.auth-page {
  isolation: isolate;
  background: radial-gradient(ellipse at 15% 15%, #e4ece5, transparent 65%), #f4f5ef;
}

.auth-background {
  position: fixed;
  z-index: -1;
  inset: 0;
  overflow: hidden;
  pointer-events: none;
  user-select: none;
  opacity: 0;
  transition: opacity 1.6s ease;
}

.auth-background.is-ready { opacity: 1; }

.auth-background::after {
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at center, rgba(244,245,239,.75), rgba(244,245,239,.12) 70%),
    linear-gradient(0deg, rgba(244,245,239,.6), transparent 18%, transparent 82%, rgba(244,245,239,.35));
  content: "";
}

.auth-background-plane {
  position: absolute;
  inset: 0;
  opacity: .64;
  transform-origin: 50% 50%;
}

.auth-background-title {
  position: absolute;
  display: block;
  width: max-content;
  max-width: min(760px, 56vw);
  color: #4b6252;
  font-family: Georgia, "Times New Roman", "Noto Serif CJK SC", "Noto Serif SC", "Source Han Serif SC", "Songti SC", "STSong", "SimSun", serif;
  font-size: 36px;
  font-weight: 500;
  line-height: 1.5;
  letter-spacing: .035em;
  overflow-wrap: anywhere;
  text-align: center;
  transform: translate(-50%, -50%);
  filter: blur(1.7px);
  opacity: 0;
  animation: auth-title-fade var(--fade-duration) ease-in-out var(--fade-delay) infinite;
}

.auth-background.is-paused .auth-background-title { animation-play-state: paused; }
.auth-background-title.is-unplaced { visibility: hidden; }

.auth-page .auth-shell { position: relative; width: 100%; min-height: 100svh; }

@keyframes auth-title-fade {
  0%, 100% { opacity: 0; }
  33.333333%, 66.666667% { opacity: var(--title-opacity); }
}

@media (max-width: 600px) {
  .auth-background-plane { opacity: .5; }
  .auth-background-title { font-size: 28px; filter: blur(1.5px); }
  .auth-page .auth-shell { padding: 24px 18px; }
}

@media (prefers-reduced-motion: reduce) {
  .auth-background { transition: none; }
  .auth-background-title { animation: none; opacity: var(--title-opacity); }
}