:root {
      --primary-gradient: linear-gradient(135deg, #6a11cb 0%, #2575fc 100%);
      --primary-gradient-hover: linear-gradient(135deg, #5a0db9 0%, #1c65e0 100%);
      --glass-bg: rgba(255, 255, 255, 0.92);
      --glass-border: rgba(255, 255, 255, 0.25);
      --shadow: 0 20px 60px rgba(0, 0, 0, 0.15), 0 0 0 1px rgba(255, 255, 255, 0.1);
      --text-primary: #1a2b3c;
      --text-secondary: #4a5b6c;
      --accent-blue: #3498db;
      --accent-blue-dark: #2980b9;
      --error: #e74c3c;
      --success: #2ecc71;
      --radius-lg: 24px;
      --radius-md: 16px;
      --radius-sm: 12px;
      --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    }

    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
      font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    }

    /* 高级粒子背景 */
    body {
      min-height: 100vh;
      display: flex;
      justify-content: center;
      align-items: center;
      padding: 20px;
      overflow: hidden;
      position: relative;
      background: #0a0e17;
    }

    /* 背景容器 */
    .background-container {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      z-index: -2;
    }

    /* 基础渐变背景 */
    .gradient-bg {
      position: absolute;
      width: 100%;
      height: 100%;
      background: 
        radial-gradient(circle at 20% 30%, rgba(106, 17, 203, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 70%, rgba(37, 117, 252, 0.15) 0%, transparent 50%),
        linear-gradient(135deg, #0a0e17 0%, #1a1f2e 100%);
      z-index: -3;
    }

    /* 微粒子效果 */
    .particles-layer {
      position: absolute;
      width: 100%;
      height: 100%;
      background-image: 
        radial-gradient(2px 2px at 20px 30px, rgba(255, 255, 255, 0.3), transparent),
        radial-gradient(1px 1px at 40px 70px, rgba(255, 255, 255, 0.4), transparent),
        radial-gradient(2px 2px at 60px 20px, rgba(255, 255, 255, 0.3), transparent),
        radial-gradient(1px 1px at 80px 50px, rgba(255, 255, 255, 0.4), transparent),
        radial-gradient(2px 2px at 100px 80px, rgba(255, 255, 255, 0.3), transparent),
        radial-gradient(1px 1px at 120px 40px, rgba(255, 255, 255, 0.4), transparent),
        radial-gradient(2px 2px at 140px 60px, rgba(255, 255, 255, 0.3), transparent),
        radial-gradient(1px 1px at 160px 90px, rgba(255, 255, 255, 0.4), transparent);
      background-size: 200px 200px;
      background-repeat: repeat;
      opacity: 0.4;
      z-index: -2;
      animation: particles-move 100s linear infinite;
    }

    /* 星星效果 */
    .stars-layer {
      position: absolute;
      width: 100%;
      height: 100%;
      background-image: 
        radial-gradient(1.5px 1.5px at 50px 150px, rgba(255, 255, 255, 0.9), transparent),
        radial-gradient(1px 1px at 150px 80px, rgba(255, 255, 255, 0.7), transparent),
        radial-gradient(1.5px 1.5px at 250px 200px, rgba(255, 255, 255, 0.9), transparent),
        radial-gradient(1px 1px at 350px 120px, rgba(255, 255, 255, 0.7), transparent),
        radial-gradient(1.5px 1.5px at 450px 50px, rgba(255, 255, 255, 0.9), transparent),
        radial-gradient(1px 1px at 550px 180px, rgba(255, 255, 255, 0.7), transparent),
        radial-gradient(1.5px 1.5px at 650px 100px, rgba(255, 255, 255, 0.9), transparent),
        radial-gradient(1px 1px at 750px 220px, rgba(255, 255, 255, 0.7), transparent),
        radial-gradient(1.5px 1.5px at 850px 70px, rgba(255, 255, 255, 0.9), transparent),
        radial-gradient(1px 1px at 950px 190px, rgba(255, 255, 255, 0.7), transparent);
      background-size: 1000px 1000px;
      opacity: 0.6;
      z-index: -2;
      animation: stars-twinkle 4s ease-in-out infinite alternate;
    }

    /* 网格线条效果 */
    .grid-layer {
      position: absolute;
      width: 100%;
      height: 100%;
      background-image: 
        linear-gradient(rgba(52, 152, 219, 0.1) 1px, transparent 1px),
        linear-gradient(90deg, rgba(52, 152, 219, 0.1) 1px, transparent 1px);
      background-size: 50px 50px;
      opacity: 0.1;
      z-index: -1;
    }

