:root {
    --primary-color: #4a6bfd;
    --primary-light: #7a93fe;
    --primary-dark: #244ae8;
    --secondary-color: #ff7e5f;
    --text-color: #2c3e50;
    --light-text: #777;
    --bg-color: #f9f9f9;
    --panel-bg: #ffffff;
    --border-color: #e0e0e0;
    --success-color: #2ecc71;
    --error-color: #e74c3c;
    --font-main: 'Inter', 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-main), serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

.app-container {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

/* Header Styles */
.header {
    background-color: var(--panel-bg);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.logo h1 {
    color: var(--text-color);
    font-size: 1.7rem;
    font-weight: 700;
}

.main-nav ul {
    display: flex;
    list-style: none;
    gap: 1rem;
}

/* Main Content Layout */
.main-content {
    display: flex;
    flex: 1;
    min-height: calc(100vh - 60px);
}

.sidebar {
    width: 240px;
    background-color: var(--panel-bg);
    border-right: 1px solid var(--border-color);
    padding: 1.5rem 1rem;
    overflow-y: auto;
    height: calc(100vh - 60px);
    position: sticky;
    top: 60px;
}

.content-area {
    flex: 1;
    padding: 2rem;
    max-width: calc(100% - 240px);
}

/* Module List Styles */
.module-list {
    margin-bottom: 2rem;
}

.module-list-item {
    padding: 0.75rem 1rem;
    margin-bottom: 0.5rem;
    border-radius: 6px;
    cursor: pointer;
    transition: background-color 0.2s;
}

.module-list-item:hover {
    background-color: rgba(74, 107, 253, 0.05);
}

.module-list-item.active {
    background-color: rgba(74, 107, 253, 0.1);
    color: var(--primary-color);
    font-weight: 600;
}

/* Lesson Container */
.lesson-container {
    background-color: var(--panel-bg);
    border-radius: 8px;
    box-shadow: var(--shadow);
    padding: 2rem;
    margin-bottom: 2rem;
}

#lesson-title {
    margin-bottom: 1rem;
    color: var(--primary-dark);
}

.lesson-description {
    margin-bottom: 2rem;
    color: var(--text-color);
    line-height: 1.7;
}

/* Challenge Container */
.challenge-container {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    margin-bottom: 2rem;
}

@media (min-width: 1024px) {
    .challenge-container {
        flex-direction: row;
    }

    .preview-area,
    .editor-container {
        width: 48%;
    }
}

.preview-area {
    background-color: #fff;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 1rem;
    overflow: hidden;
    min-height: 300px;
    display: flex;
    justify-content: center;
    align-items: center;
}

.editor-container {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.task-instruction {
    background-color: rgba(74, 107, 253, 0.05);
    border-left: 4px solid var(--primary-color);
    padding: 1rem;
    border-radius: 4px;
}

.code-editor {
    border: 1px solid var(--border-color);
    border-radius: 6px;
    overflow: hidden;
}

.editor-header {
    background-color: #f5f5f5;
    padding: 0.5rem 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.9rem;
    color: var(--light-text);
    border-bottom: 1px solid var(--border-color);
}

.editor-content {
    background-color: #1e1e1e;
    color: #d4d4d4;
    padding: 1rem;
    overflow-y: auto;
    font-family: 'JetBrains Mono', 'Fira Code', monospace;
    font-size: 14px;
    line-height: 1.5;
}

code {
    font-family: 'JetBrains Mono', 'Fira Code', monospace;
}

.code-input {
    background-color: #1e1e1e;
    color: #d4d4d4;
    border: none;
    width: 100%;
    min-height: 100px;
    font-family: 'JetBrains Mono', 'Fira Code', monospace;
    font-size: 14px;
    line-height: 1.5;
    padding: 0.5rem 0;
    outline: none;
    resize: vertical;
}

/* Controls */
.controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 1.5rem;
}

.level-indicator {
    font-size: 0.9rem;
    color: var(--light-text);
}

/* Buttons */
.btn {
    padding: 0.5rem 1rem;
    border-radius: 4px;
    border: 1px solid var(--border-color);
    background-color: #fff;
    color: var(--text-color);
    cursor: pointer;
    font-family: var(--font-main);
    font-size: 0.9rem;
    transition: all 0.2s;
}

.btn:hover {
    background-color: #f5f5f5;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
    border: 1px solid var(--primary-dark);
}

.btn-primary:hover {
    background-color: var(--primary-dark);
}

/* Modal */
.modal-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.modal {
    background-color: var(--panel-bg);
    border-radius: 8px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.2);
    width: 90%;
    max-width: 600px;
    max-height: 80vh;
    overflow-y: auto;
}

.modal-header {
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-content {
    padding: 1.5rem;
}

.modal-close {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--light-text);
}

.hidden {
    display: none;
}

/* Feedback */
.feedback-success {
    color: var(--success-color);
    font-weight: 500;
    margin-top: 1rem;
    padding: 0.5rem;
    border-radius: 4px;
    background-color: rgba(46, 204, 113, 0.1);
    border-left: 3px solid var(--success-color);
}

.feedback-error {
    color: var(--error-color);
    font-weight: 500;
    margin-top: 1rem;
    padding: 0.5rem;
    border-radius: 4px;
    background-color: rgba(231, 76, 60, 0.1);
    border-left: 3px solid var(--error-color);
}

/* Add these styles to your main.css file */

/* Success highlight for lesson container */
.success-highlight {
    box-shadow: 0 0 0 3px var(--success-color);
    transition: all 0.3s ease;
}

/* Success text color for headings */
.success-text {
    color: var(--success-color);
    transition: color 0.3s ease;
}

/* Friendlier error feedback */
.feedback-error {
    color: #996633;
    font-weight: 500;
    margin-top: 1rem;
    padding: 0.5rem;
    border-radius: 4px;
    background-color: rgba(255, 248, 230, 0.5);
    border-left: 3px solid #cc9944;
}

/* Module selector button with progress */
#module-selector-btn {
    overflow: hidden;
}

/* Button disabled state */
.btn-disabled {
    opacity: 0.6;
    cursor: not-allowed;
}