:root {
  color-scheme: light;
  --deep: #214478;
  --text: #172033;
  --muted: #647087;
  --line: #d8e1ef;
  --panel: #fff;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
  font-family: "PingFang TC", "Microsoft JhengHei", sans-serif;
  color: var(--text);
  background: radial-gradient(circle at 15% 10%, #fff 0, transparent 34%), linear-gradient(145deg, #edf3fb, #f8f9fc 55%, #e8eef8);
}

main {
  width: min(100%, 460px);
  border: 1px solid var(--line);
  border-radius: 24px;
  padding: clamp(24px, 6vw, 42px);
  background: rgb(255 255 255 / 96%);
  box-shadow: 0 24px 70px rgb(32 55 92 / 16%);
}

.mark {
  width: 54px;
  height: 54px;
  display: grid;
  place-items: center;
  border-radius: 16px;
  color: #fff;
  background: linear-gradient(145deg, #315b9c, #1e3d70);
  font-weight: 750;
  letter-spacing: 0.06em;
}

h1 {
  margin: 22px 0 8px;
  font-size: clamp(1.65rem, 5vw, 2.1rem);
}

p {
  color: var(--muted);
  line-height: 1.7;
}

.google-login {
  width: 100%;
  min-height: 48px;
  margin-top: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  border: 1px solid #b9c3d3;
  border-radius: 6px;
  color: var(--text);
  background: #fff;
  font-weight: 650;
  text-decoration: none;
  box-shadow: 0 1px 2px rgb(16 24 40 / 8%);
  transition: border-color 150ms ease, box-shadow 150ms ease, background 150ms ease;
}

.google-login:hover {
  border-color: #7d8ba1;
  background: #f8fafe;
  box-shadow: 0 3px 10px rgb(32 55 92 / 12%);
}

.google-login:focus-visible {
  outline: 3px solid rgb(49 91 156 / 28%);
  outline-offset: 3px;
}

.google-mark {
  color: #315b9c;
  font-size: 1.1rem;
  font-weight: 800;
}

.error {
  margin: 14px 0 0;
  color: #9b2c2c;
  font-size: 0.92rem;
  text-align: center;
}

.legal {
  margin-top: 22px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
  display: flex;
  justify-content: center;
  gap: 20px;
  font-size: 0.86rem;
}

.legal a {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  color: var(--deep);
}

@media (max-width: 600px) {
  body {
    padding: 16px;
    align-items: center;
  }

  main {
    border-radius: 20px;
  }
}