.shell {
  width: 100%;
  height: 100svh;
  margin: 0;
  padding: max(1rem, env(safe-area-inset-top)) 1rem max(2rem, env(safe-area-inset-bottom));
  display: grid;
  gap: 1rem;
  overflow: hidden;
}

.header {
  align-items: center;
  display: flex;
  gap: 0.5rem;
  justify-content: space-between;
  padding-top: 0.5rem;
}

.header-actions {
  align-items: center;
  display: flex;
  gap: 0.5rem;
}

.header-actions button {
  flex: 0 0 auto;
  width: auto;
}

.app-back {
  display: none;
}

.shell.game-layout .app-back {
  display: inline-block;
}

.app-back,
.theme-toggle,
.sound-toggle {
  background: transparent;
  color: var(--button-text);
  min-height: 32px;
  padding: 0.25rem 0.5rem;
}

.sound-control {
  position: relative;
}

.sound-popover {
  background: var(--surface-bg);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-sm);
  box-shadow: 0 0.35rem 1rem rgb(0 0 0 / 18%);
  inset-block-start: calc(100% + 0.4rem);
  inset-inline-end: 0;
  padding: 0.6rem;
  position: absolute;
  z-index: 30;
}

.sound-popover input {
  display: block;
  width: 9rem;
}

.app-help {
  min-width: 32px;
  padding-inline: 0.5rem;
}

h1,
h2,
h3,
h4,
p {
  margin-top: 0;
}

h1 {
  color: var(--accent);
  font-size: 1.35rem;
  letter-spacing: 0.04em;
  line-height: 1.1;
  margin: 4px;
  text-transform: uppercase;
}

.home-link {
  color: inherit;
  text-decoration: none;
}

.card {
  background: var(--surface-bg);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-md);
  padding: 1rem;
}