/* 전체 페이지 스타일 */
* {
    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: 40px 20px;
}

/* 메인 컨테이너 */
.todo-container {
    max-width: 500px;
    margin: 0 auto;
    background: white;
    border-radius: 16px;
    padding: 30px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
}

/* 제목 */
.todo-title {
    text-align: center;
    color: #333;
    font-size: 1.8rem;
    margin-bottom: 30px;
}

/* 입력 영역 */
.todo-input-area {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

.todo-input {
    flex: 1;
    padding: 12px 16px;
    font-size: 1rem;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    outline: none;
    transition: border-color 0.3s;
}

.todo-input:focus {
    border-color: #667eea;
}

.btn-add {
    padding: 12px 24px;
    font-size: 1rem;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
}

.btn-add:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

/* 할 일 목록 */
.todo-list {
    list-style: none;
}

.todo-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 15px;
    background: #f8f9fa;
    border-radius: 8px;
    margin-bottom: 10px;
    transition: background 0.2s;
}

.todo-item:hover {
    background: #f0f0f0;
}

/* 체크박스 */
.todo-checkbox {
    width: 20px;
    height: 20px;
    cursor: pointer;
    accent-color: #667eea;
}

/* 할 일 텍스트 */
.todo-text {
    flex: 1;
    font-size: 1rem;
    color: #333;
}

/* 완료된 항목 스타일 */
.todo-item.completed .todo-text {
    text-decoration: line-through;
    color: #999;
}

/* 삭제 버튼 */
.btn-delete {
    padding: 6px 12px;
    font-size: 0.85rem;
    background: #ff6b6b;
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    transition: background 0.2s;
}

.btn-delete:hover {
    background: #ee5a5a;
}

/* 통계 영역 */
.todo-stats {
    text-align: center;
    color: #666;
    font-size: 0.9rem;
    padding: 12px;
    background: #f0f0f0;
    border-radius: 8px;
    margin-bottom: 20px;
}

.todo-stats span {
    font-weight: bold;
    color: #667eea;
}

/* 필터 버튼 영역 */
.filter-area {
    display: flex;
    gap: 8px;
    margin-bottom: 20px;
}

.btn-filter {
    flex: 1;
    padding: 10px;
    font-size: 0.9rem;
    background: #f0f0f0;
    color: #666;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-filter:hover {
    background: #e0e0e0;
}

.btn-filter.active {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

/* 완료 항목 일괄 삭제 버튼 */
.btn-clear-completed {
    width: 100%;
    padding: 12px;
    margin-top: 20px;
    font-size: 0.9rem;
    background: #f8f9fa;
    color: #666;
    border: 2px dashed #ddd;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-clear-completed:hover {
    background: #fff0f0;
    border-color: #ff6b6b;
    color: #ff6b6b;
}

/* 빈 목록 메시지 */
.empty-message {
    text-align: center;
    color: #999;
    padding: 40px 20px;
    font-size: 1rem;
}