* {
  box-sizing: border-box;
}

:root {
  --bg-color: #fcfdfe;
  --text-color: #000c18;
  --accent-color: #22aa44;
  --accent-hover: #9966b8;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg-color: #000c18;
    --text-color: #b7b8b9;
  }
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen,
    Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  font-size: 1.125rem;
  line-height: 1.8;
  background: var(--bg-color);
  color: var(--text-color);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  overflow-x: hidden;
}

h1 {
  font-size: 1.75rem;
}

h2 {
  margin: 0 0 0.75em;
  font-weight: 700;
  line-height: 1.3;
  font-size: 2rem;
}

@media (max-width: 768px) {
  h1 {
    font-size: 1.75rem;
  }

  h2 {
    font-size: 1.75rem;
  }
}

header,
footer {
  padding: 0.5em;
  text-align: center;
  background: var(--bg-color);
}

header h1 {
  font-size: 1.75rem;
  padding-left: 1rem;
}

main {
  flex-grow: 1;
  max-width: 900px;
  margin: 0 auto;
  padding: 2em;
}

@media (max-width: 768px) {
  main {
    padding: 1.5em;
  }
}

footer {
  text-align: center;
  font-size: 1.05rem;
  color: var(--text-color);
}

section {
  margin-bottom: 3em;
  padding: 0 2%;
}

.header-top {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 2rem;
}

@media (max-width: 768px) {
  .header-top {
    justify-content: space-between;
    text-align: left;
  }
}

nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 2rem;
  justify-content: center;
  flex-wrap: wrap;
}

nav a {
  font-weight: 600;
  font-size: 1.125rem;
}

.menu-toggle {
  display: none;
  background: none;
  border: 0;
  font-size: 1.75rem;
  cursor: pointer;
  color: var(--text-color); 
}

@media (max-width: 768px) {
  .menu-toggle {
    display: block;
  }

  nav ul {
    flex-direction: column;
    align-items: center;
    gap: 1.25rem;
    display: none;
  }

  nav ul.open {
    display: flex;
  }

  header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: var(--bg-color);
  }
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  border: 0;
}

a {
  color: var(--accent-color);
  font-weight: 700;
  text-decoration: underline;
  text-decoration-color: transparent;
  text-underline-offset: 4px;
  text-decoration-thickness: 2px;
  transition: color 0.3s, text-decoration-color 0.3s;
}

a:hover,
a:focus {
  color: var(--accent-hover);
  text-decoration-color: currentColor;
}

a:focus-visible {
  outline: 3px solid var(--accent-color);
  outline-offset: 4px;
  border-radius: 3px;
}

.highlight {
  background: var(--accent-hover);
  color: #fcfdfe;
}