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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f5f5f5;
}

#app {
    width: 100%;
    margin: 0 auto;
    padding: 1rem;
}

@media (min-width: 768px) and (max-width: 1023px) {
    #app {
        padding: 1.5rem;
    }
}

@media (min-width: 1024px) {
    #app {
        padding: 2rem;
    }
}

/* Navigation */
.main-nav {
    background-color: #fff;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    padding: 1rem 0;
    margin-bottom: 2rem;
}

.nav-container {
    width: 100%;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

@media (max-width: 575px) {
    .nav-container {
        padding: 0 1rem;
        flex-direction: column;
        gap: 1rem;
    }
    
    .nav-links {
        width: 100%;
        overflow-x: auto;
    }
}

.nav-brand a {
    font-size: 1.5rem;
    font-weight: bold;
    color: #2563eb;
    text-decoration: none;
}

.nav-links {
    display: flex;
    gap: 1.5rem;
}

.nav-links a {
    color: #4b5563;
    text-decoration: none;
    padding: 0.5rem 0;
    position: relative;
}

.nav-links a:hover {
    color: #2563eb;
}

.nav-links a[data-link]:after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: #2563eb;
    transition: width 0.3s;
}

.nav-links a[data-link]:hover:after {
    width: 100%;
}

.auth-btn {
    background-color: #2563eb;
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.9rem;
}

.auth-btn:hover {
    background-color: #1d4ed8;
}

/* Buttons */
.btn {
    display: inline-block;
    background-color: #2563eb;
    color: white;
    padding: 0.75rem 1.5rem;
    border-radius: 6px;
    text-decoration: none;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    transition: background-color 0.3s;
}

.btn:hover {
    background-color: #1d4ed8;
}

.btn-outline {
    background-color: transparent;
    color: #2563eb;
    border: 2px solid #2563eb;
}

.btn-outline:hover {
    background-color: #2563eb;
    color: white;
}

.btn-primary {
    background-color: #2563eb;
    color: white;
}

.btn-secondary {
    background-color: #6b7280;
    color: white;
}

/* Cards */
.course-card {
    background-color: white;
    border-radius: 10px;
    padding: 1.5rem;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    transition: transform 0.3s, box-shadow 0.3s;
}

.course-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 15px rgba(0,0,0,0.1);
}

.course-header {
    display: flex;
    justify-content: space-between;
    align-items: start;
    margin-bottom: 1rem;
}

.course-level {
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: bold;
    text-transform: uppercase;
}

.course-level.beginner {
    background-color: #dcfce7;
    color: #166534;
}

.course-level.intermediate {
    background-color: #fef3c7;
    color: #92400e;
}

.course-level.advanced {
    background-color: #fee2e2;
    color: #991b1b;
}

.course-meta {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
    font-size: 0.9rem;
    color: #6b7280;
}

.course-actions {
    margin-top: 1.5rem;
    display: flex;
    gap: 1rem;
    align-items: center;
}

.btn-favorite {
    background: none;
    border: 1px solid #d1d5db;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: background-color 0.3s;
}

.btn-favorite:hover {
    background-color: #f3f4f6;
}

.btn-favorite.favorited {
    background-color: #fef2f2;
    border-color: #fecaca;
    color: #dc2626;
}

.heart-icon {
    font-size: 1.2rem;
}

/* Progress bar */
.progress-bar {
    height: 8px;
    background-color: #e5e7eb;
    border-radius: 4px;
    overflow: hidden;
    margin: 0.5rem 0;
}

.progress-fill {
    height: 100%;
    background-color: #2563eb;
    border-radius: 4px;
    transition: width 0.3s;
}

/* Forms */
.form-container {
    display: none;
}

.form-container.active {
    display: block;
}

.form-group {
    margin-bottom: 1rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.form-group input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #d1d5db;
    border-radius: 6px;
    font-size: 1rem;
}

.form-group input:focus {
    outline: none;
    border-color: #2563eb;
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

/* Messages */
.message {
    padding: 1rem;
    border-radius: 6px;
    margin-top: 1rem;
}

.message.success {
    background-color: #dcfce7;
    color: #166534;
    border: 1px solid #bbf7d0;
}

.message.error {
    background-color: #fee2e2;
    color: #991b1b;
    border: 1px solid #fecaca;
}

.message.info {
    background-color: #dbeafe;
    color: #1e40af;
    border: 1px solid #bfdbfe;
}

.global-message {
    margin-top: 1.5rem;
    padding: 1.25rem;
    font-size: 1.1rem;
    text-align: center;
    animation: fadeIn 0.5s ease-in;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Grid */
.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

/* Empty state */
.empty-state {
    text-align: center;
    padding: 3rem;
    background-color: white;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

