:root {
    --primary-color: #4e73df;
    --primary-hover: #3a5fcf;
    --secondary-color: #858796;
    --success-color: #1cc88a;
    --danger-color: #e74a3b;
    --warning-color: #f6c23e;
    --info-color: #36b9cc;
    --light-color: #f8f9fc;
    --dark-color: #5a5c69;
    --text-color: #333;
    --bg-color: #f8f9fa;
    --card-bg: #fff;
    --border-color: #e3e6f0;
    --sidebar-bg: #fff;
    --sidebar-text: #333;
    --input-bg: #fff;
}

[data-theme="dark"] {
    --primary-color: #4e73df;
    --primary-hover: #3a5fcf;
    --secondary-color: #6c757d;
    --success-color: #1cc88a;
    --danger-color: #e74a3b;
    --warning-color: #f6c23e;
    --info-color: #36b9cc;
    --light-color: #343a40;
    --dark-color: #d1d3e2;
    --text-color: #f8f9fa;
    --bg-color: #1a1a1a;
    --card-bg: #2d2d2d;
    --border-color: #444;
    --sidebar-bg: #252525;
    --sidebar-text: #f8f9fa;
    --input-bg: #3d3d3d;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    transition: background-color 0.3s, color 0.3s;
}

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

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

.app-header {
    background-color: var(--primary-color);
    color: white;
    padding: 1rem 2rem;
    box-shadow: 0 0.15rem 1.75rem 0 rgba(58, 59, 69, 0.15);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
}

.header-content h1 {
    font-size: 1.5rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.theme-toggle {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
}

.switch {
    position: relative;
    display: inline-block;
    width: 50px;
    height: 24px;
}

.switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #ccc;
    transition: .4s;
}

.slider:before {
    position: absolute;
    content: "";
    height: 16px;
    width: 16px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: .4s;
}

input:checked + .slider {
    background-color: var(--primary-color);
}

input:checked + .slider:before {
    transform: translateX(26px);
}

.slider.round {
    border-radius: 34px;
}

.slider.round:before {
    border-radius: 50%;
}

.main-content {
    display: flex;
    flex: 1;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
}

.sidebar {
    width: 250px;
    background-color: var(--sidebar-bg);
    color: var(--sidebar-text);
    padding: 1.5rem 1rem;
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
}

.sidebar-menu {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin-bottom: 2rem;
}

.sidebar-menu button {
    background: none;
    border: none;
    text-align: left;
    padding: 0.75rem 1rem;
    border-radius: 0.35rem;
    color: var(--sidebar-text);
    font-size: 0.9rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    transition: all 0.2s;
}

.sidebar-menu button:hover {
    background-color: rgba(78, 115, 223, 0.1);
    color: var(--primary-color);
}

.sidebar-menu button.active {
    background-color: rgba(78, 115, 223, 0.2);
    color: var(--primary-color);
    font-weight: 500;
}

.projects-section {
    margin-bottom: 2rem;
}

.projects-section h3 {
    font-size: 0.85rem;
    text-transform: uppercase;
    color: var(--secondary-color);
    margin-bottom: 1rem;
    letter-spacing: 0.5px;
}

.projects-list {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
    margin-bottom: 1rem;
    max-height: 200px;
    overflow-y: auto;
}

.project-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 0.75rem;
    border-radius: 0.35rem;
    cursor: pointer;
    font-size: 0.9rem;
}

.project-item:hover {
    background-color: rgba(78, 115, 223, 0.1);
}

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

#add-project-btn {
    width: 100%;
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 0.75rem;
    border-radius: 0.35rem;
    font-size: 0.9rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    transition: background-color 0.2s;
}

#add-project-btn:hover {
    background-color: var(--primary-hover);
}

.stats-section {
    margin-top: auto;
}

.stats-section h3 {
    font-size: 0.85rem;
    text-transform: uppercase;
    color: var(--secondary-color);
    margin-bottom: 1rem;
    letter-spacing: 0.5px;
}

.stats-item {
    display: flex;
    justify-content: space-between;
    padding: 0.5rem 0;
    font-size: 0.9rem;
}

.task-content {
    flex: 1;
    padding: 1.5rem 2rem;
    background-color: var(--bg-color);
}

.task-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.task-header h2 {
    font-size: 1.5rem;
    font-weight: 600;
}

.task-actions {
    display: flex;
    gap: 1rem;
}

.search-box {
    position: relative;
    display: flex;
    align-items: center;
}

.search-box i {
    position: absolute;
    left: 0.75rem;
    color: var(--secondary-color);
}

#task-search {
    padding: 0.5rem 1rem 0.5rem 2.25rem;
    border-radius: 0.35rem;
    border: 1px solid var(--border-color);
    background-color: var(--input-bg);
    color: var(--text-color);
    width: 200px;
    font-size: 0.9rem;
}

#task-search:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 0.2rem rgba(78, 115, 223, 0.25);
}

#add-task-btn, #sort-tasks-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 0.35rem;
    font-size: 0.9rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: background-color 0.2s;
}

#add-task-btn:hover, #sort-tasks-btn:hover {
    background-color: var(--primary-hover);
}

.task-filters {
    display: flex;
    gap: 1.5rem;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.filter-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.filter-item label {
    font-size: 0.9rem;
    color: var(--secondary-color);
}

