206, 201, 0.15);
  font-size: 13px;
  color: rgba(247, 245, 242, 0.5);
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 12px;
}

@media (min-width: 768px) {
  .footer-grid {
    grid-template-columns: 2fr 1fr 1fr;
  }
}

.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;
}