:root {
      --bg: #ffffff;
      --card: #f8f9fa;
      --accent: #2563eb;
      --accent-hover: #1d4ed8;
      --text: #1f2937;
      --muted: #6b7280;
      --border: #e5e7eb;
      --success: #10b981;
      --warning: #f59e0b;
      --error: #ef4444;
    }
    
    * { 
      box-sizing: border-box; 
      margin: 0;
      padding: 0;
      font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif; 
      -webkit-tap-highlight-color: transparent; 
    }

    input:focus, button:focus {
      outline: none; 
    }
    
    body {
      min-height: 100vh;
      display: flex;
      flex-direction: column;
      align-items: center;
      background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
      padding: 20px;
    }
    
    .container {
      width: 100%;
      max-width: 420px;
      display: flex;
      flex-direction: column;
      gap: 20px;
      padding-bottom: 30px;
    }
    
    .header {
      text-align: center;
      margin-bottom: 10px;
      margin-top: 20px;
    }
    
    .title {
      font-size: 1.8rem;
      color: var(--text);
      font-weight: bold;
      margin-bottom: 8px;
      background: linear-gradient(90deg, var(--accent), var(--accent-hover));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }
    
    .subtitle {
      font-size: 0.9rem;
      color: var(--muted);
    }
    
    .card {
      width: 100%;
      background: var(--card);
      border-radius: 20px;
      padding: 30px 25px;
      box-shadow: 0 10px 30px rgba(0,0,0,0.1);
      border: 1px solid rgba(255, 255, 255, 0.3);
      backdrop-filter: blur(10px);
      text-align: center;
    }
    
    .circle-wrapper {
      position: relative;
      width: 180px;
      height: 180px;
      margin: 0 auto 20px;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .circle-border {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      border-radius: 50%;
      border: 8px solid #e5e7eb;
      box-sizing: border-box;
      box-shadow: 0 4px 20px rgba(0,0,0,0.1) inset;
    }

    .code {
      font-size: 40px;
      letter-spacing: 8px;
      font-weight: 700;
      color: var(--accent);
      z-index: 2;
      font-family: 'Courier New', monospace;
      text-shadow: 0 2px 4px rgba(0,0,0,0.1);
    }
    
    .time-info {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-size: 14px;
      color: var(--muted);
      margin-top: 10px;
      padding: 0 5px;
    }
    
    .progressbar {
      width: 100%;
      height: 8px;
      background: var(--border);
      border-radius: 4px;
      margin-top: 10px;
      overflow: hidden;
    }
    
    .progress {
      height: 100%;
      width: 100%;
      background: var(--accent);
      border-radius: 4px;
      transition: background-color 0.3s ease;
    }

    .progress.danger {
      background: var(--error);
    }
    
    .copy-btn {
      width: 100%;
      padding: 16px;
      margin-top: 25px;
      background: linear-gradient(135deg, var(--accent), var(--accent-hover));
      color: white;
      border: none;
      border-radius: 12px;
      font-weight: 600;
      cursor: pointer;
      font-size: 16px;
      transition: all 0.2s ease;
      box-shadow: 0 6px 20px rgba(37, 99, 235, 0.3);
      position: relative;
      overflow: hidden;
    }
    
    .copy-btn:hover {
      transform: scale(1.02);
      box-shadow: 0 8px 25px rgba(37, 99, 235, 0.4);
    }
    
    .copy-btn:active {
      transform: scale(0.98);
      box-shadow: 0 3px 10px rgba(37, 99, 235, 0.3);
    }
    
    .copy-btn::after {
      content: '';
      position: absolute;
      top: 50%;
      left: 50%;
      width: 5px;
      height: 5px;
      background: rgba(255, 255, 255, 0.5);
      opacity: 0;
      border-radius: 100%;
      transform: scale(1, 1) translate(-50%);
      transform-origin: 50% 50%;
    }
    
