* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

:root {
    --primary-color: #6c5ce7;
    --secondary-color: #a29bfe;
    --success-color: #00b894;
    --danger-color: #d63031;
    --background-color: #f5f6fa;
    --text-color: #2d3436;
    --card-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --card-bg: white;
    --input-bg: white;
    --input-border: #e0e0e0;
    --todo-item-bg: #f8f9fa;
    --filter-btn-bg: #f0f0f0;
    --filter-btn-color: #2d3436;
}

[data-theme="dark"] {
    --primary-color: #a29bfe;
    --secondary-color: #6c5ce7;
    --background-color: #1a1a1a;
    --text-color: #ffffff;
    --card-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
    --card-bg: #2d2d2d;
    --input-bg: #3d3d3d;
    --input-border: #4d4d4d;
    --todo-item-bg: #3d3d3d;
    --filter-btn-bg: #3d3d3d;
    --filter-btn-color: #ffffff;
}

body {
    background-color: var(--background-color);
    color: var(--text-color);
    min-height: 100vh;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 1rem;
}

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

.theme-toggle {
    background: none;
    border: none;
    color: var(--text-color);
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 50%;
    transition: transform 0.3s ease, background-color 0.3s ease;
}

.theme-toggle:hover {
    transform: rotate(30deg);
    background-color: var(--card-bg);
}

/* Dashboard Styles */
.dashboard {
    background: var(--card-bg);
    border-radius: 15px;
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: var(--card-shadow);
    animation: slideDown 0.5s ease-out;
    transition: background-color 0.3s ease, box-shadow 0.3s ease;
}

.dashboard-header h1 {
    color: var(--primary-color);
    margin-bottom: 0;
    font-size: 2rem;
}

.stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
}

.stat-card {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 1.5rem;
    border-radius: 10px;
    text-align: center;
    transition: transform 0.3s ease;
    animation: fadeIn 0.5s ease-out;
}

.stat-card:hover {
    transform: translateY(-5px);
}

.stat-card i {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.stat-number {
    display: block;
    font-size: 2rem;
    font-weight: bold;
    margin: 0.5rem 0;
}

.stat-label {
    font-size: 0.9rem;
    opacity: 0.9;
}

/* Todo Container Styles */
.todo-container {
    background: var(--card-bg);
    border-radius: 15px;
    padding: 2rem;
    box-shadow: var(--card-shadow);
    animation: slideUp 0.5s ease-out;
    transition: background-color 0.3s ease, box-shadow 0.3s ease;
}

.todo-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.todo-header h2 {
    color: var(--primary-color);
}

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

#task-input {
    padding: 0.8rem 1rem;
    border: 2px solid var(--input-border);
    border-radius: 8px;
    width: 300px;
    font-size: 1rem;
    transition: border-color 0.3s ease, background-color 0.3s ease;
    background-color: var(--input-bg);
    color: var(--text-color);
}

#task-input:focus {
    outline: none;
    border-color: var(--primary-color);
}

#add-task-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 0.8rem 1.2rem;
    border-radius: 8px;
    cursor: pointer;
    transition: transform 0.3s ease, background-color 0.3s ease;
}

#add-task-btn:hover {
    background: var(--secondary-color);
    transform: scale(1.05);
}

/* Todo Filters */
.todo-filters {
    display: flex;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.filter-btn {
    padding: 0.5rem 1rem;
    border: none;
    background: var(--filter-btn-bg);
    color: var(--filter-btn-color);
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.filter-btn.active {
    background: var(--primary-color);
    color: white;
}

/* Todo List */
.todo-list {
    list-style: none;
}

.todo-item {
    display: flex;
    align-items: center;
    padding: 1rem;
    background: var(--todo-item-bg);
    border-radius: 8px;
    margin-bottom: 0.8rem;
    animation: slideIn 0.3s ease-out;
    transition: transform 0.3s ease, background-color 0.3s ease;
}

.todo-item:hover {
    transform: translateX(5px);
}

.todo-item.completed {
    opacity: 0.7;
}

.todo-item.completed .todo-text {
    text-decoration: line-through;
    color: #888;
}

.todo-checkbox {
    margin-right: 1rem;
    width: 20px;
    height: 20px;
    cursor: pointer;
}

.todo-text {
    flex-grow: 1;
    font-size: 1rem;
    color: var(--text-color);
}

.delete-btn {
    background: var(--danger-color);
    color: white;
    border: none;
    padding: 0.5rem;
    border-radius: 6px;
    cursor: pointer;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.todo-item:hover .delete-btn {
    opacity: 1;
}

/* Animations */
@keyframes slideDown {
    from {
        transform: translateY(-20px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

@keyframes slideUp {
    from {
        transform: translateY(20px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

@keyframes slideIn {
    from {
        transform: translateX(-20px);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

/* Responsive Design */
@media (max-width: 768px) {
    .todo-header {
        flex-direction: column;
        gap: 1rem;
    }

    .add-task {
        width: 100%;
    }

    #task-input {
        width: 100%;
    }

    .stats {
        grid-template-columns: 1fr;
    }
}