/* Reset */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; }

/* Base */
body {
  background: var(--sd-color-surface-page);
  color: var(--sd-color-text-primary);
  font-family: var(--sd-font-family-body);
  font-size: var(--sd-font-size-body);
  font-weight: var(--sd-font-weight-body);
  line-height: var(--sd-font-leading-body);
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }

/* Container */
.container {
  max-width: var(--sd-space-layout-max-width);
  margin: 0 auto;
  padding: 0 var(--sd-space-layout-gutter);
}

/* Eyebrow */
.eyebrow {
  font-size: var(--sd-font-size-label);
  font-weight: var(--sd-font-weight-heading);
  letter-spacing: var(--sd-font-tracking-label);
  color: var(--sd-color-text-secondary);
  text-transform: uppercase;
  margin-bottom: 16px;
}

.hero .eyebrow {
  color: var(--sd-color-text-inverse);
  opacity: 0.6;
}

/* Nav */
.nav {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--sd-color-surface-inverse);
  border-bottom: 1px solid rgba(249, 248, 246, 0.08);
}

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

.nav__wordmark {
  font-size: var(--sd-font-size-h3);
  font-weight: var(--sd-font-weight-heading);
  color: var(--sd-color-text-inverse);
  letter-spacing: var(--sd-font-tracking-heading);
}

.nav__links {
  display: flex;
  align-items: center;
  gap: 8px;
}

/* Dropdown */
.nav__dropdown {
  position: relative;
}

.nav__dropdown-trigger {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 12px;
  font-size: var(--sd-font-size-caption);
  font-weight: var(--sd-font-weight-emphasis);
  color: rgba(249, 248, 246, 0.7);
  cursor: pointer;
  border-radius: 6px;
  transition: color var(--sd-motion-interactive) var(--sd-motion-easing);
  user-select: none;
}

.nav__dropdown-trigger::after {
  content: '';
  display: inline-block;
  width: 0;
  height: 0;
  border-left: 4px solid transparent;
  border-right: 4px solid transparent;
  border-top: 4px solid currentColor;
  opacity: 0.6;
  transition: transform var(--sd-motion-interactive) var(--sd-motion-easing);
}

.nav__dropdown:hover .nav__dropdown-trigger {
  color: var(--sd-color-text-inverse);
}

.nav__dropdown:hover .nav__dropdown-trigger::after {
  transform: rotate(180deg);
}

.nav__dropdown-menu {
  position: absolute;
  top: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%);
  background: var(--sd-color-surface-raised);
  border: 1px solid var(--sd-color-border-default);
  border-radius: var(--sd-radius-panel);
  box-shadow: var(--sd-shadow-dropdown);
  min-width: 240px;
  padding: 8px;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--sd-motion-interactive) var(--sd-motion-easing),
              transform var(--sd-motion-interactive) var(--sd-motion-easing);
  transform: translateX(-50%) translateY(-4px);
}

.nav__dropdown:hover .nav__dropdown-menu {
  opacity: 1;
  pointer-events: auto;
  transform: translateX(-50%) translateY(0);
}

.nav__dropdown-item {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 10px 12px;
  border-radius: 6px;
  text-decoration: none;
  transition: background var(--sd-motion-interactive) var(--sd-motion-easing);
}

.nav__dropdown-item strong {
  font-size: var(--sd-font-size-caption);
  font-weight: var(--sd-font-weight-emphasis);
  color: var(--sd-color-text-primary);
}

.nav__dropdown-item span {
  font-size: var(--sd-font-size-label);
  color: var(--sd-color-text-tertiary);
}

.nav__dropdown-item:hover {
  background: var(--sd-color-surface-subtle);
}

.nav__dropdown-item--active strong {
  color: var(--sd-color-accent-default);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: var(--sd-space-component-sm) var(--sd-space-component-md);
  border-radius: var(--sd-radius-button);
  font-family: var(--sd-font-family-body);
  font-size: var(--sd-font-size-body);
  font-weight: var(--sd-font-weight-emphasis);
  line-height: 1;
  cursor: pointer;
  border: 1px solid transparent;
  transition: background var(--sd-motion-interactive) var(--sd-motion-easing),
              color var(--sd-motion-interactive) var(--sd-motion-easing),
              border-color var(--sd-motion-interactive) var(--sd-motion-easing);
  text-decoration: none;
}

