:root {
    --primary-color: #3b82f6;
    --completed-color: #9ca3af;
    --delete-color: #ef4444;
    --bg-color: #f3f4f6;
    --card-bg: #ffffff;
    --text-color: #1f2937;
    --border-color: #e5e7eb;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', sans-serif;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem;
}

.container {
    width: 100%;
    max-width: 600px;
}

.todo-app {
    background: var(--card-bg);
    border-radius: 1rem;
    padding: 2rem;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

h1 {
    text-align: center;
    margin-bottom: 1.5rem;
    color: var(--primary-color);
    font-size: 2rem;
}

.input-group {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

#todo-input {
    flex: 1;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: 0.5rem;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

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

.add-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 0.5rem;
    padding: 0.5rem 1rem;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.add-btn:hover {
    background-color: #2563eb;
}

.filters {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
    justify-content: center;
}

.filter-btn {
    background: transparent;
    border: 2px solid var(--border-color);
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

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

.todo-list {
    list-style: none;
    margin-bottom: 1.5rem;
}

.todo-item {
    display: flex;
    align-items: center;
    padding: 1rem;
    background: var(--bg-color);
    border-radius: 0.5rem;
    margin-bottom: 0.5rem;
    cursor: move;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.todo-item.dragging {
    opacity: 0.5;
    transform: scale(0.95);
}

.todo-item.drag-over {
    transform: scale(1.02);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.todo-checkbox {
    margin-right: 1rem;
    width: 1.2rem;
    height: 1.2rem;
    border-radius: 50%;
    border: 2px solid var(--primary-color);
    cursor: pointer;
    position: relative;
}

.todo-checkbox.checked::after {
    content: "✓";
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: var(--primary-color);
    font-size: 0.8rem;
}

.todo-text {
    flex: 1;
    font-size: 1rem;
}

.todo-item.completed .todo-text {
    text-decoration: line-through;
    color: var(--completed-color);
}

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

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

.todo-stats {
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--completed-color);
    font-size: 0.9rem;
}

#clear-completed {
    background: transparent;
    border: none;
    color: var(--completed-color);
    cursor: pointer;
    font-size: 0.9rem;
    transition: color 0.3s ease;
}

#clear-completed:hover {
    color: var(--delete-color);
}

.material-symbols-rounded {
    font-size: 1.5rem;
    font-variation-settings:
        'FILL' 1,
        'wght' 400,
        'GRAD' 0,
        'opsz' 24;
}