:root {
      --bg: #f8fafc;
      --card: #ffffff;
      --text: #0f172a;
      --muted: #64748b;
      --primary: #7c3aed;
      --border: #e2e8f0;
      --highlight: #d1fae5;
      --error: #ef4444;
    }

    @media (prefers-color-scheme: dark) {
      :root {
        --bg: #0f172a;
        --card: #1e293b;
        --text: #f1f5f9;
        --muted: #94a3b8;
        --border: #334155;
        --highlight: #065f46;
        --error: #f87171;
      }
    }

    body {
      font-family: system-ui, sans-serif;
      background: var(--bg);
      color: var(--text);
      margin: 0;
      padding: 20px;
    }

    .container {
      max-width: 400px;
      margin: 0 auto;
      padding-top: 10vh;
    }

    .header {
      margin-bottom: 1.5rem;
      text-align: center;
    }

    .title {
      font-size: 1.5rem;
      font-weight: bold;
    }

    .back-link {
      display: inline-block;
      margin-bottom: 16px;
      color: var(--primary);
      text-decoration: none;
      font-weight: 500;
    }

    .login-container {
      background: var(--card);
      border: 1px solid var(--border);
      border-radius: 8px;
      padding: 24px;
    }

    .form-group {
      margin-bottom: 1rem;
    }

    label {
      display: block;
      margin-bottom: 0.5rem;
      font-weight: 500;
    }

    .form-input {
      width: 100%;
      box-sizing: border-box;
      padding: 10px 12px;
      font-size: 1rem;
      border: 2px solid var(--border);
      border-radius: 6px;
      background: var(--card);
      color: var(--text);
    }

    .form-input:focus {
      outline: none;
      border-color: var(--primary);
    }

    .login-button {
      display: block;
      width: 100%;
      box-sizing: border-box;
      padding: 12px;
      margin-top: 20px;
      background: var(--primary);
      color: white;
      border: none;
      border-radius: 8px;
      font-size: 1rem;
      font-weight: bold;
      cursor: pointer;
    }

    .error-message {
      background-color: rgba(239, 68, 68, 0.1);
      color: var(--error);
      padding: 12px;
      border-radius: 6px;
      margin-bottom: 16px;
      font-size: 0.9rem;
    }

    .signup-link {
      margin-top: 20px;
      text-align: center;
      font-size: 0.9rem;
      color: var(--muted);
    }

    .signup-link a {
      color: var(--primary);
      text-decoration: none;
    }