/* Tabs */
.tabs {
    display: flex;
    border-bottom: 2px solid #e5e7eb;
    margin-bottom: 2rem;
}

.tab-btn {
    padding: 0.75rem 1.5rem;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    color: #6b7280;
    position: relative;
}

.tab-btn.active {
    color: #2563eb;
    font-weight: 600;
}

.tab-btn.active:after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: #2563eb;
}

/* Login page */
.login-page {
    min-height: calc(100vh - 200px);
    display: flex;
    align-items: center;
    justify-content: center;
}

.login-container {
    background-color: white;
    padding: 3rem;
    border-radius: 10px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.1);
    width: 100%;
    max-width: 500px;
}

/* Filters */
.filters {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
}

.filter-btn {
    padding: 0.5rem 1.5rem;
    background-color: white;
    border: 2px solid #e5e7eb;
    border-radius: 20px;
    text-decoration: none;
    color: #4b5563;
    transition: all 0.3s;
}

.filter-btn:hover, .filter-btn.active {
    background-color: #2563eb;
    color: white;
    border-color: #2563eb;
}

/* Course Builder */
.course-builder-page {
    padding: 2rem 0;
}

.course-builder-container {
    background-color: white;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    margin: 0 2rem;
}

.course-builder-container h2 {
    color: #2563eb;
    margin-bottom: 0.5rem;
}

.subtitle {
    color: #6b7280;
    margin-bottom: 2rem;
    font-size: 1.1rem;
}

.editor-section {
    margin: 2rem 0;
    padding: 1.5rem;
    background-color: #f9fafb;
    border-radius: 8px;
    border: 1px solid #e5e7eb;
}

.editor-section h3 {
    margin-bottom: 1rem;
    color: #374151;
}

#vditor-container {
    margin-bottom: 1.5rem;
}

.editor-help {
    margin-top: 1.5rem;
    padding: 1rem;
    background-color: #f0f9ff;
    border: 1px solid #bae6fd;
    border-radius: 6px;
}

.editor-help h4 {
    margin-bottom: 0.5rem;
    color: #0369a1;
}

.editor-help ul {
    margin-left: 1.5rem;
    color: #075985;
}

.editor-help li {
    margin-bottom: 0.5rem;
}

/* Vditor custom styles */
.vditor {
    border-radius: 6px;
    border: 1px solid #e5e7eb;
}

.vditor-toolbar {
    border-bottom: 1px solid #e5e7eb;
    background-color: #f8fafc;
}

.vditor-toolbar__item {
    color: #4b5563;
}

.vditor-toolbar__item:hover {
    background-color: #e5e7eb;
    color: #111827;
}

.vditor-toolbar__item--active {
    background-color: #dbeafe;
    color: #1d4ed8;
}

.vditor-content {
    border-top: none;
}

.vditor-reset {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
}

.vditor-preview {
    background-color: white;
}

.latex-note {
    margin-top: 1rem;
    padding: 0.75rem;
    background-color: #fef3c7;
    border: 1px solid #fde68a;
    border-radius: 6px;
    color: #92400e;
}

/* KaTeX styles */
.katex-display {
    margin: 1.5rem 0;
    padding: 1rem;
    background-color: #f8fafc;
    border-radius: 6px;
    overflow-x: auto;
    overflow-y: hidden;
}

.katex {
    font-size: 1.1em;
}

.katex .katex-mathml {
    display: none;
}

.form-actions {
    display: flex;
    gap: 1rem;
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: 1px solid #e5e7eb;
}

textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #d1d5db;
    border-radius: 6px;
    font-size: 1rem;
    font-family: inherit;
    resize: vertical;
}

textarea:focus {
    outline: none;
    border-color: #2563eb;
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #d1d5db;
    border-radius: 6px;
    font-size: 1rem;
    background-color: white;
}

select:focus {
    outline: none;
    border-color: #2563eb;
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

/* Course Structure Styles */
.course-structure-section {
    margin: 2rem 0;
    padding: 1.5rem;
    background-color: #f9fafb;
    border-radius: 8px;
    border: 1px solid #e5e7eb;
}

.course-structure-section h3 {
    margin-bottom: 0.5rem;
    color: #374151;
}

.section-description {
    color: #6b7280;
    margin-bottom: 1.5rem;
    font-size: 0.95rem;
}

.structure-actions {
    margin-bottom: 1.5rem;
}

.btn-icon {
    margin-right: 0.5rem;
    font-weight: bold;
}

.course-structure {
    min-height: 200px;
    border: 1px dashed #d1d5db;
    border-radius: 6px;
    padding: 1.5rem;
    background-color: white;
}

.empty-structure {
    text-align: center;
    padding: 3rem;
    color: #6b7280;
}

