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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

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

header {
    text-align: center;
    color: white;
    margin-bottom: 30px;
    position: relative;
}

h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
}

header p {
    font-size: 1.1em;
    margin-bottom: 20px;
}

/* Sidebar Styles */
.sidebar {
    position: fixed;
    top: 0;
    right: -450px;
    width: 450px;
    height: 100vh;
    background: white;
    box-shadow: -5px 0 20px rgba(0,0,0,0.3);
    transition: right 0.3s ease;
    z-index: 1001;
    overflow-y: auto;
}

.sidebar.open {
    right: 0;
}

.sidebar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 25px;
    border-bottom: 2px solid #f0f0f0;
    position: sticky;
    top: 0;
    background: white;
    z-index: 10;
}

.sidebar-header h2 {
    color: #333;
    font-size: 1.5em;
}

.close-btn {
    background: none;
    border: none;
    font-size: 2em;
    color: #999;
    cursor: pointer;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: all 0.2s;
}

.close-btn:hover {
    background: #f0f0f0;
    color: #333;
}

.sidebar-content {
    padding: 25px;
}

.overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.5);
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    z-index: 1000;
}

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

/* Form Styles */
.form-group {
    margin-bottom: 20px;
}

label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: #333;
    font-size: 0.95em;
}

input[type="text"],
select,
textarea {
    width: 100%;
    padding: 12px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 14px;
    font-family: inherit;
    transition: border-color 0.3s;
}

input[type="text"]:focus,
select:focus,
textarea:focus {
    outline: none;
    border-color: #667eea;
}

textarea {
    resize: vertical;
    min-height: 80px;
}

/* Button Styles */
button {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 12px 30px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
}

button:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.3);
}

button:active {
    transform: translateY(0);
}

.btn-primary {
    width: 100%;
    padding: 15px;
    font-size: 1.1em;
}

.btn-add-task {
    margin-top: 15px;
    font-size: 1.1em;
    padding: 12px 40px;
}

.btn-small {
    padding: 8px 15px;
    font-size: 14px;
}

.btn-complete {
    background: #28a745;
}

.btn-delete {
    background: #dc3545;
}

.btn-complete:hover {
    background: #218838;
}

.btn-delete:hover {
    background: #c82333;
}

/* Tasks Container */
.tasks-container {
    display: grid;
    gap: 20px;
}

.task-card {
    background: white;
    border-radius: 15px;
    padding: 20px;
    box-shadow: 0 5px 20px rgba(0,0,0,0.1);
    cursor: move;
    transition: transform 0.2s, box-shadow 0.2s;
}

.task-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.task-card.dragging {
    opacity: 0.5;
}

.task-card.drag-over {
    border: 2px dashed #667eea;
    background: #f8f9ff;
}

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

.task-title {
    font-size: 1.3em;
    font-weight: 700;
    color: #333;
    flex: 1;
}

.task-size-badge {
    padding: 5px 12px;
    border-radius: 20px;
    font-size: 0.8em;
    font-weight: 600;
    margin-left: 10px;
}

.task-size-badge.small {
    background: #e3f2fd;
    color: #1976d2;
}

.task-size-badge.medium {
    background: #fff3e0;
    color: #f57c00;
}

.task-size-badge.large {
    background: #fce4ec;
    color: #c2185b;
}

.task-description {
    color: #666;
    margin-bottom: 15px;
    line-height: 1.5;
}

/* Progress Bar */
.progress-section {
    margin-bottom: 15px;
}

.progress-label {
    display: flex;
    justify-content: space-between;
    margin-bottom: 8px;
    font-size: 0.9em;
    color: #666;
}

.progress-bar {
    width: 100%;
    height: 25px;
    background: #f0f0f0;
    border-radius: 12px;
    overflow: hidden;
    position: relative;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #667eea 0%, #764ba2 100%);
    transition: width 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 600;
    font-size: 0.85em;
}

/* Reward Section */
.reward-section {
    background: #f8f9fa;
    padding: 12px;
    border-radius: 8px;
    margin-top: 15px;
}

.reward-hidden {
    color: #999;
    font-style: italic;
}

.reward-revealed {
    color: #28a745;
    font-weight: 600;
    animation: reveal 0.5s ease;
}

@keyframes reveal {
    from {
        opacity: 0;
        transform: scale(0.9);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

/* Task Actions */
.task-actions {
    display: flex;
    gap: 10px;
    margin-top: 15px;
    flex-wrap: wrap;
}

/* Subtasks */
.subtasks-container {
    margin-top: 15px;
    padding-left: 20px;
    border-left: 3px solid #e0e0e0;
}

.subtask {
    background: #f8f9fa;
    padding: 12px;
    border-radius: 8px;
    margin-bottom: 10px;
    cursor: move;
}

.subtask-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 8px;
}

.subtask-title {
    font-weight: 600;
    color: #333;
}

.subtask-progress {
    width: 100%;
    height: 20px;
    background: #e0e0e0;
    border-radius: 10px;
    overflow: hidden;
    margin-bottom: 8px;
}

.subtask-progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #4caf50 0%, #81c784 100%);
    transition: width 0.3s ease;
}

/* Drop Zone */
.drop-zone {
    border: 2px dashed #ccc;
    border-radius: 8px;
    padding: 15px;
    text-align: center;
    color: #999;
    margin-top: 10px;
    transition: all 0.3s;
}

.drop-zone.drag-over {
    border-color: #667eea;
    background: #f0f4ff;
    color: #667eea;
}

/* Completed State */
.completed {
    opacity: 0.7;
}

.completed .task-title {
    text-decoration: line-through;
}

/* Checkbox Group */
.checkbox-group {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 15px;
}

.checkbox-group input[type="checkbox"] {
    width: 18px;
    height: 18px;
    cursor: pointer;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: white;
}

.empty-state h2 {
    font-size: 2em;
    margin-bottom: 10px;
}

.empty-state p {
    font-size: 1.2em;
    opacity: 0.9;
}

/* Loading State */
.loading {
    text-align: center;
    padding: 60px 20px;
    color: white;
}

.spinner {
    border: 4px solid rgba(255,255,255,0.3);
    border-top: 4px solid white;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    animation: spin 1s linear infinite;
    margin: 0 auto 20px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Responsive Design */
@media (max-width: 768px) {
    .sidebar {
        width: 100%;
        right: -100%;
    }

    h1 {
        font-size: 2em;
    }

    .task-header {
        flex-direction: column;
    }

    .task-size-badge {
        margin-left: 0;
        margin-top: 5px;
    }

    .task-actions {
        flex-direction: column;
    }

    .task-actions button {
        width: 100%;
    }
}