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

:root {
  --accent: #2600FF;
  --accent-dark: #1d00cc;
  --bg: #F4F4F8;
  --bg-dark: #E6E6EE;
  --text: #1A1A1F;
  --text-light: #6B6B75;
  --white: #FFFFFF;
  --radius: 16px;
  --max-width: 960px;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Helvetica Neue", Helvetica, Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

a:hover {
  text-decoration: underline;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

nav {
  padding: 20px 0;
  background: var(--bg);
}

nav .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 600;
  font-size: 1.125rem;
  color: var(--text);
  padding: 8px 4px;
  margin: -8px -4px;
}

.nav-brand img {
  width: 32px;
  height: 32px;
  border-radius: 8px;
}

.nav-links {
  display: flex;
  gap: 24px;
  list-style: none;
}

.nav-links a {
  display: inline-block;
  color: var(--text-light);
  font-size: 0.9375rem;
  font-weight: 500;
  padding: 10px 6px;
  margin: -10px -6px;
  transition: color 0.2s;
}

.nav-links a:hover {
  color: var(--accent-dark);
  text-decoration: none;
}

.hero {
  text-align: center;
  padding: 80px 0 64px;
}

.hero-icon {
  width: 128px;
  height: 128px;
  border-radius: 28px;
  box-shadow: 0 8px 32px rgba(38, 0, 255, 0.18);
  margin-bottom: 32px;
}

.hero h1 {
  font-size: 3rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 12px;
}

.hero .tagline {
  font-size: 1.375rem;
  color: var(--text-light);
  font-weight: 400;
  margin-bottom: 20px;
}

.hero .description {
  font-size: 1.0625rem;
  color: var(--text-light);
  max-width: 540px;
  margin: 0 auto 40px;
}

.app-store-badge {
  display: inline-block;
  transition: opacity 0.2s;
}

.app-store-badge:hover {
  opacity: 0.85;
}

.app-store-badge img {
  height: 54px;
  max-width: 100%;
}

.features {
  padding: 64px 0;
}

.features h2 {
  text-align: center;
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin-bottom: 48px;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--white);
  border-radius: var(--radius);
  padding: 32px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
}

.feature-icon {
  font-size: 2rem;
  margin-bottom: 16px;
}

.feature-card h3 {
  font-size: 1.1875rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.feature-card p {
  color: var(--text-light);
  font-size: 0.9375rem;
  line-height: 1.55;
}

.how-it-works {
  padding: 64px 0;
}

.how-it-works h2 {
  text-align: center;
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin-bottom: 48px;
}

.calc-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.calc-card {
  background: var(--white);
  border-radius: var(--radius);
  padding: 24px 24px 28px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
  border-top: 3px solid var(--accent);
}

.calc-card h3 {
  font-size: 1.0625rem;
  font-weight: 600;
  margin-bottom: 12px;
}

.calc-card ul {
  list-style: none;
}

.calc-card li {
  color: var(--text-light);
  font-size: 0.9375rem;
  padding: 4px 0;
  border-bottom: 1px solid var(--bg-dark);
}

.calc-card li:last-child {
  border-bottom: none;
}

.highlights {
  padding: 48px 0 64px;
}

.highlights-row {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 16px 40px;
}

.highlight {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.9375rem;
  color: var(--text-light);
}

.highlight-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
  flex-shrink: 0;
}

.cta {
  text-align: center;
  padding: 64px 0;
  background: var(--white);
  border-radius: var(--radius);
  margin-bottom: 64px;
}

.cta h2 {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 12px;
}

.cta p {
  color: var(--text-light);
  margin-bottom: 32px;
  font-size: 1.0625rem;
}

footer {
  padding: 40px 0;
  border-top: 1px solid var(--bg-dark);
  text-align: center;
}

footer .footer-links {
  display: flex;
  justify-content: center;
  gap: 24px;
  list-style: none;
  margin-bottom: 16px;
}

footer .footer-links a {
  display: inline-block;
  color: var(--text-light);
  font-size: 0.875rem;
  padding: 8px 0;
}

footer .copyright {
  color: var(--text-light);
  font-size: 0.8125rem;
}

.page-header {
  padding: 48px 0 32px;
  text-align: center;
}

.page-header h1 {
  font-size: 2.25rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.page-header p {
  color: var(--text-light);
  margin-top: 8px;
}