.empty-structure p {
    margin: 0;
}

.module-item {
    background-color: white;
    border: 1px solid #e5e7eb;
    border-radius: 6px;
    margin-bottom: 1rem;
    overflow: hidden;
}

.module-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.5rem;
    background-color: #f8fafc;
    border-bottom: 1px solid #e5e7eb;
    cursor: pointer;
    transition: background-color 0.2s;
}

.module-header:hover {
    background-color: #f1f5f9;
}

.module-title {
    font-weight: 600;
    color: #111827;
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.module-icon {
    color: #2563eb;
}

.module-duration {
    color: #6b7280;
    font-size: 0.9rem;
    margin-left: 1rem;
}

.module-actions {
    display: flex;
    gap: 0.5rem;
}

.module-action-btn {
    padding: 0.25rem 0.75rem;
    background: none;
    border: 1px solid #d1d5db;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.85rem;
    color: #4b5563;
    transition: all 0.2s;
}

.module-action-btn:hover {
    background-color: #f3f4f6;
    border-color: #9ca3af;
}

.module-action-btn.delete {
    color: #dc2626;
    border-color: #fecaca;
}

.module-action-btn.delete:hover {
    background-color: #fef2f2;
}

.module-content {
    padding: 1.5rem;
}

.lessons-list {
    margin-top: 1rem;
}

.lesson-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 1rem;
    background-color: white;
    border: 1px solid #e5e7eb;
    border-radius: 4px;
    margin-bottom: 0.5rem;
    transition: background-color 0.2s;
}

.lesson-item:hover {
    background-color: #f9fafb;
}

.lesson-info {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.lesson-number {
    background-color: #dbeafe;
    color: #1d4ed8;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.8rem;
    font-weight: 600;
}

.lesson-title {
    font-weight: 500;
    color: #374151;
}

.lesson-actions {
    display: flex;
    gap: 0.5rem;
}

/* Drag and Drop */
.drag-handle {
    cursor: grab;
    color: #9ca3af;
    font-weight: bold;
    padding: 0 0.5rem;
    user-select: none;
    transition: color 0.2s;
}

.drag-handle:hover {
    color: #4b5563;
}

.lesson-item.draggable:active .drag-handle {
    cursor: grabbing;
}

.lesson-item.dragging {
    opacity: 0.5;
    background-color: #e0f2fe;
}

.lesson-item.drag-over {
    border-color: #3b82f6;
    background-color: #eeffff;
}

.add-lesson-btn {
    margin-top: 1rem;
    padding: 0.5rem 1rem;
    background-color: #f0f9ff;
    border: 1px solid #bae6fd;
    border-radius: 4px;
    color: #0369a1;
    cursor: pointer;
    font-size: 0.9rem;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    transition: all 0.2s;
}

.add-lesson-btn:hover {
    background-color: #e0f2fe;
    border-color: #7dd3fc;
}

/* Modal styles */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 1rem;
}

.modal {
    background-color: white;
    border-radius: 8px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
    width: 100%;
    max-width: 1200px;
    max-height: 90vh;
    overflow-y: auto;
}

.modal-header {
    padding: 1.5rem 1.5rem 1rem;
    border-bottom: 1px solid #e5e7eb;
}

.modal-header h3 {
    margin: 0;
    color: #111827;
}

.modal-body {
    padding: 1.5rem;
}

.modal-footer {
    padding: 1rem 1.5rem;
    border-top: 1px solid #e5e7eb;
    display: flex;
    justify-content: flex-end;
    gap: 0.75rem;
}

/* Lesson Steps Styles */
.lesson-steps-section {
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: 1px solid #e5e7eb;
}

.lesson-steps-section h4 {
    margin-bottom: 0.5rem;
    color: #374151;
}

.steps-actions {
    margin-bottom: 1.5rem;
}

.lesson-steps {
    min-height: 100px;
    border: 1px dashed #d1d5db;
    border-radius: 6px;
    padding: 1rem;
    background-color: white;
}

.empty-steps {
    text-align: center;
    padding: 2rem;
    color: #6b7280;
}

.step-item {
    background-color: white;
    border: 1px solid #e5e7eb;
    border-radius: 6px;
    margin-bottom: 0.75rem;
    overflow: hidden;
}

.step-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    background-color: #f8fafc;
    border-bottom: 1px solid #e5e7eb;
}

.step-title {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.step-number {
    font-weight: 600;
    color: #111827;
    background-color: #dbeafe;
    padding: 0.25rem 0.75rem;
    border-radius: 4px;
    font-size: 0.9rem;
}

.step-type {
    font-weight: 500;
    color: #374151;
    font-size: 0.95rem;
}

.step-actions {
    display: flex;
    gap: 0.5rem;
}

.content-note {
    padding: 0.75rem;
    background-color: #fef3c7;
    border: 1px solid #fde68a;
    border-radius: 6px;
    color: #92400e;
    margin-top: 0.5rem;
    font-size: 0.9rem;
}