    /* 动态粒子 */
    .floating-particles {
      position: absolute;
      width: 100%;
      height: 100%;
      z-index: -1;
    }

    .floating-particle {
      position: absolute;
      border-radius: 50%;
      background: rgba(255, 255, 255, 0.1);
      animation: float-particle 20s infinite linear;
    }

    /* 光晕效果 */
    .glow-effects {
      position: absolute;
      width: 100%;
      height: 100%;
      z-index: -2;
    }

    .glow {
      position: absolute;
      border-radius: 50%;
      filter: blur(60px);
      opacity: 0.1;
      animation: glow-pulse 8s ease-in-out infinite alternate;
    }

    .glow-1 {
      width: 300px;
      height: 300px;
      background: #6a11cb;
      top: 10%;
      left: 10%;
    }

    .glow-2 {
      width: 400px;
      height: 400px;
      background: #2575fc;
      bottom: 10%;
      right: 10%;
    }

    /* 玻璃态登录容器 */
    .login-container {
      background: var(--glass-bg);
      backdrop-filter: blur(20px) saturate(180%);
      -webkit-backdrop-filter: blur(20px) saturate(180%);
      border: 1px solid var(--glass-border);
      padding: 48px 40px;
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow);
      width: 100%;
      max-width: 460px;
      position: relative;
      animation: fadeInUp 0.8s cubic-bezier(0.2, 0.8, 0.2, 1);
      overflow: hidden;
      z-index: 10;
    }

    /* 容器装饰元素 */
    .login-container::before {
      content: '';
      position: absolute;
      top: 0;
      left: 0;
      right: 0;
      height: 4px;
      background: var(--primary-gradient);
      border-radius: var(--radius-lg) var(--radius-lg) 0 0;
    }

    .login-container::after {
      content: '';
      position: absolute;
      top: 50%;
      left: 50%;
      width: 300px;
      height: 300px;
      background: radial-gradient(circle, rgba(52, 152, 219, 0.08) 0%, transparent 70%);
      transform: translate(-50%, -50%);
      z-index: -1;
    }

    /* 标题与描述 */
    .login-header {
      text-align: center;
      margin-bottom: 32px;
    }

    .login-header h1 {
      font-size: 28px;
      font-weight: 700;
      color: var(--text-primary);
      margin-bottom: 8px;
      letter-spacing: -0.5px;
    }

    .login-subtitle {
      font-size: 16px;
      color: var(--text-secondary);
      line-height: 1.5;
      font-weight: 400;
    }

    /* 表单区域 */
    .login-form {
      margin-top: 8px;
    }

    .input-group {
      margin-bottom: 24px;
      position: relative;
    }

    .input-group label {
      display: flex;
      align-items: center;
      gap: 8px;
      margin-bottom: 10px;
      font-weight: 600;
      color: var(--text-primary);
      font-size: 15px;
    }

    .input-wrapper {
      position: relative;
    }

    .input-icon {
      position: absolute;
      left: 18px;
      top: 50%;
      transform: translateY(-50%);
      color: var(--accent-blue);
      font-size: 18px;
      z-index: 1;
    }

    .input-group input {
      width: 100%;
      padding: 16px 20px 16px 50px;
      border: 2px solid rgba(0, 0, 0, 0.08);
      border-radius: var(--radius-md);
      font-size: 16px;
      transition: var(--transition);
      background-color: rgba(255, 255, 255, 0.9);
      color: var(--text-primary);
      font-weight: 500;
    }

    .input-group input:focus {
      outline: none;
      border-color: var(--accent-blue);
      background-color: white;
      box-shadow: 0 0 0 4px rgba(52, 152, 219, 0.15);
    }

    .input-group input:valid {
      border-color: rgba(0, 0, 0, 0.12);
    }

    .help-icon {
      color: var(--accent-blue);
      cursor: pointer;
      font-size: 16px;
      transition: var(--transition);
      opacity: 0.7;
    }

    .help-icon:hover {
      opacity: 1;
      transform: scale(1.1);
    }

    /* 按钮 */
    .btn-login {
      width: 100%;
      padding: 18px;
      background: var(--primary-gradient);
      color: white;
      border: none;
      border-radius: var(--radius-md);
      font-size: 16px;
      font-weight: 600;
      cursor: pointer;
      transition: var(--transition);
      letter-spacing: 0.5px;
      position: relative;
      overflow: hidden;
      margin-top: 8px;
    }

