.main-layout {
    display: flex;
    min-height: 100vh;
}

.sidebar {
    width: 260px;
    background: white;
    border-right: 1px solid #e2e8f0;
    display: flex;
    flex-direction: column;
}

.sidebar-header {
    padding: 24px 20px;
    border-bottom: 1px solid #e2e8f0;
}

.sidebar-logo {
    font-size: 18px;
    font-weight: 700;
    color: #0f172a;
}

.nav {
    flex: 1;
    padding: 20px 12px;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 16px;
    border: none;
    background: transparent;
    color: #64748b;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    border-radius: 8px;
    transition: all 0.2s ease;
    text-decoration: none;
}

.nav-item:hover {
    background: #f8fafc;
}

.nav-item.active {
    background: #f8fafc;
    color: #0f172a;
}

.nav-icon {
    font-size: 18px;
}

.nav-icon-img {
    width: 18px;
    height: 18px;
    object-fit: contain;
}

.nav-icon-img-contain {
    width: 42px;
    height: 42px;
    object-fit: contain;
    border-radius: 0;
}

.nav-divider {
    height: 1px;
    background: #e2e8f0;
    margin: 12px 0;
}

.nav-section-header {
    padding: 8px 16px;
    font-size: 11px;
    font-weight: 600;
    color: #94a3b8;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-top: 4px;
}

.folder-item {
    padding-left: 20px !important;
}

.new-folder-btn {
    color: #64748b !important;
    font-style: italic;
    border: 1px dashed #e2e8f0;
    margin: 4px 8px;
}

.new-folder-btn:hover {
    background: #f8fafc !important;
    border-color: #cbd5e1;
}

.sidebar-footer {
    padding: 20px;
    border-top: 1px solid #e2e8f0;
}

.logout-btn {
    width: 100%;
    padding: 12px;
    background: #f8fafc;
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 500;
    color: #475569;
    cursor: pointer;
    transition: all 0.2s ease;
}

.logout-btn:hover {
    background: #e2e8f0;
}

.main-content {
    flex: 1;
    overflow: auto;
    padding: 40px;
}

.content-container {
    max-width: 1200px;
    margin: 0 auto;
}

.breadcrumb {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 24px;
    font-size: 14px;
}

.breadcrumb a {
    color: #64748b;
    text-decoration: none;
    transition: color 0.2s ease;
}

.breadcrumb a:hover {
    color: #0f172a;
}

.breadcrumb-separator {
    color: #cbd5e1;
}

.breadcrumb-current {
    color: #0f172a;
    font-weight: 500;
}

.mobile-menu-toggle {
    display: none;
    position: fixed;
    top: 16px;
    left: 16px;
    z-index: 1001;
    background: white;
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    padding: 10px;
    cursor: pointer;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.mobile-menu-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: #0f172a;
    margin: 5px 0;
    transition: all 0.3s ease;
}

.mobile-menu-toggle.hide {
    display: none;
}

.mobile-sidebar-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: 999;
}

.mobile-sidebar {
    display: none;
    position: fixed;
    top: 0;
    left: -280px;
    width: 280px;
    height: 100%;
    background: white;
    z-index: 1000;
    transition: left 0.3s ease;
    overflow-y: auto;
    box-shadow: 2px 0 12px rgba(0, 0, 0, 0.15);
}

.mobile-sidebar.active {
    left: 0;
}

.mobile-sidebar-overlay.active {
    display: block;
}

.mobile-sidebar-header {
    padding: 20px;
    border-bottom: 1px solid #e2e8f0;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.mobile-sidebar-close {
    background: none;
    border: none;
    font-size: 24px;
    cursor: pointer;
    color: #64748b;
    padding: 4px;
}

.sidebar.hidden {
    display: none;
}

.folder-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 40px;
}

.folder-title-section {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.folder-header-row {
    display: flex;
    align-items: center;
    gap: 12px;
}

.editfolder-container {
    margin-top: 20px;
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
}

.editfolder-icon {
    width: 20px;
    height: 20px;
    object-fit: contain;
    flex-shrink: 0;
}

.editfolder-text {
    font-size: 14px;
    color: #64748b;
    margin-bottom: 16px;
    line-height: 1.5;
}

