:root {
    --primary-color: #3a86ff;
    --primary-dark: #2667cc;
    --secondary-color: #8338ec;
    --success-color: #06d6a0;
    --warning-color: #ffbe0b;
    --danger-color: #ef476f;
    --light-color: #f8f9fa;
    --dark-color: #212529;
    --gray-color: #6c757d;
    --light-gray: #e9ecef;
    --border-radius: 8px;
    --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

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

.app-container {
    display: grid;
    grid-template-columns: 250px 1fr;
    grid-template-rows: 70px 1fr;
    min-height: 100vh;
}

.app-header {
    grid-column: 1 / -1;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 2rem;
    background-color: white;
    box-shadow: var(--box-shadow);
    z-index: 10;
}

.header-left, .header-right {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.app-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--primary-color);
}

.sidebar {
    background-color: white;
    border-right: 1px solid var(--light-gray);
    padding: 1.5rem;
    overflow-y: auto;
}

.content-area {
    padding: 2rem;
    overflow-y: auto;
    background-color: #f5f7fa;
}

.menu-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    width: 100%;
    padding: 0.75rem 1rem;
    margin-bottom: 0.5rem;
    border-radius: var(--border-radius);
    border: none;
    background: none;
    text-align: left;
    cursor: pointer;
    transition: var(--transition);
    color: var(--gray-color);
    font-weight: 500;
}

.menu-item:hover {
    background-color: var(--light-gray);
    color: var(--dark-color);
}

.menu-item.active {
    background-color: rgba(58, 134, 255, 0.1);
    color: var(--primary-color);
}

.menu-item i {
    width: 20px;
    text-align: center;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin: 1.5rem 0 1rem;
}

.section-header h3 {
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--gray-color);
}

.category-list {
    list-style: none;
}

.category-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 0.75rem;
    margin-bottom: 0.25rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
}

.category-item:hover {
    background-color: var(--light-gray);
}

.category-color {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    flex-shrink: 0;
}

.tag-cloud {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.tag-item {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.25rem 0.75rem;
    background-color: var(--light-gray);
    border-radius: 20px;
    font-size: 0.75rem;
    cursor: pointer;
    transition: var(--transition);
}

.tag-item:hover {
    opacity: 0.8;
}

.task-controls {
    display: flex;
    gap: 1rem;
    margin-bottom: 1.5rem;
    align-items: center;
}

.search-box {
    flex: 1;
    position: relative;
    max-width: 400px;
}

.search-box i {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--gray-color);
}

.search-box input {
    width: 100%;
    padding: 0.75rem 1rem 0.75rem 2.5rem;
    border: 1px solid var(--light-gray);
    border-radius: var(--border-radius);
    transition: var(--transition);
}

.search-box input:focus {
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 0 3px rgba(58, 134, 255, 0.2);
}

.sort-options select, .filter-options select {
    padding: 0.75rem 1rem;
    border: 1px solid var(--light-gray);
    border-radius: var(--border-radius);
    background-color: white;
    cursor: pointer;
    transition: var(--transition);
}

.sort-options select:focus, .filter-options select:focus {
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 0 3px rgba(58, 134, 255, 0.2);
}

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

.task-card {
    background-color: white;
    border-radius: var(--border-radius);
    padding: 1.25rem;
    box-shadow: var(--box-shadow);
    transition: var(--transition);
    position: relative;
}

.task-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.1);
}

.task-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    margin-bottom: 0.5rem;
}

.task-title {
    font-weight: 600;
    margin-right: 1rem;
    flex: 1;
}

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

.task-description {
    color: var(--gray-color);
    margin-bottom: 1rem;
    font-size: 0.875rem;
    line-height: 1.5;
}

.task-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 1rem;
    font-size: 0.75rem;
}

.task-meta {
    display: flex;
    gap: 1rem;
    color: var(--gray-color);
}

.task-due-date {
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

.task-priority {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.25rem 0.5rem;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 500;
}

