:root {
            --bg-color-light: #f4f7f9;
            --card-bg-light: #ffffff;
            --text-color-light: #333333;
            --secondary-text-light: #666666;
            --border-color-light: #fdaaaa;
            --primary-color: #fdaaaa;
            --button-text-color: #ffffff;
            --timer-text-color: #fdaaaa;
            --explore-bg: #eaf1f7;
        }

        body.dark-mode {
            --bg-color-light: #1a1a2e;
            --card-bg-light: #16213e;
            --text-color-light: #bd86fc;
            --secondary-text-light: #b0b0b0;
            --border-color-light: #3a3a5a;
            --primary-color: #bb86fc;
            --timer-text-color: #bb86fc;
            --explore-bg: #1e2a4a;
        }

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background-color: var(--bg-color-light);
            color: var(--text-color-light);
            margin: 0;
            display: flex;
            flex-direction: column;
            justify-content: flex-start;
            align-items: center;
            min-height: 100vh;
            transition: background-color 0.3s, color 0.3s;
            overflow-x: hidden;
            padding: 20px;
        }

        .exercise-container {
            background-color: var(--card-bg-light);
            border-radius: 15px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
            padding: 30px;
            display: flex;
            flex-direction: column;
            align-items: center;
            width: 100%;
            max-width: 800px;
            position: relative;
            margin-bottom: 40px;
        }

        h1 {
            color: var(--primary-color);
            margin-bottom: 5px;
            font-size: 2.2em;
            text-align: center;
        }

        p {
            color: var(--secondary-text-light);
            margin-bottom: 20px;
            text-align: center;
            font-size: 1.1em;
        }

        .timer-display {
            font-family: 'Roboto Mono', monospace;
            font-size: 4.5em;
            font-weight: 700;
            color: var(--timer-text-color);
            margin: 20px 0 10px;
            text-shadow: 0 0 15px rgba(106, 79, 230, 0.5);
            letter-spacing: 2px;
        }

        .btn {
            padding: 12px 25px;
            border: none;
            border-radius: 25px;
            cursor: pointer;
            font-size: 1rem;
            font-weight: bold;
            transition: background-color 0.2s, transform 0.1s;
            background-color: var(--primary-color);
            color: white;
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .btn-secondary {
            background-color: var(--secondary-text-light);
        }
        
        .btn:hover {
            opacity: 0.8;
            transform: translateY(-2px);
        }

        .btn-secondary:hover {
            background-color: #555;
        }

        .theme-toggle {
            position: absolute;
            top: 20px;
            right: 20px;
            background: var(--card-bg-light);
            border: 1px solid var(--border-color-light);
            border-radius: 50%;
            width: 45px;
            height: 45px;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            transition: background-color 0.3s, border-color 0.3s, transform 0.2s;
            z-index: 101;
        }

        .theme-toggle .material-icons {
            font-size: 24px;
            color: var(--text-color-light);
            transition: color 0.3s;
        }

        .theme-toggle:hover {
            background-color: var(--bg-color-light);
            transform: scale(1.05);
        }

        /* --- Explore More Section --- */
        .explore-more-section {
            width: 100%;
            max-width: 800px;
            text-align: center;
            background-color: var(--explore-bg);
            border-radius: 15px;
            padding: 30px;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
            transition: background-color 0.3s;
        }
        .explore-more-section h2 {
            font-size: 1.8em;
            margin-top: 0;
            margin-bottom: 20px;
            color: var(--primary-color);
        }
        .explore-more-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
            gap: 20px;
        }
        .explore-card {
            background-color: var(--card-bg-light);
            border-radius: 12px;
            padding: 20px;
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
            transition: transform 0.2s, box-shadow 0.2s, background-color 0.3s;
            text-decoration: none;
            color: var(--text-color-light);
            display: flex;
            flex-direction: column;
            align-items: center;
        }
        .explore-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 6px 20px rgba(0, 0, 0, 0.1);
        }
        .explore-card .material-icons {
            font-size: 40px;
            margin-bottom: 10px;
            color: var(--primary-color);
        }
        .explore-card span {
            font-size: 1.1em;
            font-weight: bold;
        }
        
        /* Media Queries for Responsiveness */
        @media (max-width: 768px) {
            .exercise-container, .explore-more-section {
                padding: 20px;
                max-width: 100%;
            }
            h1 {
                font-size: 1.8em;
            }
            .timer-display {
                font-size: 3em;
            }
            .explore-more-grid {
                grid-template-columns: 1fr;
            }
        }