.btn--primary {
  background: var(--sd-color-accent-default);
  color: var(--sd-color-text-on-accent);
  border-color: var(--sd-color-accent-default);
}
.btn--primary:hover {
  background: var(--sd-color-accent-hover);
  border-color: var(--sd-color-accent-hover);
}

.btn--ghost {
  background: transparent;
  color: var(--sd-color-text-inverse);
  border-color: rgba(249, 248, 246, 0.25);
}
.btn--ghost:hover {
  border-color: rgba(249, 248, 246, 0.5);
}

.btn--ghost-inverse {
  background: transparent;
  color: var(--sd-color-text-inverse);
  border-color: rgba(249, 248, 246, 0.25);
}
.btn--ghost-inverse:hover {
  border-color: rgba(249, 248, 246, 0.5);
}

.btn--lg {
  padding: 14px 28px;
  font-size: var(--sd-font-size-lead);
}

/* Hero */
.hero {
  background: var(--sd-color-surface-inverse);
  padding: 80px 0 96px;
}

.hero__inner {
  max-width: 760px;
}

.hero h1 {
  font-size: clamp(2rem, 4vw, var(--sd-font-size-display));
  font-weight: var(--sd-font-weight-heading);
  line-height: var(--sd-font-leading-heading);
  letter-spacing: var(--sd-font-tracking-heading);
  color: var(--sd-color-text-inverse);
  margin-bottom: 24px;
}

.hero .lead {
  color: var(--sd-color-text-inverse);
  opacity: 0.75;
  font-size: var(--sd-font-size-lead);
  line-height: var(--sd-font-leading-body);
  margin-bottom: 40px;
  max-width: 640px;
}

.hero__actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

/* Sections */
.section {
  padding: var(--sd-space-layout-section-y) 0;
}

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

.section__heading {
  font-size: var(--sd-font-size-h1);
  font-weight: var(--sd-font-weight-heading);
  letter-spacing: var(--sd-font-tracking-heading);
  line-height: var(--sd-font-leading-heading);
  color: var(--sd-color-text-primary);
  margin-bottom: 48px;
  max-width: 600px;
}

/* Prose block (problem section) */
.prose-block {
  max-width: 680px;
}

.prose-block h2 {
  font-size: var(--sd-font-size-h1);
  font-weight: var(--sd-font-weight-heading);
  letter-spacing: var(--sd-font-tracking-heading);
  line-height: var(--sd-font-leading-heading);
  margin-bottom: 24px;
}

.prose-block .lead {
  font-size: var(--sd-font-size-lead);
  line-height: var(--sd-font-leading-body);
  color: var(--sd-color-text-secondary);
  margin-bottom: 20px;
}

.prose-block p {
  color: var(--sd-color-text-secondary);
  line-height: var(--sd-font-leading-body);
}

/* Card grid */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--sd-space-layout-gutter);
}

/* Card */
.card {
  background: var(--sd-color-surface-raised);
  border: 1px solid var(--sd-color-border-default);
  border-radius: var(--sd-radius-card);
  padding: var(--sd-space-component-xl);
  transition: box-shadow var(--sd-motion-interactive) var(--sd-motion-easing),
              border-color var(--sd-motion-interactive) var(--sd-motion-easing);
  text-decoration: none;
  display: block;
}

.card:hover {
  box-shadow: var(--sd-shadow-card-hover);
}

.card--link:hover {
  border-color: var(--sd-color-accent-default);
}

.card h3 {
  font-size: var(--sd-font-size-h3);
  font-weight: var(--sd-font-weight-heading);
  letter-spacing: var(--sd-font-tracking-heading);
  color: var(--sd-color-text-primary);
  margin-bottom: 12px;
}

.card p {
  font-size: var(--sd-font-size-body);
  color: var(--sd-color-text-secondary);
  line-height: var(--sd-font-leading-body);
  margin-bottom: 20px;
}

