:root {
    --blue-50: #eff6ff;
    --blue-100: #dbeafe;
    --blue-200: #bfdbfe;
    --blue-300: #93c5fd;
    --blue-400: #60a5fa;
    --blue-500: #3b82f6;
    --blue-600: #2563eb;
    --blue-700: #1d4ed8;
    --blue-800: #1e40af;
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --green-500: #22c55e;
    --red-500: #ef4444;
    --radius: 12px;
  }

  /* 导航栏 */
  .nav {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255,255,255,0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--gray-200);
  }

  .nav-inner {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 56px;
  }

  .nav-brand {
    font-size: 18px;
    font-weight: 700;
    color: var(--gray-800);
    text-decoration: none;
    letter-spacing: -0.3px;
  }

  .nav-brand span {
    background: linear-gradient(135deg, var(--blue-500), var(--blue-600));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
  }

  .nav-links {
    display: flex;
    align-items: center;
    gap: 8px;
  }

  .nav-links a {
    padding: 8px 16px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 500;
    color: var(--gray-600);
    text-decoration: none;
    transition: all 0.15s ease;
  }

  .nav-links a:hover {
    color: var(--blue-600);
    background: var(--blue-50);
  }

  .nav-links a.active {
    color: var(--blue-600);
    background: var(--blue-50);
  }

  .footer {
    text-align: center;
    padding: 32px 20px;
    font-size: 13px;
    color: var(--gray-400);
    line-height: 2;
    border-top: 1px solid var(--gray-200);
    background: white;
  }

  .footer a {
    color: var(--gray-500);
    text-decoration: none;
  }

  .footer a:hover {
    color: var(--blue-500);
    text-decoration: underline;
  }


body {font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;background:linear-gradient(135deg,#eff6ff 0%,#dbeafe 50%,#bfdbfe 100%);min-height:100vh;display:flex;flex-direction:column;color:var(--gray-800)}
.nav a {overflow-wrap:normal;white-space:nowrap}
.footer {margin:0;width:100%}
.footer p {margin:0}
.update-main {width:100%;max-width:820px;flex:1;margin:0 auto;padding:40px 20px 20px}
.intro {text-align:center;margin-bottom:28px}
.intro h1 {font-size:26px;font-weight:700;letter-spacing:normal;margin:0 0 8px;color:var(--gray-800)}
.intro p {font-size:15px;line-height:1.6;color:var(--gray-500);margin:0}
.update-main section {border:0;border-radius:20px;box-shadow:0 25px 50px -12px rgba(37,99,235,.15);padding:32px}
.update-main #login {max-width:480px;margin:0 auto 20px}
.update-main h2 {font-size:18px}
.update-main input:not([type=checkbox]):not([type=file]) {border:1.5px solid var(--gray-200);border-radius:12px}
.update-main input:focus {outline:2px solid var(--blue-400)}
.update-main button,.update-main .file-button {background:var(--blue-500);border-color:var(--blue-500);border-radius:12px}
.update-main .secondary {background:white;color:var(--blue-600);border-color:var(--gray-200)}
.update-main a {color:var(--blue-600)}
.update-main .hint {color:var(--gray-500)}
.main-wrapper .card {border-radius:20px;box-shadow:0 25px 50px -12px rgba(37,99,235,.15)}
.main-wrapper .header p {font-size:15px;line-height:1.6;margin-top:8px}
@media(max-width:640px){.nav-inner{padding:0 16px;height:52px}.nav-brand{font-size:16px}.nav-links a{padding:6px 10px;font-size:13px}.footer{padding:24px 16px;font-size:12px}.update-main{padding:32px 16px 20px}.update-main section{padding:24px}.intro h1{font-size:24px}}