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

:root {
  --bg: #ffffff;
  --text: #000000;
  --btn-bg: #000000;
  --btn-text: #ffffff;
}

body.dark {
  --bg: #000000;
  --text: #ffffff;
  --btn-bg: #ffffff;
  --btn-text: #000000;
}

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg);
  color: var(--text);
  transition: background 0.3s ease, color 0.3s ease;
}

.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 24px;
  text-align: center;
}

.logo {
  max-width: 520px;
  width: 100%;
  height: auto;
  margin-bottom: 32px;
}

body.dark .logo {
  filter: invert(1);
}

.cta {
  display: inline-block;
  padding: 14px 32px;
  background: var(--btn-bg);
  color: var(--btn-text);
  text-decoration: none;
  font-weight: 600;
  letter-spacing: 0.05em;
  border-radius: 999px;
  transition: transform 0.2s ease, opacity 0.2s ease;
}

.cta:hover {
  transform: scale(1.05);
  opacity: 0.9;
}

.theme-toggle {
  position: fixed;
  top: 16px;
  right: 16px;
  background: transparent;
  border: 1px solid var(--text);
  color: var(--text);
  padding: 6px 12px;
  border-radius: 999px;
  cursor: pointer;
  font-size: 14px;
  opacity: 0.6;
}

.theme-toggle:hover {
  opacity: 1;
}

@media (max-width: 480px) {
  .logo {
    max-width: 320px;
    margin-bottom: 24px;
  }

  .cta {
    padding: 12px 24px;
    font-size: 14px;
  }
}