/* CSS Variables for theming */
:root {
    --primary-color: #2965f1;
    --secondary-color: #1e4ed8;
    --background-color: #ffffff;
    --surface-color: #f8f9fa;
    --text-color: #2d3748;
    --text-secondary: #718096;
    --border-color: #e2e8f0;
    --light-gray: #ebebeb;
    --success-color: #48bb78;
    --error-color: #f56565;
    --warning-color: #ed8936;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.15);
    --border-radius: 8px;
    --transition: all 0.3s ease;
}

[data-theme="dark"] {
    --background-color: #1a202c;
    --surface-color: #2d3748;
    --text-color: #f7fafc;
    --text-secondary: #a0aec0;
    --border-color: #4a5568;
    --light-gray: #4a5568;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.4);
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: var(--transition);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
}

/* Theme Toggle */
.theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1000;
}

.theme-btn {
    background: var(--surface-color);
    border: 2px solid var(--border-color);
    border-radius: 50%;
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: 1.2rem;
    transition: var(--transition);
    box-shadow: var(--shadow);
}

.theme-btn:hover {
    transform: scale(1.1);
    box-shadow: var(--shadow-lg);
}

/* Header */
.header {
    text-align: center;
    margin-bottom: 40px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: relative;
}

.logo {
    font-size: 2rem;
    font-weight: 700;
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
}

.css-bracket {
    color: var(--primary-color);
}

.css-text {
    color: var(--secondary-color);
}

.learning-text {
    color: var(--text-color);
    margin-left: 10px;
}

.back-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-weight: 500;
    transition: var(--transition);
}

.back-btn:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
}

/* Progress Overview */
.progress-overview {
    background: var(--surface-color);
    padding: 30px;
    border-radius: var(--border-radius);
    margin-bottom: 40px;
    box-shadow: var(--shadow);
}

.progress-overview h2 {
    text-align: center;
    margin-bottom: 30px;
    color: var(--primary-color);
}

.progress-sections {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

.progress-section h3 {
    margin-bottom: 10px;
    font-weight: 600;
}

.progress-bar {
    background: var(--border-color);
    height: 8px;
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 8px;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    width: 0%;
    transition: width 0.5s ease;
    border-radius: 4px;
}

.progress-text {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

/* Tasks Container */
.tasks-container {
    margin-bottom: 40px;
}

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

.section-title {
    font-size: 1.5rem;
    margin-bottom: 20px;
    color: var(--primary-color);
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 10px;
}

.task-card {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 25px;
    transition: var(--transition);
    box-shadow: var(--shadow);
    margin-bottom: 20px;
}

.task-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.task-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
}

.task-header h3 {
    color: var(--text-color);
    font-weight: 600;
}

.task-status {
    padding: 5px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
    background: var(--border-color);
    color: var(--text-secondary);
}

.task-status.completed {
    background: var(--success-color);
    color: white;
}

.task-status.in-progress {
    background: var(--warning-color);
    color: white;
}

.task-description {
    color: var(--text-secondary);
    margin-bottom: 20px;
}

.start-task-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-weight: 500;
    transition: var(--transition);
}

.start-task-btn:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
}

/* Certificate Section */
.certificate-section {
    background: var(--surface-color);
    padding: 30px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
}

.certificate-section h2 {
    text-align: center;
    margin-bottom: 20px;
    color: var(--primary-color);
}

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

.certificate-status {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    font-size: 1.1rem;
    font-weight: 500;
}

.lock-icon {
    font-size: 1.5rem;
}

.certificate-preview {
    margin-bottom: 30px;
}

.certificate-preview h3 {
    text-align: center;
    margin-bottom: 20px;
    color: var(--text-color);
}

.certificate-container {
    text-align: center;
}

.certificate-image {
    max-width: 100%;
    height: auto;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
}

.certificate-generator {
    text-align: center;
}

.certificate-generator h3 {
    margin-bottom: 20px;
    color: var(--success-color);
}

.name-input-container {
    margin-bottom: 20px;
}

.name-input-container label {
    display: block;
    margin-bottom: 10px;
    font-weight: 500;
}

.name-input-container input {
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    margin-right: 10px;
    background: var(--background-color);
    color: var(--text-color);
}

