:root {
  --ink: #1a1f2e;
  --muted: #5b6577;
  --line: #e3e8ef;
  --brand: #1f6feb;
  --card: #ffffff;
  --danger: #b42318;
  --font: "PingFang SC", "Noto Sans SC", "Microsoft YaHei", system-ui, sans-serif;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; min-height: 100%; }
body {
  font-family: var(--font);
  color: var(--ink);
  background: #eef3fa;
  min-height: 100vh;
  overflow-x: hidden;
}
.logo-wall {
  position: fixed;
  inset: 0;
  z-index: 0;
  overflow: hidden;
  pointer-events: none;
  background: radial-gradient(1200px 700px at 50% 20%, #f7faff 0%, #e8eef7 55%, #dfe6f1 100%);
}
.logo-row {
  display: flex;
  gap: 28px;
  width: max-content;
  margin: 18px 0;
  opacity: 0.28;
  will-change: transform;
}
.logo-row img {
  width: 64px;
  height: 64px;
  object-fit: contain;
  filter: grayscale(0.15);
  border-radius: 50%;
  background: rgba(255,255,255,0.65);
  padding: 6px;
}
.logo-row.left { animation: drift-left 90s linear infinite; }
.logo-row.right { animation: drift-right 110s linear infinite; }
@keyframes drift-left {
  from { transform: translateX(0); }
  to { transform: translateX(-50%); }
}
@keyframes drift-right {
  from { transform: translateX(-50%); }
  to { transform: translateX(0); }
}
@media (prefers-reduced-motion: reduce) {
  .logo-row.left, .logo-row.right { animation: none; transform: none; }
  .logo-wall { overflow: hidden; }
}
.auth-shell {
  position: relative;
  z-index: 1;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 32px 16px;
}
.lang-toggle {
  display: flex;
  gap: 6px;
  margin-bottom: 16px;
}
.lang-btn {
  border: 1px solid rgba(15, 40, 80, 0.2);
  background: rgba(255,255,255,0.7);
  color: #0b3d91;
  border-radius: 999px;
  padding: 6px 12px;
  font: inherit;
  font-size: 0.85rem;
  cursor: pointer;
}
.lang-btn.active {
  background: #0b3d91;
  color: #fff;
  border-color: #0b3d91;
  font-weight: 600;
}
.auth-card {
  width: min(420px, 100%);
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 18px;
  box-shadow: 0 18px 50px rgba(15, 32, 64, 0.12);
  padding: 28px 24px 24px;
}
.auth-card h1 { margin: 0 0 6px; font-size: 1.35rem; }
.lead { margin: 0 0 18px; color: var(--muted); font-size: 0.94rem; }
.tabs { display: flex; gap: 8px; margin-bottom: 16px; }
.tab {
  flex: 1;
  border: 1px solid var(--line);
  background: #f6f8fb;
  border-radius: 10px;
  padding: 8px 10px;
  font: inherit;
  cursor: pointer;
  color: var(--muted);
}
.tab.active {
  background: #e8f0fe;
  border-color: #c5d7fb;
  color: #0b3d91;
  font-weight: 600;
}
.field { display: block; margin: 0 0 12px; }
.field span { display: block; font-size: 0.85rem; margin-bottom: 4px; color: var(--muted); }
.field input {
  width: 100%;
  font: inherit;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 10px 12px;
  background: #fff;
}
.field input:focus { outline: 2px solid #c5d7fb; border-color: var(--brand); }
.hint { margin: 0 0 12px; color: var(--muted); font-size: 0.82rem; }
.form-error { margin: 0 0 12px; color: var(--danger); font-size: 0.9rem; }
.submit {
  width: 100%;
  border: 0;
  border-radius: 10px;
  padding: 11px 14px;
  font: inherit;
  font-weight: 600;
  color: #fff;
  background: linear-gradient(135deg, #0b3d91, #1f6feb);
  cursor: pointer;
}
.submit:disabled { opacity: 0.65; cursor: wait; }
.hidden { display: none !important; }