* { box-sizing: border-box; }
    html, body { margin: 0; min-height: 100%; }
    body {
      min-height: 100vh;
      min-height: 100svh;
      display: grid;
      place-items: center;
      padding: 24px;
      background: #132c4e;
      isolation: isolate;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    }
    .background {
      position: fixed;
      inset: 0;
      width: 100%;
      height: 100%;
      object-fit: cover;
      object-position: center;
      z-index: 0;
      pointer-events: none;
    }
    body::before {
      content: "";
      position: fixed;
      inset: 0;
      z-index: 1;
      pointer-events: none;
      background: linear-gradient(180deg, rgba(7, 18, 35, .03), rgba(7, 18, 35, .15));
    }
    .enter-button {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 14px;
      max-width: 100%;
      min-height: 64px;
      padding: 18px 32px;
      border: 1px solid rgba(222, 242, 255, .55);
      border-radius: 18px;
      color: #fff;
      background: rgba(18, 43, 74, .62);
      box-shadow: 0 12px 40px rgba(2, 12, 30, .28), inset 0 1px 0 rgba(255, 255, 255, .16);
      -webkit-backdrop-filter: blur(16px) brightness(.72);
      backdrop-filter: blur(16px) brightness(.72);
      font-size: clamp(17px, 3.8vw, 20px);
      font-weight: 600;
      letter-spacing: .06em;
      text-decoration: none;
      text-shadow: 0 2px 8px rgba(0, 0, 0, .25);
      transition: transform .25s ease, background .25s ease, box-shadow .25s ease;
      animation: arrive .7s ease-out both;
      -webkit-tap-highlight-color: transparent;
    }
    .enter-button svg { width: 20px; height: 20px; flex: none; transition: transform .25s ease; }
    @media (hover: hover) {
      .enter-button:hover {
        transform: translateY(-3px);
        background: rgba(40, 79, 118, .78);
        box-shadow: 0 16px 48px rgba(2, 12, 30, .35), 0 0 28px rgba(118, 197, 255, .16);
      }
      .enter-button:hover svg { transform: translateX(3px); }
    }
    .enter-button:focus-visible { outline: 3px solid #d6f1ff; outline-offset: 6px; }
    .enter-button:active { transform: translateY(1px); }
    @keyframes arrive { from { opacity: 0; } to { opacity: 1; } }
    @media (max-width: 600px) {
      .background { object-position: 36% center; }
      .enter-button { padding: 17px 24px; border-radius: 16px; }
    }
    @media (prefers-reduced-motion: reduce) {
      .enter-button, .enter-button svg { animation: none; transition: none; }
    }
main { position: relative; z-index: 2; max-width: 100%; }

/* 与夜景背景协调的柔白入口文字 */
.enter-button, .enter-button:hover { background: transparent; color: #edf3fa; text-shadow: 0 2px 8px rgba(3,12,25,.8); }