.signin {
  max-width: 26rem;
  margin: 4rem auto;
  text-align: center;
}
.signin h1 { margin-bottom: 0.5rem; }
.signin-btn {
  display: inline-block;
  margin-top: 1.25rem;
  padding: 0.6rem 1.4rem;
  border-radius: 8px;
  background: var(--accent);
  color: #10131a;
  font-weight: 600;
}
.signin-btn:hover { text-decoration: none; filter: brightness(1.08); }