.prose {
  max-width: 680px;
  margin: 0 auto;
  padding-bottom: 80px;
}

.prose h2 {
  font-size: 1.375rem;
  font-weight: 600;
  margin-top: 40px;
  margin-bottom: 12px;
}

.prose p {
  margin-bottom: 16px;
  color: var(--text);
  font-size: 0.9375rem;
}

.prose ul,
.prose ol {
  margin-bottom: 16px;
  padding-left: 24px;
}

.prose li {
  color: var(--text);
  font-size: 0.9375rem;
  margin-bottom: 6px;
}

.prose a {
  color: var(--accent-dark);
  text-decoration: underline;
  text-underline-offset: 2px;
}

details {
  border-bottom: 1px solid var(--bg-dark);
  padding: 16px 0;
}

details:first-of-type {
  border-top: 1px solid var(--bg-dark);
}

summary {
  font-weight: 600;
  font-size: 0.9375rem;
  cursor: pointer;
  list-style: none;
  padding: 8px 28px 8px 0;
  margin: -8px 0;
  position: relative;
  color: var(--text);
}

summary:hover {
  color: var(--accent-dark);
}

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

summary::after {
  content: '';
  position: absolute;
  right: 4px;
  top: 50%;
  width: 7px;
  height: 7px;
  border-right: 2px solid var(--accent);
  border-bottom: 2px solid var(--accent);
  transform: translateY(-75%) rotate(45deg);
  transition: transform 0.2s ease;
}

details[open] summary::after {
  transform: translateY(-25%) rotate(-135deg);
}

details > p,
details > ul,
details > ol {
  margin-top: 10px;
  font-size: 0.9375rem;
  color: var(--text);
}

.contact-card {
  background: var(--white);
  border-left: 3px solid var(--accent);
  border-radius: 12px;
  padding: 20px 24px;
  margin: 24px 0 36px;
  font-size: 0.9375rem;
}

.contact-card p {
  margin: 4px 0;
}

.notfound {
  min-height: 70vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 60px 32px;
}

.notfound .big {
  font-size: clamp(3rem, 10vw, 5rem);
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 1;
  margin-bottom: 16px;
}

.notfound .big .accent {
  color: var(--accent);
}

.notfound .subtitle {
  font-size: 1.125rem;
  color: var(--text-light);
  max-width: 460px;
  margin: 0 auto 32px;
}

.btn-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  justify-content: center;
}

.btn {
  display: inline-flex;
  align-items: center;
  font-size: 0.9375rem;
  font-weight: 600;
  padding: 12px 24px;
  border-radius: 980px;
  text-decoration: none;
  transition: transform 0.15s, box-shadow 0.15s, border-color 0.15s, color 0.15s;
}

.btn-primary {
  color: var(--white);
  background: var(--accent);
  box-shadow: 0 4px 14px rgba(38, 0, 255, 0.25);
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(38, 0, 255, 0.32);
  text-decoration: none;
  color: var(--white);
}

.btn-secondary {
  color: var(--text-light);
  border: 1.5px solid var(--bg-dark);
}

.btn-secondary:hover {
  border-color: var(--text-light);
  color: var(--text);
  text-decoration: none;
}

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

@media (max-width: 640px) {
  .container {
    padding: 0 20px;
  }

  .hero {
    padding: 48px 0 40px;
  }

  .hero h1 {
    font-size: 2.25rem;
  }

  .hero .tagline {
    font-size: 1.125rem;
  }

  .features-grid,
  .calc-grid {
    grid-template-columns: 1fr;
  }

  .feature-card {
    padding: 24px;
  }

  .nav-links {
    gap: 12px;
  }
}