body {
    font-family: 'Segoe UI', Arial, sans-serif;
    text-align: center;
    margin: 0;
    padding: 20px;
    background-color: #f0f2f5;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

.app-container {
    display: flex;
    gap: 20px;
    max-width: 1200px;
    width: 95%;
    margin: auto;
}

#quiz-container {
    flex: 1;
    padding: 30px;
    background-color: white;
    border-radius: 15px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

#notes-container {
    flex: 1;
    padding: 30px;
    background-color: white;
    border-radius: 15px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    display: flex;
    flex-direction: column;
    overflow-y: auto;
    max-height: 800px;
}

.option {
    display: block;
    width: 100%;
    margin: 12px 0;
    padding: 15px;
    background-color: #f8f9fa;
    border: 2px solid #e9ecef;
    border-radius: 8px;
    cursor: pointer;
    font-size: 16px;
    transition: all 0.3s ease;
}

.option:hover {
    background-color: #e9ecef;
    transform: translateY(-2px);
}

#progress-container {
    width: 100%;
    height: 10px;
    background-color: #eee;
    border-radius: 5px;
    margin-bottom: 20px;
}

#progress-bar {
    height: 100%;
    background-color: #3498db;
    border-radius: 5px;
    width: 0%;
    transition: width 0.3s ease-in-out;
}

.correct {
    background-color: #d4edda !important;
    border-color: #28a745 !important;
    color: #155724;
}

.incorrect {
    background-color: #f8d7da !important;
    border-color: #dc3545 !important;
    color: #721c24;
}

#score {
    font-size: 20px;
    font-weight: bold;
    color: #2c3e50;
    margin: 20px 0;
}

#restart {
    display: none;
    margin: 20px auto;
    padding: 12px 30px;
    background-color: #2ecc71;
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 16px;
    transition: background-color 0.3s ease;
}

#restart:hover {
    background-color: #27ae60;
}

.notes-section {
    margin-bottom: 30px;
}

.notes-section h3 {
    color: #2c3e50;
    margin-bottom: 15px;
    padding-bottom: 5px;
    border-bottom: 2px solid #e9ecef;
}

.note-card {
    background-color: #f8f9fa;
    border-radius: 8px;
    padding: 15px;
    margin-bottom: 15px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
    transition: transform 0.2s ease;
}

.note-card:hover {
    transform: translateY(-2px);
}

.note-card h4 {
    color: #3498db;
    margin: 0 0 10px 0;
}

.note-card p {
    color: #2c3e50;
    margin: 0;
    line-height: 1.5;
}

.note-card ul {
    margin: 10px 0;
    padding-left: 20px;
    text-align: left;
}

.note-card li {
    color: #2c3e50;
    margin: 5px 0;
    line-height: 1.4;
}

/* Mobile Responsive Styles */
@media screen and (max-width: 768px) {
    .app-container {
        flex-direction: column;
        padding: 10px;
        gap: 20px;
    }

    #quiz-container {
        width: 100%;
        padding: 15px;
        margin-bottom: 20px;
    }

    #notes-container {
        width: 100%;
        padding: 15px;
    }

    .option {
        padding: 12px;
        font-size: 14px;
        margin-bottom: 10px;
    }

    h1 {
        font-size: 24px;
    }

    h2 {
        font-size: 20px;
    }

    h3 {
        font-size: 18px;
    }

    h4 {
        font-size: 16px;
    }

    .note-card {
        padding: 15px;
        margin-bottom: 15px;
    }

    .note-card p {
        font-size: 14px;
    }

    .note-card ul {
        font-size: 14px;
        padding-left: 20px;
    }

    .note-card li {
        margin-bottom: 8px;
    }

    #notes-area {
        height: 100px;
        font-size: 14px;
    }

    .notes-buttons {
        flex-direction: column;
        gap: 10px;
    }

    .notes-buttons button {
        width: 100%;
        padding: 10px;
    }

    .saved-note {
        padding: 12px;
        margin-bottom: 12px;
    }

    .note-date {
        font-size: 12px;
    }

    .note-content {
        font-size: 14px;
    }
}

/* Small Mobile Devices */
@media screen and (max-width: 480px) {
    .app-container {
        padding: 5px;
    }

    #quiz-container, #notes-container {
        padding: 10px;
    }

    .option {
        padding: 10px;
        font-size: 13px;
    }

    h1 {
        font-size: 22px;
    }

    h2 {
        font-size: 18px;
    }

    h3 {
        font-size: 16px;
    }

    h4 {
        font-size: 15px;
    }

    .note-card {
        padding: 12px;
    }

    .note-card p, .note-card ul {
        font-size: 13px;
    }

    #notes-area {
        height: 80px;
        font-size: 13px;
    }

    .notes-buttons button {
        padding: 8px;
        font-size: 13px;
    }

    .saved-note {
        padding: 10px;
    }

    .note-date {
        font-size: 11px;
    }

    .note-content {
        font-size: 13px;
    }
}

/* Landscape Mode */
@media screen and (max-height: 500px) and (orientation: landscape) {
    .app-container {
        flex-direction: row;
    }

    #quiz-container, #notes-container {
        width: 50%;
        height: 100vh;
        overflow-y: auto;
    }

    #notes-area {
        height: 60px;
    }
}