.filter-item select {
    padding: 0.35rem 0.75rem;
    border-radius: 0.35rem;
    border: 1px solid var(--border-color);
    background-color: var(--input-bg);
    color: var(--text-color);
    font-size: 0.85rem;
    cursor: pointer;
}

.filter-item select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 0.2rem rgba(78, 115, 223, 0.25);
}

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

.task-card {
    background-color: var(--card-bg);
    border-radius: 0.5rem;
    padding: 1.25rem;
    box-shadow: 0 0.15rem 1.75rem 0 rgba(58, 59, 69, 0.1);
    border-left: 4px solid transparent;
    transition: transform 0.2s, box-shadow 0.2s;
}

.task-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 0.5rem 1.5rem 0 rgba(58, 59, 69, 0.2);
}

.task-card.high-priority {
    border-left-color: var(--danger-color);
}

.task-card.medium-priority {
    border-left-color: var(--warning-color);
}

.task-card.low-priority {
    border-left-color: var(--success-color);
}

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

.task-title {
    font-weight: 500;
    font-size: 1.05rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

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

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

.task-action-btn {
    background: none;
    border: none;
    color: var(--secondary-color);
    cursor: pointer;
    font-size: 0.9rem;
    padding: 0.25rem;
    border-radius: 50%;
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
}

.task-action-btn:hover {
    background-color: rgba(78, 115, 223, 0.1);
    color: var(--primary-color);
}

.task-action-btn.important {
    color: var(--warning-color);
}

.task-action-btn.important.active {
    color: var(--warning-color);
}

.task-description {
    color: var(--secondary-color);
    font-size: 0.9rem;
    margin-bottom: 0.75rem;
    line-height: 1.5;
}

.task-details {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    font-size: 0.8rem;
    color: var(--secondary-color);
}

.task-detail {
    display: flex;
    align-items: center;
    gap: 0.35rem;
}

.task-detail i {
    font-size: 0.9rem;
}

.task-priority {
    padding: 0.25rem 0.5rem;
    border-radius: 0.25rem;
    font-size: 0.75rem;
    font-weight: 500;
    text-transform: uppercase;
}

.task-priority.high {
    background-color: rgba(231, 74, 59, 0.1);
    color: var(--danger-color);
}

.task-priority.medium {
    background-color: rgba(246, 194, 62, 0.1);
    color: var(--warning-color);
}

.task-priority.low {
    background-color: rgba(28, 200, 138, 0.1);
    color: var(--success-color);
}

.task-project {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    padding: 0.25rem 0.5rem;
    border-radius: 0.25rem;
    background-color: rgba(78, 115, 223, 0.1);
    color: var(--primary-color);
    font-size: 0.75rem;
}

.task-labels {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 0.75rem;
}

.task-label {
    padding: 0.25rem 0.5rem;
    border-radius: 0.25rem;
    background-color: rgba(108, 117, 125, 0.1);
    color: var(--secondary-color);
    font-size: 0.75rem;
}

.empty-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 3rem 1rem;
    text-align: center;
    color: var(--secondary-color);
}

.empty-state i {
    font-size: 3rem;
    margin-bottom: 1rem;
    color: var(--border-color);
}

.empty-state p {
    max-width: 300px;
}

.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    justify-content: center;
    align-items: center;
}

.modal-content {
    background-color: var(--card-bg);
    border-radius: 0.5rem;
    width: 100%;
    max-width: 500px;
    padding: 1.5rem;
    box-shadow: 0 0.5rem 1.5rem rgba(0, 0, 0, 0.2);
    position: relative;
}

.modal h2 {
    margin-bottom: 1.5rem;
    font-size: 1.25rem;
    font-weight: 600;
}

.close-btn {
    position: absolute;
    top: 1rem;
    right: 1rem;
    font-size: 1.5rem;
    color: var(--secondary-color);
    cursor: pointer;
    background: none;
    border: none;
    padding: 0.25rem;
}

.close-btn:hover {
    color: var(--text-color);
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
    font-weight: 500;
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 0.75rem;
    border-radius: 0.35rem;
    border: 1px solid var(--border-color);
    background-color: var(--input-bg);
    color: var(--text-color);
    font-size: 0.9rem;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 0.2rem rgba(78, 115, 223, 0.25);
}

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

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

.submit-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 0.35rem;
    font-size: 0.9rem;
    cursor: pointer;
    width: 100%;
    margin-top: 0.5rem;
    transition: background-color 0.2s;
}

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

.sort-options {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.sort-option {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.sort-option input {
    width: auto;
}

.sort-option label {
    margin-bottom: 0;
    font-weight: 400;
    cursor: pointer;
}

.sort-order {
    display: flex;
    gap: 1.5rem;
    margin-bottom: 1.5rem;
}

@media (max-width: 768px) {
    .main-content {
        flex-direction: column;
    }

    .sidebar {
        width: 100%;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
    }

    .task-content {
        padding: 1.5rem;
    }

    .task-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }

    .task-actions {
        width: 100%;
        flex-direction: column;
        gap: 0.75rem;
    }

    #task-search {
        width: 100%;
    }

    #add-task-btn, #sort-tasks-btn {
        width: 100%;
        justify-content: center;
    }

    .task-filters {
        flex-direction: column;
        gap: 1rem;
    }

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

    .modal-content {
        margin: 1rem;
        width: calc(100% - 2rem);
    }
}