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

body {
    background-color: #f5f7fa;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
}

.container {
    background-color: white;
    border-radius: 12px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    width: 100%;
    max-width: 500px;
    padding: 30px;
}

h1 {
    color: #4a6fa5;
    text-align: center;
    margin-bottom: 25px;
    font-weight: 600;
}

.todo-input {
    display: flex;
    margin-bottom: 20px;
}

input {
    flex: 1;
    padding: 12px 15px;
    border: 1px solid #e1e5eb;
    border-radius: 6px 0 0 6px;
    font-size: 16px;
    outline: none;
    transition: border-color 0.3s;
}

input:focus {
    border-color: #4a6fa5;
}

#add-button {
    background-color: #4a6fa5;
    color: white;
    border: none;
    padding: 12px 20px;
    border-radius: 0 6px 6px 0;
    cursor: pointer;
    font-size: 16px;
    transition: background-color 0.3s;
}

#add-button:hover {
    background-color: #3a5a8a;
}

.todo-list {
    margin-bottom: 20px;
}

.todo-item {
    display: flex;
    align-items: center;
    padding: 12px 15px;
    background-color: #f9fafc;
    border-radius: 6px;
    margin-bottom: 10px;
    animation: fadeIn 0.5s ease;
    transition: all 0.3s;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.todo-item:hover {
    background-color: #f0f3f8;
}

.todo-item input[type="checkbox"] {
    margin-right: 10px;
    width: 18px;
    height: 18px;
    cursor: pointer;
}

.todo-item .task-text {
    flex: 1;
    font-size: 16px;
    color: #4a5568;
    transition: all 0.3s;
}

.todo-item.completed .task-text {
    text-decoration: line-through;
    color: #a0aec0;
}

.delete-btn {
    background: none;
    border: none;
    color: #e53e3e;
    cursor: pointer;
    font-size: 18px;
    opacity: 0.7;
    transition: opacity 0.3s;
}

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

.clear-all {
    width: 100%;
    padding: 12px;
    background-color: #e2e8f0;
    color: #4a5568;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 16px;
    transition: background-color 0.3s;
}

.clear-all:hover {
    background-color: #cbd5e0;
}

@media (max-width: 480px) {
    .container {
        padding: 20px;
    }
    
    .todo-input {
        flex-direction: column;
    }
    
    input {
        border-radius: 6px;
        margin-bottom: 10px;
    }
    
    #add-button {
        border-radius: 6px;
    }
}