:root {
  --bg1: #0b1f1c;
  --bg2: #12352f;
  --panel: rgba(255, 255, 255, 0.94);
  --text: #13231f;
  --muted: #5b6b66;
  --line: #d7e3df;
  --accent: #0f766e;
  --danger: #b42318;
  --font: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font);
  color: var(--text);
  background:
    radial-gradient(circle at 18% 20%, rgba(45, 212, 191, 0.28), transparent 36%),
    radial-gradient(circle at 85% 10%, rgba(14, 116, 144, 0.22), transparent 30%),
    linear-gradient(145deg, var(--bg1), var(--bg2));
}

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

.panel {
  width: min(420px, 100%);
  background: var(--panel);
  border: 1px solid rgba(255, 255, 255, 0.55);
  border-radius: 18px;
  padding: 32px 28px 28px;
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.28);
  backdrop-filter: blur(8px);
}

.brand {
  margin: 0 0 8px;
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 700;
}

h1 {
  margin: 0 0 8px;
  font-size: 28px;
  letter-spacing: -0.03em;
}

.hint {
  margin: 0 0 24px;
  color: var(--muted);
  font-size: 14px;
}

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

label {
  display: grid;
  gap: 6px;
}

label span {
  font-size: 13px;
  color: var(--muted);
}

input {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 12px 14px;
  font: inherit;
  background: #fff;
}

input:focus {
  outline: 2px solid rgba(15, 118, 110, 0.25);
  border-color: var(--accent);
}

button {
  margin-top: 6px;
  border: 0;
  border-radius: 12px;
  padding: 12px 16px;
  font: inherit;
  font-weight: 600;
  color: #fff;
  background: linear-gradient(135deg, #0f766e, #0e7490);
  cursor: pointer;
}

button:hover { filter: brightness(1.05); }
button:disabled { opacity: 0.6; cursor: wait; }

.error {
  margin: 0;
  color: var(--danger);
  background: #fef3f2;
  border: 1px solid #fecdca;
  border-radius: 10px;
  padding: 10px 12px;
  font-size: 13px;
}