/* Wide screen optimization for course builder */
@media (min-width: 768px) and (max-width: 1023px) {
    .course-builder-container {
        margin: 0 3rem;
    }
}

@media (min-width: 1024px) {
    .course-builder-container {
        margin: 0 auto;
        max-width: 95%;
    }
}

@media (min-width: 1440px) {
    .course-builder-page {
        padding: 3rem 0;
    }
    
    .course-builder-container {
        padding: 3rem;
        margin: 0 auto;
        max-width: 95%;
    }
}

@media (min-width: 1920px) {
    .course-builder-container {
        padding: 4rem;
        margin: 0 auto;
        max-width: 140rem;  /* Ограничение для удобства чтения */
    }
}

/* Vditor wide screen optimization */
@media (min-width: 1440px) {
    .vditor {
        height: 600px;
    }
    
    .vditor-toolbar {
        padding: 0.75rem 1rem;
    }
    
    .vditor-ir--panel {
        width: 55%;
    }
}

@media (min-width: 1920px) {
    .vditor {
        height: 700px;
    }
}

/* Nav Section labels */
.nav-section {
    color: #9ca3af;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    padding-left: 0.5rem;
}

/* Dev Tools Page */
.dev-tools-page {
    padding: 2rem 0;
}

.dev-tools-container {
    max-width: 900px;
    margin: 0 auto;
    padding: 0 1rem;
}

.dev-tools-section {
    margin-bottom: 3rem;
    padding: 2rem;
    background-color: white;
    border-radius: 10px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.dev-tools-section h2 {
    margin-bottom: 0.5rem;
    color: #374151;
}

.section-description {
    margin-bottom: 1.5rem;
    color: #6b7280;
}

.tools-list {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.tool-item {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    padding: 1.5rem;
    border: 1px solid #e5e7eb;
    border-radius: 8px;
    background-color: #f9fafb;
}

@media (min-width: 640px) {
    .tool-item {
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
    }
}

.tool-info {
    flex: 1;
}

.tool-info h3 {
    margin: 0 0 0.25rem 0;
    color: #374151;
    font-size: 1.1rem;
}

.tool-desc {
    margin: 0;
    color: #6b7280;
    font-size: 0.9rem;
}

.btn-danger {
    background-color: #dc2626;
    color: white;
}

.btn-danger:hover {
    background-color: #b91c1c;
}

.btn-warning {
    background-color: #f59e0b;
    color: white;
}

.btn-warning:hover {
    background-color: #d97706;
}

/* Dropdown menu */
.nav-dropdown {
    position: relative;
    display: inline-block;
}

.nav-dropdown-btn {
    background: none;
    border: none;
    padding: 0.5rem 0;
    color: #4b5563;
    cursor: pointer;
    font-size: 0.95rem;
    font-weight: 400;
}

.nav-dropdown-btn:hover {
    color: #2563eb;
}

.nav-dropdown-content {
    display: none;
    position: absolute;
    top: 100%;
    left: -0.5rem;
    background-color: white;
    min-width: 150px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    border-radius: 6px;
    z-index: 100;
    padding: 0.5rem 0;
}

.nav-dropdown:hover .nav-dropdown-content {
    display: block;
}

.nav-dropdown-content a {
    display: block;
    padding: 0.5rem 1rem;
    color: #4b5563;
    text-decoration: none;
    white-space: nowrap;
}

.nav-dropdown-content a:hover {
    background-color: #f3f4f6;
    color: #2563eb;
}

/* Draft management */
.badge {
    display: inline-block;
    background-color: var(--primary-color);
    color: white;
    padding: 0.1rem 0.4rem;
    border-radius: 10px;
    font-size: 0.7rem;
    margin-left: 0.5rem;
}

.drafts-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.no-drafts {
    text-align: center;
    color: #6b7280;
    padding: 2rem;
}

.draft-item {
    border: 1px solid #e5e7eb;
    border-radius: 6px;
    padding: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

@media (min-width: 640px) {
    .draft-item {
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
    }
}

.draft-info {
    flex: 1;
}

.draft-title {
    margin: 0;
    color: #374151;
    font-size: 1rem;
}

.draft-meta {
    font-size: 0.8rem;
    color: #6b7280;
    margin: 0.25rem 0;
}

.draft-desc {
    font-size: 0.85rem;
    color: #6b7280;
    margin: 0.5rem 0 0;
}

.draft-actions {
    display: flex;
    gap: 0.5rem;
}

.btn-sm {
    padding: 0.3rem 0.6rem;
    font-size: 0.85rem;
}