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

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-base);
  font-size: var(--text-body-size);
  font-weight: var(--text-body-weight);
  line-height: var(--text-body-lh);
  color: var(--color-ink);
  background: var(--color-canvas);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a {
  color: var(--color-primary);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}

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

/* NAV */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  height: 48px;
  display: flex;
  align-items: center;
  padding: 0 var(--space-6);
  background: var(--color-acrylic-overlay);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--color-border);
}
@supports not (backdrop-filter: blur(1px)) {
  .nav {
    background: var(--color-acrylic-fallback);
  }
}
.nav__logo {
  font-size: var(--text-heading-size);
  font-weight: var(--text-heading-weight);
  color: var(--color-ink);
  margin-right: var(--space-8);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}
.nav__logo-icon {
  width: 24px;
  height: 24px;
  color: var(--color-primary);
}
.nav__links {
  display: flex;
  gap: var(--space-5);
  list-style: none;
}
.nav__link {
  font-size: var(--text-body-size);
  color: var(--color-ink-muted);
  transition: color var(--motion-fast) var(--motion-easing);
}
.nav__link:hover {
  color: var(--color-ink);
  text-decoration: none;
}
.nav__link--active {
  color: var(--color-primary);
  font-weight: 600;
}
.nav__hamburger {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-2);
  margin-left: auto;
  color: var(--color-ink);
}

/* MAIN */
.main {
  flex: 1;
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--space-8) var(--space-6);
}

/* HERO */
.hero {
  text-align: center;
  margin-bottom: var(--space-8);
}
.hero__title {
  font-size: var(--text-display-size);
  font-weight: var(--text-display-weight);
  line-height: var(--text-display-lh);
  letter-spacing: var(--text-display-ls);
  color: var(--color-ink);
  margin-bottom: var(--space-2);
}
.hero__subtitle {
  font-size: 16px;
  color: var(--color-ink-muted);
  font-weight: 400;
}

/* SECTION */
.section {
  margin-bottom: var(--space-9);
}
.section__title {
  font-size: var(--text-heading-size);
  font-weight: var(--text-heading-weight);
  line-height: var(--text-heading-lh);
  color: var(--color-ink);
  margin-bottom: var(--space-4);
}
.section__subtitle {
  font-size: 16px;
  font-weight: 600;
  color: var(--color-ink);
  margin-bottom: var(--space-3);
}

/* EDITOR LAYOUT */
.editor-layout {
  display: flex;
  min-height: 480px;
  margin-bottom: var(--space-5);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-card);
  background: var(--color-surface-1);
}

.editor-pane {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
}

.editor-pane__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-3);
  background: var(--color-surface-2);
  border-bottom: 1px solid var(--color-border);
  height: 36px;
  flex-shrink: 0;
}

.editor-pane__title {
  font-size: var(--text-caption-size);
  font-weight: 600;
  color: var(--color-ink-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.editor-pane__actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.editor-divider {
  width: 6px;
  cursor: col-resize;
  background: var(--color-surface-2);
  border-left: 1px solid var(--color-border);
  border-right: 1px solid var(--color-border);
  flex-shrink: 0;
  position: relative;
  transition: background var(--motion-fast);
}
.editor-divider:hover,
.editor-divider--active {
  background: var(--color-primary);
  opacity: 0.3;
}

/* FOOTER */
.footer {
  background: var(--color-surface-2);
  border-top: 1px solid var(--color-border);
  padding: var(--space-7) var(--space-6);
  margin-top: auto;
}
.footer__inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: var(--space-6);
}
.footer__col {
  min-width: 160px;
}
.footer__heading {
  font-size: var(--text-body-size);
  font-weight: 600;
  color: var(--color-ink);
  margin-bottom: var(--space-3);
}
.footer__links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}
.footer__link {
  font-size: var(--text-body-size);
  color: var(--color-ink-muted);
  transition: color var(--motion-fast);
}
.footer__link:hover {
  color: var(--color-primary);
  text-decoration: none;
}
.footer__copy {
  font-size: var(--text-caption-size);
  color: var(--color-ink-subdued);
  width: 100%;
  text-align: center;
  margin-top: var(--space-4);
  padding-top: var(--space-4);
  border-top: 1px solid var(--color-border);
}

/* CARD GRID */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: var(--space-5);
}

/* CONTENT (prose) */
.content p {
  margin-bottom: var(--space-4);
  line-height: 1.7;
}
.content h2 {
  font-size: var(--text-heading-size);
  font-weight: var(--text-heading-weight);
  margin-top: var(--space-8);
  margin-bottom: var(--space-4);
}
.content h3 {
  font-size: 16px;
  font-weight: 600;
  margin-top: var(--space-6);
  margin-bottom: var(--space-3);
}
.content ul,
.content ol {
  padding-left: var(--space-6);
  margin-bottom: var(--space-4);
}
.content li {
  margin-bottom: var(--space-2);
  line-height: 1.7;
}
.content code {
  font-family: var(--font-mono);
  font-size: var(--text-mono-size);
  background: var(--color-surface-2);
  padding: 1px 6px;
  border-radius: var(--radius-sm);
}
.content table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: var(--space-5);
}
.content th,
.content td {
  padding: var(--space-3) var(--space-4);
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}
.content th {
  font-weight: 600;
  background: var(--color-surface-2);
}

/* RESPONSIVE */
@media (max-width: 768px) {
  .nav {
    padding: 0 var(--space-4);
  }
  .nav__links {
    display: none;
    position: absolute;
    top: 48px;
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--color-surface-1);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-card);
    padding: var(--space-3) var(--space-4);
    gap: 0;
  }
  .nav__links--open {
    display: flex;
  }
  .nav__links li {
    padding: var(--space-3) 0;
  }
  .nav__hamburger {
    display: block;
  }
  .main {
    padding: var(--space-6) var(--space-4);
  }
  .hero__title {
    font-size: 24px;
  }
  .editor-layout {
    flex-direction: column;
    min-height: auto;
  }
  .editor-divider {
    width: 100%;
    height: 6px;
    cursor: row-resize;
    border-left: none;
    border-right: none;
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
  }
  .editor-pane {
    min-height: 280px;
  }
  .footer__inner {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (max-width: 480px) {
  .hero__title {
    font-size: 20px;
  }
  .card-grid {
    grid-template-columns: 1fr;
  }
}