    .copy-btn:focus:not(:active)::after {
      animation: ripple 1s ease-out;
    }
    
    .secret-section {
      margin-top: 20px;
      display: flex;
      gap: 10px;
    }
    
    input[type="text"] {
      flex: 1;
      padding: 12px 16px;
      border-radius: 10px;
      border: 2px solid var(--border);
      background: #fff;
      color: var(--text);
      font-size: 14px;
      transition: all 0.3s ease;
    }
    
    input[type="text"]:focus {
      border-color: var(--accent);
      box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
    }
    
    #apply-btn {
      padding: 12px 20px;
      background: linear-gradient(135deg, var(--text), #374151);
      border: none;
      border-radius: 10px;
      color: white;
      font-weight: 600;
      cursor: pointer;
      font-size: 14px;
      transition: all 0.2s ease;
    }
    
    #apply-btn:hover {
      transform: scale(1.05);
      box-shadow: 0 4px 12px rgba(0,0,0,0.15);
    }
    
    #apply-btn:active {
      transform: scale(0.95);
    }
    
    .instructions {
      width: 100%;
      background: rgba(255, 255, 255, 0.9);
      border-radius: 12px;
      padding: 20px;
      border: 1px solid var(--border);
      margin-top: 10px;
      backdrop-filter: blur(5px);
    }
    
    .instructions h3 {
      color: var(--text);
      margin-bottom: 10px;
      font-size: 1.1rem;
    }
    
    .instructions p {
      color: var(--muted);
      line-height: 1.6;
      font-size: 13px;
      margin-bottom: 5px;
    }

    .status-bar {
      font-size: 12px;
      text-align: center;
      margin-top: 10px;
      color: #9ca3af;
    }

    .toast {
      position: fixed;
      left: 50%;
      top: 50%;
      transform: translate(-50%, -50%);
      background: rgba(0,0,0,0.85);
      color: white;
      padding: 12px 24px;
      border-radius: 8px;
      display: none;
      z-index: 100;
      font-size: 14px;
      text-align: center;
      backdrop-filter: blur(4px);
      box-shadow: 0 4px 20px rgba(0,0,0,0.3);
      animation: fadeIn 0.3s ease;
    }
    
    .icon {
      width: 16px;
      height: 16px;
      display: inline-block;
      vertical-align: middle;
      margin-right: 6px;
    }
    
    .sync-icon {
      width: 12px;
      height: 12px;
      border-radius: 50%;
      display: inline-block;
      margin-right: 6px;
    }
    
    .sync-icon.success {
      background-color: var(--success);
      box-shadow: 0 0 0 2px rgba(16, 185, 129, 0.2);
    }
    
    .sync-icon.warning {
      background-color: var(--warning);
      box-shadow: 0 0 0 2px rgba(245, 158, 11, 0.2);
      animation: pulse 1.5s infinite;
    }
    
    .sync-icon.error {
      background-color: var(--error);
      box-shadow: 0 0 0 2px rgba(239, 68, 68, 0.2);
    }
    
    @keyframes ripple {
      0% {
        transform: scale(0, 0);
        opacity: 0.5;
      }
      20% {
        transform: scale(25, 25);
        opacity: 0.3;
      }
      100% {
        opacity: 0;
        transform: scale(40, 40);
      }
    }
    
    @keyframes fadeIn {
      from { opacity: 0; transform: translate(-50%, -50%) scale(0.9); }
      to { opacity: 1; transform: translate(-50%, -50%) scale(1); }
    }
    
    @keyframes pulse {
      0% { opacity: 0.6; }
      50% { opacity: 1; }
      100% { opacity: 0.6; }
    }
    
    @keyframes codeChange {
      0% { transform: scale(1); opacity: 1; }
      50% { transform: scale(1.05); opacity: 0.7; }
      100% { transform: scale(1); opacity: 1; }
    }
    
    .code-change {
      animation: codeChange 0.3s ease;
    }
    
    @media (max-width: 480px) {
      .container {
        padding: 10px;
      }
      
      .card {
        padding: 20px 15px;
      }
      
      .circle-wrapper {
        width: 150px;
        height: 150px;
      }
      
      .code {
        font-size: 32px;
        letter-spacing: 6px;
      }
      
      .secret-section {
        flex-direction: column;
      }
    }