.generate-btn {
    background: var(--success-color);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-weight: 500;
    transition: var(--transition);
}

.generate-btn:hover {
    background: #38a169;
    transform: translateY(-2px);
}

.generated-certificate {
    margin-top: 20px;
    text-align: center;
    padding: 20px;
    background: var(--surface-color);
    border-radius: var(--border-radius);
}

#certificateCanvas {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.1);
    background: white;
}

.download-options {
    margin-top: 20px;
}

.download-options h4 {
    margin-bottom: 15px;
}

.download-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 8px 16px;
    border-radius: var(--border-radius);
    cursor: pointer;
    margin: 0 5px;
    transition: var(--transition);
}

.download-btn:hover {
    background: var(--secondary-color);
}

/* Editor Interface */
.editor-interface {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--background-color);
    z-index: 500;
}

.editor-container {
    height: 100%;
    display: flex;
    flex-direction: column;
    padding: 20px;
}

.task-instructions {
    background: var(--surface-color);
    padding: 20px;
    border-radius: var(--border-radius);
    margin-bottom: 20px;
    border-left: 4px solid var(--primary-color);
}

.code-editor-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    background: var(--surface-color);
    border-radius: var(--border-radius);
    overflow: hidden;
}

.editor-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
    background: var(--light-gray);
    border-bottom: 1px solid var(--border-color);
}

.editor-tabs {
    display: flex;
    gap: 10px;
}

.tab {
    padding: 8px 16px;
    background: var(--background-color);
    border-radius: 4px 4px 0 0;
    font-weight: 500;
    color: var(--text-color);
    cursor: pointer;
    transition: var(--transition);
}

.tab.active {
    background: var(--primary-color);
    color: white;
}

.tab:hover:not(.active) {
    background: var(--border-color);
}

.editor-actions {
    display: flex;
    gap: 10px;
}

.action-btn {
    padding: 8px 16px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-weight: 500;
    transition: var(--transition);
}

.run-btn {
    background: var(--success-color);
    color: white;
}

.run-btn:hover {
    background: #38a169;
}

.validate-btn {
    background: var(--primary-color);
    color: white;
}

.validate-btn:hover {
    background: var(--secondary-color);
}

.editor-content {
    flex: 1;
    display: flex;
}

.code-editor {
    flex: 1;
    display: flex;
    flex-direction: column;
}

#htmlEditor, #cssEditor {
    flex: 1;
    border: none;
    padding: 20px;
    font-family: 'Monaco', 'Consolas', monospace;
    font-size: 14px;
    background: var(--background-color);
    color: var(--text-color);
    resize: none;
    outline: none;
}

.preview-panel {
    flex: 1;
    border-left: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
}

.preview-header {
    padding: 10px 20px;
    background: var(--light-gray);
    font-weight: 500;
    border-bottom: 1px solid var(--border-color);
}

#previewFrame {
    flex: 1;
    border: none;
    background: white;
}

.validation-result {
    margin-top: 20px;
    padding: 15px;
    border-radius: var(--border-radius);
    font-weight: 500;
}

.validation-result.success {
    background: #c6f6d5;
    color: #22543d;
    border: 1px solid #68d391;
}

.validation-result.error {
    background: #fed7d7;
    color: #742a2a;
    border: 1px solid #fc8181;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    .header {
        flex-direction: column;
        gap: 20px;
    }
    
    .logo {
        font-size: 1.5rem;
        position: static;
        transform: none;
    }
    
    .progress-sections {
        grid-template-columns: 1fr;
    }
    
    .editor-content {
        flex-direction: column;
    }
    
    .preview-panel {
        border-left: none;
        border-top: 1px solid var(--border-color);
    }
    
    .editor-header {
        flex-direction: column;
        gap: 15px;
    }
    
    .name-input-container input {
        margin-right: 0;
        margin-bottom: 10px;
        width: 100%;
    }
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.task-card, .progress-overview, .certificate-section {
    animation: fadeIn 0.6s ease;
}

@keyframes progressFill {
    from { width: 0%; }
    to { width: var(--target-width); }
}

.progress-fill[data-progress="100"] {
    animation: progressFill 1s ease;
}