    .btn-login::before {
      content: '';
      position: absolute;
      top: 0;
      left: -100%;
      width: 100%;
      height: 100%;
      background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
      transition: 0.5s;
    }

    .btn-login:hover {
      background: var(--primary-gradient-hover);
      transform: translateY(-3px);
      box-shadow: 0 8px 20px rgba(37, 117, 252, 0.3);
    }

    .btn-login:hover::before {
      left: 100%;
    }

    .btn-login:active {
      transform: translateY(0);
    }

    /* 错误提示 */
    .error-message {
      color: var(--error);
      font-size: 14px;
      margin-top: 16px;
      text-align: center;
      display: none;
      background: rgba(231, 76, 60, 0.08);
      padding: 14px;
      border-radius: var(--radius-sm);
      border-left: 4px solid var(--error);
      font-weight: 500;
      animation: slideIn 0.3s ease-out;
    }

    /* 安全提示 */
    .security-note {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      margin-top: 24px;
      color: var(--text-secondary);
      font-size: 13px;
      padding: 12px;
      background: rgba(52, 152, 219, 0.05);
      border-radius: var(--radius-sm);
    }

    /* 弹窗 */
    .modal {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: rgba(0, 0, 0, 0.7);
      display: flex;
      justify-content: center;
      align-items: center;
      z-index: 1000;
      opacity: 0;
      visibility: hidden;
      transition: var(--transition);
      backdrop-filter: blur(8px);
    }

    .modal.active {
      opacity: 1;
      visibility: visible;
    }

    .modal-content {
      background: var(--glass-bg);
      backdrop-filter: blur(20px) saturate(180%);
      padding: 32px;
      border-radius: var(--radius-lg);
      max-width: 90%;
      width: 380px;
      text-align: center;
      box-shadow: var(--shadow);
      transform: translateY(20px) scale(0.95);
      transition: var(--transition);
      border: 1px solid var(--glass-border);
    }

    .modal.active .modal-content {
      transform: translateY(0) scale(1);
    }

    .modal h3 {
      color: var(--text-primary);
      margin-bottom: 16px;
      font-size: 22px;
      font-weight: 700;
    }

    .modal p {
      color: var(--text-secondary);
      line-height: 1.6;
      font-size: 15px;
      margin-bottom: 24px;
    }

    .close-modal {
      background: var(--primary-gradient);
      color: white;
      border: none;
      padding: 12px 28px;
      border-radius: var(--radius-sm);
      cursor: pointer;
      font-weight: 600;
      transition: var(--transition);
    }

    .close-modal:hover {
      transform: translateY(-2px);
      box-shadow: 0 6px 12px rgba(37, 117, 252, 0.2);
    }

    /* 动画定义 */
    @keyframes fadeInUp {
      from { opacity: 0; transform: translateY(30px); }
      to { opacity: 1; transform: translateY(0); }
    }

    @keyframes particles-move {
      0% { background-position: 0 0; }
      100% { background-position: 200px 200px; }
    }

    @keyframes stars-twinkle {
      0% { opacity: 0.4; }
      100% { opacity: 0.8; }
    }

    @keyframes float-particle {
      0%, 100% { transform: translate(0, 0) rotate(0deg); }
      25% { transform: translate(10px, 20px) rotate(90deg); }
      50% { transform: translate(20px, 0) rotate(180deg); }
      75% { transform: translate(10px, -20px) rotate(270deg); }
    }

    @keyframes glow-pulse {
      0% { opacity: 0.05; transform: scale(1); }
      100% { opacity: 0.15; transform: scale(1.1); }
    }

    @keyframes slideIn {
      from { opacity: 0; transform: translateY(-10px); }
      to { opacity: 1; transform: translateY(0); }
    }

    /* 响应式调整 */
    @media (max-width: 480px) {
      .login-container {
        padding: 36px 24px;
        border-radius: 20px;
      }
      
      .login-header h1 {
        font-size: 24px;
      }
      
      .login-subtitle {
        font-size: 14px;
      }
      
      .input-group input {
        padding: 14px 18px 14px 46px;
      }
      
      .particles-layer, .stars-layer {
        animation-duration: 200s;
      }
    }