:root {
  --bg: #f6f8fb;
  --surface: #ffffff;
  --text: #07142b;
  --muted: #617086;
  --line: #d8e2ee;
  --blue: #18aee7;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--text);
  font-family: "Inter", "Yu Gothic", "Meiryo", system-ui, sans-serif;
}

a { color: inherit; text-decoration: none; }

.auth-shell {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 28px;
}

.brand {
  position: fixed;
  left: 28px;
  top: 22px;
  font-size: 28px;
  font-weight: 900;
}

.auth-card {
  width: min(430px, 100%);
  padding: 28px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: 0 14px 34px rgba(16, 35, 64, .09);
}

h1 {
  margin: 0 0 22px;
  text-align: center;
  font-size: 24px;
}

form {
  display: grid;
  gap: 16px;
}

label {
  display: grid;
  gap: 8px;
  color: #243854;
  font-size: 14px;
  font-weight: 800;
}

input {
  width: 100%;
  height: 44px;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 0 12px;
  font: inherit;
}

button {
  height: 46px;
  border: 0;
  border-radius: 6px;
  background: var(--blue);
  color: #fff;
  font: inherit;
  font-weight: 900;
  cursor: pointer;
}

.error-message {
  min-height: 20px;
  margin: -4px 0 0;
  color: #ef3030;
  font-size: 13px;
  font-weight: 800;
}

.auth-links {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin-top: 18px;
  color: var(--muted);
  font-size: 13px;
}

@media (max-width: 520px) {
  .auth-shell {
    place-items: start center;
    padding: 86px 16px 24px;
  }

  .brand {
    left: 16px;
    font-size: 24px;
  }

  .auth-card {
    padding: 22px;
  }

  .auth-links {
    flex-direction: column;
  }
}