.folder-icon {
    width: 40px;
    height: 40px;
    object-fit: contain;
    flex-shrink: 0;
}

.folder-title {
    font-size: 36px;
    font-weight: 700;
    color: #0f172a;
    margin: 0;
    letter-spacing: -0.5px;
}

.folder-shareCode {
    font-size: 16px;
    color: #64748b;
    margin: 0;
    padding-left: 52px;
}

.study-options-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 24px;
    margin-bottom: 48px;
}

.study-option-card {
    background: white;
    padding: 32px;
    border-radius: 12px;
    border: 1px solid #e2e8f0;
    text-decoration: none;
    color: inherit;
    cursor: pointer;
    transition: all 0.3s ease;
}

.study-option-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.study-option-icon {
    font-size: 40px;
    margin-bottom: 16px;
}

.study-option-card h3 {
    font-size: 18px;
    font-weight: 600;
    color: #0f172a;
    margin-bottom: 8px;
}

.study-option-card p {
    font-size: 14px;
    color: #64748b;
    margin-bottom: 16px;
    line-height: 1.5;
}

.study-option-count {
    font-size: 13px;
    color: #94a3b8;
    font-weight: 500;
}

.summary-section {
    margin-top: 48px;
    padding: 32px;
    background: white;
    border-radius: 12px;
    border: 1px solid #e2e8f0;
}

.summary-label {
    font-size: 14px;
    font-weight: 600;
    color: #64748b;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 16px;
}

.summary-input-container {
    position: relative;
}

.add-summary-btn {
    width: 100%;
    padding: 20px;
    background: rgba(248, 250, 252, 0.5);
    border: 2px dashed rgba(203, 213, 225, 0.5);
    border-radius: 8px;
    color: rgba(100, 116, 139, 0.7);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: center;
}

.add-summary-btn:hover {
    background: rgba(248, 250, 252, 0.8);
    border-color: rgba(203, 213, 225, 0.8);
    color: rgba(100, 116, 139, 1);
}

.summary-input-area {
    animation: fadeIn 0.3s ease-out;
}

.summary-textarea {
    width: 100%;
    padding: 16px;
    border: 1.5px solid #e2e8f0;
    border-radius: 8px;
    font-size: 15px;
    font-family: 'DM Sans', sans-serif;
    color: #0f172a;
    background: white;
    resize: vertical;
    min-height: 100px;
    transition: border-color 0.2s ease;
    outline: none;
}

.summary-textarea:focus {
    border-color: #94a3b8;
}

.summary-textarea::placeholder {
    color: #cbd5e1;
}

.summary-actions {
    display: flex;
    gap: 12px;
    margin-top: 12px;
    justify-content: flex-end;
}

.summary-save-btn {
    padding: 10px 24px;
    background: #0f172a;
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s ease;
}

.summary-save-btn:hover {
    background: #1e293b;
}

.summary-cancel-btn {
    padding: 10px 24px;
    background: white;
    color: #64748b;
    border: 1px solid #e2e8f0;
    border-radius: 6px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
}

.summary-cancel-btn:hover {
    background: #f8fafc;
}

.summary-display {
    position: relative;
    animation: fadeIn 0.3s ease-out;
}

.summary-text {
    padding: 20px;
    background: #f8fafc;
    border-radius: 8px;
    font-size: 15px;
    line-height: 1.6;
    color: #475569;
    white-space: pre-wrap;
    word-wrap: break-word;
}

.summary-edit-btn {
    position: absolute;
    top: 12px;
    right: 12px;
    padding: 6px 16px;
    background: white;
    border: 1px solid #e2e8f0;
    border-radius: 6px;
    font-size: 13px;
    font-weight: 500;
    color: #64748b;
    cursor: pointer;
    transition: all 0.2s ease;
    opacity: 0.7;
}

.summary-edit-btn:hover {
    opacity: 1;
    background: #f8fafc;
}

.sidebar-logo {
    display: flex;
    flex-direction: row;
    align-items: center;
    gap: 8px;
}

.sidebar-logo-img {
    width: 28px;
    height: 28px;
    object-fit: contain;
    flex-shrink: 0;
}

.mobile-sidebar .sidebar-footer {
    position: static;
    bottom: auto;
    flex-shrink: 0;
    margin-top: 16px;
}