*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --brand: #00C8E0;
  --brand-dark: #00A8C0;
  --text: #111111;
  --text-secondary: #666666;
  --surface: #F2F2F7;
  --border: #E5E5EA;
  --max-width: 960px;
  --gutter: 1.5rem;
}

html {
  font-family: "Inter", sans-serif;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  color: var(--text);
  line-height: 1.6;
  background: #fff;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

body > .site-footer {
  margin-top: auto;
}

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

a {
  color: var(--brand-dark);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* Layout */

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

/* Header */

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
}

.site-header__logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  color: var(--text);
}

.site-header__logo img {
  width: 28px;
  height: 28px;
  border-radius: 6px;
}

.site-header__logo span {
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: -0.02em;
}

.btn {
  display: inline-block;
  background: var(--brand);
  color: #fff;
  font-weight: 600;
  font-size: 0.875rem;
  padding: 0.5rem 1.25rem;
  border-radius: 8px;
  text-decoration: none;
  letter-spacing: -0.01em;
}

.btn:hover {
  background: var(--brand-dark);
  text-decoration: none;
}

/* Section spacing */

section {
  padding: 5rem 0;
}

section.surface {
  background: var(--surface);
}

/* Typography */

h1, h2, h3 {
  letter-spacing: -0.03em;
  line-height: 1.15;
}

h1 {
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 700;
}

h2 {
  font-size: clamp(1.5rem, 3.5vw, 2.25rem);
  font-weight: 700;
}

h3 {
  font-size: 1.125rem;
  font-weight: 600;
}

.section-sub {
  color: var(--text-secondary);
  font-size: clamp(1rem, 2vw, 1.25rem);
  margin-top: 0.75rem;
  line-height: 1.5;
}

/* Hero */

.hero .container {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 2.5rem;
  padding-top: 4rem;
  padding-bottom: 4rem;
}

.hero__text {
  max-width: 480px;
}

.hero__text h1 {
  margin-bottom: 1rem;
}

.hero__text .section-sub {
  margin-top: 0;
  margin-bottom: 2rem;
}

.hero__image {
  width: 100%;
  max-width: 300px;
  align-self: center;
}

.app-store-badge {
  height: 48px;
  width: auto;
  display: inline-block;
}

/* Device frame */

.device-frame {
  background: #111;
  border-radius: 36px;
  padding: 8px;
  display: inline-block;
}

.device-frame img {
  border-radius: 28px;
  display: block;
}

/* How It Works */

.how-it-works {
  text-align: center;
}

.how-it-works h2 {
  margin-bottom: 3rem;
}

.how-it-works__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 3rem;
  max-width: 800px;
  margin: 0 auto;
}

.how-it-works__step {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
}

.how-it-works__number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--brand);
  color: #fff;
  font-weight: 700;
  font-size: 1rem;
}

.how-it-works__step h3 {
  margin-bottom: 0.25rem;
}

.how-it-works__step p {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  max-width: 240px;
}

.how-it-works__step .device-frame img {
  width: 200px;
}

/* Details (two-column text + image) */

.details .container {
  display: flex;
  flex-direction: column;
  gap: 2.5rem;
}

.details__text {
  max-width: 480px;
}

.details__text h2 {
  margin-bottom: 1.5rem;
}

.details__list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.details__list li {
  display: flex;
  align-items: baseline;
  gap: 0.5rem;
  font-size: 0.9375rem;
}

.details__list li strong {
  font-weight: 600;
  white-space: nowrap;
}

.details__list li span {
  color: var(--text-secondary);
}

.details__image {
  width: 100%;
  max-width: 300px;
  align-self: center;
}

/* Dual frame section */

.dual-frame {
  text-align: center;
}

.dual-frame h2 {
  margin-bottom: 0.75rem;
}

.dual-frame .section-sub {
  max-width: 560px;
  margin: 0 auto 3rem;
}

.dual-frame__images {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.dual-frame__images .device-frame img {
  width: 200px;
}

/* FAQ */

.faq {
  padding: 4rem 0;
}

.faq h2 {
  margin-bottom: 2rem;
}

.faq__list {
  max-width: 720px;
}

.faq__item {
  border-bottom: 1px solid var(--border);
}

.faq__item:first-child {
  border-top: 1px solid var(--border);
}

.faq__item summary {
  font-weight: 600;
  font-size: 1.0625rem;
  padding: 1.25rem 0;
  cursor: pointer;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

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

.faq__item summary::after {
  content: "\276F";
  font-size: 0.875rem;
  color: var(--text-secondary);
  flex-shrink: 0;
  margin-left: 1rem;
  transform: rotate(90deg);
  transition: transform 0.2s ease;
}

.faq__item[open] summary::after {
  transform: rotate(270deg);
}

.faq__item p {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  line-height: 1.7;
  padding-bottom: 1.25rem;
}

/* CTA */

.cta {
  text-align: center;
  padding: 4rem 0;
}

.cta h2 {
  margin-bottom: 1.5rem;
}

.cta .app-store-badge {
  margin-bottom: 1.5rem;
}

.cta p {
  color: var(--text-secondary);
  font-size: 0.9375rem;
}

.cta a {
  color: var(--text-secondary);
}

/* Footer */

.site-footer {
  border-top: 1px solid var(--border);
  padding: 2rem 0;
  color: var(--text-secondary);
  font-size: 0.8125rem;
}

.site-footer .container {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 2rem;
}

.site-footer a {
  color: var(--text-secondary);
}

.site-footer a:hover {
  color: var(--text);
}

/* Privacy / article styles */

.article {
  max-width: 720px;
  margin: 0 auto;
  padding: 3rem var(--gutter);
}

.article h1 {
  margin-bottom: 2rem;
}

.article h2 {
  margin-top: 2rem;
  margin-bottom: 0.75rem;
  font-size: 1.25rem;
}

.article p {
  margin-bottom: 1rem;
  color: var(--text-secondary);
  font-size: 0.9375rem;
  line-height: 1.7;
}

.article ul {
  margin-bottom: 1rem;
  padding-left: 1.5rem;
}

.article li {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  line-height: 1.7;
  margin-bottom: 0.5rem;
}

.article strong {
  color: var(--text);
}

/* Responsive: desktop */

@media (min-width: 768px) {
  .hero .container {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    text-align: left;
    padding-top: 6rem;
    padding-bottom: 6rem;
  }

  .hero__text {
    flex: 1;
  }

  .hero__image {
    flex-shrink: 0;
    align-self: auto;
  }

  .how-it-works__grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
  }

  .details .container {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
  }

  .details__text {
    flex: 1;
  }

  .details__image {
    flex-shrink: 0;
    align-self: auto;
  }

  .dual-frame__images .device-frame img {
    width: 240px;
  }
}