body {
    font-family: 'Poppins', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    color: #333;
    overflow-x: hidden;
}

.container {
    background: rgba(255, 255, 255, 0.95);
    padding: 2rem;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    width: 100%;
    max-width: 500px;
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
}

header {
    text-align: center;
    margin-bottom: 1.5rem;
}

header h1 {
    margin: 0;
    font-size: 2rem;
    font-weight: 600;
    color: #667eea;
}

header h1 i {
    margin-right: 0.5rem;
    color: #764ba2;
}

#task-form {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

#task-input {
    flex: 1;
    padding: 0.8rem 1rem;
    border-radius: 10px;
    border: 2px solid #e0e0e0;
    outline: none;
    font-size: 1rem;
    font-family: inherit;
    transition: border-color 0.3s, box-shadow 0.3s;
}

#task-input:focus {
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

#add-btn {
    padding: 0.8rem 1.5rem;
    border-radius: 10px;
    border: none;
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: #fff;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
}

#add-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.3);
}

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

.filter-btn {
    padding: 0.5rem 1rem;
    border-radius: 20px;
    border: 2px solid #667eea;
    background: transparent;
    color: #667eea;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s;
}

.filter-btn.active,
.filter-btn:hover {
    background: #667eea;
    color: #fff;
}

.todo {
    background: #fff;
    border-radius: 10px;
    margin-bottom: 0.8rem;
    display: flex;
    align-items: center;
    padding: 1rem;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    transition: all 0.3s;
    border-left: 4px solid #667eea;
}

.todo:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
}

.todo.completed {
    background: #f8f9fa;
    border-left-color: #28a745;
}

.complete-checkbox {
    margin-right: 0.8rem;
    transform: scale(1.2);
    accent-color: #28a745;
}

.task {
    flex: 1;
    font-size: 1rem;
    margin-right: 0.5rem;
    transition: all 0.3s;
}

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

.edit,
.delete {
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.3rem;
    border-radius: 5px;
    transition: all 0.2s;
    color: #6c757d;
}

.edit:hover {
    background: #e9ecef;
    color: #007bff;
}

.delete:hover {
    background: #f8d7da;
    color: #dc3545;
}

.fade-in {
    animation: fadeIn 0.5s ease-in;
}

.slide-out {
    animation: slideOut 0.3s ease-out forwards;
}

.toast {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 1rem 1.5rem;
    border-radius: 10px;
    color: #fff;
    font-weight: 500;
    display: none;
    z-index: 1000;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

.toast.success {
    background: #28a745;
}

.toast.error {
    background: #dc3545;
}

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

@keyframes slideOut {
    to {
        opacity: 0;
        transform: translateX(100%);
    }
}

/* Responsive Design */
@media (max-width: 600px) {
    .container {
        margin: 1rem;
        padding: 1.5rem;
    }

    header h1 {
        font-size: 1.5rem;
    }

    #task-form {
        flex-direction: column;
    }

    #add-btn {
        align-self: stretch;
    }

    .filters {
        flex-wrap: wrap;
    }

    .todo {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }

    .task {
        width: 100%;
    }
}