:root {
  --bg-a: #102438;
  --bg-b: #0d1729;
  --card: #ffffff;
  --text: #102238;
  --muted: #4f647e;
  --accent: #1f7ae0;
  --accent-hover: #165cad;
  --error: #b42318;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Trebuchet MS", "Segoe UI", sans-serif;
  color: var(--text);
  background: linear-gradient(160deg, var(--bg-a), var(--bg-b));
  display: grid;
  place-items: center;
  padding: 1.5rem;
}

.shell {
  width: min(460px, 100%);
}

.card {
  background: var(--card);
  border-radius: 16px;
  padding: 2rem;
  box-shadow: 0 24px 50px rgba(0, 0, 0, 0.28);
}

h1 {
  margin: 0;
  font-size: 1.9rem;
}

.subtitle {
  margin: 0.6rem 0 1.4rem;
  color: var(--muted);
}

.form {
  display: grid;
  gap: 0.65rem;
}

label {
  font-size: 0.88rem;
  color: var(--muted);
}

input {
  width: 100%;
  border: 1px solid #d8dfeb;
  border-radius: 10px;
  padding: 0.72rem 0.8rem;
  font-size: 1rem;
}

button {
  margin-top: 0.45rem;
  border: 0;
  border-radius: 10px;
  padding: 0.78rem 1rem;
  background: var(--accent);
  color: #fff;
  font-weight: 600;
  cursor: pointer;
}

button:hover {
  background: var(--accent-hover);
}

.error {
  min-height: 1.25rem;
  margin: 0.85rem 0 0;
  color: var(--error);
  font-size: 0.92rem;
}