.card__cta {
  font-size: var(--sd-font-size-caption);
  font-weight: var(--sd-font-weight-emphasis);
  color: var(--sd-color-accent-default);
}

/* Detail grid (product pages) */
.detail-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--sd-space-layout-gutter);
}

.detail-card {
  padding: var(--sd-space-component-xl) 0;
  border-top: 1px solid var(--sd-color-border-default);
}

.detail-card h3 {
  font-size: var(--sd-font-size-h3);
  font-weight: var(--sd-font-weight-heading);
  letter-spacing: var(--sd-font-tracking-heading);
  margin-bottom: 12px;
}

.detail-card p {
  font-size: var(--sd-font-size-body);
  color: var(--sd-color-text-secondary);
  line-height: var(--sd-font-leading-body);
  margin-bottom: 20px;
}

/* Badge */
.badge {
  display: inline-block;
  font-size: var(--sd-font-size-label);
  font-weight: var(--sd-font-weight-heading);
  letter-spacing: var(--sd-font-tracking-label);
  color: var(--sd-color-accent-default);
  background: var(--sd-color-accent-subtle);
  border-radius: var(--sd-radius-badge);
  padding: var(--sd-space-component-xs) 10px;
  margin-bottom: 16px;
}

/* Feature list */
.feature-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.feature-list li {
  font-size: var(--sd-font-size-caption);
  color: var(--sd-color-text-secondary);
  padding-left: 16px;
  position: relative;
}

.feature-list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 7px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--sd-color-accent-default);
  opacity: 0.5;
}

/* Steps */
.steps {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 40px;
  max-width: 680px;
}

.step {
  display: grid;
  grid-template-columns: 40px 1fr;
  gap: 24px;
  align-items: start;
}

.step__number {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: 1.5px solid var(--sd-color-border-default);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--sd-font-size-caption);
  font-weight: var(--sd-font-weight-heading);
  color: var(--sd-color-text-secondary);
  flex-shrink: 0;
  margin-top: 2px;
}

.step__content h3 {
  font-size: var(--sd-font-size-h3);
  font-weight: var(--sd-font-weight-heading);
  letter-spacing: var(--sd-font-tracking-heading);
  margin-bottom: 8px;
}

.step__content p {
  color: var(--sd-color-text-secondary);
  line-height: var(--sd-font-leading-body);
}

/* CTA block */
.cta-block {
  max-width: 600px;
}

.cta-block h2 {
  font-size: var(--sd-font-size-h1);
  font-weight: var(--sd-font-weight-heading);
  letter-spacing: var(--sd-font-tracking-heading);
  line-height: var(--sd-font-leading-heading);
  margin-bottom: 20px;
}

.cta-block .lead {
  font-size: var(--sd-font-size-lead);
  color: var(--sd-color-text-secondary);
  line-height: var(--sd-font-leading-body);
  margin-bottom: 12px;
}

.cta-note {
  font-size: var(--sd-font-size-caption);
  color: var(--sd-color-text-tertiary);
  margin-bottom: 32px;
}

/* Footer */
.footer {
  border-top: 1px solid var(--sd-color-border-default);
  padding: 40px 0;
}

.footer__inner {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer__wordmark {
  font-size: var(--sd-font-size-body);
  font-weight: var(--sd-font-weight-heading);
  color: var(--sd-color-text-secondary);
}

.footer__copy {
  font-size: var(--sd-font-size-caption);
  color: var(--sd-color-text-tertiary);
  max-width: 640px;
  line-height: var(--sd-font-leading-body);
}

/* Responsive */
@media (max-width: 640px) {
  .hero {
    padding: 48px 0 64px;
  }

  .section {
    padding: 64px 0;
  }

  .card-grid {
    grid-template-columns: 1fr;
  }

  .hero__actions {
    flex-direction: column;
    align-items: flex-start;
  }

  .step {
    grid-template-columns: 32px 1fr;
    gap: 16px;
  }

  .step__number {
    width: 32px;
    height: 32px;
  }
}