:root {
  --overlay: rgba(0, 0, 0, 0.55);
  --card-bg: rgba(18, 18, 22, 0.06);
  --card-border: rgba(255, 255, 255, 0.12);
  --text-primary: #f5f5f7;
  --text-secondary: rgba(245, 245, 247, 0.62);
  --btn-bg: rgba(18, 18, 22, 0.78);
  --btn-fg: #f5f5f7;
  --btn-border: rgba(255, 255, 255, 0.14);
}

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

html,
body {
  height: 100%;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  color: var(--text-primary);
  background-color: #000;
  background-image: linear-gradient(var(--overlay), var(--overlay)),
    url("/images/bg.jpg");
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  background-attachment: fixed;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 1.5rem;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

main {
  width: 100%;
  max-width: 380px;
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 14px;
  padding: 2.5rem 2rem;
  backdrop-filter: blur(8px) saturate(120%);
  -webkit-backdrop-filter: blur(8px) saturate(120%);
  text-align: center;
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.4);
}

.card h1 {
  font-size: 1.4rem;
  font-weight: 500;
  letter-spacing: -0.015em;
  margin-bottom: 1.75rem;
}

.signin {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.65rem;
  width: 100%;
  padding: 0.8rem 1.25rem;
  background: var(--btn-bg);
  color: var(--btn-fg);
  border: 1px solid var(--btn-border);
  border-radius: 10px;
  font-size: 0.95rem;
  font-weight: 500;
  text-decoration: none;
  cursor: pointer;
  transition: transform 0.12s ease, box-shadow 0.18s ease,
    background-color 0.15s ease;
}

.signin:hover {
  transform: translateY(-1px);
  background: rgba(28, 28, 32, 0.88);
  box-shadow: 0 10px 24px rgba(0, 0, 0, 0.4);
}

.signin:active {
  transform: translateY(0);
  box-shadow: none;
}

.signin:focus-visible {
  outline: 2px solid rgba(255, 255, 255, 0.7);
  outline-offset: 3px;
}

.credit {
  position: fixed;
  bottom: 0.85rem;
  right: 1rem;
  font-size: 0.68rem;
  color: rgba(245, 245, 247, 0.32);
  letter-spacing: 0.01em;
  pointer-events: auto;
}

.credit a {
  color: inherit;
  text-decoration: none;
  border-bottom: 1px solid rgba(245, 245, 247, 0.18);
  transition: color 0.15s ease, border-color 0.15s ease;
}

.credit a:hover {
  color: rgba(245, 245, 247, 0.6);
  border-bottom-color: rgba(245, 245, 247, 0.5);
}

@media (max-width: 480px) {
  .credit {
    bottom: 0.6rem;
    right: 0.7rem;
    font-size: 0.6rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .signin {
    transition: none;
  }
}