:root {
  color-scheme: dark;
  --page-start: #111923; --page-middle: #1C2836; --page-end: #121821;
  --card-start: #23303D; --card-middle: #1C2733; --card-end: #151E28;
  --accent: #E7B866; --accent-end: #DD9267;
  --text: #F7F8FB; --muted: #C9CCD6; --quiet: #9DA1AE;
}
* { box-sizing: border-box; }
body { margin: 0; min-height: 100vh;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial,
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: linear-gradient(135deg, var(--page-start) 0%, var(--page-middle) 48%,
    var(--page-end) 100%); }
.login-shell { min-height: 100vh; padding: 24px; display: flex; align-items: center;
  justify-content: center; }
.login-card { width: min(520px, 100%); border: 2px solid var(--accent); border-radius: 20px;
  padding: 36px 34px 26px;
  background: linear-gradient(145deg, var(--card-start) 0%, var(--card-middle) 55%,
    var(--card-end) 100%);
  box-shadow: 0 24px 70px rgba(0,0,0,.48), 0 0 0 1px color-mix(in srgb,
    var(--accent) 12%, transparent); }
.brand-logo { display: block; width: min(300px, 80%); height: 58px; object-fit: contain;
  margin: 0 auto 12px; }
h1 { margin: 10px 0 8px; text-align: center; color: var(--text); font-size: 26px; }
.app-icon { color: var(--accent); }
.subtitle { margin: 0 0 20px; text-align: center; color: var(--muted); font-size: 14px; }
.field { margin: 12px 0; }
input { width: 100%; height: 48px; border: 1px solid #505463; border-radius: 12px;
  padding: 0 14px; outline: none; background: #1C1E27; color: var(--text);
  caret-color: var(--accent); font-size: 15px;
  transition: border-color .18s ease, box-shadow .18s ease, background-color .18s ease; }
input::placeholder { color: var(--quiet); opacity: 1; }
input:hover { border-color: #686D7D; }
input:focus { border-color: var(--accent); background: #20232D;
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 18%, transparent); }
button { width: 100%; height: 48px; margin-top: 10px; border: 0; border-radius: 12px;
  background: linear-gradient(90deg, var(--accent), var(--accent-end)); color: #15231F;
  box-shadow: 0 12px 28px color-mix(in srgb, var(--accent) 20%, transparent);
  cursor: pointer; font-size: 16px; font-weight: 750;
  transition: filter .18s ease, transform .18s ease, box-shadow .18s ease; }
button:hover { filter: brightness(1.06);
  box-shadow: 0 14px 32px color-mix(in srgb, var(--accent) 28%, transparent); }
button:active { transform: translateY(1px); }
button:focus-visible { outline: 3px solid rgba(247,248,251,.9); outline-offset: 3px; }
.error { margin: 0 0 14px; padding: 10px 12px; border-radius: 10px;
  color: #FFD4E2; background: #5A273C; text-align: center; white-space: pre-line; }
.foot { margin-top: 20px; text-align: center; color: var(--quiet); font-size: 12px; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }
@media (max-width: 480px) { .login-shell { padding: 16px; }
  .login-card { padding: 30px 20px 22px; border-radius: 18px; }
  .brand-logo { width: min(280px, 86%); } }