*, *::before, *::after { box-sizing: border-box; }
html, body { height: 100%; margin: 0; }
body {
  display: flex; align-items: center; justify-content: center;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: #f3f5fb; color: #1b2133;
}
.login-card {
  width: min(360px, 92vw); padding: 32px 28px; background: #fff;
  border: 1px solid #e0e5f2; border-radius: 14px;
  box-shadow: 0 8px 30px rgba(40, 60, 140, .08);
}
.mark { font-size: 34px; color: #4361ee; line-height: 1; }
h1 { margin: 6px 0 2px; font-size: 24px; }
.sub { margin: 0 0 20px; color: #6a7390; font-size: 14px; }
label { display: block; margin: 14px 0 5px; font-size: 13px; font-weight: 600; }
input {
  width: 100%; padding: 10px 12px; font: inherit; color: inherit;
  border: 1px solid #cfd6ea; border-radius: 8px; background: #fff;
}
input:focus { outline: 2px solid #c7d0fb; border-color: #4361ee; }
button {
  width: 100%; margin-top: 20px; padding: 11px; font: inherit; font-weight: 600;
  color: #fff; background: #4361ee; border: 0; border-radius: 8px; cursor: pointer;
}
button:hover:not(:disabled) { background: #3651d4; }
button:disabled { opacity: .6; cursor: default; }
.error { margin: 14px 0 0; padding: 9px 11px; font-size: 13px; color: #b42318; background: #fef3f2; border: 1px solid #fecdca; border-radius: 8px; }