/* 기본 스타일 리셋 */
* {
    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;
    color: #333;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
}

/* 헤더 스타일 */
header {
    text-align: center;
    margin-bottom: 30px;
    color: white;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

header p {
    font-size: 1.1rem;
    opacity: 0.9;
}

/* 할일 입력 폼 */
.todo-form {
    background: white;
    border-radius: 15px;
    padding: 25px;
    margin-bottom: 20px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
}

.input-group {
    display: flex;
    gap: 10px;
}

#todoInput {
    flex: 1;
    padding: 15px 20px;
    border: 2px solid #e1e5e9;
    border-radius: 10px;
    font-size: 1rem;
    transition: all 0.3s ease;
}

#todoInput:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

/* 버튼 스타일 */
.btn {
    padding: 15px 25px;
    border: none;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

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

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

.btn-secondary {
    background: #6c757d;
    color: white;
}

.btn-secondary:hover {
    background: #5a6268;
    transform: translateY(-2px);
}

.btn-danger {
    background: #dc3545;
    color: white;
}

.btn-danger:hover {
    background: #c82333;
    transform: translateY(-2px);
}

.btn-success {
    background: #28a745;
    color: white;
}

.btn-success:hover {
    background: #218838;
    transform: translateY(-2px);
}

/* 필터 탭 */
.filter-tabs {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin-bottom: 20px;
}

.filter-btn {
    padding: 10px 20px;
    border: 2px solid rgba(255,255,255,0.3);
    background: rgba(255,255,255,0.1);
    color: white;
    border-radius: 25px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 500;
}

.filter-btn.active,
.filter-btn:hover {
    background: white;
    color: #667eea;
    transform: translateY(-2px);
}

/* 통계 */
.todo-stats {
    display: flex;
    justify-content: center;
    gap: 30px;
    margin-bottom: 30px;
}

.stat {
    text-align: center;
    color: white;
}

.stat-number {
    display: block;
    font-size: 2rem;
    font-weight: bold;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

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

/* 할일 목록 */
.todo-list {
    background: white;
    border-radius: 15px;
    padding: 20px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    min-height: 200px;
}

.todo-item {
    display: flex;
    align-items: center;
    padding: 15px;
    margin-bottom: 10px;
    background: #f8f9fa;
    border-radius: 10px;
    transition: all 0.3s ease;
    border-left: 4px solid #667eea;
}

.todo-item:hover {
    transform: translateX(5px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

.todo-item.completed {
    opacity: 0.7;
    border-left-color: #28a745;
}

.todo-item.completed .todo-text {
    text-decoration: line-through;
    color: #6c757d;
}

.todo-checkbox {
    margin-right: 15px;
    width: 20px;
    height: 20px;
    cursor: pointer;
}

.todo-text {
    flex: 1;
    font-size: 1rem;
    line-height: 1.5;
}

.todo-actions {
    display: flex;
    gap: 10px;
}

.todo-actions button {
    padding: 8px 12px;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 0.9rem;
}

.edit-btn {
    background: #ffc107;
    color: white;
}

.edit-btn:hover {
    background: #e0a800;
}

.delete-btn {
    background: #dc3545;
    color: white;
}

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

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

.empty-state i {
    font-size: 4rem;
    margin-bottom: 20px;
    opacity: 0.5;
}

.empty-state h3 {
    font-size: 1.5rem;
    margin-bottom: 10px;
}

.empty-state p {
    opacity: 0.8;
}

/* 모달 */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.5);
    z-index: 1000;
    animation: fadeIn 0.3s ease;
}

.modal.show {
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-content {
    background: white;
    border-radius: 15px;
    width: 90%;
    max-width: 500px;
    animation: slideIn 0.3s ease;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 25px;
    border-bottom: 1px solid #e1e5e9;
}

.modal-header h3 {
    margin: 0;
    color: #333;
}

.close-btn {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: #6c757d;
    padding: 5px;
}

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

.modal-body {
    padding: 25px;
}

#editInput {
    width: 100%;
    padding: 15px;
    border: 2px solid #e1e5e9;
    border-radius: 10px;
    font-size: 1rem;
    transition: all 0.3s ease;
}

#editInput:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: 10px;
    padding: 20px 25px;
    border-top: 1px solid #e1e5e9;
}

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

@keyframes slideIn {
    from { 
        opacity: 0;
        transform: translateY(-50px);
    }
    to { 
        opacity: 1;
        transform: translateY(0);
    }
}

/* 반응형 디자인 */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    header h1 {
        font-size: 2rem;
    }
    
    .input-group {
        flex-direction: column;
    }
    
    .filter-tabs {
        flex-wrap: wrap;
    }
    
    .todo-stats {
        gap: 20px;
    }
    
    .stat-number {
        font-size: 1.5rem;
    }
    
    .todo-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }
    
    .todo-actions {
        align-self: flex-end;
    }
    
    .modal-content {
        margin: 20px;
        width: calc(100% - 40px);
    }
}

@media (max-width: 480px) {
    .todo-stats {
        flex-direction: column;
        gap: 15px;
    }
    
    .modal-footer {
        flex-direction: column;
    }
    
    .modal-footer .btn {
        width: 100%;
    }
}