* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  min-height: 100%;
  width: 100%;
  overflow-x: hidden;
}

body {
  font-family: var(--font-body);
  color: var(--color-text);
  background: #121212;
}

#app-shell {
  position: relative;
  z-index: 1;
  min-height: 100vh;
  display: grid;
  grid-template-rows: auto 1fr auto;
  overflow-x: clip;
}

.bg-shape {
  display: none;
}

.bg-shape-a {
  width: 40vw;
  height: 40vw;
  background: var(--color-accent);
  top: -16vw;
  left: -10vw;
}

.bg-shape-b {
  width: 34vw;
  height: 34vw;
  background: #9cd3ff;
  bottom: -12vw;
  right: -10vw;
}

main {
  width: min(1120px, 92vw);
  margin: var(--space-6) auto;
}

h1,
h2,
h3 {
  font-family: var(--font-title);
  margin: 0;
}

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

a:hover {
  text-decoration: underline;
}

.back-to-top-btn {
  position: fixed;
  right: var(--space-4);
  bottom: var(--space-4);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface-3);
  color: var(--color-text);
  font-weight: 700;
  width: 48px;
  height: 48px;
  padding: 0;
  font-size: 1.25rem;
  box-shadow: var(--shadow-md);
  cursor: pointer;
  z-index: 25;
}

@media (max-width: 768px) {
  main {
    width: min(100%, 96vw);
    margin: var(--space-5) auto;
  }
}