:root {
            --bg-color: #f0f2f5;
            --container-bg: #ffffff;
            --text-color: #333;
            --input-bg: #f9f9f9;
            --primary-color: #4a90e2;
            --border-color: #ccc;
        }

        body.dark-mode {
            --bg-color: #1e1e2f;
            --container-bg: #2e2e3e;
            --text-color: #f0f0f0;
            --input-bg: #3a3a4a;
            --primary-color: #4a90e2;
            --border-color: #555;
        }

        html, body {
            margin: 0;
            padding: 0;
            height: 100%;
            overflow-x: hidden;
        }

        body {
             background-color: var(--bg-color);
            color: var(--text-color);
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
            transition: background-color 0.3s ease, color 0.3s ease;
            font-family: 'Segoe UI', sans-serif;
        }

        .login-container {
            background-color: var(--container-bg);
            padding: 40px;
            border-radius: 10px;
            box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
            width: 100%;
            max-width: 400px;
        }

        .logo {
            text-align: center;
            margin-bottom: 30px;
        }

        .logo img {
            width: 60px;
        }

        .logo h1 {
            font-size: 24px;
            margin-top: 10px;
        }

        .input-group {
            margin-bottom: 20px;
        }

        label {
            display: block;
            margin-bottom: 6px;
            font-weight: 500;
        }

        input[type="text"], input[type="password"], input[type="email"] {
            width: 100%;
            padding: 12px;
            border: 1px solid var(--border-color);
            background-color: var(--input-bg);
            border-radius: 6px;
            outline: none;
            font-size: 14px;
        }

        .options {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 20px;
            font-size: 14px;
        }

        .options label {
            display: flex;
            align-items: center;
        }

        .options input[type="checkbox"] {
            margin-right: 6px;
        }

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

        .login-btn {
            width: 100%;
            padding: 12px;
            background-color: var(--primary-color);
            border: none;
            color: white;
            font-size: 16px;
            border-radius: 6px;
            cursor: pointer;
        }

        .login-btn:hover {
            background-color: #3b79c4;
        }

        .footer {
            text-align: center;
            margin-top: 20px;
            font-size: 14px;
        }

        .footer a {
            color: var(--primary-color);
            text-decoration: none;
            cursor: pointer;
        }

        .dark-mode-toggle {
            position: absolute;
            top: 20px;
            right: 20px;
            background: none;
            border: 2px solid var(--primary-color);
            color: var(--primary-color);
            padding: 6px 10px;
            border-radius: 20px;
            cursor: pointer;
        }

        .dark-mode-toggle:hover {
            background: var(--primary-color);
            color: white;
        }

        .hidden {
            display: none;
        }

        @media (max-width: 480px) {
            .login-container {
                padding: 30px 20px;
            }

            .logo h1 {
                font-size: 20px;
            }
        }