:root {
  --bg0: #071018;
  --bg1: #0d1824;
  --line: rgba(140, 170, 200, 0.22);
  --text: #e7eef6;
  --muted: #8fa3b8;
  --accent: #3ecf8e;
  --danger: #e85d6c;
  --input: #0a121b;
}

* { box-sizing: border-box; }
html, body {
  margin: 0;
  min-height: 100%;
  font-family: "Segoe UI", Tahoma, sans-serif;
  color: var(--text);
  background:
    radial-gradient(900px 500px at 15% -10%, rgba(62, 207, 142, 0.14), transparent 55%),
    radial-gradient(700px 420px at 100% 0%, rgba(90, 167, 217, 0.12), transparent 50%),
    linear-gradient(165deg, var(--bg0), var(--bg1));
}

.shell {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
}

.panel {
  width: min(420px, 100%);
  background: rgba(10, 18, 27, 0.88);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 28px 26px 30px;
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.35);
}

.brand {
  font-size: 12px;
  letter-spacing: 0.28em;
  font-weight: 800;
  color: var(--accent);
  margin-bottom: 10px;
}

h1 {
  margin: 0 0 6px;
  font-size: 28px;
  letter-spacing: 0.02em;
}

.sub {
  margin: 0 0 22px;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.45;
}

form {
  display: grid;
  gap: 14px;
}

label {
  display: grid;
  gap: 6px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
}

input {
  width: 100%;
  border: 1px solid var(--line);
  background: var(--input);
  color: var(--text);
  border-radius: 8px;
  padding: 12px 12px;
  font-size: 16px;
}

input:focus {
  outline: none;
  border-color: rgba(62, 207, 142, 0.7);
}

button {
  margin-top: 6px;
  border: 0;
  border-radius: 8px;
  padding: 12px 14px;
  font-size: 15px;
  font-weight: 800;
  letter-spacing: 0.04em;
  cursor: pointer;
  color: #04140c;
  background: linear-gradient(180deg, #56e0a4, var(--accent));
}

button:hover { filter: brightness(1.05); }

.err {
  margin-bottom: 14px;
  padding: 10px 12px;
  border-radius: 8px;
  border: 1px solid rgba(232, 93, 108, 0.45);
  background: rgba(232, 93, 108, 0.12);
  color: #ffc1c8;
  font-size: 13px;
}