.priority-low {
    background-color: rgba(6, 214, 160, 0.1);
    color: var(--success-color);
}

.priority-medium {
    background-color: rgba(255, 190, 11, 0.1);
    color: var(--warning-color);
}

.priority-high {
    background-color: rgba(239, 71, 111, 0.1);
    color: var(--danger-color);
}

.task-tags {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.task-tag {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.25rem 0.75rem;
    background-color: var(--light-gray);
    border-radius: 20px;
    font-size: 0.75rem;
}

.task-category {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.75rem;
    background-color: rgba(58, 134, 255, 0.1);
    color: var(--primary-color);
}

.completed .task-title {
    text-decoration: line-through;
    color: var(--gray-color);
}

.important .task-title::before {
    content: "★ ";
    color: var(--warning-color);
}

.modal {
    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: 100;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
}

.modal.active {
    opacity: 1;
    visibility: visible;
}

.modal-content {
    background-color: white;
    border-radius: var(--border-radius);
    width: 100%;
    max-width: 700px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
    transform: translateY(-20px);
    transition: var(--transition);
}

.modal.active .modal-content {
    transform: translateY(0);
}

.modal-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--light-gray);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-body {
    padding: 1.5rem;
}

.modal-content.small {
    max-width: 500px;
}

.form-group {
    margin-bottom: 1.25rem;
}

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

.form-group input[type="text"],
.form-group input[type="datetime-local"],
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1px solid var(--light-gray);
    border-radius: var(--border-radius);
    transition: var(--transition);
}

.form-group input[type="text"]:focus,
.form-group input[type="datetime-local"]:focus,
.form-group select:focus,
.form-group textarea:focus {
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 0 3px rgba(58, 134, 255, 0.2);
}

.form-row {
    display: flex;
    gap: 1rem;
}

.form-row .form-group {
    flex: 1;
}

.form-actions {
    display: flex;
    justify-content: flex-end;
    gap: 1rem;
    margin-top: 1.5rem;
}

.primary-button {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-weight: 500;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

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

.secondary-button {
    background-color: var(--light-gray);
    color: var(--dark-color);
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-weight: 500;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.secondary-button:hover {
    background-color: #dee2e6;
}

.icon-button {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: none;
    border: none;
    cursor: pointer;
    color: var(--gray-color);
    transition: var(--transition);
}

.icon-button:hover {
    background-color: var(--light-gray);
    color: var(--dark-color);
}

.icon-button.small {
    width: 30px;
    height: 30px;
}

#editor-container {
    height: 200px;
    margin-bottom: 1.25rem;
}

.tag-input {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    min-height: 44px;
    padding: 0.5rem;
    border: 1px solid var(--light-gray);
    border-radius: var(--border-radius);
}

.tag-input .tag-item {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.25rem 0.75rem;
    background-color: var(--light-gray);
    border-radius: 20px;
    font-size: 0.75rem;
}

.tag-input input {
    flex: 1;
    min-width: 100px;
    border: none;
    outline: none;
    padding: 0.5rem;
}

.empty-state {
    text-align: center;
    padding: 3rem 0;
    color: var(--gray-color);
}

.empty-state i {
    font-size: 3rem;
    margin-bottom: 1rem;
    opacity: 0.5;
}

.empty-state h3 {
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.empty-state p {
    margin-bottom: 1.5rem;
}

@media (max-width: 992px) {
    .app-container {
        grid-template-columns: 1fr;
        grid-template-rows: 70px auto 1fr;
    }

    .sidebar {
        grid-row: 2;
        border-right: none;
        border-bottom: 1px solid var(--light-gray);
    }

    .content-area {
        grid-row: 3;
    }
}

@media (max-width: 768px) {
    .task-controls {
        flex-direction: column;
        align-items: stretch;
    }

    .search-box {
        max-width: none;
    }

    .form-row {
        flex-direction: column;
        gap: 0;
    }
}